Department of Physical Education and Sport Science
Aristotle University of Thessaloniki
Giannakopoulou 16, 56123 Thessaloniki
*Corresponding author: firstname.lastname@example.org, telephone +302310992481
Overall, approximately 18% of persons at or over the age of 65 are dependent in one or more activities of daily living (King, 2002). As the age increases, so does dependency on others in performing daily activities and therefore affecting the quality of life. Mobility impairment and low physical performance are predictors of loss of independence. The performance of daily activities is dependent on several factors, such as strength, balance, flexibility and endurance. (Branch, 2004; Mooreland, 2004)
It is generally accepted that regular exercise is especially important in order to prevent cardiovascular problems such as coronal disease and hypertension osteoporosis and diabetes While a big part of research has been focused on the benefits from the exercise to the cardiovascular system, in recent years research shows that, strength training can also be beneficial to the general population (Work, 1989)
Older persons usually don’t end up in the nurseries due to their illnesses but due to their weaknesses (Bellew & Yates, 2000).
Several studies have shown that extremity muscle strength declines with age and that decreased levels of arm or leg strength are associated with increased risk of death (Al Snih, Markides, Ray, Ostir, and Goodwin, 2002; Metter, Talbot, Schrager, & Conwit, 2002; Newman, Kupelian, Visser, Simonsick, Goodpaster, & Kritchevsky,2006; Rantanen,Volpato, Ferucci, Heikinnen, Fried, & Guralnik, 2003; Rolland, Lauwers-Cances, Cesari, Vellas, Pahor, & Grandjean, 2006). While the association between extremity muscle strength and mortality is well established, the biologic basis for this association is poorly understood (Newman, 2006). It is unlikely that extremity muscle strength contributes directly to mortality; rather it is more likely that extremity muscle strength is a proxy for other processes which lead to death, particularly those involving changes in skeletal muscle. (Buchman, Boyle, Wilson, Liping, Bienias, & Benett, 2008)
When people reach the age of 50 they pay the price of a sedentary life. Age results in changes in the physical synthesis, meaning the lean muscular mass, strength, joint flexibility and bone density, in combination with an increase of body fat and weight. The corporal inertia combined with the increasing age is the most crucial factor in these changes, because natural activity is one of the factors that affect the physical synthesis from the early age until old age.
The number of people over the age of sixty years is constantly increasing. The demographic problem is not seen only in Greece but in all the economically developed countries. Finding a way of keeping the elderly in good levels of physical condition, in order to prevent premature hospitalization is important.
Nearly 20 billion $ of direct medical costs are associated with fatal and non-fatal falls (Stevens, Corso, Finkeltein & Miller, 2006). A National Conference in the USA, concluded that if the risk of falls (which can result in serious condition such as hip fractures) in the elderly population was reduced, the financial gain alone to the health service would be significant (Drought, 1994).
Injuries from falls constitutes an important reason for mobility the elderly (Aniansson & Zettemberg, 1984; Nevitt et al., 1989; Powel et al, 1987; Fyndorff, Wyman, Nyman & Croghan, 2007; Hess & Woollacott, 2005). They have also tremendous impact for this frail population in terms of loss of function, anxiety, depression, increased hospital stay and increased financial burden (Vetter & Ford,1989; Murphy & Isaacs,1982; Bates, Pruess, Souney, & Platt, 1995).
Approximately forty to forty five percent, (Kose & Gable, 2006) of the people over the age 65, a fall at least once in a year (Keskin et al., 2008), whereas people over the age of 85 have more a greater chance to die as the result of a fall than from a heart illness. Donald & Bulpitt (1999) reported that people older than 75 in comparison to younger age groups, are 4 to 5 times more likely to be admitted to a long-term care facility for a year or longer following a fall.
In 2002 in the US alone, nearly 13.000 individuals died from fall-related injuries, and more than 60% of them were 75 and older (Murphy, 2000). A study of cares homes in England showed that residents fell 2-6 times a year on average, resulting in various physical injuries (Tinetti, 2003; Dickson and Woodward, 2000). Additional information reveals that of all fall-related fractures, hip fractures cause the greatest number of deaths and lead to the most severe health problems and reduced quality of life (Wolinsky, Fitzgerald & Stump, 1997; Hall, Williams, Senior, Goldswain & Criddle, 2000; Rubenstein, Josephson, & Osterweil, 1996).
Epidemiological studies of falls in the elderly, whereas men are less prone than women (Callisaya, Blizzard, Schmidt, McGinley, & Srikanth, 2008), have indicated that falls are a multi-causal phenomenon with a complex interaction between intrinsic and extrinsic factors. The most relevant intrinsic predictors from falls are decreased mobility, cognitive impairment, use of medication, depression, urinary incontinence, overweight, depression, stroke, joint complaint, postural hypotension, dizziness and impaired vision (Leveille, Bean, Bandeen-Roche K., et al. (2002); Tromp, Smit, Deeg, et al. (1998); Stalenhoef, Diederiks, & Knottnerus, (2000); DeRekeneire, Visser, & Peila, (2003); Stel, Smit, & Pluijim,(2004); O’Loughlin, Robitaille, & Boivinn, (1993); Tas, et al., (2007)). Environmental conditions are the most extrinsic factors and may result in exposure to hazardous situations (Jamison, Neuberger, & Miller,2003).
Among a number of strategies proposed to reduce the risk of falls, improving muscle strength has been applied as a successful preventive strategy. (Persch, Ugrinowitsch, Pereira, & Rodacki, 2009). Indeed it has been shown that elderly who suffer a fall have only 37% and 10% of the knee extensor and plantar flexor muscles strength in comparison to normative values (Whipple, Wolfson, & Amerman, 1987). In addition, slow gait speed is a common characteristic associated with low functional ability and risk of fall (Cao 2007; Montero - Odasso, 2005)
Although lower muscle strength has been implicated in the literature in the risk profile of elderly fallers, (Tinetti, Speechley, & Gintner, 1988; Nevitt, Cummings, & Hudes, 1991; DeRekeneire, Visser, & Peila, 2003) some studies have found no association between falls and lower limb muscle strength (Melzer, Benjuya, & Kaplanski, 2004; Skelton, Kennedy, & Rutherford, 2002). Hurley & Roth (2000) stated that muscular strength alone is independently associated with functional ability in the elderly.
Recent evidence has, however, implicated daily activities as the cause of falls (Tinetti, Stel, Smit, & Pluijim ,2003; Feskanich, Willett, & Colditz, 2002). Stel et al (2003) reported from walking tests and muscle strength evaluation that physical activity was the risk factor most related to fracture. In a nursing home population, Tinetti (1987) found that the most active participants suffered the highest frequency of injurious falls.
Several studies have shown that lower extremity strength is a common factor associated with balance impairment in elderly fallers (Tinetti, Williams & Mayewski,1986; Era, 1988; Nevitt, Cummings, Kidd, & Black, 1989; Gehlsen & Whaley,1990).
In order to improve the stability of the aged, there is the capability of exercising programs for the balance like the method sensory visual integration. But their results have not been determined clearly. A research that was carried out by Seidler & Martin (1997), could not prove that a program like that has positive relativity with the balanced improvement. In contrast it has been experimentally proved that training invigoration improves considerably their balance. (Wolff et al., 1999; Solfon et al., 1996). Additionally Pages et al.,(2006); and Pijnappels et al. (2008), found that in the elderly population there is a considerable alteration in dynamic balance and a decrease in quadriceps strength that is related to falls, suggesting exercise and resistance training is needed in order to re-educate balance and enhance the quadriceps and consequently reduce the possibility of falls.
The most common exercise in older people is aerobic exercise. Research showed that the protocols in aerobic exercise of high burden have much better results than the one of moderate burden, but they can have even better results, if they combine with strength exercises (Dalsky et al, 1988; Pruitt et al., 1992; Wolff et al., 1999). A physiotherapy study conclude that the commonest clinical problem in the elderly is their difficulty in standing up from the chair rather than running across the road. That restricts their daily living more, giving more significance in their strength levels and less in their aerobic ability (Work, 1989).
Research has shown that changes relevant to the age, like the preservation of the lean body mass, decrease of the bone density and generally the weakness in activity of everyday life, can be prevented or even inverted through resistance strength training (Adams, O’Shea, O’Shea, 1999; Fiaratone et al., 1990; Braith et al., 1996; Bowers & Sshmidt, 1997; Grimly et al., 1992).
STRENGTH AND AGE.
Strength is a basic component of quality life. Without adequate levels of strength, even the most basic activities are hard or even unaccomplished without help (Israel, 1991).
Research has shown that from the age of 30 till 80’s, the strength of the back, hands and legs decreases 30% to 40% from its peak (Grimby & Saltin, 1983; Thrash & Kelly, 1987). Israel noticed that a decrease in strength and muscular mass in men between 30 and 70 years old of about 30%. In another research, the muscular mass expressed in creatine secretion per kilo of body weight, was decreased by 6% every decade in a sample of men between 22 and 87 years old. According to Borkan et al., (1983); Morse, Thom, Davis, Fox, Birch, & Varici, 2004; Narici, Maganaris, Reeves, & Capodaglio, 2003, in a research among men between 41 and 76 years old, found that the muscular tissue is decreased according to age, while the fat is redistributed. Viitasalo et al., (1985), studied three different aging groups. 31-35, 51-55 and 71-75 years old. In the age group of 71-75 he noticed a decrease in strength in quadriceps (47%), in biceps (35%), in strength grip of the palm (42%), in trunk extension (42%) and in the trunk bend (35%). Vandervoot & McComas (1986) in a research about the strength of the ankle joint found that the decrease of the muscular mass is responsible for the lower level of strength in older people. Klitgaagrd et al., (1990) noticed also the inability of older people to be able to activate all their muscular groups simultaneously.
Men between 11 and 70 years old were studied by Larsson et al.,(1978). Their isometric strength was raised in the third decade, remained stable in the fifth and from then on showed a steady decrease. Reed (1991) noticed decrease of strength per muscle unit as age increases. He also suggests that in order to preserve the muscular balance, people have to make additional effort through strength training as they grow up.
Patrick (1982) suggests that the maintenance of strength in older people is very important, since he noticed in his research a decrease of about 4% in the periphery of the thigh and 5% decrease in the ratio of muscle to body mass in retired workers. Brooks & Faulker, 1994; Porter et al., 1995; Young & Skelton, 1994, mention that the total decrease in muscular mass in people of age between 60-70 is about 20-30%. In people of 70 years old and above the total decrease of muscular fibres type I, is decreased by 15-20%, while the ratio of muscular fibres type II is decreased about 40% (Hendrick, 1998).
STRENGTH TRAINING AND AGE.
Recently, numerous studies have investigated the effect of resistance training in the elderly (Barry & Carson, 2004; Hunter, McCarthy, & Bamman, 2004; Latham, Benett, Stretton & Anderson, 2004; Macaluso & De Vito, 2004; Reeves, Narici, & Maganaris, 2006)
Resistance training resulting in active skeletal muscle use may attenuate or even reverse this muscle wasting that is associated with advanced age (Hurley & Roth, 2000). This reversal is thought to result in improvements in functional abilities and health status in the elderly, by increasing muscle mass, strength and power and by increasing bone mineral density. High-intensity resistance training has been shown to improve muscle strength, and to reduce fatigue and pain, in elderly, physically frail individuals (Larson & Bergmann, 2008). In a comprehensive review of the role of resistance training for health, the President’s Council on Physical Fitness and Sports recommended resistance training as a preventive measure against falls among the elderly (Pollock & Vincent, 1996). The well documented losses of muscular strength and muscle mass known as sarcopenia, have also other important implications , such as hip fractures, a decrease in bone density and an increase in glucose intolerance (Hurley & Roth, 2000; Pijnappels, Reeves, Maganaris, & Van Dieen, 2008). Cross-sectional data have shown that sarcopenia is associated with aging and can be limited by structured physical training. (Raguso, et al., 2006).
Research in the elderly showed that strength training is effective in the metabolism improvement, at corporal constitution and function (Charette et al., 1991; Fiaratone et al., 1990; Fiaratone et al., 1985; Frontera et al., 1988; Pyka et al., 1994). The military service of USA relevant to the health and exercise suggests that the growth of strength can improve the ability of a person to exert activities and avoid an injury, and resistance strength training contributes importantly to a better balance, co-ordination and agility helping older people to avoid falls (US Department of Health and Human services, 1996).
In the research by Hurley & Roth (2000), was found that about 2 months of strength training essentially reverses at least 2 decades of strength loss that is age related. Similar reversals can be observed with muscle mass, which is lost at a rate of about 6% per decade after the age of 50 years old and increased by about 12% within the first couple of months of strength training. Thus it is believed that two decades of age-induced muscle mass loss can be reversed with only two weeks of strength training.
There are clues that resistance strength training causes functional and metabolic adjustments that help to prevent sacropenia, osteoporosis and weight gain and to improve the functional ability of older people (Campbell et al., 1994; Hughes et al, 1995; Nichols et al., 1993; Sipla & Soumine, 1995; Hess & Woollacott, 2005).
According to Jette & Branch (1981) after the age of 74, 28% of men and 66% of women in USA cannot raise a load of 4,5 kilos. Many believe that strength decrease is an inevitable fact relating the age increase, but as we have shown this is not necessarily the case.
In a case study, O’Shea (1976) looked into how much strength could decrease in a person with a history of a long athletic career, at the age of 51. A program lasting one year was implemented, comprising of seat-ups seats in high intensity. The exercise gave particular emphasis on the training of big muscular groups around the hips, knees, and the lower back but with care as so to avoid muscle fatigue or even injuries. The results were interesting. He repeated the same test with the same sample to the age of 60, after 8 years. The subjects could lift the weight they were able to lift when they were at the age of 30 decreased by only 30%. Generally the results show that this way of resistance strength training can cause important improvements in healthy middle-aged people.
Larsson (1982), suggests that tissue atrophy is because of disuse and a resistance training of high burden can lead to a bigger muscular mass and strength. A similar result is found by Barnes & Donovan (1987) in a research that was carried out in subjects who suffered a hip fracture that was attributed in muscle weakness.
A group of subjects aged 60 to 72 years old carried out a resistance training program for biceps and quadriceps in a Universal machine for 12 weeks in 80% of the maximum repetition (Frontera et al., 1988). The frequency was three times a week from 3 to 8 repetitions in every test. After a strength control test, an increase of about 107% was found in quadriceps and 226% for biceps. For Graig (2002), the most effective programs are these that use exercises with high tension that exceed at least 70% of the maximum repetition.
Fiaratone et al., (1990) in a group of people of aged 86 to 96 years old, carried out a program using weights for quadriceps 3 times a week from 3 to 8 sets in 80% of intensity. The strength of quadriceps was increased by 174% with a decrease of strength by 32% only 4 weeks after the end of the program. The speed of step was increased by 42%. Two people from the sample did not need crutches anymore in order to walk, and one did not need help to stand up from the chair. Muscular hypertrophy was noticed in some people. It ended up to the conclusion that the risk of injury from such a program is dwarfed from the possibilities of injury caused from falls.
Young & Skelton (1994), found that for healthy women over 75 years old, the isometric strength of biceps and quadriceps was increased by 13-30% after twelve weeks of training. A research from Pratley et al., (1994), in men of 50-65 years old was found increase of 40% of their total strength after an invigoration program of 16 weeks. A research by Clarkson & Dedrick (1988) suggests that older people are able to compete in a carefully designed resistance strength program, since by the results the natural activity is able to minimize the decrease in strength that stems from age (Bortz, 1982).
Resistance training is also a possible intervention that may attenuate the lumbar strength loss seen with aging. Resistance training improves muscle strength and muscle mass in peripheral muscles and lumbar extensor muscles. (Carpenter & Nelson, 1999; Risch, Norvell & Pollock, 1993). In a study by Vincent, Braith & Vincent (2006) searching the influence of resistance exercise on lumbar strength in elderly overweight adults, upper body and lower body strength increased by 18,3% and 12,7% respectively by using a resistance training program for 6 months.
On the contrary, a variety of findings in some studies have failed to show any improvement in strength or balance control, even after 16 to 26 months of training, whereas others have shown improvements in both parameters (Hess & Woollacott, 2005.)
Training using weights can be of value in people older than the age of 50 that desire to improve their agility, strength and cardiovascular system (Pearson, 1998) and consequently to preserve their independence in their daily activities.
The exercise program should include both free weights and machine assisted exercise.
While machines cause an important improvement in strength, it is very possible that this improvement can be more beneficial if it is achieved with free load since free load exercise is more advantageous regarding neuromuscular function balance and agility.
One common weakness of the papers that investigate training is that the amplitude of the training intensity, the frequency of the repetitions and training days is unclear. Only a few researches have followed the principle of the progression augment of the burden that is the basic principle of the strength resistance training. Regardless, of what mechanisms are responsible for training-induced muscle hyperthrophy in the elderly, it is clear that when older people maintain muscular active, the age related losses in strength reduced substantially (Hurley & Roth, 2000).
MUSCULAR POWER AND AGE.
The power refers to the extend of the work that a muscle can produce per time unit (Larsson, 1982, O’ Shea, 1996). The increase of power gives the ability to the older person to improve thoroughly their efficiency in everyday moves that require strength combined with speed (Adams et al., 1992; O’Shea, 1996), averting the phenomenon of their falls (Nelson et al., 1994).
A review of the literature available to us, reveal papers focusing on the efficiency of power in older people. Sale (1991) mentioned that the increased neural adjustment as a result of strength resistance training, can lead to a bigger threshold, a larger number of locomotive units and as a result incresed power. The muscular fibres type II are related with high speed, dynamic movements (Kohrt et al., 1997; Noth, 1991; O’ Shea, 1996). Significant relation was noticed between the percentage of muscular fibers type II and the mechanic power as it was recorded from the handstand jump (Kohrt et al., 1997). The muscular fibers type II decrease in proportion as age advances (Essen-Gustavsson, Borges, 1986; Kohrt et al.,1997; Larsson et al., 1978) and as a result a decrease in power ability. This decrease is believed to be reversible through strength resistance training, leading to decrease or even improvement of the muscular power.
Training programs experimentally designed can also improve the neuromuscular coordination, leading to power increase (Frontera et al., 1988; O’Shea, 1991). This is important for the elderly, for whom coordination and balance, along with the right function of the appropriate mechanisms, can help more that enough in everyday activities.
FLEXIBILITY AND AGE.
Agility has been defined as the total range of motion of a joint. Sufficient agility helps a person to cope with the functional requirements of life (Beaulieu, 1981; Hutton, 1991).
The range of motion of a joint is dependent to factors, such as the surrounding muscles, bones, tendons and connecting tissue and the dysfunction of one which can be secondary to lack of exercise can be one of the factors responsible for the reduce of agility (Barbosa et al., 2002). As age advances, the ligaments, cartilage and tendons change in their mechanical ability and biochemical composition. These changes reduce muscular flexibility (Gosselin et al., 1998), leading to reduced agility.
Lack of agility can increase the possibility of injury and can create functional problems (Alexander et al., 1991; Cornelius, 1990; Hutton, 1991). Agility is an important factor that reflects the overall health, and its decrease has been related with the inability and weakness (Schultz, 1992; Vandervoort et al., 1992).
Agility decreases proportionally with age (Chapman et al., 1972; Einkauf et al., 1987; Smith, 1989; Snow-Harter et al., 1990) by 20% to 30% between the ages of 30 to 70 (Smith, 1989; Chapman et al., 1972). Johns & Wright (1962) suggested that this reduction depends on soft tissues: synovial capsules 47%, muscle and its fascia 41%, tendons and ligaments 10% and skin 2%. Immobility or lack of exercise increases the reversal of collagen fibers, shortening the muscular tissues, reducing muscular mass and as a result decreasing agility.
Murray et al., (1969) compared the gait in young and older men between the age of 20 to 84. The study revealed that as we get older our steps shorten due to the reduced range of flexion and extension of the hip and reduced flexion of ankle. Johnson & Smidt (1970) concluded that tying of shoe laces requires the biggest range of motion among our the everyday movements and hence it is a good indicator of flexibility.
Goldspink (1991) suggests that exercise can reduce that phenomenon and preserve the agility in old age, something which is agreed by several authors (Adrian, 1981; Anderson et al., 1984; Chapman et al., 1972; Heyward, 1984).
STRENGTH TRAINING AND FLEXIBILITY
Strength and flexibility are two parameters equally important with aerobic physical status. In fact they are more important, because strength and flexibility are required in basic every day activities, such as standing up from chair or getting off a car, dressing or carrying objects (Reimers, 1995).
Exercise which focuses so the joints go throu a full range of motion, improves flexibility over time (Cornelius, 1990; Heyward, 1984; Hutton, 1991). Disuse due to lack of physical activity, causes contractures and reduction of connective tissues, while increased flexibility in the muscle-tendon system is caused by repeated, active contractions, that increases local circulation of muscle and gradually increases the tendon strength (Anderson et al., 1984; Goldspink, 1991; Heyward, 1984). In addition, apart from flexibility increase, strength training averts the loosening of the joints by strengthening the muscles that surround them (Cornelius, 1990; O’Shea,1996; Wathen, 1987).
Buccola & Stone (1975) presented an improvement of flexibility of the trunk and of the lower limbs in people between the age of 60 and 70 with their participation in a walking and running program that lasted 14 weeks.
Chapman et al., (1972) observed the flexibility in men between the age 15 to 19 and 63 to 88. The results showed reduction of flexibility in proportion to the age increase. The gradually increasing strength training however, improved flexibility to both age groups, with older people being equally positive to training as younger people did. Similar results were recorded from Hartley-O’Brien (1980) where they registered important improvement of flexibility after strength training with resistance at full range of motion.
Brown et al., (2000) evaluated the effects of both a supervised and unsupervised, low intensity, flexibility exercise program of 3-month duration on physical performance, balance, strength, and coordination. No significant difference was found for any of the variables, between the groups, with the exception of range of motion and flexibility.
The effects that resistance strength training can have on flexibility were also examined by Leighton (1964). The program that lasted 8 weeks was mainly composed of multi joint exercises with high burden such as seats, twists, dead lifts, press. The training resulted in the improvement of 27 out of 30 body points that their flexibility was examined. So he concluded that training with resistance that aims in strength and muscular volume improves flexibility. As it was ascertained from other researchers, these exercises must be carried out in full range of motion in order to present important result (Anderson et al., 1984; Ohta et al., 1992; O’Shea, 1996; Wathen et al., 1987).
O’Shea (1996) mentioned that a resistance program that is located in full seats, led to flexibility improvement in posterior sartorius, hips and the lower part of the back, and when it is combined with the strength increase, we have control and stability increase in other activities. Free load training emphasizing in strength present improvement in the performance through full range of motion (Anderson et al.,1984; Leighton, 1964). Anderson (1984) formulated the opinion that an appropriately designed program with resistance is more sufficient than a program that aims solely in flexibility. In the same conclusion came Barbosa (2002), and Trash & Kelly (1987) in their research, where a solely flexibility program was implemented on older people, and a strength training without flexibility exercises. They found out that, flexibility in strength training improved importantly without flexibility exercises being necessary.
Flexibility is an important factor of physical status of the elderly. In every age good flexibility means good mobility. Flexibility in combination with strength allows somebody to carry out all every day activities with increased safety.
A strength program with free load, combined with a program of flexibility and swimming as well, improves and maintains the good function of joints (their ability to extend, allows the joint to move to its maximum range). The most important muscle groups are around the hips (abductors), the muscles of lower back, thighs (hamstrings) and posterior-anterior sartorius). If these muscles are flexible, they importantly contribute to improved quality of life (Adams et al, 1999). While static stretching exercises indeed improve flexibility, stretching of type PNF is considered the best method. However the presence of an assistant is necessary, in combination with excellent knowledge of their execution.
BONE DENSITY AND AGE.
Starting from the age of 50), bone density decreases mainly in females. Low bone density results in increased risk of osteoporotic fractures. Firstly, osteoporosis is combined with lack of calcium and impotence in exercising (Ayalon et al., 1987; Beaulieu, 1981).
Menopause leads to bone density reduce of 4% every year in the period before it shows up, and a reduction of 20% right after (Graig, 2002). Research from Munnings (1992), showed that osteoporosis is responsible for 13 million fractures every year. One third of women over the age of 65, suffer from osteoporosis fractures in the spine and at about 15% of the hips. Research from Dalsky et al., (1998) proves that women can lose up to 20-30% of their bone mass.
That constant reduction in bone density leads to increased bone weakness and simultaneously to increased risk of fracture. Women with low estrogens and calcium levels, don’t seem to respond to a strength training (Maddalozzo, 1998).
There is a positive correlation between strength and bone density. Stronger people present bigger bone density, in contrast to weaker people (Conroy et al., 1993; Snow-Harter, 1990). Snow-Harter (1990) said that strength is a factor that affects the apparition of bone density.
STRENGTH TRAINING AND BONE DENSITY.
In theory, strength training is an exceptional way in order to maintain bone density (Graig, 2002; Munnings, 1993). Maddolozzo (1998) studied the influence of a strength training program with resistance that lasted 6 months in the total bone density of 28 healthy men 54 years old and 26 women 52 years old. He compared the affects of a moderate tension program with a high tension program with free load. The results showed that the program with free load of high tension improved the bone density of the sample, in contrast with the other 2 programs in which observable improvement was not seen.
Other research showed that athletes that lifted weights had bigger bone density in relation with athletes of other sports (Nilsson & Westlin, 1971; Treuth et al., 1994; Whalen, 1998). Indeed athletes that lifted load with the bigger bone density were the successful ones.
When it comes to the female population where the problem is bigger, from research it is showed that invigoration with resistance training thoroughly improves the percentage of bone density or even prevents that big reduce before and after menopause (Dalsky et al., 1988; Notelovitz et al., 1991; Hedrick, 1998).
Reduction of bone density (osteoporosis) increases the risk of inefficiency fractures. High tension strength training with free load and with the use of exercises like deep seats or dead lifts, help very much in the increase of bone density. Strength training with machines doesn’t show important results.
MACHINES OR FREE LOAD?
The review of the literature available to us shows that training with free load is more beneficial than strength training with machines (Adams et al., 1992; Ohta et al., 1992; O’Shea, 1981, 1996; Stone & O’Bryant, 1987; Sylvester et al., 1981). Eyigor, Karapolat,, & Durmaz, (2007) in their research stated that free weights were used for resistance exercises, in the form of hand-held dumbbells and ankle cuff weights available in 0.5-1kg increments.
Research that has been carried out and based on the theory that machines control the range of motion and the speed of exercise execution, preventing the possibilities of injury couldn’t prove such thing (Atha, 1981; Hay, 1991; Maddalozzo, 1998). On the contrary machines restrict acceleration, leading in profile that abstain from dynamic of functional everyday movements.(Garhammer, 1982). In addition to that, many machines reduce the counter movements. That lowers the ballistic impulses and the phenomenon “action-reaction», reducing as a result the training influences (Adams, et al., 1992; Garhammer, 1991; Kohrt et al., 1997; O’Shea, 1996). Promptly these machines provide important support in the back, reducing the danger of injury especially in beginners, getting them easily in that kind of exercise while they hold practice in a certain range of motion (McCaw & Friday, 1994; Vincent, Braith & Vincent, 2006; Persch, Ugrinowitsch, Pereira, & Rodacki,2009).
On the other hand, free load require balance and good technique knowledge. That is why Bowers and Schmidt (1997) suggest that the beginner should start with machines so as to familiarize with free load. And they end up that the most ideal combination of machines and free load in one program is the best way of exercise.
It is generally believed that free load provide proprioceptive kinesthetic feedback similar to the one that is provided to the functional everyday movements leading to neuromuscular coordination between agonist and antagonist muscles and to their synchronization (Hatfield, 1989; O’Shea, 1996; Schmidtbleicher, 1991; Snow-Harter, et al., 1990). They also improve thoroughly the balance and the coordination (Foran, 1995; Munnings, 1993). In a more realistic deal of the relationship between free load and machines, it is not possible to be said that a program composed only of free load is the ideal of all the population. The best would be a combination of both. Apart from all the other, the variety in training is one of the basic training motives for exercise that lasts many years.
There are also people that either due to serious health problems or of advanced age, are not able to exercise with free load.
BASIC RULES IN EXERCISE
Programs are administered with a a frequency of 2-3 times per week and duration of 8-24 weeks.( Skelton, Young, Greig et al., 1995; Lord & Castell , 1994; Krebs, Jette & Assmann, 1998; Kongsgaard, Backer, Jorgensen, Kjaer & Beyer, 2004; Eyigor, Karapolat,, & Durmaz, 2007). For other researchers the strength training program should last 1-year in order to be effectine in improving life-style and functional abilities in healthy elderly. (Capodaglio & Capodaglio, 2005). For Pijnappels, Reeves, Maganaris, & Van Dieen,(2008), 16 weeks of training is the exact appropriate time to present sufficient improvements. These researchers also state that training only once a week may be sufficient to increase strength in the elderly.
To encourage the older people to focus on fewer and more important muscle groups
It is preferable to exercise with free load than with isometric or static ones
Directions should be given to people to perform the exercise slowly and in all the movement width,
It is suggested that warming up should be precluded, that will be composed of either light aerobic program or few repeats from every exercise without burden.
Every exercise must be executed for 10-12 repeats until fatigue, or 8 reps at 80% of 1-RM (Kongsgaard, Backer, Jorgensen, Kjaer & Beyer, 2004).
A two minute resting interval between sets is nesseccary (Persch, Ugrinowitsch, Pereira, & Rodacki,2009)
It is basic the learning of breath pace, especially in older people that might suffer from hypertension problems. Holding of breath can raise blood pressure.
Every exercise must be executed for 3 to 4 sets, while the burden must be close to 80% of the maximum repeat (Drought, 1994).
The American College of sports Medicine (1998) though suggests 80% of 1-RM for 8 repetitions, and that is commonly used in studies for older adults corresponding to the lower repetition limit.
The program that is going to be implemented does not differ much from that one which should implemented to younger people. Fiatarone & Evans (1993) have suggested that some researchers, perhaps fearing injury to their subjects, have not used protocols of sufficient intensity to promote muscle strength gains. Other studies have shown that older adults can safely perform high-intensity strength training, resulting in muscle gains (Hauer, Rost, Rutschle, Opitz, Specht, Bartsch P., et al., 2001), but findings are mixed as to the effect of strength training on balance control.
Special attention must be given to the rehabilitation period that must be bigger than in the younger ones. Research has shown that older people show bigger sense of fatigue than the younger that need 3-4 days in order to fully revert. The older people need 3-4 days of rehabilitation at least (Hendrick, 1998; Wilson, 1995).
The start of a strength program with high tensions so as to achieve long lasting profits is sometimes difficult to be implemented with older people or people that present health problems (Graig, 2002). As it has been mentioned better results are presented with high and not moderate tensions. Besides, high tensions are the choice of researchers in researches that was carried out in older people, with tension close to 80% of the maximum, as ACSM also recommend (Fiaratone et al., 1985,1990; Frontera et al., 1988, 1990; Hunter et al., 1992; Vincent, Braith & Vincent, 2006). Drought (1994) suggests from his research that only a program of high tension can have an effect on the strength of older people that are close to 90 years old. Fiaratone et al., (1990) presented that high tension training is directly connected with important improvements in strength and in muscular hypertrophy in people of 96 years old and above. The research by Beneka et al., (2005), proved that high intension training protocol caused the most impressive improvement of the knee extensors isokinetic performance as compared to low intension or medium intension at all testing velocities. However, moderate and low- intensity training groups caused a significant strength improvement as well, but at a lesser extent.
High resistance training has been reported to be beneficial in maintaining muscle strength, size and range of motion in older men following a 12-16 weeks of progressive resistance training program (Fatouros, Taxildaris, Tokmakidis, et al.,2002; Trappe, Wlliamson, & Godard, 2002).
Proportional is the opinion of Frontera et al., (1988), where with high tensions training the strength in the extension of the knees increased by 107% and in flexion by 227% after training that lasted only 12 weeks in people that were 60 years old and above. If of course the choice is the high tensions resistances, it is believed that the results will be radical, but there is always the risk of being lost some of the people of the sample because of injury. Another opinion (Eyigor, Karapolat,, & Durmaz, 2007), say that the optional intensity for elderly women exclusively should be a combined-intermediate program, with group-based exercises, that can raise their scores in the quality of life assessment.
The number of repetitions of each exercise performed 2-3 days per week, vary from 8 to 13 reps, which is commonly used in those studies (Vincent, Braith & Vincent, 2006; Larson & Bergmann, 2008).
Low or medium tension training produces, according to Drought (1994) produce little or no improvement in the strength of the older people, as it referred by Aniansson & Gustafson (1981), Larsson (1982), Hagberg et al., (1989). The exact opposite is the result that presents in his research Hunter & Treuth (1995) where in older women and after exercise with medium and high burden, presented improvement with the medium strength training.
Another important situation is the number of resistance training applied, two or three times per week. In the study by Kongsgaard, Backer, Jorgensen, Kjaer & Beyer, (2004) the improvements produced in isometric knee extension and isokinetic knee extension were lower than those found by Simpson, Killian, McCartney, Stubbing, & Jones, (1992), and Spruit, Gosselin, Troosters, De Paepe, & Decramer, (2002) respectively. However, these studies applied resistance training three times a week, whereas the subjects of the former study trained only twice a week.
Graig (2002) mentions that from lab researches, exercise in medium tensions can improve the size of the bone and the functional ability for a very long time. Exercises that were implemented were of medium tension, but included aerobic and anaerobic movements.
The main aim of strength training must be the creation of the appropriate dynamic in order for the people to be able to cope with their everyday moves until the end of their lives and also to avoid unwanted falls and fractures. While training must start from an early age, training in ages of 50 and above can give very important results. The profits from a program with resistance depend clearly from the type of the exercise, from the burden and from the muscular groups that are exercised.
Researches show that elderly prefer free load rather than machines, the high tension in relation with the medium, and emphasis in multi joint exercises that are carried out in full range of motion of the joint, with the hips and knees being the most important points that determine functional ability. Machines are preferable to be used by very old people, where lack of balance is intense.
Adams, K., J.P. O’Shea, K.L. O’Shea, and M.Climstein. (1992). The effect of six weeks of squat, plyometric and squat-plyometric training on power production. J.Appl.Sport Sci. Res. 6:36-41.
Adams, K., P. O’Shea, and K.L. O’Shea (1999). Aging: its effects on strength, power, flexibility, and bone density. Strength & Condi. J., April, pp 65-77.
Adrian, M.J. (1981). Flexibility in the aging adult. In: Exercise and Aging: The scientific Basis. E.L. Smith and R.C. Serfass, eds. Hillside, Nj:Enslow, pp 45-47.
Al Snih S., Markides KS., Ray L., Ostir GV., and Goodwin JS. (2002). Handgrip strength and mortality in older Mexican Americans. J.Am. Geritr.Soc. 50(7):1250-1256.
Alexander, N.B, A.B. Schultz and D.N. Warwick. (1991). Rising from a chair: Effects of age and functional ability on performance biomechanics. J. Gerontol. 46(3):91-98.
American College of Sports Medicine Position Stand (1998). The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults. Med. Sci. Sports Exerc. 30(6):975-91.
Anderson, B., J.E. Beaulieu, W.L. Cornelius, R.H. Dominguez, W.E. Prentice, and L. Wallace. (1984). Flexibility. Natl.Strength Cond. Assoc. J. pp10-22, 71-73.
Aniansson, A., and A. Zetterberg (1984). Impaired muscle function with aging: a background factor in the incidence of fractures of the proximal end of the femur. Clin.Orthop. 191:193-201.
Aniansson, A., and E. Gustafsson. (1981). Physical training in elderly men with special reference to quadriceps muscle strength and morphology. Clin.Physiol. 1:87-98.
Atha, J. (1981). Strengthening muscle. In: Exercise and Sports Science Reviews. Vol.9, D.I. Miller, ed. The Franklin Institute, pp 1-74.
Ayalon, J., A . Simkin, I. Leichter, and S. Raifmann. (1987). Dynamic bone loading exercises for postmenopausal women: Effect of the density of the distal radius. Arch. Phys. Med. Rehabil. 68:280-283.
Barbosa A.D., J.M. Santarem, W.J. Filho, and M.F.Nunes. (2002). Effects of resistance training on the sit-and-reach test in elderly women. J.Strength and Cond. Res. 16(1), 14-18.
Barry BK., and Varson RG. (2004). Transfer of resistance training to enhance rapid coordinated force production by older adults. Exp. Brain Res. 159(2):225-8.
Bates D., Pruess K., Souney P., and Platt R. (1995). Serious falls in hospitalized patients: correlates and resource utilization. Am. J. Med. 99:137-143.
Bealieu, J.E.(1981) Developing a stretching program. Physician and Sportmed. 9(11): 59-62.
Bellew J.W. & Yates J.W. (2000). Coecentric versus Eccentric Strength of the quadriceps femoris in endelry and young women.Journal of Strength and Conditioning Research, 14(4), 419-425.
Beneka A., Malliou P., Fatouros I., Jamurtas A., Gioftsidou A., Godolias G., and Taxildaris K. (2005). Resistance training effects on muscular strength of elderly are related to intensity and gender. J. Sci Med. Sport. 8:3:274-283.
Borkan, G.A., D.E. Hults, S.G. Gerzof, A.H. Robbins and C.K. Silbert. (1983). Age changes in body composistion revealed by computed tomography. J.Gerontol. 38(6):673-677.
Bortz, W.M. (1982). Disuse and aging. J. Am.Med. Assoc. 240 (10)1203-1208.
Bowers C.J., and Schmidt E. (1997). Weight Training for Older Americans. Strength and Conditioning, 42-47.
Braith, R.W., Mills Jr R.M., Welsch M.A., Keller J.W., and Pollock M.L. (1996). Resistance exercise restores bone mineral density in heart transplant recipients. J.Am.Coll. Cardiol. 28:1471-1477.
Branch JS., Simonsick EM., Kritchvsky S., Yaffe K., and Newman AB. (2004). The association between physical function and lifestyle activity and exercise in the health, aging and body composition study. J.Am. Geriatr. Soc. 52:502-509.
Brooks,S.V., and J.A. Faulkner (1994). Skeletal muscle weakness in old age: Underlying mechanisms. Med. Sci. Sports Exerc. 26: 432-439.
Brown M., Sinacore DR., Ehsani AA., Binder EF., Hollszy JO., and Kohrt WM. (2000). Low-intensity exersice as a modifier of physical frailty in older adults. Arch. Phys. Med. Rehabil. 81:960-965.
Buccola, V.A and W.J. Stone. (1975) Effects of jogging and cycling programs on physiological and personality variables in aged men. Res. Q. Exerc. Sport. 46(2):134-139.
Buchman AS., Boyle PA., Wilson RS., Liping Gu, BIenias JL., and Benett DA (2008). Pulmonary function muscle strength and mortality in old age. Mechanisms of Ageing and Development. 129:625-631.
Burnes, B., and Dunovan , K. (1987). Functional outcomes after hip fracture. Phys. Ther. 67(11): 1675-1679.
Burr, D.B., R.B. Martin and P.A. Martin. (1983). Lower extremity loads stimulate bone formation in the vertebral column: Implications for osteoporosis. Spine. 8(7): 681-686.
Callisaya ML., Blizzard L., Schmidt MD., McGinley JL., and Srikanth VK. (2008).Sex modifies the relationship between age and gait: a population-based study of older adults. J. Gerontol. A. Bio. Sci. Med. Sci. 63(2): 165-170.
Campbell, W.W., M.C. Crim, V.R. Young and W.J. Evans. (1994). Increased energy requirements and changes in body composition with resistance training in older adults. Am.J.Clin.Nutr. 60:167-175.
Cao ZB., Maeda A., Shima N., Kurata H., and Nishizono H. (2007). The effect of a 12-week combined exercise intervention program on physical performance and gait kinematics in community-dwelling elderly women. J.Physiol. Anthropol. 26(3):325-332.
Capodaglio EM., and Capodaglio P. (2005). Changes in life style and function in 70-83 year old subjects participating in a 1-year strength training program. International Congress Series 1280.:353-358.
Carpenter D.M., and Nelson B.W. (1993). Low back strengthening for the prevention and treatment of low back pain. Med. Sci. Sports Exerc. 31:18-24.
Chapman, E.A., H.A. deVries and R.Swezey. (1972). Joint stiffness: Effects of exercise on young and old men. J. Gerontol. 27(2):218-221.
Charette, S.L., L. McEcoy, G. Pyka, C. Snow-Harter, D. Guido, R.A. Wiswill, and R.Marcus. (1991). Muscle hypertrophy response to resistance training in older women. J.Appl. Physiol. 70:1912-1916.
Clarkson, P.M., and M.E. Dedrick. (1988). Exercise induced muscle damage, repair, and adaptation in young and old subjects. J. Gerontol. 43(4): M91-M96.
Conroy, B.P., W.J. Kraemer, C.M.. Maresh, S.J. Fleck, M.H. Stone, A.C. Fry, P.D. Miller, and G.P. Dalsky. (1993). Bone mineral in elite junior Olympic weightlifters. Med. Sci. Sports Exerc. 25(10): 1103-1109.
Cornelius, W.L (1990). Benefits from flexibility exercise. Natl. Strength Cond. Assoc. J. 12(5):61-64.
Dalsky, G., K.S. Stocke, A.A. Eshani, E. Slatopolsky, W.C. Lee, and S.J. Birge. (1988) Weight bearing exercise training and lumbar bone mineral content in postmenopausal women. Ann. Intern. Med. 108:824-828.
DeRekeneire N., Visser M., and Peila R. (2003). Is a fall just a fall: correlates of falling in healthy older persons. The health, aging and body composition study. J. Am. Geriatr Soc. 51: 841-6.
Dickson B., and Woodward M. (2000). Accident prevention in the elderly in nursing; 2nd year report. Newcastle: Gateshead, South Tyneside, Sunderland and Northumberland Registration and Inspection Areas for Care Homes.
Donald IP., and Bulpitt CJ. (1999). The prognosis of falls in elderly people living at home. Age Aging. 28:121-5.
Drought, H.J. (1994). Resistance training and strength benefits for elderly individuals. Strength and Conditioning, 16(3):26-30.
Einkauf, D.V., M.L. Gohdes, G.M. Jensen and M.J. Jewell. (1987). Changes in spine mobility with increasing age in women. Phys. Therap. 67(3): 370-375.
Era P. (1988). Posture control in the elderly. Int J. Technol. Aging. 1:166-79.
Essen-Gustavsson, B., and O. Borges. (1986). Histochemical and metabolic characteristics of human skeletal muscle in relation to age. Acta Physiol. Scand. 126:107-114.
Eyigor S., Karapolat H., and Durmaz B. (2007). Effects of a group-based exercise program on the physical performance, muscle strength and quality of life in older women. Archives of Gerontology and Geriatrics. 45:259-271.
Fatouros I., Taxildaris K., and Tokmakidis S. (2002). The effects of strength training, cardiovascular training and their combination on flexibility of inactive older adults. Inter J. Sports Med.. 23:112-119.
Feskanich D., Willett W., and Colditz G. (2002). Walking and leisure time activity and risk of hip fracture in postmenopausal women. J.A.M.A. 288:2300-6.
Fiaratone, M.A, E.C. Marks, N.D. Ryan, C.N. Meredith, L.A. Lipsity, and Evans W.J. (1990). High-intensity strength training in nonanegarians: Effects on skeletal muscle. J.A.M.A. 263: 3029-3034.
Fiaratone, M.A., E.F. O’Neil, N.D. Ryan, R.M. Clements, G.R. Solores, M.E. Nelson, S.B. Roberts, J.J. Fehayias, L.A. Lipsity. and W.J. Evans. (1985). Exercise training and nutritional supplementation for physical frailty in very elderly people. New Engl J .Med. 330 :1769 -1775.
Fiatarone M., and Evans W. (1993). The aetiology and reversibility of muscle dysfunction in the aged. J. Gerontol. 48:77-83.
Foran, B. (1995). Advantages and disandvantages of isokinetics, variable resistance and free weights. NSCA Journal. Jan/Feb pp 24-25.
Frontera, W.R., C.N. Meredith, K.P. O’Reilly, H.G. Knuttgen and W.J. Evans (1988). Strength conditioning in older men: Skeletal muscle hypertrophy and improved function. J.Appl.Physiol.64:1038-1044.
Fyndorff M.J., Wyman J.F., Nyman J.A., and Croghan C.F. (2007). Measuring the direct healthcare costs of a fall injury event. Nurse Res. 56:283-7.
Garhammer, J. (1982). Free weight equipment for the development of athletic strength and power-part I. Natl. Strength Cond. Assoc. J. 24-26, 33.
Garhammer, J.(1981).Free weight equipment for the development of athletic strength and power-Part I. NSCA Journal 3(6):24-26, 33.
Gehlsen GM., and Whaley MH. (1990).Falls in the elderly: part I, gait. Arch Phys Med. Rehabil. 71:735-8.
Goldspink, G. (1991).Cellular and molecular aspects of adaptation in skeletal muscle. In : Strength and Power in Sport. P.V. Komi, ed. Boston, MA: Blackwell Scientific, pp 211-229.
Gosselin, L.E., C.Adams, T.A. Cotter, R.J. McCormick and D.P. Thomas. (1998). Effect of exercise training on passive stiffness in locomotor skeletal muscle: role of extracelullar matrix. J.Appl.Physiol, 85:1011-1016.
Graig, B.W. (2002). Resistance training and bone growth in the elderly. National Strength & Conditioning Association, 24(3): 63-64.
Grimby, G., and B. Saltin. (1983). The aging muscle. Clin Physiol. 3: 209-218.
Grimly G., Aninasson A., Hedberg M., Henning G.B., Grangard U., and Kvist H. (1992). Training can improve muscle strength and endurance in 78 to 84 years old men. J.Appl. Physiol. 73:2517-2523.
Hagberg, J.M., J.E. Graves, and M. Limacher. (1989). Cardiovascular responses of 70 to 79 year old men and women to exercise training. J.Appl. Physiol. 66:2589-2594.
Hall S.E., Williams J.A., Senior J.A., Goldswain P.R, and Criddle R.A. (2000).Hip fractures outcomes: quality of life and functional status in older adults living in the community. Aust NZ J Med. 30:327-32.
Hartley-O’Brien, S.J. (1980). Six mobilization exercises for active range of hip flexion. Res. Q. Exerc. Sport 51(4):625-635.
Hatfield, F.C. (1989). Power- A Scientific Approach. Chicago, IL: Contemporary Books Inc.
Hauer K., Rost B., Rutschle K., Opitz H., Specht N., Bartsch P., et al.(2001). Exercise training for rehabilitation and secondary prevention of falls in geriatric patients with a history of injurious falls. J. Am. Geriatr Soc.49:10-20.
Hay, J.G. (1991). Mechanical basis of strength expression. In: Strength and Power in Sport. P.V. Komi, er. Boston, MA: Blackwell Scientific, pp 197-210.
Hendrick A. (1998). Resistance training with older populations: Justifications, Benefits, protocol. Strength and Conditioning, April, pp 32-39.
Hess JA., and Woollacott M. (2005). Effect of high-intensive strength training on functional measures of balance ability in balance-impaired older adults. Journal of manipulative and Phyisological Therapeutics. 582-560.
Heyward, V.H. (1984). Advanced fitness Assessment and Exercise Prescription. (2nd ed.) Champaign, IL: Human Kinetics.
Hughes, V.A., W.R. Frontera, G.E. Dalla, K.J. Luts, E.C. Fisher, and W.J. Evans. (1995). Muscle strength and body composition: associations with bone density in older subjects. Med. Sci. Sports Exerc. 27:967-974.
Hunter G.R., and Treuth M.S. (1995). Relative training intensity and increases in strength in older women. J. of Strength and Cond. Res., 9(3):188-191.
Hunter GR., McCarthy JP., and Bamman MM. (2004). Effects of resistance training on older adults. Sports Med. 34(5):329-48.
Hunter, G.R., T.Szabo, and A.Schnitzler (1992). Metabolic cost/vertical work relationship during knee extensioin and knee flexion weight training exercise. J.Appl.Sport Sci.Res.6:42-48.
Hurley B.F., and Roth S.M. (2000). Strength training in the elderly. Effects on risk factors for age-related diseases. Sports Med. 30(4): 249-268.
Hutton, R.S. (1991). Neuromuscular basis of stretching exercises. In : Strength and Power in Sport. P.V. Komi, ed. Boston, MA: Blackwell Scientific, pp 39-63.
Israel, S. (1992). Age-related changes in strength and special groups. In: Strength and Power in Sport. P.V. Komi, ed. Boston:Blackwell Scientific, pp:319-328.
Jamison M., Neuberger GB., and Miller PA. (2003). Correlates of falls and fear of falling among adults with rheumatoid arthritis. Arthritis Pheum. 49:673-80.
Jette, A.M., and L.G. Branch. (1981). The Framingham disability study: Physical disability among the aging. Am. J. Public Health, 71: 1211-1216.
Johns, R.J., and V. Wright (1962). Relative importance of various tissues in joint stiffness. J.Appl. Physiol. 17:824-828.
Johnson, R.C., and G.L. Smidt.(1970). Hip motion measurements for selected activities of daily living. Clin Observations, 72:205-215.
Keskin P., Borman P., Erzoz M., Kurtanran A., Bodur H., and Akyuz M. (2008). The risk factors related to falling in elderly females. Geriatric Nursing, Vol.29 (1): 58-63.
King MB., Whipple RH., Gruman CA., Judge JO., Schmidt JA., and Wolfson LI. (2002). The performance enhancement project : improving physical performance in older persons. Arch. Phys. Med. Rehabil. 83:1060-1069.
Kliigaard, H., M. Mantoni, S. Schiaffinpo, S. Ausoni, L. Gorza, C. Laurent-Winter, P. Schnohr, and B. Saltin. (1990). Function, morphology, and protein expression of aging skeletal muscle: A cross-sectional study of the elderly men with different trainings backgrounds. Acta Physiol. Scand. 140:41-54.
Kongsgaard M., Backer V., Jorgensen K., Kjaer M., and Beyer N. (2004). Heavy resistance training increases muscle size, strength and physical function in elderly male COPD-patients-a pilot study. Respiratory Medicine. 98: 1000-1007.
Krebs DE., Jette AM. and Assmann SF. (1998). Moderate exercise improves gait stability in disabled elders. Arch Phys Med. Rehab. 79:1489-1495.
Larson L., and Bergmann T.F. (2008). Taking on the fall: The etiology and prevention of falls in the elderly. Clinincal Ciropractic. 11:148-154.
Larsson L., Sjodin B., and Karlsson J. (1978). Histochemichal and biomechanical changes in human skeletal muscle with age in sedentary males, age 22-65 years. Acta Physiol. Scand. 103:31-39.
Larsson, L. (1982). Physical training effects on muscle morphology on sedentary males at different ages. Med. Sci. Sports Exe. 14:203-206.
Latham NK., Benett DA., Stretton and Anderson CS. (2004). Systematic review of progressive resistance strength training in older adults. J. Gerontol. A. Bio Sci Med Sci. 59 (1) : 48-61.
Leighton, J.R. (1964). A study of the effect of progressive weight training on flexibility. J. Assoc. Phys. Ment. Rehabil. 18:101.
Leveille, SG., Bean J., Bandeen-Roche K., et al. (2002). Musculoskeletal pain and risk of falls in older disables women living in the community. JAGS:50:671-7.
Lord SR., and Castell S. (1994). Physical activity program for older persons: Effect on balance, strength neuromuscular control, and reaction time. Arch Phys Med Rehab. 75:648-642.
Macaluso A., and De Vito G. (2004) Muscle strength, power and adaptations to resistance training in older people. Eur J. Appl.Physiol.91(4):450-72.
Maddalozzo, G. (1998). Effects of two resistance training protocols on insulin-like factors, muscle strength and bone mass in older adults. PhD. Dissertation, Oregon State Un., Corvallis, OR.
McCaw, S.T., and J.J. Friday(1994). A comparison of muscle activity between a free weight and machine bench press. J.Strength Cond. Res. 8:259-264.
Melzer I., Benjuya N., and Kaplanski J. (2004). Postural stability in the elderly. A comparison between fallers and nonfalllers. Age Aging. 33:602-7.
Metter EJ., Talbot LA., Schrager M., and Conwit R. (2002). Skeletal muscle strength as a predictor of all-cause mortality in healthy men. J. Gerontol. A. Biol.Sci.Med.Sci. 57(10):359-365.
Montero-Odasso M., Schapira M., Soriano ER., Varela M., Kaplan R., and Camera LA. (2005). Gait velocity as a single predictor of adverse events in healthy seniors aged 75 years and older. J. Gerontol. A. Biol.Sci.Med.Sci. 60(10):1304-1309.
Moreland JD., Richardson JA., Goldsmith CH., Clase CM.,and Chir B. (2004). Muscle weakness and falls in older adults: a systematic review and metanalysis. J. Am. Geriatr. Soc. 52:1121-1129.
Morse CI., Thom JM., Davis MG., Fox KR., Birch KM., and Varici MV. (2004). Reduced plantar flexor specific torque in the elderly is associated with a lower activation capacity. Eur J.appl. Physiol. 92:219-226.
Munnings F. (1992).Osteoporosis:What is the role of exercise? Phys.Sportsmed. 20(6):133-135.
Munnings, F. (1993). Strength training-not only for the young. Phys. Sportsmed. 21(4):259-264.
Murphy J., and Isaacs B. (1982). The post fall syndrome: a study of 36 elderly inpatients. Gerontology. 28: 265-70.
Murphy S.L. (2000). Deaths: final data for 1998. National vital statistics report, MD: National Center for Health Statistics. 48, no 11.
Murray, M.P., R.C. Kory and B.H. Clarkson. (1969). Walking patterns in healthy old men. J. Gerontol. 24: 169-178.
Narici MV., Maganaris CN., Reeves ND., and Capodaglio (2003). Effect of aging on human muscle architecture. J.Appl. Physiol.95(6):2229-34.
Nelson, M.E., Fiaratone M.A., Morganti C.M., Trice I., Greenberg R.A., and Evans W.J. (1994). Effects of high-intensity strength training on multiple risk factors for osteoporotic fractures: A randomized controlled trial. J.A.M.A., 272:1909-1914
Nevitt MC., Cummings SR., and Hudes ES. (1991). Risk factors for injurious falls: a prospective study. J. Gerontol. 46:164-70.
Nevitt MC., Cummings SR., Kidd S., and Black D. (1989). Risk factors for recurrent nonsyncopal falls. JAMA. 261:2663-8.
Nevvit, M.C., S.R. Cummings, S Kidd, and D. Black. (1989). Risk factors for recurrent nonsyncopol falls: A prospective study. J.A.M.A. 261:2663-2668.
Newman AB., Kupelian V., Visser M., Simonsick EM., Goodpaster BH., and Kritchevsky SB.(2006). Strength, but not muscle mass, is associated with mortality in the health, aging and body composition study cohort. J. Gerontol. A. Biol. Sci. Med. Sci. 61(1):72-77.
Nichols, J.F., D.K. Omizo, K.K. Peterson and K.P. Nelson. (1993). Efficacy of heavy-resistance training for active women over sixty: Muscular strength, body composition, and program adherence. J.Am. Geriatr. Soc. 41:205-210.
Nilsson, B.E., and N.E. Westlin. (1971). Bone density and athletes. Clin. Orhtop. 77:179-182.
Notelovitz M., Martin D., Tesar R. (1991). Estrogen therapy and variable resistance weight training increase bone mineral in surgically menopausal women. J.Bone Min. Res. 6:583-590.
O’Loughlin JL., Robitaille Y., Boivinn JF (1993). Incidence of and risk factors for falls and injurious falls among the community-dwelling elderly. Am J. Epidemiol. 137:342-54.
O’Shea, J.P. (1976). Scientific principles and methods of strength fitness. Boston, MA: Addison Wesley.
O’Shea, J.P. (1981). Master power weight training. A case study. Physician Sport Med. 9(8): 133-134.
O’Shea, J.P. (1991). The science off cross-training: Theory and application for peak performance. Natl. Strength Cond.Assoc.J. 6:40-44.
O’Shea, J.P. (1996). Quantum strength and power training. Corvallis, OR:Patricks Books.
Ohta, M., K. Makita, Y. Suda, T. Ikeda, T. Masuzawa and S. Nozawa. (1992). Influence of oophorectomy on serum levels of sex steroids and bone metabolism and assessment of bone mineral density in lumbar trabecular bone by QCT-C value. J. Bone Miner. Res. 7(6): 659-665.
Goldswain P.G. and Roth S. (2000). Safety of maximal power, strength and endurance testing in older African American women. J. of Strength and Cond. Res., 14(3), 254-260.
Pages E., Sanchez J., Cuxart A., Martin R., & Martinez L. (2006). Assessment of balance and strength in the elderly population living in the community and the relationship between these factors and falls. Academy annual assembly abstracts. Arch Phys. Med. Rehabil. Vol. 87.
Patrick, J.M., E.J. Bassey, and P.H. Fentem. (1982). Changes in body fat and muscle in manual workers at and after retirement. Eur. J.Appl.Physiol. 49:187-196.
Pearson, D.R. (1998). Strength training in ageless. Strength and Conditioning, June, pp 12-13.
Persch LN., Ugrinowitsch C., Pereira G., and Rodacki ALF (2009). Strength training improves fall-related gait kinematics in the elderly: A randomized controlled trial. Clinical Biomechanics. 24:819-825.
Pijnappels M., Reeves ND., Maganaris K., and Van Dieen JH. (2008). Tripping without falling; a lower limb strength, a limitation for balance recovery and a target for training in the elderly. J. of Electromyography and Kinesiology. 18:188-196.
Pollack, J.L., J.E. Graves, and S.Leggett. (1989). Injuries and adherence to aerobic and strength training exercise programs for the elderly. Presented at the Annual Meeting of the American College of Sports Medicine. Baltimore.
Pollock M.L. and Vincent K.R. (1996). Resistance training for health. The president’s Council on physical fitness and sports research digest, series 2, vol. 8.
Porter, M.M., A.A. Vandervoot and J. Lexell (1995). Aging of human muscle: Structure, function and adaptation. Med.Sci.Sports 5:129-151.
Pratley, R., B.Nicklas, M. Rubin, J. Miller, A. Smith, M. Smith, B.Hurley and A. Goldberg (1994). Strength training increases resting metabolic rate and norepinephrine levels in healthy 50 to 65 years old men. J. Appl.Physiol. 66:133-137.
Pruitt, L., R.D. Jackson, R.L. Bartels, and H.J. Lehhard. (1992). Weight training effects on bone density in early post-menopausal women. J. Bone Miner. Res. 7:179-186.
Pyka, G., E. Linderberger, S. Charette, and R. Marcus (1994). Muscle strength and fiber adaptations to a year long resistance training program in elderly men and women. J.Gerontol. 49:M22-M27.
Raguso CA, Kyle U., Kossovsky MP., Roynette, Giacobino AP., Hans D., Genton L., and Pichard C. (2006). A 3 year longitudinal study on body composition changes in the elderly: Role of physical exercise. Clinical Nutrition. 25:573-580.
Rantanen T.,Volpato S., Ferucci L., Heikinnen E., Fried LP., and Guralnik JM. (2003). Hand-grip strength and cause specific and total mortality in older disabled women: exploring the mechanism.J.Am.Geriatr.Soc. 51(5):636-641.
Reed, R.L., L. Pearlmutter, K. Yochum, K.E. Meridith and A.D. Mooradian. (1991). The relationship between muscle mass and muscle strength in the elderly. J.Am.Geriatric Soc. 39:555-561.
Reeves ND., Narici MV., and Maganaris CN. (2006). Myotendinous plasticity to ageing and resistance exercise in humans. Exp Physiol.91(3):483-98.
Reimers, K.J. (1995). An emerging population: older adults. Strength and Conditioning, April, pp 38-39.
Risch S.V., Norvell N.K, Pollock M.L., et al. (1993). Lumbar strengthening in chronic low back pain patients. Physiologic and phychological benefits. Spine, 18:232-238.l
Rolland Y., Lauwers-Cances V.,Cesari m., Vellas B., Pahor M., and Grandjean H. (2006). Physical performance measures as predictors or mortality in a cohort of community-dwelling older French women. Eur.J.Epidemiol.21(2):113-122.
Rolland Y., Lawers-Cance V., Cristini C., Grandjean H., Banks W., Morley JE., and Vellas B. (2007). Disability in obese elderly women: Lower limb strength and recreational physical activity. Obesity Research & clinical Practice. 1:39-51.
Rose J., and Gable JG. (2006). Human walking. Williams & Wilkins, Baltimore.
Rubenstein L.Z., Josephson K.R., and Osterweil L.D. (1996). Falls and fall prevention in the nursing home. Clin Geriatr Med. 12: 881-902.
Sale, D.G. (1991). Neural adaptation to strength training. In: Strength and Power in sport. P.V. Komi, ed. Boston, MA:Blackwell Scinetific. pp 249-265.
Sale, D.G., D.E. Moroz, R.S. McKelvie, J.D. MacDougall, and N. McCartney.(1994) Effect of training on blood pressure response to weight lifting. Can. J.Appl.Physiol. 19:60-74.
Schmidtbleicher, D. (1991). Training and power of events. In: Strength and Power in Sport. P.V. Komi, ed. Boston, MA: Blackwell Scientific, pp 381-396.
Schultz, A.B. (1992). Mobility impairment in the elderly: Challenges for biomechanics research. J. Biomech. 4:3-12.
Seidler R.D., and Martin P.E. (1997). The effects of short term balance training on the postural control of older adults. Gait and Posture, 6:224-236.
Simpson K., Killian K., McCartney N., Stubbing DG., and Jones NL.(1992). Randomized control trial of weightlifting exercise in patients with chronic airflow limitation. Thorax. 47:70-75.
Sipila, S., and H.Suominen (1995). Effects of strength and endurance training on thigh and leg muscle mass and composition in elderly women. J. Appl.Physiol. 78:334-340.
Skelton DA., Kennedy J., and Rutherford OM. (2002). Explosive power and asymmetry in leg muscle function in frequent fallers and non fallers aged over 65. Age Aging. 31:119-25.
Skelton DA., Young A., Greig CA. et al. (1995). Effects of resistance training on strength, power and selected functional abilities of women aged 75 and older. J. Am. Geriatr Soc. 43(10):1081-1087.
Smith, E.L. (1989). Exercise in the elderly to prolong and improve the quality of life. In future Directions in Exercise and Sport Science Research. J.S. Skinner, C.B. Corbin., D.M. Landers, P.E. Martin and C.L. Wells, eds. Champaign IL: Human Kinetics, pp 259-266.
Snow-Harter, C., M. Bouxsein, B. Lewis, S. Charette, P. Weistein and R. Marcus. (1990). Muscle strength as a predictor of bone mineral density in young women. J. Bone Miner. Res. 5(6):589-595.
Spruit MA., Gosselin R., Troosters T., De Paepe K., and Decramer M.(2002). Resistance versus endurance trining in patients with COPD and peripheral muscle weakness. Eur Respir J. 19:1072-8.
Stalenhoef PA., Diederiks JP., and Knottnerus JA. (2000). The construction of a patient record based risk model for recurrent falls among elderly people living in the community. Fam Pract. 17:490-6.
Stel VS., Smit JH., and Pluijim JM. (2003). Balance and mobility performance as a treatable risk factors for recurrent falling in the older persons. J. Clin Epidemiol. 51:1356-60.
Stel VS., Smit JH., and Pluijim SMF. (2004). Consequences of falling in older men and women and risk factors for health service use and functional decline. Age Aging. 33:58-65.
Stevens J.A., Corso P.S., Finkeltein E.A., and Miller T.R. (2006). The final costs of fatal and nonfatal falls among older adults. Inj Prev. 12:290-5.
Sylvester, L.F., C. Stiggins, C. McGown, and G.R. Bryan. (1981). The effect of variable resistance and free-weight training programs on strength and vertical jump. Natl. Strength Cond. Assoc. J. 3(6):30-33.
Tas U., Verhagen AP., Bierna-Zeinstra S.MA., Hofman A., Odding E., Pols H.AP., and Koes B.W. (2007). Incidence of risk factors of disability in the elderly: The Rotterdam study. Preventive Medicine. 44: 272-278.
Tinetti M.E. (2003). Clinical practice. Preventing falls in elderly persons. N Engl J Med. 348:42-9.
Tinetti ME. (1987). Factors associated with serious injury during falls by ambulatory nursing home residents. J. Am. Geriatr Soc. 35: 644-8.
Tinetti ME., Speechley M., and Gintner SF.(1988). Risk factors from falls among elderly persons living in the community. New Engl J. Med. 319:1701-7.
Tinetti ME., Willimas TF., and Mayewski R. (1986). Fall risk index for elderly patients based on number of chronic disabilities. Am. J. Med. 80:429-34.
Trappe S., Wlliamson D., and Godard M. (2002). Maintenance of whole muscle strength and size following resistance training in older men. J. Gerontol. 75A(4):B138-B143.
Trash, K., and B. Kelly. (1987). Flexibility and strength training. J.Appl. Sports Sci.Res. 4:74-75.
Treuth, M.S., A.S. Ryan, R.E. Pratley, M.A. Rubin, J.P. Miller, B.J. Nicklas, J.Sorikin, S.M. Harman, A.P. Goldberg and B.F.Hurley (1994). Effects of strength training on total and regional body composition in older men. J.Appl. Physiol. 77:614-620.
Tromp AM., Smit JH., Deeg DJ., et al. (1998). Predictors for falls and fractures in the longitudinal aging study. J Bone Mineral Res. 13:1932-9.
U.S. Department of health and human services.(1996). Physical activity and health: A report of the Surgeon General. Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion.
Vandervoort, A.A., B.M. Chesworth, D.A. Cunningam, D.H. Paterson, P.A. Rechnitzer and J.J. Kovall. (1992). Age and sex effects on mobility of the human ankle. J.Gerontol. 47:M17-21.
Vandervoot, A.A., and McComas A.J. (1986). Contractile changes in opposing muscles of the human ankle joint with aging. J. Appl. Physiol. 61:361-367.
Vetter N., and Ford D. (1989) Anxiety and depression scores in elderly fallers. Int J Geriatr Psych. 4:168-73.
Viitasalo, J.T., P. Era, A.L. Leskinen, and E. Heikkinen. (1985). Muscular strength profiles and anthropometry in random samples of men aged 31-35, 51-55 and 71-75 years. Ergonomics. 28(11):1563-1574.
Vincent, K.R., Braith R.W., and Vincent H.R (2006). Influence of resistance exercise on lumbar strength in older, overweight adults. Arch Phys Med Rehabil. 87:383-389.
Wathen, D. (1987). Flexibility: place in warm up activities. Natl. Strength Cond. Assoc. J. 2:47-48.
Whalen, R.T., D.R. Carter and C.R. Steele. (1988). Influence of physical activity on the regulation of bone density. J. Biomech. 21:825-837.
Whipple RH., Wolfson LI., and Amerman PM. (1987). The relationship of knee and ankle weakness to falls in nursing home residents; an isokinetic study. J.Am. Geriat. 35(1):13-20.
Wilson, G.J (1995). The effect of age and gender on the development of muscular function. Strength Cond. Coach 3(1):3-5.
Wolff, I., J.J. Van Croonenborg, H.C. Kemper, P.J. Kontense and J.W. Twisk. (1999). The effect of exercise training program of bone mass: A meta-analysis of published controlled trials in pre- and postmenopausal women. Osteoporos. Int. 9(1):1-12.
Wolinsky F.D., Fitzgerald J.F and Stump T.E. (1997). The effect of hip fracture on mortality, hospitalization, and functional status: a prospective study. Am J Public Health. 87:398-403.
Work, J.A. (1989). A bridge to independence for the elderly. Phys. Sportsmed.
Young, A. & Skelton D.A. (1994). Applied physiology of strength and power on old age. Int. J. Sports Med., Apr 15(3):149-151.