Introduction
            
             With the onset of 2000, the average North American's life span has been extended by three years. The predictable consequences are detrimental changes in body composition, including loss of lean body mass, strength, flexibility, and bone density, along with the increase in body weight and body fat. Inactivity with aging is the primary factor in these changes, because physical activity levels are one of the most important factors affecting body composition from childhood through old age. (Adams, K., O'Shea, P., & O'Shea, K. 1999)
             Our knowledge of the affects of aging on fatigability, endurance, the ability to maintain force and power output is limited, and the few studies that have been performed are inconclusive. It is therefore important to assess these areas to give a more detailed account of muscle fatigue, endurance, and contractibility of aging humans. The results of the studies could prove beneficial in helping to prepare older humans to overcome and enhance his or her ability to live an independent lifestyle.
             With advancing age, muscle volume is reduced, and the aging atrophy, referred to as "sarcopenia" is accompanied by a decrease in muscle strength. The reduction in muscle strength seems to be equal for both sexes, but women are generally weaker than men throughout all ages. (Lindstrom, B., Lexell, J., Gerdle, B., & Downham, D. 1997)
             Since gait pattern also changes with age, especially in women, older individuals have an increased risk of falls and hip fractures. However, both arm and leg muscles in aging men and women can adapt successfully to increased use, in particular following periods of heavy resistance training. Physical exercise is therefore, considered beneficial in reducing the risk of muscle atrophy among older humans. (Linstrom, et al., 1997)
             It has been suggested that once strength declines below certain threshold levels required for activities of daily living, ...