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The aim of this study is to examine the age-related changes in human neuromuscular functions in respect to gender and physical activity. Women and men aged 20-79 years are volunteers in the present study. The body of subjects is distributed in 6 age groups: (1) 20-29-year-olds; (2) 30-39-year-olds; (3) 40-49-year-olds; (4) 50-59-year-olds; (5) 60-69-year-olds and (6) 70-79-year-olds. Each age group is divided to 2 sub-groups according to physical activity: (1) women and men performing regular recreational physical activities; (2) sedentary women and men. Isometric dynamometry is used to measure maximal voluntary contraction (MVC) force of the hand, back and plantarflexor muscles, and MVC force and rate of force development of the knee extensor muscles. Cybex II isokinetic dynamometer is used for measuring the peak torque and power output of the knee extensor muscles at different angular velocities, and for measuring the muscular endurance during 30 maximal knee extensions. Two force platforms are used for measuring the static balance during normal standing. Electrical stimulation is used for measuring the twitch contractile properties of the plantarflexor muscles. Vertical jumping tests are performed on force platform. Habitual physical activity over the years and health status are assessed by specialized questionnaires. The planned study provides additional scientific information about age-related changes in several indicators of motor function: muscle strength and endurance, neuromuscular coordination, sensorimotor reaction and static standing balance. This study examines the age-related decline of functional capacity in both sides of motor system - motor centres and peripheral neuromuscular apparatus. The study is specially designed to measure age-related changes in electrically evoked twitch contractile properties of human skeletal muscles. The recorded changes can be used for direct measuring of force-generating capacity, speed of contraction and relaxation of the muscle fibers. One purpose of this study is to examine the gender differences in age-related decline in neuromuscular performance characteristics. The present study also designed to investigate the effect of regular recreational physical activity to age-related changes in different neuromuscular functions in middle-aged and elderly people. The results of this study can be used by gerontologists and geriatrists, social workers, health related fitness instructors and can applied for improving the effectiveness of recreational physical activity programs for eldery people. |