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Effect of age on peak force and EMG signal parameters during maximal voluntary concentric and eccentric contractions
Effect of o n e - h a n d e d e x e r c i s e on the s t r e n g t h of the c o n t r a l a t e r a l hand M. Kasbparast* IslamicAzad UniversityKaraj-lran In the present research, it is tried to impress on remedy aspect of exercise in such a way that if one of the part of body like hand or foot was injured and the patient has to keep it immovable for a long time, he can prevent the weakness of injured organ of strengthen it by remedy exercise. The way of work in this research was in such away that first of all the range of power of triceps muscle in both tested hands is measured by Electronic dynamometer instrument. Then with a program and by the McQueen method, they just worked on the stronger hand during 1 5 session and then after the second measuring. The range of improvement on both hand are observed and it was proved that the power range increases (20 percent) on the hand which hadn't has any exercise. So if any person has broken organ or dislocation or any fact which limits movement in the upper and lower extremity and based on the results of the research and doing the proper program in spite of any immovement in the injured organ and appearing atrophy, they can not only prevent any atrophy of the injured organ, bul also can strengthen the other organ too.
E f f e c t of a g e on p e a k f o r c e and E M G signal p a r a m e t e r s during m a x i m a l v o l u n t a r y c o n c e n t r i c and e c c e n t r i c c o n t r a c t i o n s J. Cannon,K.Tarpenning*,F. Marino& D. Kay HumanMovementStudiesUnit,CharlesSturtUnivertsity,BathurstNSW,Australia The purpose of the present investigation was to compare integrated electromyography (iEMG) and the mean power frequency (MF) of maximal voluntary concentric and eccentric contractions between young and middle-aged men. Nine young men (YM; 20.3 +1.4 years) and seven middle-aged men (MM; 54.9 + 3.3 years) performed maximal voluntary concentric and eccentric contractions of the quadriceps on an isokinetic dynamometer at 60o/s with surface electromyography sampled from the rectus femoris. Peak eccentric force (YM; 684 + 204 N, MM; 566 + 87 N) was significantly greater than peak concentric force (YM; 566 + 87 N, MM; 351 + 59 N) in both age groups. No difference was observed in iEMG or MF between contraction types in YM or MM. Peak concentric force was significantly greater for YM than MM, however no difference was observed between age groups under eccentric conditions, iEMG was significantly higher for YM than MM during both the concentric and eccentric contractions. However, the MF for the concentric and eccentric contractions remained similar between age groups. These results suggest that maintenance of peak eccentric force with age is primarily related to changes in muscle structure and/or the mechanics of contraction, rather than increased muscle activation or the selective recruitment of Type II fibres.
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E f f e c t of a g e on p e a k f o r c e and E M G signal p a r a m e t e r s during m a x i m a l v o l u n t a r y c o n c e n t r i c and e c c e n t r i c c o n t r a c t i o n s J. Cannon,K.Tarpenning*,F. Marino& D. Kay HumanMovementStudiesUnit,CharlesSturtUnivertsity,BathurstNSW,Australia The purpose of the present investigation was to compare integrated electromyography (iEMG) and the mean power frequency (MF) of maximal voluntary concentric and eccentric contractions between young and middle-aged men. Nine young men (YM; 20.3 +1.4 years) and seven middle-aged men (MM; 54.9 + 3.3 years) performed maximal voluntary concentric and eccentric contractions of the quadriceps on an isokinetic dynamometer at 60o/s with surface electromyography sampled from the rectus femoris. Peak eccentric force (YM; 684 + 204 N, MM; 566 + 87 N) was significantly greater than peak concentric force (YM; 566 + 87 N, MM; 351 + 59 N) in both age groups. No difference was observed in iEMG or MF between contraction types in YM or MM. Peak concentric force was significantly greater for YM than MM, however no difference was observed between age groups under eccentric conditions, iEMG was significantly higher for YM than MM during both the concentric and eccentric contractions. However, the MF for the concentric and eccentric contractions remained similar between age groups. These results suggest that maintenance of peak eccentric force with age is primarily related to changes in muscle structure and/or the mechanics of contraction, rather than increased muscle activation or the selective recruitment of Type II fibres.
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