The mechanical efficiency of locomotion in men and women with special emphasis on stretch-shortening cycle exercises

Summary The mechanical efficiency of the leg extensor musculature of men and women was examined with a special sledge ergometer. The subjects (ten males and ten females) performed (a) pure positive work, (b) pure negative work and (c) a combination of negative and positive work (strech-shortening cycle). The mechanical efficiency of pure positive work was on average 19.8±1.2% for female subjects and 17.4±1.2% for male subjects (t=4.12, P<0.001), although the work intensity was equal in both groups. The mechanical efficiency of pure negative work was slightly lower in women than in men (59.3±14.4% vs 75.6±29.3%). The mechanical efficiency of positive work (₊) in a stretch-shortening cycle exercise was 38.1±6.8% in men and 35.5±6.9% in women. The utilization of prestretch was better for female subjects at low prestretch levels, whereas males showed greater potentiation of elastic energy at higher prestretch levels. Regarding absolute W_el (work due to elasticity) values, male subjects showed greater (P<0.001) values than females (189±44 J vs 115±36 J, respectively). Fundamental differences in neuromuscular functions in men and women might cause the differences in the results obtained.