In the last symposium we reported that pull-up action enhanced (increased) the index of force effectiveness (IFE), which is defined as the ratio between the total force (FT) and the effective force (FE), when comparing to the conditions under push and preferred cycling during short-term bicycle exercise. However no significant difference could be observed in EMGs obtained from four leg muscles among three pedaling techniques. In the present study we, therefore, attempt to differentiate the EMG activities in eight leg and hip muscles during short-term cycling, and to elucidate the effect of long-term exercise on the change of IFE, oxygen uptake (VO_2) and EMG by using a newly developed cycle ergometer system in our laboratory. Four college cyclists performed 3 short-term exercise bouts for 3 min (Exp.l) and 3 long-term exercise bouts for 15 min (Exp.2) under three pedaling techniques; pull-up, push and preferred. In the Exp.l, it was reconfirmed that that IFE was the highest under pull-up pedaling and the lowest under push pedaling, although insignificant differences were observed in muscular activities. Furthermore, in the Exp.2 it seemed that IFE gradually decreased when VO_2 increased systematically from 5 to 15 min from the onset of exercise, whereas IFE remained a steady state when VO_2 kept constant. These results indicate that, in the nonsteady state exercise in VO_2, FT increased and thereby IFE decreased gradually, and thus the mechanical efficiency would be decreased.