漸増負荷ペダリング運動中における下肢関節モーメントの変化

抄録

  Lower leg muscle’s electromyography (EMG) amplitude increases non-linearly during incremental pedaling exercise, and the breakpoint is called EMG threshold (EMGT). Although it is said that EMGT can estimate lactate threshold (LT), it is not revealed what changes are occurred in kinetic data during this exercise. If the rapid increase in EMG amplitude results from the rise of mechanical force, EMGT can’t substitute LT correctly. So, in this study, we investigated the relation between lower limb joint moments and EMGT of lower leg muscles. Although, the muscle that showed the highest detection rate was gluteus maximus (GM), it is not appropriate to use this muscle’s EMGT for estimation of LT because hip extension moment for which GM mainly works began to increase at EMGT. On the other hand, knee extension moment didn’t increase at the workload over EMGT. So, rectus femoris and vastus lateralis, which show high EMGT detection rate in previous studies, possibly can substitute LT. In addition to that, regarding the change of pedaling technique, it is indicated that the contribution of hip as a power generator and knee as a power transporter were enhanced during incremental exercise.