Comparison of static muscle coordination in two different movements models.

Coordination of the thigh muscles was studied in static knee and leg extension (kicking and jumping). In both movements the five male subjects performed maximal and submaximal efforts through the entire range of extension movements. Although the testing positions of both movements were exactly the same, the results differed dramatically from each other. In knee extension the quadriceps group worked forcefully throughout the movement range. In leg extension the quadriceps group was even more activated in flexed positions of the knee angle (n.s.) but toward the end of the movement quadriceps activity was greatly reduced and observed to be at much lower level compared to that in the knee extension movement (p < .001). However, the efficiency of the muscle work in both movements appeared contradictory since the force values at the end of the movement were at least five times greater in the case of leg extension (p < .001). These significant differences suggest that the human movement apparatus is very finely programmed according to the specific purpose of the movement.