When riding a bicycle, which of the following muscular contraction(s) can be used to speed the bicycle up?
at the ankle:
-concentric plantar flexion during push down
-concentric dorsiflexion during pull up
at the knee:
-concentric knee extension during push down
-concentric knee flexion during pull up
at the hip:
-concentric hip extension during push down
-concentric hip flexion during pull up