When exploring knee flexion during dynamic back extensions, Park and Yoo (2014) also found that increased
knee flexion led to increased gluteus maximus EMG amplitude.
They found that hip extension performed in
knee flexion led to greater gluteus maximus EMG amplitude than hip extension performing in knee extension (23 % vs. 13 % of MVIC).
Similarly, since previous studies have found that
knee flexion leads to increased gluteus maximus EMG amplitude through active insufficiency of the hamstrings, placing the knee into flexion during back extensions might also be expected to increase gluteus maximus EMG amplitude during back extensions.
Not exact matches
Increasing load and wearing running shoes rather than no footwear appear to
lead to more acute peak
knee flexion angles.
However, increases in muscle fascicle length are also likely dependent on the mechanical load incurred by the prime mover, as
knee flexion (hamstring only) exercise seems to
lead to greater adaptations in the hamstrings than hip extension (hamstring, gluteus maximus, and adductor magnus) exercise, even when muscle length at peak contraction is shorter (Bourne et al. 2016).
By doing that toe lift, I'm starting to increase the
flexion in the hips with the raising up of the foot and it
leads to good mechanics where the foot is coming up and
knees going forward.
Where exercises display peak hamstrings EMG amplitude at different degrees of
knee flexion, this may imply that they could
lead to increases in strength and hypertrophy in different parts of the hamstring muscles.
Exploring multiple sets of the Nordic hamstring curl exercise, Marshall et al. (2015) noted that a single set of 5 repetitions
led to substantial reductions in peak eccentric
knee flexion moments during the exercise, with even further reductions in subsequent sets, implying that performing the Nordic hamstring curl prior to practice or other exercise might not be advisable.
It is thought that lower hip abduction strength
leads to a reduced ability to control the hip abduction and internal rotation movements of the thigh during
knee flexion.
Knee flexion force production seems to be greater in prone than in supine (Barr & Duncan, 1988; Worrell et al. 1990), while standing may
lead to greater force than prone (Kramer et al. 1996).