Trunk rocks forward and back with each kick
The lateral core cannot resist the leg swinging; hip stability fails.
Overactive muscles
Hip flexorsErector spinae
Corrective work
Foam RollHip flexors↗StretchHalf-kneeling hip flexor stretch↗The lateral core cannot resist the leg swinging; hip stability fails.
QL and lateral trunk assist the kick instead of the hip flexors working alone.