Hips sag — body not in a rigid plank
Core fails; the chest press becomes a hinge and the load is reduced.
Overactive muscles
Hip flexorsErector spinae
Corrective work
Foam RollHip flexors↗StretchHalf-kneeling hip flexor stretch↗Core fails; the chest press becomes a hinge and the load is reduced.
Anterior shoulder is stressed; pec loses the target line of pull.