Knees bend to achieve the pike
Hamstring tightness prevents the straight-leg pike; reduce the range.
Overactive muscles
HamstringsGastrocnemius
Corrective work
Foam RollHamstrings↗StretchHamstring stretch with strap↗Hamstring tightness prevents the straight-leg pike; reduce the range.
Core and hip flexor strength insufficient for the full pike.