Upright torso — no forward lean
Can't generate horizontal force; pushing against gravity instead of sled.
Overactive muscles
Erector spinaeHip flexors
Corrective work
Foam RollHip flexors↗StretchHalf-kneeling hip flexor stretch↗Can't generate horizontal force; pushing against gravity instead of sled.
Knees cave inward during each push-off step.
Cervical spine flexes under the effort — suboccipitals and SCM strain.