PENDULUM SQUAT — FREE BODY DIAGRAM

v6 Force Analysis · ROM Animation · Phase Classification

Movement phase

—

Joint kinematics

Arm angle (from vert.)—

Knee flexion—

Hip flexion—

Ankle dorsiflexion—

Force magnitudes (× BW)

GRF (ground reaction)—

Knee joint compression—

Hip joint compression—

Quad tendon force—

Knee ext. moment (Nm)—

Muscle activation estimate

Vector legend

Ground reaction

Body load

Quad force

Glute force

Moment arm

Joint centre

t = 0.00s

Speed Space play/pause ←→ step

Corrections from v5: Descent is now correctly labelled eccentric (quads lengthening under load); ascent is concentric (quads shortening). Angle is explicitly defined as pendulum arm angle from vertical. All force vectors are computed analytically from the instantaneous geometry each frame — not baked into PNGs. Angle progression follows a sine-eased curve to model natural acceleration and deceleration through the arc.