Wall Ball · Torso-Tibia Alignment

Why this matters

In a well-organized squat, the torso and the shin stay parallel. This is the geometric signature of a quad-driven squat — the strongest, most fatigue-resistant muscle available carries the load. When the torso tips forward of the shins, the lift migrates onto the lower-back erectors: a "good-morning" squat that fatigues fast and, under 100 reps of wall ball, becomes a low-back injury pattern.

Measuring the deviation between the two lines is the cleanest way to catch this drift.

What good looks like

• Torso and shin forming roughly parallel lines at the bottom.
• Chest up, hips sitting between the knees.
• The squat looks like a front squat, not a deadlift.

Common faults

Good-Morning (> 25°)

The torso is well ahead of the shins. The load has shifted onto the posterior chain and lower back. Each rep adds erector fatigue, and recovery between reps slows.

Causes: limited ankle mobility (shins can't travel forward), weak quads, or a habitual hip-dominant squat pattern.

Effect: high lumbar load, slower turnaround, injury risk over volume.

Forward Bias (12–25°)

The torso is starting to tip ahead of the shins. Sustainable for a while but trending toward the good-morning fault under fatigue.

Coaching cues

• "Chest up, sit between the knees" — keeps the torso tracking the shin.
• "Knees forward over the toes" — uses ankle range so the shin angle matches the torso.
• Goblet squats / front-squat tempo work — re-pattern an upright torso off the track.

How to draw

1. Pause on the same lowest-point frame as the Depth Standard.
2. Torso line: acromion → greater trochanter (drawn downward).
3. Shin line: lateral femoral condyle → lateral malleolus (drawn downward).
4. Draw both in the same direction so the reading is the deviation from parallel (≈ 0° = parallel = good).

Related measurements

• Squat Depth Standard — same frame; this checks how the depth was reached.
• Trunk Angle at Catch — an upright catch makes a parallel-aligned bottom far easier.