Sled Pull · Elbow Extension (Step-Back)

Why this matters

In the step-back drag, the arms are supposed to be rigid cables that transmit the bodyweight lean to the rope — nothing more. The moment the elbow starts bending, the athlete is rowing the sled with their arms, which is the cardinal fault of the technique: it cycles the biceps and brachialis under load, and they burn out fast. Every degree of elbow flex is also an energy leak at the joint, force absorbed instead of delivered to the sled.

The key is not just how extended, but that the angle doesn't change across strides. A truly locked arm reads the same frame after frame.

What good looks like

From the side, the arm is a straight line from shoulder to wrist, 170–180°, and it stays there pull after pull. The elbow is a hinge that isn't hinging — all the movement comes from the legs walking back and the body leaning away.

Reading the result

• Rowing (<150°): arms are actively pulling — the cardinal fault. Cue "arms are cables, not pistons"; tape the elbows in training to reinforce the lock.
• Soft (150°–170°): arms aren't fully transmitting; some force is being absorbed in the elbow.
• Locked (170°–180°): on standard — the lean drives the sled, the arms just carry the tension.

Coaching cues

• "Arms are cables, not pistons" — names the fault and the fix in one line.
• "Long arms, lean back" — ties the lock to the lean that's supposed to be doing the work.

How to mark

1. Use a lateral-view clip. Sample any mid-pull stride; the elbow should read the same on every one.
2. Points: acromion (shoulder) → lateral epicondyle (elbow) → ulnar styloid (wrist).
3. The tool reports the interior elbow angle.

Common mistake: picking a frame where the analyst was rowing with the arms — the reading will correctly come back < 170°.

Related measurements

• Global Lean (Step-Back) — the bodyweight lean the locked arms exist to transmit.
• Knee Anchor (Step-Back) — the stance that lets the athlete lean without collapsing.