SkiErg · Global Extension at Catch

Why this matters

SkiErg is a closed-chain, gravity-fed power tool. The energy that drives the flywheel comes almost entirely from the downward drop of the body's weight — and the higher the body starts, the more potential energy is available. Stroke length and stroke power are essentially the same variable on a SkiErg.

Global extension is the geometric measure of "how much of your body did you actually use to set up the stroke." A 180° line from ankle to hip to shoulder means the whole posterior chain is stacked and ready to fall. Anything less is starting the stroke partway down — wasting potential energy before the flywheel has even seen force.

What good looks like

• Ankle, hip, and shoulder visually stack into one straight line.
• Elite athletes will rise onto the toes (slight plantarflexion) to gain another inch or two of height. This isn't required, but it isn't a fault either.
• Knees can have a soft bend (5°–10°) — full lockout isn't necessary, just close-to-straight.

Common faults

Short Stroke (interior angle < 160°)

Hips remain slightly flexed. The athlete is starting the drive from a half-folded position. Every stroke is mechanically shorter than it could be.

Causes: poor hip-extension mobility, fatigue, or an unconscious habit of "saving energy" by not going all the way up.

Effect: more strokes needed to cover the same distance / cardio cost goes up.

Adequate Reach (160°–170°)

Workable, but leaves length on the table. Often appears after the first 200 m as fatigue starts and the athlete stops reaching fully.

Coaching cues

• "Reach for the ceiling" — straightforward visual cue to extend through the whole body.
• "Stack ankle–hip–shoulder" — the geometric cue that names the actual measurement.
• "Tall through the chest" — bias toward thoracic extension (helps reach height without rolling shoulders back into overreach).

How to draw

1. Pause on the highest-handle frame, just before the downward motion begins. Avoid the rebound — pick the rising frame so you capture peak position.
2. First line: lateral malleolus → greater trochanter.
3. Second line: greater trochanter → acromion.
4. The interior angle at the hip is the reading.

Related measurements

• Shoulder Flexion at Catch — same frame; complements the global-extension check by isolating the upper-arm reach.
• Hip Flexion at Finish — the opposite-extreme angle in the same plane. Together they describe the total range the body travels through per stroke.