Skater Jump Lateral Power Test: A Field Protocol for Frontal-Plane Power

A basketball player comes back from a lateral ankle sprain, clears the vertical jump test with a number that looks fine, and three weeks later rolls the same ankle cutting hard to her left. The vertical jump never tested the thing that actually failed her — pushing off sideways under load. Most testing menus are built around jumping up or jumping forward, because those are easy to measure with a jump mat or a tape on the floor. Nobody plants sideways and drives off one leg in a straight vertical jump, but almost every cutting, skating, and defensive-slide sport demands exactly that.

The skater jump — a single-leg lateral bound, landed and stuck on the opposite leg — closes that gap. It's cheap to run, takes about ten minutes per athlete, and surfaces a frontal-plane power deficit or a side-to-side asymmetry that a standing broad jump or a countermovement jump can miss entirely. This guide covers the setup, the step-by-step protocol, how to score both the jump and the landing, and what the limb symmetry number actually means once you have it.

Meylan and colleagues (2009) tested 80 physically active men and women on single-leg vertical, horizontal, and lateral countermovement jumps and found the three jump directions shared less than 50% of their variance with each other. In plain terms, an athlete's vertical jump result tells you almost nothing reliable about how they'll perform on a lateral bound — the two rely on different force-production strategies, not the same underlying power with a different label. The same study found the jumps' ability to predict 10m sprint and change-of-direction time was limited, with R² values under 43%, so a lateral jump score is a movement-quality read on its own merit, not a proxy for game speed.

The reliability side holds up. Donskov, Brooks, and Dickey (2021) ran a single-leg, medial (lateral-pushoff) countermovement jump on a force plate with 10 competitive youth ice hockey players across a 10-day test-retest window and found moderate-to-excellent reliability across 12 force-plate variables (ICC 0.50-0.98), with the lateral concentric power measured in the last 100 milliseconds before takeoff — the part of the push-off closest to what a skate stride or a defensive slide actually demands — landing at the high end, ICC 0.86-0.98. That's a small sample and a force-plate lab setup most programs don't have, but it establishes that the movement pattern itself produces consistent, trainable numbers rather than noise.

You need a flat, non-slip surface at least 3m long, a tape measure fixed to the floor, and chalk or low-profile tape for the takeoff line. A phone camera at 60fps or higher, front-on at hip height about 2.5m back, lets you review the landing in slow motion instead of trusting a live call.

Test in training footwear and warm up with 5 minutes of general movement plus 3-4 submaximal skater jumps per side before scoring — a cold first attempt undershoots distance and overshoots landing sloppiness, skewing both halves of the score.

The test is short per rep, but the protocol depends on consistent trial count and rest to keep the comparison fair between legs and between sessions.

1. Set the takeoff line. Mark it with tape, perpendicular to the direction of the jump.
2. Position the athlete single-leg. Toes at the line, opposite leg lifted off the floor, hands free to swing.
3. Cue the jump. Bend the standing knee into a quarter-squat, then bound laterally as far as possible, landing on the opposite leg only.
4. Stick the landing. The athlete must hold the landing position, single-leg, for a minimum of 2 seconds before the rep counts. A hop, a step-down, or a hand touch to the floor voids the trial.
5. Measure distance. From the takeoff line to the heel of the landing foot at first contact, not where the foot ends up after any wobble.
6. Run 3 trials per leg, alternating sides, with 15-20 seconds rest between reps. Record the best valid trial per leg — a voided landing gets re-run, not scored as zero.
7. Calculate the limb symmetry index (LSI). Weaker-leg distance divided by stronger-leg distance, multiplied by 100.

Distance is only half the score. A jump that travels far but ends in a collapsed landing is telling you the athlete can produce lateral force but can't control it on the way back down — arguably the more important half for injury-prevention purposes.

Score each fault as present or absent across the three trials per leg, the same way a tuck jump or a landing-error scoring system works. A leg that jumps far but racks up three or four faults isn't cleared just because the tape measure looks good.

The limb symmetry index borrows its logic from the broader hop-test literature, most notably the return-to-sport criteria built around single-leg hop testing after ACL reconstruction. Grindem and colleagues (2016) followed 106 athletes returning to pivoting sports and found that those who met a symmetry and strength threshold of at least 90% before returning had a 5.6% reinjury rate over the following two years, versus 38.2% among athletes who returned without meeting it — roughly a sevenfold difference in a single cohort. That data comes from hop-for-distance testing generally, not the skater jump specifically, but it's the reason 90% has become the working line in the field rather than an arbitrary round number.

Treat 90% as a floor to clear, not a target that guarantees anything on its own — the Grindem cohort also required quadriceps strength and functional test scores together, and a single lateral jump number in isolation carries less weight than that combined picture.

Most athletes who score poorly aren't weak everywhere — they're weak or unstable in one specific part of the lateral chain.

• Short distance, clean landing on both legs: a force-production gap. Lateral bounds for distance, band-resisted lateral walks, and single-leg lateral box step-ups build the missing output over 4-6 weeks.
• Good distance, knee valgus or trunk lean on one side: a control gap that shows up under speed even when strength looks fine standing still. Slow the movement down with sustained single-leg lateral holds before adding jump volume back.
• LSI under 80% with a healthy training history: worth a closer look at hip and ankle strength asymmetry, since a gap this large rarely comes from lateral power training alone.

Retest on the same 4-6 week cycle, and keep the same rater and camera angle across sessions — a different vantage point changes what faults are visible, which makes month-to-month comparisons unreliable even when the athlete hasn't actually changed.