Repeated Jump Anaerobic Endurance Test: Protocol, Fatigue-Slope Scoring, and Norms

A volleyball setter can post a 58cm max jump on test day and still be landing flat-footed by the fourth set, arriving a half-beat late on transition attacks she was first to a month ago. Coaches usually chase this with more max-effort jump training, and the number doesn't move — because peak jump height was never measuring the problem. It captures how high she can go once, fresh. It says nothing about what happens to that height on jump twelve, or eighteen, when the legs are still resetting from the last landing before the next one arrives.

Most repeated-jump testing collapses the whole story into two numbers: best jump and worst jump, subtracted and divided. That throws away everything in between. A player who fades gradually across a set and one who holds steady for fifteen jumps and then falls off a cliff on the last five can post an identical first-to-last decrement, even though a coach would train them completely differently. The protocol below scores the shape of the decline instead — a fatigue slope fit across every jump in the set — so two athletes with the same drop-off number stop looking the same on paper.

Why First-vs-Last Comparisons Hide the Real Fatigue Pattern

Anaerobic endurance in a jumping context isn't one thing. Part of it is how fast phosphocreatine stores refill in the split second between landing and the next takeoff. Part of it is how well the stretch-shortening cycle holds up as ground contact time creeps longer and the calf-and-quad complex stops firing with the same timing. A decrement built from only the first and last rep tells you the total damage but nothing about when it happened — and when it happened is exactly what a coach needs to design around.

Picture two athletes who both drop 20% from jump one to jump twenty. The first loses 1% per jump in a straight line — a genuine, gradual anaerobic-endurance limiter. The second holds within 3% of baseline through jump fifteen and then collapses over the last five reps, which looks more like a technical breakdown or pacing error than a metabolic one. Same headline number, two different problems, two different training responses. Fitting a slope across all twenty points, rather than just the two endpoints, is what separates those athletes on paper the way they're already separated on the court.

Equipment and Setup

The test needs a way to log jump height on every single rep, not just spot-check a few, plus a flat non-compliant surface and a fixed rhythm the athlete can lock onto without staring at a screen mid-set.

A soft mat or springy court surface inflates apparent jump height and can mask the true rate of decline late in the set, so test on the same surface every time and note it on the score sheet — a slope measured on a sprung wood floor isn't comparable to one measured on concrete.

Step-by-Step Testing Protocol

1. Warm-up (8-10 minutes): Five minutes of easy movement, ankle and hip mobility work, then three submaximal countermovement jumps at roughly 70%, 85%, and 95% effort with full recovery between each.
2. Familiarization: Five continuous rebound jumps at a comfortable pace to confirm the athlete can land and reset with minimal ground contact time before the real set starts.
3. Standardize technique: Hands fixed on the hips for the whole set — arm swing changes jump height enough on its own to distort a slope that's supposed to reflect fatigue, not arm-use fatigue.
4. Set the rhythm: Cue each takeoff at a fixed 2-second interval using a metronome or audible countdown, and hold that interval identical across the whole set and every future retest.
5. Maximal set: 20 consecutive maximal countermovement jumps at the fixed 2-second cadence, each one a genuine max effort, not a paced-out submaximal hop.
6. Record every rep: Log jump height for all 20 jumps individually, not just the first and last — the slope calculation needs the full series.
7. Valid trial criteria: Rerun the set if the athlete breaks cadence, loses hand position, or the first three jumps show more than 5% variability from each other, which usually signals an incomplete warm-up rather than a real baseline.

Total time, warm-up included, runs about 15 minutes; the maximal set itself takes roughly 40 seconds, but a rushed familiarization phase is the single fastest way to bury jump one in noise that then drags the whole slope calculation off.

Scoring: Fitting the Fatigue Slope

Instead of subtracting the last jump from the first, run a simple linear regression with jump number (1 through 20) as the independent variable and jump height as the dependent one. The slope of that line — centimeters of height dropped per jump, on average, across the whole set — is the fatigue slope.

Fatigue Slope (cm/jump) is the least-squares regression coefficient of jump height against jump number. A slope of -0.30 means the athlete loses roughly 0.3cm of height with every rep, averaged across all twenty.

Relative Fatigue Slope (%/jump) normalizes that number so athletes of different absolute jump heights can be compared: Relative Slope = (Fatigue Slope / Jump 1 Height) × 100. A tall middle blocker and a much shorter libero can post very different raw slopes while sharing the same relative one.

Worked example: an athlete jumps 45cm on rep one and the regression fits a slope of -0.35cm per jump, predicting roughly 38.4cm by jump twenty. Relative Slope = (-0.35 / 45) × 100 ≈ -0.78% per jump. Report the R² of the fit alongside the slope — above roughly 0.7 the decline is genuinely linear; a low R² means the real pattern is a plateau-then-crash or an erratic bounce that a single slope will flatten and mislead on.

What the Research Shows

Buchheit, Spencer, and Ahmaidi (2010), publishing in the International Journal of Sports Physiology and Performance, examined a combined repeated-sprint-and-jump test in trained team-sport athletes and reported that the jump-decrement component was reliable enough session to session to track meaningfully, while correlating only moderately with the decrement seen in the sprint portion of the same test. Repeated-jump fatigue and repeated-sprint fatigue are related but not interchangeable qualities, so a jump-based protocol like this one is a genuine measurement in its own right, not a stand-in for a track test a team can't run. The limitation worth carrying forward: their sample was young, trained team-sport athletes, so the specific reliability figures don't automatically transfer to recreational or masters populations without their own baseline testing.

Bosco, Luhtanen, and Komi (1983), in the classic European Journal of Applied Physiology paper underlying most modern repeated-jump testing, validated using flight time from consecutive jumps to estimate mechanical power output, and found the calculated values tracked closely with direct measures of lower-limb power output in their athletes — the foundation every jump-mat or IMU-based repeated jump test still leans on today. The limitation the authors themselves noted: the flight-time math assumes a fairly consistent landing and takeoff posture, so as technique degrades under real fatigue — deeper knee flexion, longer ground contact, a jump quietly turning into more of a squat-and-push — the estimated numbers drift further from what a force plate would show directly, which is exactly why standardizing hand position matters as much as the math itself.

Reading the Score: Slope Bands

The bands below are a field reference built from typical repeated-jump decrement patterns reported across the jump-testing literature, not a strict pass-fail line. Weigh a relative slope against the athlete's own testing history before comparing it across athletes.

An athlete with a strong peak jump height but a steep slope has a specific, coachable target: repeated-effort capacity, not raw jump height. More single-jump training tends to nudge the peak number without touching the slope at all.

Mistakes That Skew the Slope

Building a Plan Around a Steep Slope

A steep fatigue slope is a training target, not a verdict on an athlete's jumping ability. Athletes in the moderate or steep bands typically respond well to short blocks of genuinely repeated jumping work — sets of 12-15 maximal jumps at a fixed cadence, once or twice a week alongside normal jump and strength training, not instead of it. Retest every 4-6 weeks; the slope moves more slowly than peak height, and testing sooner mostly captures noise rather than adaptation.

If an athlete tests well on a single max jump but shows a steep slope here, resist filing it under general conditioning. It's tied to how well the stretch-shortening cycle and phosphocreatine system hold up under back-to-back efforts, not overall fitness, and it's one of the few field tests that maps directly onto what a fourth-set, fourth-quarter possession demands from a jumping athlete.