Triple Hop Test: protocol and reference values

The Triple Hop Test is one of the great classics of sports rehab, especially after knee injuries (such as ACL reconstruction). It involves chaining three consecutive single-leg hops, measuring the total distance covered, and comparing it between legs.

Its real value lies in what it reveals when there's an asymmetry: if one leg "falls behind" during a repeated explosive effort, that's a clear warning sign before clearing an athlete for return to sport.

What does this test measure?

It assesses the power, neuromuscular control, and force absorption/reproduction capacity of a single leg across repeated jumps, and allows you to calculate a Limb Symmetry Index (LSI), one of the most commonly used metrics in return-to-sport criteria.

Equipment needed

• Flat, non-slip surface
• Measuring tape
• Marked starting line (tape or chalk)

Test protocol

1. The subject stands on one leg behind the starting line, arms free to assist with momentum
2. Tell them to perform three consecutive forward hops on the same leg, without pausing, trying to cover as much distance as possible
3. The landing of the third hop must be controlled and held (at least 2 seconds without losing balance) for the attempt to be valid
4. Measure the total distance from the starting line to the heel contact point on the third landing
5. Repeat with the other leg
6. Perform 2-3 valid attempts per leg and record the best for each side

Common mistakes

• Allowing an unstable third landing or letting the subject support themselves with the other leg (invalid attempt)
• Not alternating the order of legs between attempts (can cause accumulated fatigue in one leg)
• Comparing results only in absolute distance without calculating the limb symmetry index
• Running it too early in the rehab process, before the athlete has the necessary confidence and control

How to interpret the result

The most relevant data point isn't the absolute distance, but the Limb Symmetry Index (LSI):

$$LSI (\%) = \frac{\text{Affected leg distance}}{\text{Healthy leg distance}} \times 100$$

LSI	Interpretation
≥ 90%	Good symmetry — common criterion for progressing toward return to sport
80-90%	Moderate deficit — keep working on power and confidence in the affected leg
< 80%	Significant deficit — not advisable to progress to more demanding phases without specific work

Important: this test is usually combined with others (single leg jump, single leg CMJ), since no single test should be the only criterion for return to sport.

Relationship with other tests

The triple hop is part of typical unilateral batteries in rehab. It pairs well with:

• Single Leg Hop Test — the single-hop version, simpler and quicker
• Single Leg Explosive Strength Test (single leg CMJ) — adds the countermovement component to assess the eccentric phase

Track and monitor

In rehab processes, tracking the limb symmetry index over the weeks is key information for decisions about clearance to return to sport. With Movalytics you can log the distance for each leg separately, let the app calculate the symmetry index automatically, and visualize how it evolves week by week until reaching return-to-sport criteria.

Frequently asked questions

When is it safe to do this test after a knee injury? It's generally not introduced until advanced rehab phases, once the athlete already tolerates simple single-leg hops well and has confidence in the affected limb. It should be assessed by the medical/physiotherapy team. What symmetry index is considered a safe "medical clearance" threshold? The most cited threshold is ≥90%, although there's growing consensus that it should be combined with other criteria (strength, time since surgery, psychological factors) and not used in isolation. Is it useful for athletes without a prior injury? Yes, it's also useful as a unilateral power test for any athlete, to detect asymmetries that might go unnoticed with bilateral tests.