Noyes et al. tested four one-legged hop tests in 67 chronic ACL-deficient patients to determine how well each detects functional limb asymmetry. A limb symmetry index (LSI) below 85% defined an abnormal result. The study asks: how many tests are needed, and which test performs best?
A normal hop test score does not clear an ACL patient. Half of patients with a confirmed ACL rupture and measurable laxity on KT-1000 will pass a single hop test. That result is not reassuring — it reflects the test's ceiling, not the patient's recovery.
In clinic, always run at least two hop tests. The detection rate rises from ~50% to 62% with a second test, and no single combination is superior, so choose based on availability and patient tolerance.
Pair hop data with isokinetic quadriceps strength testing. The correlation is weak (r = 0.49), but abnormal low-velocity quadriceps deficit (present in 69% of this cohort) provides independent confirmation of deficit that hop tests may miss.
Think of hop tests as confirmation tools, not screening tools. A positive result (LSI <85%) confirms functional asymmetry. A negative result leaves the question open. In a symptomatic patient with a normal hop score, dig deeper. Don't downgrade your concern.
Noyes et al. tested four one-legged hop tests in 67 chronic ACL-deficient patients to determine how well each detects functional limb asymmetry. A limb symmetry index (LSI) below 85% defined an abnormal result. The study asks: how many tests are needed, and which test performs best?
A normal hop test score does not clear an ACL patient. Half of patients with a confirmed ACL rupture and measurable laxity on KT-1000 will pass a single hop test. That result is not reassuring — it reflects the test's ceiling, not the patient's recovery.
In clinic, always run at least two hop tests. The detection rate rises from ~50% to 62% with a second test, and no single combination is superior, so choose based on availability and patient tolerance.
Pair hop data with isokinetic quadriceps strength testing. The correlation is weak (r = 0.49), but abnormal low-velocity quadriceps deficit (present in 69% of this cohort) provides independent confirmation of deficit that hop tests may miss.
Think of hop tests as confirmation tools, not screening tools. A positive result (LSI <85%) confirms functional asymmetry. A negative result leaves the question open. In a symptomatic patient with a normal hop score, dig deeper. Don't downgrade your concern.