ABSTRACT
CONTEXT: After a lower extremity injury, patients often return to sport (RTS) when the injured limb's performance on unilateral hopping tests is similar to that of the uninjured limb. However, the exact target symmetry value patients must reach before the RTS is unclear. OBJECTIVE: To identify variables that predict limb symmetry index (LSI) values on 6 unilateral hopping tests in healthy, physically active adults. DESIGN: Cross-sectional study. SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: In total, 275 healthy, physically active adults, consisting of recreational athletes (n = 198), National Collegiate Athletic Association Division I student-athletes (n = 56), and Army Reserve Officer Training Corps cadets (n = 21), volunteered to participate (143 men, 132 women, age = 20.16 ± 2.19 years, height = 172.66 ± 10.22 cm, weight = 72.64 ± 14.29 kg). INTERVENTION(S): Each participant completed 3 speed (6-m crossover-hop, side-hop, figure-8 hop) and 3 distance (triple-crossover-hop, lateral-hop, medial-hop) functional performance tests on both limbs. MAIN OUTCOME MEASURE(S): Mean performance of the dominant and nondominant limbs and LSI values. Two multiple regression models were used to find variables that might help to predict a participant's LSI for each functional performance test. RESULTS: The models helped to predict limb symmetry for 10 of the 12 multiple regressions. Unilateral limb performance was the best predictor of LSI values, as it was statistically significant in 11 of the 12 regression models. Sex and body mass index were significant predictor variables for the side hop and figure-8 hop, respectively. CONCLUSIONS: We found significant predictor variables that clinicians can use in the absence of baseline testing to determine patient-specific LSI values. Individualizing RTS decisions in this way may help to minimize subjectivity in the decision-making process and ensure a safe and timely return to competition.
