Single-Leg Hop Test Performance and Isokinetic Knee Strength After Anterior Cruciate Ligament Reconstruction in Athletes

Abstract

Background:Isokinetic strength and hop tests are commonly used to assess athletes’ readiness to return to sport after knee surgery.Purpose/Hypothesis:The purpose of this study was to investigate the results of single-leg hop and isokinetic knee strength testing in athletes who underwent anterior cruciate ligament reconstruction (ACLR) upon returning to sport participation as well as to study the correlation between these 2 test batteries. The secondary purpose was to compare the test results by graft type (patellar tendon or hamstring). It was hypothesized that there would be no statistically significant limb difference in either isokinetic knee strength or single-leg hop tests, that there would be a moderate to strong correlation between the 2 test batteries, and that there would be no significant difference between graft types.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Twenty-nine high school and collegiate athletes who underwent ACLR participated in this study. At the time of return to full sport participation, a series of hop tests and knee extension/flexion isokinetic strength measurements were conducted. The results were analyzed using analysis of variance and Pearson correlation (r).Results:The timed 6-m hop test was the only hop test that showed a significant difference between the involved and uninvolved limbs (2.3 and 2.2 seconds, respectively; P = .02). A significant difference between limbs in knee strength was found for flexion peak torque/body weight at 180 deg/s (P = .03), flexion total work/body weight at 180 deg/s (P = .04), and flexion peak torque/body weight at 300 deg/s (P = .03). The strongest correlation between the hop tests and knee strength was found between the total distance of the hop tests and flexion total work/body weight at 300 deg/s (r = 0.69) and between the timed 6-m hop test and flexion peak torque/body weight at 300 deg/s (r = –0.54). There was no statistically significant difference in hop test performance or isokinetic knee strength between graft types.Conclusion:The single-leg hop tests and isokinetic strength measurements were both useful for a bilateral comparison of knee functional performance and strength. Knee flexion strength deficits and flexion-to-extension ratios seemed to be correlated with single-leg hop test performance. There was no difference in postoperative hop test performance or knee strength according to graft type.

Off-Season Training Habits and BMI, Not Preseason Jump Measures, Are Associated with Time-Loss Injury in Female Collegiate Soccer Players

“…Sports medicine professionals and coaches often administer functional performance tests (FPTs) during the off-season or preseason to identify athletes who may be at risk for injury [4,5]. An FPT is an assessment tool designed to serve as a clinical correlate for a laboratory test (e.g., single-leg hop tests may be used to evaluate progress during rehabilitation if isokinetic testing is unavailable) [6,7].…”

Impaired neuromuscular control up to postoperative 1 year in operated and nonoperated knees after anterior cruciate ligament reconstruction

“…[12,14,15] However, there is still no universal test to objectively assess neuromuscular control after ACLR. [16] Recently, the isokinetic test has been widely used to evaluate neuromuscular function in ACL injuries. In the isokinetic test, the peak torque has been considered as a gold standard.…”

The 6-m timed hop test is a prognostic factor for outcomes in patients with meniscal tears treated with exercise therapy or arthroscopic partial meniscectomy: a secondary, exploratory analysis of the Odense–Oslo meniscectomy versus exercise (OMEX) trial

“…Patients treated with APM had almost four times higher possibility for scoring better or much better in GRC Pain than patients treated with ET (65% versus 17%), and smaller differences in hop test results at baseline were associated with clinical relevant KOOS results [20] [36]. Our cohort used more time (2.84 s) and had a larger coefficient of variation compared to these populations (54% vs. 9-12%) [29,36]. In our study, those who had the highest This study has some limitations.…”