Hop test does not correlate with neuromuscular control during drop vertical jump test: A prognostic comparative study utilizing healthy subjects

Abstract

Background: A functional hop test is an established tool used to assess performance prior to return to sport. The effect of demographics, limb strength and flexibility, and neuromuscular control on hop test performance is not fully understood. Our hypothesis is that successful hop testing strongly (r>0.7) correlates with increased strength and neuromuscular control in a healthy athletic population. Methods: In this prospective clinical performance evaluation, 25 asymptomatic, active individuals participated. Flexibility measurements were recorded with a standard goniometer, strength measurements were recorded with a handheld dynamometer, and kinematic data were collected during a drop vertical jump (DVJ) using a 14-camera 3D markerless motion analysis system. Frontal plane knee abduction angle and hip rotation were measured during DVJ. Each participant underwent triple hop, cross hop, and timed 6-m hop tests. Pearson product moment correlation (moderate correlation: r value 0.4–0.7, strong correlation: r>0.7) analysis was used to assess the relationship between performance on hop tests and gender, body mass index, strength and flexibility, and frontal plane knee abduction angle and hip rotation on DVJ. Results: Hip abduction strength, external rotation strength, quadriceps and hamstring strength each had moderate correlations to the triple hop test (r values=0.52, 0.62, 0.46, 0.50, respectively) and the cross-hop test (r values=0.56, 0.65, 0.54, 0.55, respectively). Hop test performance did not strongly correlate with frontal plane projection angle and hip internal rotation. Conclusions: Functional hop tests correlated with strength but had weak to minimal correlation with neuromuscular control. Individuals with neuromuscular deficits may still do well on standard hop tests. Level of Evidence: Level III.