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Article Title

RELATIONSHIP BETWEEN FUNCTIONAL HOP PERFORMANCE AND QUADRICEPS RATE OF TORQUE DEVELOPMENT IN ACL RECONSTRUCTED FEMALES

Abstract

C.M.S. Mulligan1, Y.L. Huang2, S.T. Johnson1, M.F. Norcross1

1Oregon State University, Corvallis, Oregon; 2University of Wisconsin-Eau Claire, Eau Claire, WI

Greater quadriceps rate of torque development (RTD) is associated with sagittal-plane landing strategies that are consistent with lesser ACL injury risk. While it is recommended to include quadriceps RTD in return to play testing, the necessary equipment is inaccessible to many clinicians. Therefore, quantifying absolute performance (AP) in a single-leg triple hop (SLTH) that requires the quadriceps to both control landing and to propel the body forward could provide an accessible measure for quadriceps RTD. PURPOSE: To determine the relationship between SLTH AP and quadriceps RTD from 0-100ms and 0-200ms. METHODS: Nineteen physically active females who have undergone ACLR (Age: 19.2 ± 1.8 years, Height: 164.1 ± 7.0 cm, Mass: 63.8 ± 7.6 kg) were included. RTD was calculated from isometric torque-time curves averaged over three trials of the ACLR limb by fitting a line of best fit through 100ms and 200ms after onset and normalized to body mass. AP for the SLTH was quantified by taking the average distance traveled across three trials and normalized to body height. Relationships between AP and RTD were assessed via Pearson correlation coefficients (α ≤ 0.05). RESULTS: Means and standard deviations for AP and RTD are included in Table 1. No significant relationships were identified between AP and RTD (Table 1). CONCLUSION: While a requisite level of quadriceps strength is needed to perform a SLTH, these results suggest that AP is not indicative of improvements in quadriceps RTD. Because RTD is influenced by the intent to move fast, the lack of relationship could be explained by the nature of the task. A SLTH is measured by distance traveled with no instruction on the intent to move fast. Additionally, compensatory propulsion strategies through the hip or ankle can also influence AP. Therefore, future research should assess multi-joint propulsion strategies and whether functional hop tasks that are measured by time-to-completion and that instruct the individual to move quickly (i.e. 6-m hop for time) are associated with RTD.

Supported by the NATA Research and Education Foundation Doctoral Grant.

Table 1.docx (12 kB)
Table 1

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