Using the Modified Wingate Test to Assess Unilateral Lower Limb Muscle Power in a Healthy and Knee Injury Population: An Exploratory Pilot Study
Vazhapandal Nandakumar, Avinash
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Objective The primary objective of this study was to explore the use of the modified unilateral Wingate anaerobic cycle test to assess unilateral lower limb power in a healthy population; and to determine if any significant relationship exists with a 30-repetition isokinetic measure of knee extensor power and functional hop and jump tests. A secondary objective was to examine the power profiles of two participants with anterior cruciate ligament (ACL) reconstruction using the unilateral Wingate test. Study design An exploratory cross-sectional pilot study, involving assessment of power variables (peak power, mean power, and fatigue index) across limbs during a unilateral version of the Wingate test was undertaken by 11 healthy participants with no previous history of knee ligament injury. Comparison of Wingate power measures were made with knee extensor power produced during a 30-repetition isokinetic knee extension test. Two ACL reconstruction participants were also assessed for descriptive comparison. Background Many team sports and recreational activities require significant muscle power. Lack of adequate muscle power might impact a players’ performance. Additionally, deficits in unilateral lower limb power may contribute to injury. To improve player performance, a tool to evaluate unilateral lower limb power in a rehabilitation context is required to construct power-focused exercise programmes. The Wingate anaerobic cycle test has been used previously to assess bilateral lower limb muscle power. However, to date, no study has used the Wingate test to assess unilateral lower limb power in recreational young adults and knee injured participants. Method Ten men and one women (mean age of 26 years) with no previous history of knee injury, and one man and one woman two years following ACL reconstruction took part in the study. A Watt bike was used for the unilateral Wingate test to assess peak power, mean power, and fatigue index. A Biodex isokinetic dynamometry was used to assess isokinetic peak and average power of knee extensors over 30 repetitions. Functional performance tests, including the single-leg hop, triple hop for distance, and vertical jump test were also undertaken to evaluate distance reached, and power was calculated from peak height during the single leg vertical jump. Self-reported outcomes were assessed using the Lower Limb Task Questionnaire (LLTQ) and Knee and Osteoarthritis Outcome Score (KOOS). All testing procedures were performed in one session that lasted for 60 minutes (approximately). Statistical analyses was performed using SPSS software. Descriptive statistics were calculated for all measures and for comparisons of the two ACL case studies with healthy subject data. Paired t-tests were used for inter-limb comparison in healthy participants and Pearson correlation coefficients were used to identify significant relationships between functional, isokinetic and Wingate test results. The alpha value was set at <0.05. Results No significant difference in muscle power and fatigue index was identified between dominant and non-dominant leg in the healthy participants for the modified Wingate test, isokinetic assessment, and functional performance testing. One ACL reconstruction participant had deficits in lower limb muscle power in the injured side compared with the non-injured side across all tests; whereas no deficits were identified in the other participant across limbs for all tests. There was a significant moderate correlation between the peak power in the Wingate test and peak power in the isokinetic testing (r=0.57; P<0.05). Further, there was a strong correlation between the peak power in the Wingate test and power calculated from the vertical jump test (left r=0.84; right r=0.86). However, there were low to moderate correlations between the Wingate test and the single leg hop test (left r=0.2; right r=0.5) and the Wingate test and the triple hop for distance (left r=0.42; right r=0.54; P<0.5). A moderate to poor correlation was identified between the fatigue index of the Wingate test and the isokinetic test (left r=0.438; right r=0.25). Conclusion The unilateral Wingate test was able to detect key measures of unilateral lower limb power (peak and average power, and fatigue index) that were typically assessed during the bilateral version of the test with no significant interlimb differences in these measures in uninjured healthy participants. Power profiles during the unilateral Wingate test were similar to that produced during repeated isokinetic knee extension test, further indicating that this test assesses power and targets the anaerobic energy system. The low to moderate correlations between power measures in the unilateral Wingate and traditional hop tests may indicate that these tests measure different constructs of power and place dynamic balance, and neuromuscular co-ordination demands that differ to Wingate test; whereas the high correlation with vertical jump power indicates that both tests measure a similar construct of muscle power and anaerobic capacity. Findings from the two ACL reconstruction case studies indicate the potential of the unilateral Wingate test to detect unilateral lower limb power deficits following ACL reconstruction. However, this remains speculative and a larger study with increased statistical power is required to substantiate these case study findings.