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J Athl Train. 1993 Spring; 28(1): 55–58.
PMCID: PMC1317892

Comparison of Three Methods of Assessing Muscle Strength and Imbalance Ratios of the Knee

Crayton L. Moss, EdD, ATC
Crayton L. Moss is Director of the Athletic Training Program and Assistant Professor at School of Health, Physical Education, and Recreation, Bowling Green State University, Bowling Green, OH 43403.


Three strength measurement methods for determining muscle strength and imbalance ratios of the knee were compared in 41 (23 female, 18 male) NCAA Division I track and field athletes. Peak quadriceps extensions and hamstring flexions were measured isotonically, isometrically, and isokinetically. Isokinetic measurements were performed on a Cybex II at 60°/s. Isometric extension and flexion measurements were performed using the Nicholas Manual Muscle Tester (Lafayette Instruments; Lafayette, Ind). Isotonic measurements were done on both Universal and Nautilus apparatuses. Testing order was randomized to avoid a treatment order effect. A repeated measures ANOVA and a post hoc Tukey test were used to compare the three methods of assessing strength and imbalance ratios of the knee. Absolute strength values were significantly different according to gender and mode of testing. Bilateral strength imbalance ratios for knee flexion were significantly lower for the Nautilus leg curl machine. Ipsilateral strength imbalance ratios were significantly greater for the Cybex II. Our results indicated that absolute strength values cannot be interchanged between testing modes. Except for Cybex II (ipsilateral) and Nautilus (bilateral knee flexion), strength imbalance ratios could be interchanged.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
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Articles from Journal of Athletic Training are provided here courtesy of National Athletic Trainers Association