Preferred leg and strength asymmetries : A cross sectional study comparing perceived and measured laterality

Sammanfattning: Aim: The aim of this study was to examine the relationship between the degree of self-perceived leg preference and the degree of strength asymmetries in well-trained adults. Method: All tests took place during two separate days at the Swedish School of Sport and Health Sciences. Preferred and non-preferred leg was examined via questionnaires. Concentric and eccentric strength measurements were executed in an isokinetic dynamometer in both right and left leg. Left and right leg peak force when performing CMJ’s, RCMJ-B and RCMJ-B was collected via floor fit force plates. Degree of self-perceived laterality was then compared with the degree of strength asymmetries using Spearman’s rho and strength asymmetries was compared using Pearson’s correlation. Results: Self-perceived laterality and degree of strength asymmetries showed a significant correlation in three of the measured variables: LP-C300 and self-perceived stronger leg (=0.74), CMJ and self-perceived preferred leg for landing (=0.67), RCMJ-B and the self-perceived leg for balancing (=0.65). Strength asymmetries that were significantly correlated: LP-C10 and LP-E300 (=0.78), LP-C10 and RCMJ-B (=0.63), LP-E50 and LP-E100 (=0.91), LP-E50 and LP-E300 (=0.62), LP-E50 and RCMJ-E (=-0.73), LP-E100 and LP-E300 (=0.62), LP-E100 and RCMJ-E (=-0.70). Conclusion: In conclusion, three of the self-perceived laterality results were significantly positively correlated to strength asymmetries; the self-perceived stronger leg and the LP-C300test, the self-perceived preferred leg for landing and the CMJ -test, and the self-perceived preferred leg for balancing and the RCMJ-B-test. Strength asymmetries correlated, showing that there are in fact significant correlations between strength asymmetries in eccentric leg presses in different speeds as well as in slow concentric movements and the first RCMJ-jump.