Comparison of Peak Torque and Aerobic Capacity Asymmetries in the Lower Limbs

Abstract

Introduction: Although lower limb muscle strength asymmetries are well documented, the existence of muscle aerobic capacity asymmetries and the potential relationship with muscular strength asymmetries has yet to be determined. The purpose of this investigation was to quantify lower limb dominance and non- dominance for muscular strength and aerobic capacity and determine if asymmetries in muscle strength were related to asymmetries aerobic capacity.
Methods: Fifteen young, healthy adults performed unilateral knee extensor peak torque at 60o, 180o, and 300o/s for each limb. Single-leg cycling tests were performed with dominant limb (DL) and non-dominant limb (NDL) to determine VO2 peak and VO2 at ventilatory threshold (VT). Limb symmetry index (LSI) was used to determine asymmetry= [(1-NDL (Nm) /DL (Nm))*100]. Paired Samples T-tests were utilized to compare dependent variables between DL and NDL while Pearson R correlations assessed for relationships between strength and aerobic capacity LSI.
Results: Limb asymmetry existed for mean peak torque (DL = 89.5±34.8 Nm, NDL = 82.0±30.8 Nm, P=0.002). However, there were no differences for DL and NDL VO2 peak (DL = 34.0±5.1 ml/kg/min, NDL = 34.4±8.1 ml/kg/min, P=0.679), or VO2 at VT (DL = 17.4±4.6 ml/kg/min, NDL = 16.5±3.8 ml/kg/min, P=0.296). LSI relationships for mean peak torque and aerobic capacity outcomes were not strongly correlated (P≤0.05), (VO2 peak, R= 0.374, and VO2 at VT, R= 0.062).
Conclusions: Although there were asymmetries in muscular strength, they are not strongly correlated with aerobic capacity asymmetries in young, healthy adults.