Thigh Lean Mass Is Associated With Improved Running Economy In Female Endurance Runners

Running economy (RE) is a multifactorial measure reflecting efficiency of the cardiorespiratory, metabolic, biomechanical, and neuromuscular systems. Increased leg length and proximally distributed body mass are associated with improved RE, however there is a paucity of female participant representation in prior studies. PURPOSE: Examine the relationship between segment length, segment mass distribution and segment lean mass on RE in female endurance athletes. METHODS: 31 female endurance runners (World Athletics 2017 score > 500; VO2 max: 52 ± 4 ml/kg/min; age: 33 ± 9 yrs; height: 164.4 ± 7.0 cm; mass: 56.7 ± 7.1 kg) who performed a graded maximal cardiopulmonary exercise test (CPET) and whole-body dual energy x-ray absorptiometry (DXA) scan were selected from a cohort of subjects in an ongoing study of endurance athletes. CPET protocol was dictated by self-selected half marathon race pace with 1kph increments every 3 min until volitional fatigue. RE was defined as the mean VO2 during the last minute of a common speed stage of 12.8kph. DXA-derived bilateral femur and tibia length (height normalized) and thigh and shank lean mass (body mass normalized) were calculated. Lean segment mass was calculated as the bilateral sum of thigh and shank lean segment mass (lean mass normalized). Segment mass distribution was calculated as ([shank mass/thigh mass] x 100). Pearson correlations (r) were used to assess the relationship between anthropometric variables and RE. RESULTS: Thigh lean mass was moderately correlated with RE (r = -0.39; p = 0.02). No other significant correlations were observed (p > 0.05; Table). CONCLUSION: Higher thigh segment lean mass was associated with improved RE in female endurance runners. Segment length and overall mass distribution did not significantly correlate with RE in these athletes. This study received funding from Apple Inc. The funding source had no role in the analysis andinterpretation of the data or in the submission of this abstract .