The increase in hydric volume is associated to contractile impairment in the calf after the world's most extreme mountain ultra-marathon

Abstract

Background: Studies have recently focused on the effect of running a mountain ultra-marathon (MUM) and their results show muscular inflammation, damage and force loss. However, the link between peripheral oedema and muscle force loss is not really established. We tested the hypothesis that, after a MUM, lower leg muscles' swelling could be associated with muscle force loss. The knee extensor (KE) and the plantar flexor (PF) muscles' contractile function was measured by supramaximal electrical stimulations, potentiated low- and high-frequency doublets (PS10 and PS100) of the KE and the PF were measured by transcutaneous electrical nerve stimulation and bioimpedance was used to assess body composition in the runners (n = 11) before (Pre) and after (Post) the MUM and compared with the controls (n = 8).

Results: The maximal voluntary contraction of the KE and the PF significantly decreased by 20 % Post-MUM in the runners. Hydration of the non-fat mass (NF-Hyd) and extracellular water volume (Ve) were increased by 12 % Post-MUM (p < 0.001) in the runners. Calf circumference (+2 %, p < 0.05) was also increased. Significant relationships were found for percentage increases in Ve and NF-Hyd with percentage decrease in PS10 of the PF (r = -0.68 and r = -0.70, p < 0.05) and with percentage increase of calf circumference (r = 0.72 and r = 0.73, p < 0.05) in the runners.

Conclusions: The present study suggests that increases in circumference and in hydric volume are associated to contractile impairment in the calf in ultra-marathon runners.

Keywords: Inflammation; Muscle force loss; Oedema; Ultra-endurance; Ultra-running.

Fig. 1

Relationships between percentage change of bioimpedance parameters and percentage change in neuromuscular parameters in runners. Pearson’s correlation coefficients were calculated between Pre- and Post-mountain ultra-marathon percentage change of bioimpedance parameters with percentage change of neuromuscular and calf and thigh circumference in runners (n = 11). Correlations between percentage change of extracellular water volume (Ve) and total hydration of the non-fat mass (NF-Hyd) with percentage change of potentiated low-frequency doublets of the plantar flexor (PS10) (a, b) and with percentage change of calf and thigh circumference (c, d) were calculated. The black circles represent data obtained from calf and the white circles represent data obtained from thigh. p value of 0.05 was accepted as the level of significance for all correlations