Effects of Ultratrail Running on Skeletal-Muscle Oxygenation Dynamics

Purpose:To quantify changes in skeletal-muscle oxygenation and pulmonary O2 uptake (VO2) after an extreme ultratrail running bout. Methods:Before (PRE) and after (POST) the race (330-km, 24000 D±), profiles of vastus lateralis muscle oxygenation (ie, oxyhemoglobin [O2Hb], deoxyhemoglobin [HHb], and tissue oxygenation index [TOI]) and VO2 were determined in 14 athletes (EXP) and 12 control adults (CON) during two 4-min constant-load cycling bouts at power outputs of 1 (p1) and 1.5 (p1.5) W/kg performed in randomized order. Results:At POST, normalized [HHb] values increased (p1, +38.0%; p1.5, +27.9%; P 0.05). An “overshoot“ in normalized [HHb]:VO2 was observed, although the increase was significant only during p1.5 (+58.7%, P = .003). No difference in the aforementioned variables was noted in CON (P > .05). Conclusions:The concentric and, particul...