Effects of Ultratrail Running on Skeletal-Muscle Oxygenation Dynamics.
OBJECTIVE
To quantify changes in skeletal-muscle oxygenation and pulmonary O2uptake (V̇O2) 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 V̇O2were 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 < .05), while normalized [O2Hb] (p1, -20.4%; p1.5, -14.4%; P < .05) and TOI (p1, -17.0%; p1.5, -17.7%; P < .05) decreased in EXP. V̇O2values were similar (P > 0.05). An "overshoot" in normalized [HHb]:V̇O2was 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, particularly, the eccentric loads characterizing this extreme ultratrail-running bout may have led to variations in muscle structure and function, increasing the local muscle deoxygenation profile and the imbalance between O2delivery to working muscles and muscle O2consumption. This highlights the importance of incorporating graded training, particularly downhill bouts, to reduce the negative influence of concentric and severe eccentric loads to the microcirculatory function and to enhance the ability of runners to sustain such loading.
Gianluca
G
Vernillo
Alfredo
A
Brighenti
Eloisa
E
Limonta
Pietro
P
Trabucchi
Davide
D
Malatesta
Grégoire P
GP
Millet
Federico
F
Schena
D000328:Adult; D056352:Athletes; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D010108:Oxyhemoglobins / Q000032:analysis; D052097:Quadriceps Muscle / Q000502:physiology*; D012420:Running / Q000502:physiology*
D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin
mountain ultramarathon; muscle deoxygenation; near-infrared spectroscopy; pulmonary oxygen uptake; trail running