Author(s): RUPP, T., GOEPP, T.1,3, NIVET, M.1,2, MILLET, G.Y.4,5, HAYES, M.3, Institution: UNIVERSITY SAVOIE MONT BLANC (CHAMBÉRY), Country: FRANCE, Abstract-ID: 2102

INTRODUCTION:
Cognitive-motor dual-task performance is prevalent in many sports and appears to be impaired during high-intensity exertion, in association with exacerbated neuromuscular central fatigue and cerebral deoxygenation. It has been reported that women may exhibit lower neuromuscular fatigability during exercise, and studies assessing cognitive performance in isolation have yielded mixed findings, with some favoring males, others favoring females, and still others reporting no sex differences. However, the extent to which these responses differ between males and females during low to high-intensity cognitive-motor dual-tasking remains unknown.
METHODS:
Forty-eight trained young adults (16 females), matched for fitness level completed an incremental cycling test with concurrent sustained attention Mackworth task. The protocol consisted of 3-min ramp stages (starting at 1 W/kg, +0.4 W/kg per stage) until “extremely strong” perceived effort (Borg CR100 scale), considered as task-failure. At each stage, cognitive performance (Mackworth score), quadriceps isometric maximal voluntary contraction (IMVC), neuromuscular fatigue assessed via femoral nerve stimulation (peripheral: twitch force, Pt; central: voluntary activation), and prefrontal oxygenation measured by near-infrared spectroscopy (tissue saturation index, TSI) were evaluated.
RESULTS:
Both sexes reached similar normalized power output (⁓3.3±0.5 W/kg) and heart rate (⁓175±7 bpm) at task-failure (all P>=0.25). Mackworth performance declined at task-failure (P=0.014), with no sex differences (males: -9±28%; females: -4±28%; P=0.56). However, prefrontal oxygenation was lower in women than men at baseline and task-failure (main effect of sex; TSI -3.0±2.6% in females; P=0.031, ηp2=0.13), and female participants exhibited a smaller increase in prefrontal total-haemoglobin throughout the test (time X sex interaction; P<0.001, ηp2=0.27). IMVC declined less in women throughout the cognitive-motor test (time X sex interaction, P=0.021, ηp2=0.25), which was accompanied by smaller impairments in potentiated twitch force (main effect of sex; P=0.008, ηp2=0.16), similar reductions in voluntary activation in both sexes (P=0.62), and comparable increases in perceived effort (P=0.73).
CONCLUSION:
Although high-intensity exercise similarly impaired concurrent sustained attention performance and voluntary activation in both sexes, women exhibited lower neuromuscular and peripheral fatigability, along with a blunted prefrontal oxygenation response. These results extend the understanding of women’s reduced (primarily peripheral) fatigability to whole-body exercise under a challenging dual-task paradigm. Further research is needed to determine whether cognitive-motor dual-task training should be sex-specific and whether men and women differ in their responses.