This study investigated the effect of performing prolonged mental exertion during submaximal cycling exercise on exercise tolerance and fatigue. Participants performed 5 experimental sessions. Session 1: determination of cycling peak power output. Sessions 2 and 3: cycling to exhaustion at 65% peak power output with mental exertion or watching a movie. Sessions 4 and 5: cycling for 45 min at 65% peak power output with mental exertion or while watching a movie. During sessions 2–5, rate of perceived exertion and heart rate were recorded while cycling and cortisol and prolactin concentrations, psychomotor vigilance task performance, and maximal voluntary contraction were measured pre-and post-sessions. During sessions 2 and 3, time to exhaustion was reduced (p<0.01) and rate of perceived exertion was increased (p<0.01) in session 2 compared to 3. Cortisol, prolactin and heart rate increased and psychomotor vigilance task and maximal voluntary contraction decreased from pre-to post-sessions with no difference between sessions. Cortisol, prolactin and rate of perceived exertion were higher (p<0.03) in session 4 than 5. Heart rate increased and maximal voluntary contraction decreased from pre-to post-sessions with no difference between sessions. Prolonged mental exertion during cycling exercise reduces exercise tolerance, which appears to be mediated psychologically rather than physiologically.

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Aim: Postnatal skeletal muscle growth is strongly associated with a satellite cell pool. Early adolescence might be a crucial period when different exercise training interventions have specific consequence on satellite cells. Pax7 and MyoD have been suggested as the leading indicators of satellite cell activation.Methods: In this study, pre-adolescent male rats (n = 18) were either subjected to an enriched environment that facilitated physical activities or combined training or control for three weeks. The flexor hallucis longus muscle was removed for biochemical and histochemical analysis.Results: Findings demonstrated that exercise trained rats displayed high levels of serum IGF-1 (p &lt;0.05). There was an increase in Pax7 (p &lt;0.05) and MyoD (p &lt;0.001) mRNA expression. A significant increase in the mean fiber area (p &lt;0.01), satellite cell (p &lt;0.001), and myonuclear numbers (p &lt;0.01) were also observed in both intervention groups. Importantly, enriched rats showed lower corticosterone levels (p &lt;0.05) compared to training ones. Regarding performance, trained and enriched rats had significant improvement in forelimb grip strength (p &lt;0.01) and load-carrying capacity (p &lt;0.05).Conclusion: Type of physical exercise is an essential part in changing satellite cells pool. Different and frequent physical activities in an enriched environment can be effective for muscle development.

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