Author(s): MARCHAND, F., PAGEAUX, B., MONJO, F., Institution: UNIVERSITÉ SAVOIE MONT-BLANC, Country: FRANCE, Abstract-ID: 1639

INTRODUCTION:
Effort perception is a major regulator of physical activity engagement and pacing strategies for endurance races [1,2]. In this framework, reducing effort perception during physical activity could be beneficial to both performance and physical activity engagement. A study has demonstrated that muscle spindles desensitization induced by a 10-min tendon vibration protocol reduces effort perception during subsequent isometric contractions of elbow flexors [3]. However, the effects of tendon vibration on effort perception during ecological tasks such as cycling remains to be explored. Therefore, the present study aims to assess the effects of tendon vibration on effort perception during cycling. We hypothesized that, for a same perceived effort, power output and vastus lateralis electrical activity would be higher after a tendon vibration protocol.
METHODS:
Fifteen participants attended the laboratory for 2 experimental visits, involving Vibration and Sham Vibration conditions. In each visit, participants completed two 3-minute cycling bouts on an ergometer before (PRE) and two 3-minute bouts after (POST) a 10-minute tendon vibration protocol administered bilaterally to the patellar and Achilles tendons (100Hz frequency 1mm amplitude for Vibration; 15 Hz frequency 0.5mm amplitude for Sham Vibration). For each individual bout, participants were instructed to maintain a constant perceived effort level. Specifically, they pedaled at either a moderate (23) or a strong perceived effort level (50), as determined by the CR100 scale. Relative changes in power output and vastus lateralis electromyography (EMG) between PRE and POST were analyzed with a 2-Condition × 2-Intensity repeated analysis of variances (ANOVAs). Effect sizes were expressed as partial eta-squared and when ANOVAs were significant, Bonferroni post hoc tests were performed. Significance was set at p < 0.05.
RESULTS:
For mean power output, the ANOVA revealed a significant main effect of the condition (F = 20.8 ; p < 0.001 ; η2p = 0.598). Relative power output changes in the Vibration condition were positive (+18% at 23 and in +2% at 50) but were negative in the Sham vibration Condition (~-7% for both intensities). The ANOVA revealed similar outcomes for vastus lateralis EMG.
CONCLUSION:
In line with our hypothesis, we found that power output and VL electrical activity increased after the ten-minute vibration protocol at controlled perceived effort intensities. This suggests that the desensitization of muscle spindles actually leads to a reduction in the perception of effort during submaximal cycling exercises.
REFERENCES:
Behrens M. et al., (2023). Fatigue and Human Performance: An Updated Framework. Sports medicine, 53, 7–31.
Cheval B., & Boisgontier, M. P. (2021). The Theory of Effort Minimization in Physical Activity. Exercise and sport sciences reviews, 49, 168–178.
Monjo F. et al., (2018). The sensory origin of the sense of effort is context-dependent. Experimental brain research, 236, 1997–2008.