Author(s): BIELITZKI, R., BEHRENS, M., BEHRENDT, T., ROß, L.M., DOROW, N., SCHEGA, L., Institution: OTTO VON GUERICKE UNIVERSITY, Country: GERMANY, Abstract-ID: 1170

INTRODUCTION:
The influence of the menstrual cycle (MC) on female athletic performance and its underlying mechanisms have been largely investigated with conflicting results. A recent study by Ansdell et al. (J Appl Physiol. 2019;126:1701–12) revealed that time-to-exhaustion during a submaximal task was higher on Day 21 [mid-luteal] compared to Day 2 [early follicular] without differences in the strength, voluntary activation and decline in contractile function of the knee extensors. However, endurance performance (i.e., time-to-exhaustion) is not only influenced by neuromuscular but also perceptual factors. Therefore, the present study aimed to investigate time-to-exhaustion and the perceptual responses during the same exercise used by Ansdell et al. across the MC. Furthermore, the influence of trait fatigue and trait mood (assessed over the last 7 days) was examined.
METHODS:
Fifteen eumenorrheic females (24.1±3.3yrs, 63.4±4.8kg, 166.2±5.0cm) participated in a pseudo-randomized, counterbalanced cross-over study. Participants completed a familiarization session and three experimental trials on different days during the MC (Day 2 [early follicular], 14 [late follicular], and 21 [midluteal]). The fatiguing exercise consisted of isometric knee extensions at 60% of maximal voluntary isometric contraction (MVIC) torque until exhaustion. The protocol consisted of sets with 12 repetitions (3s contraction/ 2s rest). On each 12th repetition, a MVIC was performed to quantify the performance reduction (i.e., motor performance fatigue) At the end of each set perceived motor fatigue, affective valence, arousal, pain and effort percep-tion were queried. Furthermore, motivation to perform the fatiguing task (Dundee Stress State Questionnaire), trait fatigue (Modified Fatigue Impact Scale), and trait mood (Profile of Mood States) were recorded before each experimental session.
RESULTS:
There were no differences in time-to-exhaustion, the MVIC decline and the perceptual responses during exercise across the 3 trials. However, motivation to perform the fatiguing task was lower on Day 2 compared to Day 21 (p=0.030. d=0.45) and trait mood was worse on Day 2 compared to Day 14 (p=0.007, d=0.85). Of note, a high but non-significant effect was found for trait fatigue (p=0.081, ηp2=0.18) with higher values on Day 2 compared with Day 14 (p=0.079, d=0.56).
CONCLUSION:
The MC had an effect on motivation to perform the fatiguing task and trait mood as well as trait fatigue with the worst values on Day 2. However, time-to-exhaustion, motor performance fatigue, and the perceptual responses during exercise were not affected. These results indicate that MC-related alterations in motivation, trait mood and trait fatigue do not inevitably affect motor task performance and/or motor performance fatigue.