Author(s): CAI, M.Y.1, KUO, S.C.2, CHEN, Y.E.3, CHOU, P.J.1, HSU, P.C.2, LIN, Y.J.2, Institution: NATIONAL TAIWAN UNIVERSITY OF SCIENCE AND TECHNOLOGY, Country: TAIWAN, Abstract-ID: 2474

INTRODUCTION:
This study investigated phase-specific neuromuscular responses to resistance training in female triathletes. Given the potential influence of menstrual cycle fluctuations on performance, we examined whether training adaptations differed between the follicular and luteal phases.
Thirty-two female triathletes participated in this study. Participants were categorized based on resistance training exposure (RT vs CON). Separate 2 (group) × 2 (time: pre vs post) mixed ANOVAs were conducted for the follicular and luteal phases. Countermovement jump (CMJ) performance was assessed using jump height, flight time, and rate of force development.
A significant group × time interaction was observed during the follicular phase (p < 0.05), indicating greater improvements in the RT group compared with the CON group. In contrast, no significant interaction effects were detected during the luteal phase.
These findings suggest that resistance training–related neuromuscular adaptations may be phase-dependent. However, given the uneven sample distribution and variability in training exposure, the results should be interpreted cautiously. Further studies with balanced phase representation are warranted.
METHODS:
Thirty-two female triathletes participated in this exploratory study and were allocated to a resistance training group (RT) or control group (CON) based on actual training exposure. Athletes completing ≥6 resistance training sessions were classified as RT. Countermovement jump (CMJ) performance was assessed using a contact platform, with hands on hips. Jump height, flight time, and rate of force development (RFD) were calculated. Menstrual phases were identified via self-reported cycle tracking and categorized as follicular or luteal. Separate 2 (group) × 2 (time) mixed ANOVAs were conducted for each phase (p < 0.05).
RESULTS:
A significant group × time interaction was observed during the follicular phase (p < 0.05), with greater improvements in CMJ performance in the RT group compared with CON. No significant interaction effects were found during the luteal phase (p > 0.05). Considerable inter-individual variability was present, particularly due to uneven phase distribution and limited RT participation.
CONCLUSION:
Resistance training–related CMJ improvements were evident during the follicular phase but not during the luteal phase, suggesting phase-dependent neuromuscular responsiveness in female triathletes. Hormonal fluctuations, particularly lower progesterone levels during the follicular phase, may facilitate explosive performance adaptations. Given the exploratory design, uneven sample distribution, and self-reported phase identification, findings should be interpreted cautiously. Nonetheless, these results highlight the potential relevance of menstrual cycle phase when evaluating resistance training adaptations. Further studies with larger, balanced samples and hormonal verification are warranted.