The influence of menstrual cycle on bioimpedance vector patterns, performance, and flexibility in elite soccer players

To examine whether menstrual cycle affects body composition and bioimpedance vector analysis (BIVA) patterns, jumping and sprinting ability, and flexibility in elite soccer players. Methods: A total of 20 elite female soccer players (age: 23.8 [3.4] y, height: 1.63 [0.04] m, body mass: 61.4 [5.9] kg, and body mass index: 22.5 [2.4] kg/m2) were monitored during the early follicular and ovulatory phase across 2 consecutive menstrual cycles. Bioimpedance analysis was performed using foot-to-hand technology, and total body water and fat mass were determined by specific equations developed for athletes. Bioelectrical resistance and reactance were adjusted according to the BIVA procedures and plotted as a vector within the resistance–reactance graph. In addition, countermovement jump, 20-m sprint, and sit and reach were assessed. Results: A time effect (P < .05) was found for body mass, total body water, bioelectrical resistance and reactance, and flexibility. Specifically, body mass increased (P = .021) along with a gain in total body water (P = .001) from the ovulatory to the early follicular phase, while it decreased from the early follicular to the ovulatory phase during the second menstrual cycle. The BIVA vector shortened during the early follicular phases (P < .001). No change in jumping and sprinting capacity was observed (P > .05). Flexibility was impaired during the early follicular phases (P < .05). Conclusions: Specific bioelectrical impedance analysis and BIVA procedures are able to detect menstrual cycle–induced changes in body composition in elite soccer players. The early follicular phase resulted in fluid accumulations and BIVA vector shortening. In addition, while menstrual cycle did not affect performance, a fluctuation in flexibility was observed.