Abstract
The rise of female athletes achieving record-breaking feats has driven increased research into female physiology and its impact on sports performance and exercise. However, further exploration is still needed on the menstrual cycle (MC) and its influence on injury risk factors such as muscle strength, flexibility and joint stability in the lower extremity. The aim of the study was to determine the effects of each phase of the MC on selected modifiable intrinsic injury risk factors among female soccer players in Johannesburg.
The study was an observational repeated-measures study which involved 50 female soccer players aged 18 and older in Johannesburg who were training three days per week and had started menstruating. The participants used the FitrWoman app or the manual calendar-based method to log their MC. Muscle strength, flexibility and stability were measured using handheld VALD DynaMo Plus (Newstead, Queensland, Australia) and the Balance Error Scoring System. The measurements focused on all the movements of the lower limb excluding ankle inversion and eversion. The study used descriptive and inferential statistics to analyse data from the Statistical Package of Social Sciences (SPSS, version 28). The Kolmogorov-Smirnov test was used for normality testing. Analysis of variance (ANOVA) was used to analyse muscle strength, flexibility and joint stability across the different phases of the MC. Post hoc tests with Bonferroni corrections were conducted to identify significant differences. A 95% confidence interval was used with a p-value of <0.05.
The non-dominant leg (NDL) and dominant leg (DL) were the strongest during the late follicular phase, with hip abductors being the strongest muscle group bilaterally (NDL = 148.26 ± 37.00 kg; DL = 148.94 ± 36.65 kg). Most muscle groups were weakest during the menstruation phase. For both the NDL (134.76 ± 14.86˚) and DL (132.98 ± 15.44˚), the highest ROM was reported during knee flexion and the lowest ROM for both the NDL (−2.50 ± 8.54˚) and DL (−1.98 ± 9.63˚) was during knee extension. The majority of the ROM values were at their highest during the late follicular phase bilaterally. Stability tests had the highest mean values during the late follicular phase, except for two-legged stances and tandem stances. One-legged stances had the highest errors during the menstruation phase (4.72 ± 2.21).
The findings of the study show that muscle strength and flexibility are both at their highest during the late follicular phase, and stability is at its lowest during the late follicular phase. ...