The effect of menstrual cycle phases on sports performance indicators in tennis players

This study aimed to examine the effects of different phases of the menstrual cycle (follicular and ovulation) on the sports performance indicators of female tennis players. Sixteen voluntary female athletes with regular menstrual cycles and cycle lengths ranging from 28 to 35 days participated in the study. The participants' mean age was 26.38 ± 1.82 years, mean height was 165.69 ± 4.08 cm, and mean body weight was 56.00 ± 7.21 kg. The research was conducted using a crossover experimental design. Measurements of eight participants were taken on the 2nd day of the menstrual cycle (follicular phase), while measurements of the other eight participants were taken on the 14th day (ovulation phase). In the second measurement, the phases were reversed — the first group was tested in the ovulation phase, and the second group in the follicular phase. On the designated days, participants came to the laboratory and, following a standardized warm-up protocol, were tested for forehand, backhand, and serve speed, agility time (T-test), and handgrip strength. Data were analyzed using the SPSS 27 software package. For normally distributed variables, a paired samples t-test was applied, and the level of significance was set at p<.05. According to the analysis results, significant increases were found in forehand, backhand, and serve speeds during the ovulation phase compared to the follicular phase (p<.05). Agility time significantly decreased in the ovulation phase (p<.001), and handgrip strength increased significantly (p<.05). The effect sizes were moderate for forehand, backhand, and serve speeds, large for agility time, and moderate for handgrip strength. In conclusion, it was determined that the ovulation phase has significant and positive effects on both technical performance (stroke speeds) and physical performance (agility and strength) in female tennis players. These findings indicate that considering the phases of the menstrual cycle in the training and competition planning of female athletes is important for performance optimization. Key Words: Menstrual cycle, tennis performance, serve speed.