Cycling time trial performance during different phases of the menstrual cycle
European Journal of Applied Physiology
School of Physiology, University of the Witwatersrand, 7 York Road, Parktown 2193, South Africa; UCT/MRC Research Unit for Exercise Science and Sports Medicine, Sport Science Institute of South Africa, Newlands 7725, South Africa; Department of Human and Animal Physiology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
Submaximal exercise performance has not previously been assessed in the late follicular phase of the menstrual cycle, which is associated with a pre-ovulatory surge in oestrogen. Therefore, we compared cycling time trial performance during the early follicular (EF), late follicular (LF) and mid-luteal (ML) phase of the menstrual cycle in trained and untrained eumenorrhoeic women who cycled 30 and 15 km, respectively, in a non-fasted state. The women completed the three cycling time trials on a conventional racing bicycle mounted on an air-braked ergometer. We required resting oestrogen to increase by at least twofold above EF phase values in both the LF and ML phases and this resulted in a number of exclusions reducing the sample size of each group. No significant difference was noted in the finishing time between the different menstrual phases in trained (n = 5) or untrained (n = 8) group, albeit limited by sample size. However, analysis of the combined trained and untrained group data (n = 13) revealed a trend for a faster finishing time (P=0.027) in the LF phase compared to the EF phase as 73% of the subjects showed improvements with an average of 5.2±2.9% (or 2.1±1.1 min) in the LF phase (for α=0.05 requires P < 0.017). Combined group analysis yielded no difference between performance in the EF and ML phase or between the LF and ML phase. Thus, further research is encouraged to confirm the tendency for a faster time trial in the LF phase, which coincides with the pre-ovulatory surge in oestrogen. © Springer-Verlag 2005.
estrogen; luteinizing hormone; adult; article; bicycle ergometry; clinical trial; controlled clinical trial; controlled study; estrogen blood level; exercise; female; follicular phase; heart rate; human; human experiment; luteal phase; luteinizing hormone blood level; menstrual cycle; normal human; oxygen consumption; physical capacity; priority journal; progesterone blood level; statistical analysis; statistical significance; Adult; Bicycling; Estrogens; Exercise Test; Female; Follicular Phase; Humans; Luteal Phase; Menstrual Cycle; Physical Education and Training; Task Performance and Analysis; Time Factors