Farklı Menstrüal Döngü Fazlarında Sirkadiyen Ritme Göre Tekrarlı Sprint Performans Değişimlerinin İncelenmesi

Abstract

The purpose of this study was to investigate the repeated sprint performance changes according to the circadian rhythm at different menstrual cycle phases (MCP). Twelve eumenorrheic women performed 5 x 6 sec repeated sprints on cycle ergometer in the morning (08:30 – 10:00) and evening (18:00 – 19:00) sessions during the mid-follicular(MP) (6 – 10th days) and luteal phases (LP) (19 – 24th days) of the MC. Before repeated sprint tests (RST) body weight, body temperature, resting heart rate (HRREST) and resting lactate levels (LAREST) were measured. Additionally, estrogen, progesterone and cortisol levels were measured from the blood samples. Blood lactate was measured immediately after and at the 3rd, 5th and 7th minutes after RST, RPE values were recorded between sprints. HR was recorded throughout the test sessions. Absolute peak power (PPABS), relative peak power (PPREL), absolute mean power (MPABS), relative mean power (MPREL) and percentage of performance decrement (PD%) were recorded for RST and each sprints. Effects of time of day and MCP on performance and physiological responses were analyzed by 2x2 (phase x time) repeated measures analysis of variance. Effects of MCP and time of day on performance for each sprints were analyzed by 2x2x5 (phase x time x repetition) repeated measures analysis of variance. Bonferroni Multiple Comparison Test was used to determine which repetition caused the difference. Body temperature was significantly higher in the evening (p<0.05). Cortisol levels were higher during MP (p<0.05). LAREST values were not affected from MCP and time of day. However, Phase x Time of Day interaction was significant (p<0.05). MCP and time of day effect (p> 0.05) and Phase x Time of Day interaction was insignificant (p> 0.05) on PPABS, PPREL and MPABS, MPREL and PD%. There was significant repetition effect for PPABS, PPREL, MPABS and MPREL (p<0.05). For MPABS and MPREL phase x repetition interaction was significant (p<0.05). Maximum blood lactate values were was significantly higher in the evening (p<0.05). However, HR responses, body weight and RPE values were not affected from MCP and time of day and Phase x Time of Day interaction was insignificant (p> 0.05). Results of this study showed that MCP and time of day had no effect on RST performance and only maximum blood lactate, which is an anaerobic metabolism marker, were affected by the time of day in physiological responses to exercise.