Participants
Eight physically active women, who signed the Physical Activity Readiness Questionnaire (PAR-Q) were eligible for inclusion, took part in this pilot study (26.2 ±1.9 years; 56.3 ± 1.6 kg; 159 ± 0.04 cm; 29.5 ± 4.9 % fat). The training characteristics required were: one to two years of experience in CrossFit®, three to five days·wk-1 of training frequency and being familiar with the 3 previously mentioned benchmark workouts, namely CrossFit total, Jerry and Fran. The participants self-reported regular MC (between 28 and 31 days), with no history of disorders related to the endocrine system and/or MC. They did not use ergogenic substances and did not have any limitations that would prevent the tests performance. The participants were informed of the benefits and risks of the investigation prior to signing the informed consent document to participate in the study. The experimental protocol was approved by the Local Human Research Ethics Committee (#4177256/2020).
Experimental Design
The entire experimental protocol lasted four weeks, a period in which the participants performed evaluation sessions on nine different occasions, between 4:00 pm and 10:00 pm. All participants were familiarized with the tests and procedures. All three benchmark workouts (CrossFit® Total, Jerry, and Fran) were repeated in each MC phase on fixed days: Follicular (FP), Ovulatory (OP), and Luteal (LP). The evaluations comprised: 1ª) maximum strength performance obtained from CrossFit® total workout; 2ª) aerobic performance achieved in Jerry workout; 3ª) high intensity exercise in Fran workout. The evaluation sessions followed the MC phases, in which specific days were fixed for the workouts, so that the participants had enough time to recover between the evaluations. Thus, the three benchmark workouts (CrossFit Total, Jerry and Fran) were repeated in the three MC phases. During the FP, days three, five and seven were, respectively, scheduled for CrossFit Total, Jerry and Fran. On days 10, 12 and 14, during the OP, the participants performed CrossFit Total, Jerry and Fran, respectively. Finally, during the LP, day 19 was chosen for CrossFit Total, day 21 for Jerry, and day 23 for Fran.
All evaluation sessions were performed in a CrossFit® affiliated Box under the supervision of a level-one coach in order to ensure that standard movements were met.
At the end of each MC phase, the participants answered the Daily Analysis of Life Demands in Athletes (DALDA) [6] for monitoring sources and symptoms of stress. Furthermore, after each workout, the session rating of perceived exertion (sRPE) was registered using the CR-10 scale [7,8].
CrossFit Total Workout
The CrossFit Total benchmark workout is used to assess maximal strength. It consisted of determining the 1-repetition maximum (1RM) of three exercises: back squat, strict shoulder-press, and deadlift. For this, before each exercise, there was a specific 10-minute warm-up with approximately 50% of 1RM for each participant. After warm-up, they had three attempts to determine 1RM, with 3-5 min of rest between the attempts in each exercise. Total duration of the workout was 90 min, and 1RM loads (kg) of each exercise were added to determine the individual score [1].
Jerry Workout
Jerry was the benchmark workout used to determine aerobic performance, in which each participant ran one mile (1609.34 m), followed by two kilometers of exercise on the rowing simulator ergometer and, finally, another mile running. At the end, the total time to perform the three exercises (running, rowing, running) was computed (min), and recorded by a manual stopwatch1.
Fran Workout
The benchmark Fran workout consisted of a high intensity exercise. Participants completed 21-15-9 repetitions of thrusters and pull-ups, where thrusters were performed with 29.5 kg. The entire workout consisted of completing 21 thrusters, then 21 pull-ups, 15 thrusters and 15 pull-ups, nine thrusters, and nine pull-ups at a time. The time to complete all repetitions was recorded with a manual stopwatch [1].
Sources and symptoms of stress
To evaluate the sources and symptoms of stress, the Daily Analysis of Life Demands in Athletes (DALDA) questionnaire [6] was filled out at the end of each MC phase. The DALDA is divided into parts A (9 questions) and B (25 questions), which represents the sources and symptoms of stress. The response options available for each item are ‘better than normal’, ‘normal’ and ‘worse than normal’. The sum of the scores marked as “worse than normal” was recorded for analysis.
Statistical analysis
The data were analyzed using the Statistical Package for the Social Sciences software (SPSS® Inc., USA). Shapiro-Wilk test was used to check the normality of the data distribution, and is presented as mean ± standard deviation (SD). The analysis of variance (ANOVA) with repeated measures was used to compare the MC phases for all variables. The sphericity assumption was checked by Mauchly’s test and, where violations occurred, degrees of freedom were corrected using Greenhouse-Geisser (epsilon ≤ 0.75) or Huynd-Feldt (epsilon > 0.75) estimates of sphericity. Bonferroni post hoc was performed for multiple comparisons. Statistical significance was set at P < 0.05.