The Effects of 24-h Fasting on Exercise Performance and Metabolic Parameters in a Pilot Study of Female CrossFit Athletes.

Many studies have tested intermittent fasting (IF) in athletes, but its effects on female CrossFit athletes remain relatively unexplored in the existing literature. The aim of this study was to evaluate and compare the effects of 24-h IF on the physical performance of female CrossFit practitioners. Eleven female CrossFit athletes (age: 30.91 ± 3.42, weight: 65.26 ± 7.55 kg, height: 1.66 ± 0.05 m) participated in the study. The study used a crossover design with fasting and eating conditions. Participants completed an exercise test, standing long jump, and handgrip strength assessment. Hydration status, heart rate, blood lactate, blood glucose, rates of perceived exertion, and hunger were measured. Results showed significant differences in blood lactate concentration (F = 5.435, p = 0.042, η2p = 0.352). Resting blood lactate concentration was significantly lower in the fasting trial than in the eating trial (p < 0.001), but post-exercise blood lactate concentrations were higher in the fasting trial than in the eating trial (p < 0.001). No differences were found in performance times (p > 0.05). In conclusion, this pilot study of females suggests that 24-h fasting does not impair exercise performance or negatively affect physiological parameters in CrossFit athletes.

Hydration, Hyperthermia, Glycogen, and Recovery: Crucial Factors in Exercise Performance-A Systematic Review and Meta-Analysis.

Hyperthermia accelerates dehydration and can lead to a glycolysis malfunction. Therefore, to deeply understand the relationship between dehydration and hyperthermia during exercise, as well as in the recovery time, there might be important factors to improve athletic performance. A systematic review was carried out in different databases using the words "hydration" OR "dehydration" AND "glycogen" OR "glycogenesis" OR "glycogenolysis" AND "muscle" OR "muscle metabolism" OR "cardiovascular system" and adding them to the "topic section" in Web of Science, to "Title/Abstract" in PubMed and to "Abstract" in SPORTDiscus. A total of 18 studies were included in the review and 13 in the meta-analysis. The free statistical software Jamovi was used to run the meta-analysis (version 1.6.15). A total sample of 158 people was included in the qualitative analysis, with a mean age of 23.5 years. Ten studies compared muscle glycogen content after hydration vs. remaining dehydrated (SMD -4.77 to 3.71, positive 80% of estimates, \hat{\mu} = 0.79 (95% CI: -0.54 to 2.12), z = 1.17, p = 0.24, Q-test (Q(9) = 66.38, p < 0.0001, tau2 = 4.14, I2 = 91.88%). Four studies examined the effect of temperature on postexercise muscle glycogen content (SMD -3.14 to -0.63, 100% of estimates being negative, \hat{\mu} = -1.52 (95% CI: -2.52 to -0.53), (z = -3.00, p = 0.003, Q-test (Q(3) = 8.40, p = 0.038, tau2 = 0.68, I2 = 66.81%). In conclusion, both hyperthermia and dehydration may contribute to elevated glycogenolysis during exercise and poor glycogen resynthesis during recovery. Although core and muscle hyperthermia are the key factors in glycogen impairments, they are also directly related to dehydration.

Pelvic Floor Muscle Training Interventions in Female Athletes: A Systematic Review and Meta-analysis.

CONTEXT: Athletes are almost 3 times more at risk of experiencing urinary incontinence (UI) than sedentary women, with prevalence rates varying from 10.9% in low-impact sports such as cycling to 80% when engaging in high-impact sports such as trampoline gymnastics. To treat UI, pelvic floor muscle (PFM) training (PFMT) is recommended as a first line of treatment. OBJECTIVE: The aim of the present study was to perform a meta-analysis of the available literature on the efficacy of PFMT interventions in young, nulliparous female athletes. DATA SOURCES: A literature research was conducted using PubMed, Sport Discus, and Web of Science. STUDY SELECTION: The inclusion criteria were studies with PFMT intervention in female athletes or recreationally active women. Interventions could be carried out for treatment or prevention of pelvic floor dysfunctions. STUDY DESIGN: Systematic review with meta-analysis. LEVEL OF EVIDENCE: Level 5. DATA EXTRACTION: A descriptive analysis of the articles included in the systematic review was carried out. Meta-analyses could be performed on 6 of the included articles, evaluating the maximal voluntary contraction (MVC) of the PFMs, the amount of urinary leakage (AUL), and the vaginal resting pressure (VRP). Random-effects model and standardized mean differences (SMD) ± 95% CI were reported. RESULTS: The meta-analysis showed that PFMT produced a significant increase in MVC (SMD, 0.60; 95% CI, 0.11 to 1.08; P = 0.02) and a significant reduction of AUL (SMD, -1.13; 95% CI, -1.84 to -0.41; P < 0.01) in female athletes. No effects were shown in VRP (SMD, -0.05; 95% CI, -1.27 to 1.17; P = 0.93). CONCLUSION: PFMT is shown to be effective in increasing PFM strength and reducing urine leakage in female athletes, being a powerful tool to prevent and treat pelvic floor dysfunction in this population.

Effect of Kegel Exercises on Lower Urinary Tract Symptoms in Young Gymnasts: A Prospective Cohort Study.

IMPORTANCE: Lower urinary tract symptoms (LUTS) have been shown to exist in young athletes. The use of pelvic floor muscle training as a preventive strategy at an early age may be useful to avoid possible pelvic floor dysfunction in the future. OBJECTIVES: The aim of the study was to describe LUTS in underaged gymnasts. We also aimed to evaluate the effects of a 12-week Kegel exercise intervention for LUTS and urinary incontinence (UI) and their relationship to bother. STUDY DESIGN: A quasi-experimental (nonrandomized, noncontrolled) pre-post study was conducted. Nineteen gymnasts with a mean age of 13.21 ± 1.84 were selected from a gymnastics club in Madrid, Spain. Outcomes of LUTS and quality of life were measured using the International Consultation on Incontinence Questionnaire-Female Lower Urinary Tract Symptoms validated questionnaire at baseline and at the end of the 12-week intervention. RESULTS: The participants presented with certain LUTS such as urgency UI (57.7%) or stress UI (47.4%), which negatively affect their daily lives by feeling annoyed in various aspects (when practicing gymnastics, getting up during the night to urinate or feeling bladder pain among others). No significant differences in LUTS and quality of life variables were observed after the exercise intervention ( P > 0.05). CONCLUSIONS: A high prevalence of LUTS was observed in a sample of underaged high-level gymnasts. The 12-week Kegel exercise intervention did not significantly reduce the presence of pelvic floor problems and even intensified some of them, probably because of an increased awareness. Pelvic floor muscle training as a preventive strategy at an early age seems to be necessary to avoid possible pelvic floor dysfunction in the future.

Ergogenic Aids to Improve Physical Performance in Female Athletes: A Systematic Review with Meta-Analysis.

Most intervention studies investigating the effects of ergogenic aids (EAs) on sports performance have been carried out in the male population. Thus, the aim of this systematic review and meta-analysis was to summarize the effects in the existing literature of EAs used by female athletes on performance. A literature research was conducted, and a descriptive analysis of the articles included in the systematic review was carried out. Meta-analyses could be performed on 32 of the included articles, evaluating performance in strength, sprint, and cardiovascular capacity. A random-effects model and the standardized mean differences (SMD) ± 95% confidence intervals (CI) were reported. The results showed that caffeine helped to improve jumping performance, isometric strength values, and the number of repetitions until failure. Caffeine and sodium phosphate helped to improve sprint performance. Aerobic tests could be improved with the use of taurine, caffeine, and beta-alanine. No conclusive effects of beetroot juice, polyphenols, or creatine in improving aerobic performance were shown. In terms of anaerobic variables, both caffeine and sodium phosphate could help to improve repeated sprint ability. More studies are needed in female athletes that measure the effects of different EAs on sports performance, such as beetroot juice, beta-alanine or sodium phosphate, as the studies to date are scarce and there are many types of EA that need to be further considered in this population, such as creatine and taurine.