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Purpose: This study aimed to assess hydration status before and after training using the bioelectrical impedance vector analysis (BIVA) method., Design: Pre-post quasi-experimental designs., Method: Twenty-four young water polo players (mean age: 13.30 ± 0.55) underwent assessment for bioelectrical and anthropometric measurements before and after a water polo training session., Results: Most players fell within the 50 % percentile of the bioelectrical tolerance ellipses of the reference population. The BIA vector differed statistically between players who achieved growth peaks (PGA: T 2  = 9.1, p  = 0.013) and those who did not (GPNA, T 2  = 28.9, p  < 0.001) compared to the reference and also differed between them (T 2  = 37.7, p  < 0.001). After training, a decrease in body mass (BM) and BM adjusted for water intake ( p  = 0.0001) and changes in BIA variables ( p  < 0.05) were observed. BIVA also showed a significant pre-post vector migration in both GPA (T 2  = 24.7; p  < 0.001) and GNPA (T 2  = 43.1; p  < 0.001), characterized by a decrease in resistance and opposite reactance directions (T 2  = 33.6, p  < 0.001)., Conclusion: Young water polo players exhibit a significant BM loss after training (∼2.5 %). Ad libitum water intake seems to partially compensate dehydration. The resistance reduction indicates that BIVA captured the compensation for dehydration resulting from fluid intake., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 Published by Elsevier Ltd.)

Background: This study aimed to compare and examine the local and non-local effects of a foam rolling (FR) and static stretching (SS) intervention applied to the plantar flexor (PF)., Methods: Fourteen female participants were investigated. Each participant underwent three conditions in a random order at least 48h apart and at the same time of the day: Control (CC), SS, and FR. Each condition was performed unilaterally in the dominant PF for 4 sets (apart from CC). SS was performed for 30 s. The FR included 30 rolls (15 in each direction) over a period of 30 s. A rest of 30 s was provided between each set for all conditions. Outcome variables were ankle dorsiflexion range of movement (ROM), tissue hardness, localized bioimpedance analysis at 50 kHz (L-BIA), and pain pressure thresholds (PPT). Tissue hardness, L-BIA, and PPT were measured in the lower leg and thigh. Measures were assessed pre (T0), immediately post (T1), and 10-min after (T2) the intervention., Results: No differences were found for time for the CC or between the T0 of each condition. Concerning the lower leg, ROM improved for SS and FR from T0 to T1 while returning to baseline in T2. A significant increase in PPT was observed only for SS in T1. L-BIA showed a significant increase for both phase angle and impedance only for FR in T1. Tissue hardness did not change for any group at any time-point. Concerning the thigh, no measure at any time point showed significant differences., Conclusion: Both, FR and SS were able to acutely improve ankle ROM. The observed changes were probably caused by a change in viscoelastic properties and local pain perception, without any variation in tissue morphology. FR was the only intervention to improve the intracellular-to-extracellular ratio and decrease fluids. Non-local effects were not observed., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Objectives: The study aimed to investigate the relationship between raw bioelectrical data and physical performance in track and field athletes. Specifically, the objectives were to determine: 1) whether a regional bioelectrical impedance approach provides additional insights compared to whole-body analysis, 2) the reliability of the Levi Muscle Index (LMI) in this context, and 3) whether there are differences in these relationships between male and female athletes., Design: This study utilized a cross-sectional design involving thirty-one female athletes (mean age 21.4 ± 3.8 years) and thirty male athletes (mean age 21.1 ± 2.6 years) from track and field. On a single day, participants underwent whole-body and regional bioelectrical impedance assessments focusing on the lower limbs, alongside strength and speed performance tests., Results: The study found no significant differences in the relationship between whole-body versus regional bioelectrical impedance and performance tests. Resistance (R) demonstrated an inverse correlation, while phase angle (PhA) and Levi Muscle Index (LMI) showed direct correlations with most performance variables in track and field athletes. Significant differences were observed between male and female athletes across all parameters, with male athletes exhibiting superior performance, higher PhA and LMI values, and stronger correlation coefficients compared to females., Conclusions: In summary, this study highlights the intricate relationship between body composition and physical performance in athletes. It underscores the importance of considering sex differences and the reliability of raw bioelectrical data, whether obtained through regional or whole-body approaches, in assessing athletic performance., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Objectives: CrossFit® is a high-intensity sport characterized by various workouts that require strength, speed, endurance, or agility, impacting participants' body composition. This observational study aimed to determine the morphological (anthropometrical and bioelectrical) profile of CrossFit® athletes and to compare them with other athletic populations., Methods: Anthropometrical measurements and bioelectrical vector analysis (classic and specific approaches) were performed on 145 CrossFit® practitioners (107 men aged 30.7 ± 8.4 years and 38 women aged 28.1 ± 6.7 years). Each participant's relative somatotype was calculated and compared between sexes and with a Spanish CrossFit® athletes' group. Resistance-reactance graphs and Hotelling's T2 test were applied to characterize the sample, compare them with an athletes' reference population, and identify differences between somatotype groups., Results: The most represented somatotype in both groups was the balanced mesomorph (male 3.5-5.2 - 1.7 and female 4.4-4.5 - 1.8). Compared with Spanish CrossFit® athletes, significant differences were denoted for men but not women (SAD = 2.3). The bioelectrical graphs indicated that the distribution of CrossFit® athletes is quite heterogeneous and within average values for the athlete's reference. The mesomorphic and endomorphic components were associated with a higher phase angle., Conclusions: CrossFit® practitioners predominantly present a mesomorphic component and show a body type like other power athletes, although with less pronounced characteristics. The somatotype may influence the vector's position in the RXc graphs. This study provided the bioelectrical tolerance ellipses for CrossFit® practitioners in classic and specific approaches for the first time., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)