Increases in Intracellular Water Explain Strength and Power Improvements over a Season

Abstract

Changes in body components occur over a season, but their impact on performance is still unclear. We aimed to analyze the relationship between changes in leg strength and jump performance with body composition over a season in highly trained athletes. Measures from the beginning to the main competitive periods of a season were obtained in 40 male and 23 female basketball, handball and volleyball players (20±5 years) for fat (FM) and fat-free mass (FFM) estimated by DXA. Total body water (TBW) and extracellular water (ECW) were assessed by deuterium and bromide dilution, respectively, and intracellular water (ICW) was calculated as TBW minus ECW. Maximal strength was determined by the leg press, while jumping height was assessed with squat (SJ) and countermovement (CMJ) jumps. Significant improvements in strength (12.5±20.8%) and jumping height (SJ:8.3±13.9%; CMJ:6.3±8.5%) were found. FFM, TBW and ECW significantly increased (3.0±2.7%; 1.7±5.5%; 3.0±8.6%, respectively), while %FM decreased (-4.5±9.1%) and no changes were observed in ICW (1.2±9.7%). Among body composition changes only ICW was associated with performance even adjusted for gender, age, season length and sport (strength: β=71.209, p=0.012; SJ: β=0.311, p=0.049; CMJ: β=0.366, p=0.018). Body composition, strength and jumping height improved over a season and ICW was the main predictor of performance in national level players.

Intracellular Water Content in Lean Mass is Associated with Muscle Strength, Functional Capacity, and Frailty in Community-Dwelling Elderly Individuals. A Cross-Sectional Study

“…Our results also agree with those published by Goulet et al, who suggest that acute dehydration of 1% of body weight in healthy active 60 to 75 years old mencould affect muscle endurance, power and strength [25]. Moreover, the correlation between ICW and muscle strength has also been observed in young adult athletes [26], with some authors suggesting that cell volume is a metabolic signal that regulates cellular function and also that cellular swelling leads to anabolism and cellular shrinkage promotes catabolism and protein degradation [27,28]. Although dehydration and hyperosmotic stress affect all bodily cells and tissues, these do not all respond in the same way.…”

Influence of Specific Collagen Peptides and Concurrent Training on Cardiometabolic Parameters and Performance Indices in Women: A Randomized Controlled Trial

“…Although the influence of different training regimes on FM and FFM has been extensively explored, to the best of our knowledge, no investigation has studied the effects of long-term CT on body water distribution. Previous investigations indicate that maintaining or increasing ICW with a simultaneously elevated FFM and TBW are related to performance, irrespective of sex and type of sports (82)(83)(84). However, due to the different populations, investigation or intervention periods and measurement methodologies these findings should be taken with caution when extrapolating it to our results.…”

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“…Again, an increased TBW is predominantly due to an increment in ICW compartment. More recently, Silva et al (2014) found that although mean ICW did not change in elite basketball, handball & volleyball players in their study, but those players who increased the ICW pool increased strength and jumping performance from the beginning to the main competitive periods. This fact was further justified by our result as relative back strength was strong and significantly correlated with ICW % (Fig.…”