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Objective: To examine the effects of euhydration, mild-dehydration, rehydration, and ad libitum drinking on countermovement jump (CMJ), handgrip strength, and performance of balance error scoring system test (BESS). Methods: Eighteen healthy male subjects (mean[M]±standard deviation[SD]; age, 23±3y; body mass, 80.1 ± 9.7 kg; height, 175.8 ± 5.7 cm) participated in this study. Participants reported to the laboratory to perform CMJ, handgrip strength, and BESS with different hydration statuses (euhydrated, EUH; when they initially sensed thirst, THIRST; dehydrated, DEH; following 30 minutes of rehydration, REH; and following 24-h ad libitum drinking, AD). Results: CMJ at EUH (M±SD; 54.6 ± 3.0 cm) was significantly higher than DEH (52.8 ± 3.0 cm, p = 0.027) and REH (52.6 ± 2.8 cm, p < 0.001). However, there was no difference between DEH and REH (p = 0.643). CMJ at THIRST (54.9 ± 3.0 cm, p = 0.004) was higher than REH. Also, AD (53.8 ± 2.8 cm, p = 0.027) was higher than REH. In left handgrip strength, THIRST (48.6 ± 9.5 kg) was higher than EUH (46.7 ± 10.1 kg, p = 0.018), DEH (45.8 ± 10.0 kg, p = 0.013), REH (46.1 ± 9.5 kg, p = 0.004), and AD (47.1 ± 9.7 kg, p = 0.05). Additionally, in the single-leg stance on a foam pad, more BESS errors were found at THIRST (6 ± 2) compared to EUH (5 ± 2, p = 0.007) and AD (5 ± 2, p = 0.002). Conclusion: The findings of this study were: â¼2% of mild dehydration induced by 24-h fluid restriction decreased lower body power measured by CMJ, acute rehydration did not restore the loss of lower body power induced by dehydration, and â¼0.5-0.9% of dehydration did not decrease lower body power.
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Exercise-associated muscle cramps (EAMCs) are common and frustrating for athletes and the physically active. We critically appraised the EAMC literature to provide evidence-based treatment and prevention recommendations. Although the pathophysiology of EAMCs appears controversial, recent evidence suggests that EAMCs are due to a confluence of unique intrinsic and extrinsic factors rather than a singular cause. The treatment of acute EAMCs continues to include self-applied or clinician-guided gentle static stretching until symptoms abate. Once the painful EAMCs are alleviated, the clinician can continue treatment on the sidelines by focusing on patient-specific risk factors that may have contributed to the onset of EAMCs. For EAMC prevention, clinicians should obtain a thorough medical history and then identify any unique risk factors. Individualizing EAMC prevention strategies will likely be more effective than generalized advice (eg, drink more fluids).
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Cãibra Muscular , Exercícios de Alongamento Muscular , Humanos , Cãibra Muscular/etiologia , Cãibra Muscular/prevenção & controle , Atletas , Fatores de RiscoRESUMO
BACKGROUND: The aim of this study was to determine the physiological, perceptual, and exercise performance responses to breathing cooled air during and following exercise in the heat. METHODS: Twelve trained male cyclists (26±4 y; 180.5±5.6 cm; 56.4±7.5 mL/kg/min VÌO
Assuntos
Temperatura Alta , Gelo , Ciclismo , Regulação da Temperatura Corporal/fisiologia , Temperatura Baixa , Frequência Cardíaca/fisiologia , Humanos , MasculinoRESUMO
Current models of afferent inputs to the brain, which influence body water volume and concentration via thirst and drinking behavior, have not adequately described the interactions of subconscious homeostatic regulatory responses with conscious perceptions. The purpose of this investigation was to observe the interactions of hydration change indices (i.e., plasma osmolality, body mass loss) with perceptual ratings (i.e., thirst, mouth dryness, stomach emptiness) in 18 free-living, healthy adult men (age, 23 ± 3 y; body mass, 80.09 ± 9.69 kg) who participated in a 24-h water restriction period (Days 1-2), a monitored 30-min oral rehydration session (REHY, Day 2), and a 24-h ad libitum rehydration period (Days 2-3) while conducting usual daily activities. Laboratory and field measurements spanned three mornings and included subjective perceptions (visual analog scale ratings, VAS), water intake, dietary intake, and hydration biomarkers associated with dehydration and rehydration. Results indicated that total water intake was 0.31 L/24 h on Day 1 versus 2.60 L/24 h on Day 2 (of which 1.46 L/30 min was consumed during REHY). The increase of plasma osmolality on Day 1 (297 ± 4 to 299 ± 5 mOsm/kg) concurrent with a body mass loss of 1.67 kg (2.12%) paralleled increasing VAS ratings of thirst, desire for water, and mouth dryness but not stomach emptiness. Interestingly, plasma osmolality dissociated from all perceptual ratings on Day 3, suggesting that morning thirst was predominantly non-osmotic (i.e., perceptual). These findings clarified the complex, dynamic interactions of subconscious regulatory responses with conscious perceptions during dehydration, rehydration, and reestablished euhydration.