Airflow-Restricting Mask Reduces Acute Performance in Resistance Exercise.

BACKGROUND: The aim of this study was to compare the number of repetitions to volitional failure, the blood lactate concentration, and the perceived exertion to resistance training with and without an airflow-restricting mask. METHODS: Eight participants participated in a randomized, counterbalanced, crossover study. Participants were assigned to an airflow-restricting mask group (MASK) or a control group (CONT) and completed five sets of chest presses and parallel squats until failure at 75% one-repetition-maximum test (1RM) with 60 s of rest between sets. Ratings of perceived exertion (RPEs), blood lactate concentrations (Lac-), and total repetitions were taken after the training session. RESULTS: MASK total repetitions were lower than those of the CONT, and (Lac-) and MASK RPEs were higher than those of the CONT in both exercises. CONCLUSIONS: We conclude that an airflow-restricting mask in combination with resistance training increase perceptions of exertion and decrease muscular performance and lactate concentrations when compared to resistance training without this accessory. This evidence shows that the airflow-restricting mask may change the central nervous system and stop the exercise beforehand to prevent some biological damage.

Muscle lesions and inflammation in futsal players according to their tactical positions.

A futsal player's performance depends on his technical and tactical skills but may be improved by a less harmful inflammatory profile that is better adjusted to his tactical position in the game. Thus, the purpose of this study was to characterize muscle lesion and inflammation in futsal players according to their positions in an official match. The participants in this study were 5 goalkeepers (23 ± 1.2 years old, body mass = 74 ± 2.5 kg, height = 178 ± 3.2 cm, body fat = 13 ± 2%, VO2max = 40 ± 2 ml·kg(-1)), 8 defenders (21 ± 1 years, body mass = 69 ± 2 kg, height = 174 ± 1 cm, body fat = 10 ± 2%, VO2max 42 ± 1 ml·kg(-1)), 8 wingers (22 ± 1 years, body mass = 68 ± 2 kg, height = 169 ± 3 cm, body fat = 11 ± 2%, VO2max = 48 ± 1 ml·kg(-1)), and 8 pivots (25 ± 2 years, body mass 71 ± 2 kg, height 173 ± 2 cm, body fat 10 ± 2%, VO2max 46 ± 2 ml·kg(-1)). Blood samples were collected from the participants before and immediately after a match. Muscle damage was detected based on CK and lactate dehydrogenase (LDH) activity. The inflammatory status was evaluated by determining C-reactive protein and cytokines (TNF-α, interleukin [IL]-1ß, IL-6, IL-10, and IL-1ra). Goalkeepers showed higher LDH and IL-6 than players occupying other tactical positions, leading to the conclusion that the tactical position of futsal goalkeeper causes more inflammation and muscle damage than other positions. Moreover, this position is usually occupied by athletes with higher body mass and percentage of body fat and lower VO2max than players in the other positions.