Treino de corrida não interfere no desempenho de força de membros superiores

Effect of High-Intensity Interval Treadmill Exercise on Subsequent Lower and Upper Limb Strength Performance

Purpose: The aim of this study was to analyze the acute effect of a treadmill high-intensity interval protocol on subsequent upper body and lower body strength exercise performance. Method: Sixteen young men had their maximal aerobic capacity and one-repetition maximum (1RM) determined and underwent four randomized conditions: a half-squat control session; a bench press control session; a treadmill interval protocol followed by a half-squat experimental session; and a treadmill interval protocol followed by a bench press experimental session. During the control sessions, four sets to failure for each exercise were performed at 80% of 1RM. In the experimental sessions, participants performed eight sprints of 40 s at 100% velocity of maximal oxygen uptake with 20 s of passive interval between them, followed by the same strength exercise protocol of the control sessions. The number of repetitions during each protocol and participants' heart rate (HR),and blood lactate concentration ([lac]) were compared pre and post protocols and exercises. Results: Fewer repetitions were completed in the experimental session compared to the control sessions (p < .001). Moreover, the reduction in number of repetitions performed was more evident in half-squat compared to bench press (p = .018). HR was higher at the end of sessions with the interval protocol for both exercises (p < .001). The [lac] was higher at the end of session with the interval protocol for half-squat (p = .003). Conclusions: These findings suggest that previous high-intensity interval running may impair subsequent strength exercise performance, but the magnitude of the negative effect is greater in the lower limbs.

High-intensity interval running impairs subsequent upper limb strength performance

BACKGROUND

This study compared the effect of treadmill running on subsequent upper limb exercise performance in young men.

METHODS

Seventeen young men (24.8±5.2 years) completed a: 1) bench press resistance exercise control session; 2) treadmill interval running protocol followed by the bench press session; and 3) treadmill continuous running protocol followed by the bench press session. Four sets of the bench press exercise were performed at 80% of 1RM up to volitional failure. In the interval protocol, eight sprints of 40s at 100% of the velocity of maximal oxygen uptake, with 20s of passive interval between them were performed, whereas in the continuous protocol 30-min of treadmill running at 90% of the heart rate corresponding to second ventilatory threshold was performed. The number of maximal repetitions completed in each set and condition was recorded and compared using a two-way repeated measures ANOVA.

RESULTS

The interval protocol (18.7±4.9 repetitions) resulted in a reduction in the number of bench press repetitions compared to the control protocol (21.4±5.4 repetitions) (P=0.002); whereas continuous running did not affect the bench press performance (20.6±4.4 repetitions). The total number of repetitions reduced from set to set in all protocols (P<0.001).

CONCLUSIONS

The results evidenced an impairment in the upper limb strength performance after high intensity interval, but not moderate intensity continuous running, which has implication for concurrent training planning and prescription.

THE EFFECT OF BCAA ON ISOMETRIC FORCE FOLLOWING ENDURANCE EXERCISE IN A HOT ENVIRONMENT

ABSTRACT Introduction: Fatigue due to endurance exercise results from both peripheral and central changes, and may influence subsequent performance during a strength task. The increase in serotonin concentration is one of the central factors associated with endurance exercise-induced fatigue, particularly in hot environments. A nutritional strategy employed to reduce serotonergic activation is supplementation with branched-chain amino acids (BCAA). Objective: To investigate whether BCAA supplementation attenuates the reduction in isometric force caused by prior endurance exercise in a hot environment. Methods: Nine volunteers (aged 25.4 ± 1.2 years) performed a 2-min maximal voluntary isometric contraction (MVCISO) of upper limb muscles before and after an endurance exercise on a cycle ergometer at 40% of the maximal aerobic power. The volunteers underwent three experimental trials: 1) endurance exercise in a temperate environment (23°C and 60% RH); exercise in a hot environment (35°C and 60% RH) with the ingestion of: 2) a placebo solution or 3) a solution containing BCAA 30 mg.kg−1. During the MVCISO test, the isometric force of flexor muscles of the right elbow, core body temperature (TCORE) and heart rate (HR) were measured. Results: Isometric force decreased following endurance exercise in the hot environment, and BCAA administration did not attenuate this reduction. Greater TCORE and HR values were observed following endurance exercise in the heat, compared to pre-exercise values, and supplementation did not interfere with these physiological responses. Conclusion: The reduction in isometric force, caused by previous endurance exercise in a hot environment, was not diminished by supplementation with BCAA. Level of evidence I; Type of study: Therapeutic studies - Investigation of treatment outcomes.

Diferentes aquecimentos no desempenho de repetições máximas na musculação

Introdução: Apesar do aquecimento ser considerado essencial na prática dos esportes, pouco se conhece sobre seu efeito no treinamento de força.Objetivo: Avaliar o efeito de diferentes estratégias de aquecimento no desempenho neuromuscular em adultos jovens submetidos a testes de repetições máximas de membro superior e inferior.Métodos: Dois experimentos foram realizados separadamente. Para o primeiro experimento, 16 adultos jovens hígidos realizaram um teste de repetições máximas a 70% de 1RM no supino reto (previamente determinado). Quatro condições de aquecimento foram testadas: Controle (CON) sem aquecimento prévio, esteira (EST) 5' a 60% VO2max, resistência de força (REF) 15 repetições com 40% de 1RM e força máxima (FM) duas séries de duas repetições com 90% de 1RM. Para o segundo experimento, 14 adultos jovens hígidos, realizaram um teste de repetições máximas a 70% de 1RM no leg press unilateral (previamente determinado). Cinco condições de aquecimento foram testadas: controle (CON) sem aquecimento prévio, esteira (EST) 5' a 60% VO2max, bicicleta (BIC) 5' a 60% VO2max, resistência de força (REF) 15 repetições com 40% de 1RM e força máxima (FM) duas séries de duas repetições com 90% de 1RM. Para ambos os experimentos o número de repetições realizadas e a percepção subjetiva de esforço foram avaliadas.Resultados: Para o primeiro experimento o protocolo FM foi superior a todos os outros protocolos. Não foram observadas diferenças entre as outras condições. Para o segundo experimento, foi observado diferenças entre todos os protocolos, exceto CON e EST. Sendo FM>BIC>REF>EST=CON.Conclusão: Os resultados do presente estudo sugerem que um aquecimento de força máxima levou a uma maior produção de força para os membros superiores e inferiores. Adicionalmente, aquecimentos aeróbios e de resistência de força apresentaram melhora no desempenho de força para os membros inferiores em uma menor magnitude.