RESUMO
Abstract A specific drop jumps (DJs) protocol (using 100 jumps) has been largely used to induce muscle damage. However, it failed to show relevant drop in performance in well-trained individuals. Trained subjects may require a protocol with greater volume to induce decrease of muscle performance. The aim of this study was to assess muscle performance after two DJs damaging protocols with different volumes in well-trained individuals. Eighteen strength and/or power-trained males (4.92 ± 2.78 years of training experience) were randomly assigned into one of two groups: DJ100 (five sets of 20 DJs) or DJ140 (seven sets of 20 DJs), with 2-min of rest interval. DJs were performed from a 60-cm box. After landing, the volunteers performed a maximal vertical rebound jump. Muscle swelling increased significantly on both DJ100 and DJ140 (p < 0.001). Maximal isometric torque (MIT) decreased significantly on both DJ100 (p = 0.005) and DJ140 (p < 0.001). MIT showed no between-group difference on pre-assessment (p = 0.815). However, on post-assessment, MIT was significantly lower on DJ140 than DJ100 (p = 0.043). Countermovement jump (CMJ) decreased significantly on DJ140 (p = 0.001), but not on DJ100 (p = 0.802). There was no between-group difference on pre-assessment (p = 0.978). However, on post-assessment, CMJ was significantly lower on DJ140 than DJ100 (p = 0.038). DJ140 induced greater drop in isometric strength than DJ100 and only DJ140 significantly reduced jump performance. These results demonstrated that well-trained individuals require a great volume of DJs to reduce substantially muscle performance.
Resumo Um protocolo específico de Drop Jumps (DJs), com 100 saltos, tem sido amplamente utilizado para induzir o dano muscular. Entretanto, este protocolo tem falhado em mostrar uma queda relevante em indivíduos treinados. Objetivou-se avaliar o desempenho muscular após dois protocolos de DJs com diferentes volumes em indivíduos treinados. Dezoito homens treinados em força e/ou potência (4,92 ± 2,78 anos de treinamento) foram aleatoriamente designados em um dos dois grupos: DJ100 (cinco séries de 20 DJs) ou DJ140 (sete séries de 20 DJs), com 2 minutos entre as séries. Os DJs foram executados de uma caixa de 60 cm de altura. Após a aterrisagem, os voluntários executaram um salto vertical máximo. O inchaço muscular aumentou significativamente em ambos os grupos (p < 0,001). O torque isométrico máximo (TIM) reduziu significativamente tanto no DJ100 (p = 0,005) quanto no DJ140 (p < 0,001). O TIM não apresentou diferenças entre grupos no momento pré (p = 0,815). Entretanto, no momento pós, o TIM foi significativamente inferior no DJ140 em relação ao DJ100 (p = 0,043). O salto com contra movimento (SCM) reduziu significativamente no DJ140 (p = 0,001), mas não no DJ100 (p = 0,802). No momento pós, o SCM foi significativamente inferior no DJ140 em relação ao DJ100. O DJ140 induziu uma queda maior na força isométrica em relação do DJ100, e somente o DJ140 reduziu significativamente o desempenho no salto. Esses resultados demonstraram que indivíduos bem treinados requerem um grande volume DJs para reduzir substancialmente o desempenho muscular.
Assuntos
Humanos , Masculino , Adulto , Educação Física e Treinamento/métodos , Músculo Esquelético/lesões , Desempenho Atlético , Teste de EsforçoRESUMO
The purpose of this study was to investigate the effects of a single-dose of ß-hydroxy-ß-methylbutyrate free acid (HMB-FA) supplementation on muscle recovery after a high-intensity exercise bout. Twenty-three trained young males were randomly assigned to receive either a single-dose supplementation of 3 g of HMB-FA (n = 12; age, 22.8 ± 3.0 years) or placebo (PLA; n = 11; age, 22.9 ± 3.1 years). A muscle damage protocol was applied 60 min after supplementation, and consisted of 7 sets of 20 drop jumps from a 60-cm box with 2-min rest intervals between sets. Muscle swelling, countermovement jump (CMJ), maximal voluntary isometric torque (MVIT), and work capacity (WC) were measured before, immediately after, and 24, 48, and 72 h after the exercise protocol. Muscle swelling, CMJ, and MVIT changed similarly in both groups after the exercise protocol (p < 0.001), but returned to pre-exercise levels after 24 h in both groups. WC decreased similarly in both groups after the exercise protocol (p < 0.01). For HMB-FA, WC returned to pre-exercise level 24 h after exercise protocol. However, for PLA, WC did not return to pre-exercise level even 72 h after the exercise protocol. In summary, a single-dose of HMB-FA supplementation improved WC recovery after a high-intensity exercise bout. However, HMB-FA did not affect the time-course of muscle swelling, MVIT, and CMJ recovery.