Ischemic Preconditioning and Placebo Intervention Improves Resistance Exercise Performance

Abstract

This study evaluated the effect of ischemic preconditioning (IPC) on resistance exercise performance in the lower limbs. Thirteen men participated in a randomized crossover design that involved 3 separate sessions (IPC, PLACEBO, and control). A 12-repetition maximum (12RM) load for the leg extension exercise was assessed through test and retest sessions before the first experimental session. The IPC session consisted of 4 cycles of 5 minutes of occlusion at 220 mm Hg of pressure alternated with 5 minutes of reperfusion at 0 mm Hg for a total of 40 minutes. The PLACEBO session consisted of 4 cycles of 5 minutes of cuff administration at 20 mm Hg of pressure alternated with 5 minutes of pseudo-reperfusion at 0 mm Hg for a total of 40 minutes. The occlusion and reperfusion phases were conducted alternately between the thighs, with subjects remaining seated. No ischemic pressure was applied during the control (CON) session and subjects sat passively for 40 minutes. Eight minutes after IPC, PLACEBO, or CON, subjects performed 3 repetition maximum sets of the leg extension (2-minute rest between sets) with the predetermined 12RM load. Four minutes after the third set for each condition, blood lactate was assessed. The results showed that for the first set, the number of repetitions significantly increased for both the IPC (13.08 ± 2.11; p = 0.0036) and PLACEBO (13.15 ± 0.88; p = 0.0016) conditions, but not for the CON (11.88 ± 1.07; p > 0.99) condition. In addition, the IPC and PLACEBO conditions resulted insignificantly greater repetitions vs. the CON condition on the first set (p = 0.015; p = 0.007) and second set (p = 0.011; p = 0.019), but not on the third set (p = 0.68; p > 0.99). No difference (p = 0.465) was found in the fatigue index and lactate concentration between conditions. These results indicate that IPC and PLACEBO IPC may have small beneficial effects on repetition performance over a CON condition. Owing to potential for greater discomfort associated with the IPC condition, it is suggested that ischemic preconditioning might be practiced gradually to assess tolerance and potential enhancements to exercise performance.

Pré-condicionamento isquêmico e desempenho: há viabilidade/racionalidade na sua aplicação?

“…Portanto, análises mais holísticas 28,30 e específicas ao subtipo de modalidade [31][32][33][34][35] são desejáveis. Outro ponto ressaltado em alguns estudos é que o efeito do IPC poderia ter base motivacional 18,20 , visto que alguns deles mostram que a aplicação da manobra de IPC repetidas vezes minimiza o desempenho físico 19,36 ao longo do tempo. O efeito placebo, altamente reconhecido em estudos sobre o desempenho humano 37 , portanto, precisa ser controlado e considerado na interpretação e tomada de decisão sobre qualquer estratégia 19,25 .…”

“…Ressaltamos que, apesar da "explosão" de publicações científicas sobre IPC e desempenho ocorrer a partir do estudo de Libonati e seus colegas em 2001, na verdade desde 1958 fisiologistas Alemães testaram o IPC como recursos ergogênico potencial e encontraram resultados controversos 8 . Porém, considerando a partir do "de novo" de Libonati e colaboradores, estudos relatam melhoria ou nenhum efeito agudo do IPC sobre o desempenho em atividades como ciclismo 17 , sprints, natação 18 , treinamento resistido 19,20 , futebol 21 e remo em apneia 22 . Também surgiram trabalhos tentando verificar efeito ergogênico do IPC sobre o processo de recuperação do desempenho 7,23,24 , com achados igualmente inconclusivos.…”

Ischemic preconditioning: Potential impact on exercise performance and underlying mechanisms

“…Furthermore, the authors reported that the number of repetitions during elbow flexion exercise significantly increased in the early sets, but they tended to decrease over four trials 25) . These two studies suggest that IPC has minor beneficial effects, but these apparently fade over time and may possibly have a placebo effect because, compared with control (CON), the SHAM condition also improved repetitions along with IPC 24,25) . Beaven et al (2012) compared the early (immediate) and late (24 h later) effects of IPC on power production, and they found that IPC showed beneficial effects in both periods 8) .…”

“…For example, IPC prolonged the time to failure during rhythmic handgrip at an intensity of 45% of maximal voluntary contraction (MVC) 23) . Marocolo et al (2016a) also reported that IPC and SHAM conditions resulted in significantly greater repetitions versus the control condition on the first and second sets, but not on the third set during leg extension at a 12 RM load 24) . Furthermore, the authors reported that the number of repetitions during elbow flexion exercise significantly increased in the early sets, but they tended to decrease over four trials 25) .…”

Efeito de jogo de futsal sobre o desempenho intermitente de alta intensidade em futebolistas amadoras

“…Com o número de estágios realizados, calculamos a distância total percorrida para cada futebolista. Com o propósito de evitar quaisquer efeitos placebo ou nocebo, comuns em estudos com testes de desempenho físico 23,24 as jogadoras não foram informadas sobre o real objetivo do presente trabalho. Apenas foi ressaltado que o objetivo era realizar o melhor desempenho possível nos testes.…”