Acute effects of an upper body repeated sprint protocol in hypoxia induced by voluntary hypoventilation

• Autor(a) principal: Rosa, Cristóvão Henriques da Cruz da
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.5/26099
• topic: Voluntary hypoventilation with low lung volume; Hypoxia; Repeated sprinting; Repeated sprinting in hypoxia; Arm cycle ergometer; Brazilian Jiu-Jitsu; Hipoventilação voluntária com baixo volume pulmonar; Hipoxia; Sprint repetido; Sprints repetidos em hipoxia; Ciclo-ergómetro de braços; Jiu-jitsu brasileiro; Domínio/Área Científica::Ciências Sociais::Outras Ciências Sociais

Voluntary hypoventilation at low lung volume (VHL) consists of breath holding with partly empty lungs after an exhalation, leading to the functional residual capacity (Woorons, 2014). When combining with exercise, VHL induces severe arterial oxygen desaturation, as well as muscular and cerebral deoxygenation, causing both an hypoxic and hypercapnic effect. When combined with repeated sprint exercise (RSE), VHL has showed great improvements in repeated sprint ability (RSA) attributed to enhanced glycolytic utilization and buffer capacity. Previous studies have analyzed a wide range of modalities, running, cycling, and swimming. Given that Brazilian Jiu Jitsu (BJJ) could benefit with this kind of training we propose to investigate metabolic, muscle oxygenation and performance acute effects of an upper body repeated sprint protocol with VHL. Eighteen male well trained BJJ athletes (mean ± SD; age 32 ± 7.3 years; body mass 73.75 ± 11.1 kg;) of national and international level participated in this study. This was an experimental study with a randomized crossover design. Participants performed three sessions, a familiarization session and two moments of evaluation, consisting of a repeated sprint protocol with normal breathing (RSN) and the other using the same repeated sprint protocol with VHL (RSH-VHL) in an arm cycle ergometer. Peak power output (PPO), mean power output (MPO) and total work (TW) were measured, also repeated sprint ability decrement score (RSAdecs) was calculated. Arterial oxygen saturation (SpO2), heart rate (HR), gas exchange and muscle concentrations of oxyhaemoglobin/myoglobin (O2Hb) and deoxyhaemoglobin/myoglobin (HHb) were continuously recorded throughout exercise. Blood lactate concentration ([La]) was measured at the end of the first (S1) and second set (S2). Bench press throw peak power (BPPPO) and isometric hand grip strength (HGiso) were recorded before and after the repeated sprint protocol in order to assess differences. RSN MPO (162 ± 3.83 SE) was greater than MPO in RSH-VHL (156 ± 4.0 SE), p<0.01. On the other hand, RSAdecs and bench press throw peak power drop after the repeated sprint protocol were not impacted by VHL. A significant SpO2 drop was observed at the end of the second set in RSH-VHL (97.62 ± 2.60) when compared with RSN (98.71 ± 1.86), p=0.03 but there were no significant changes in muscle deoxygenation. Blood lactate concentration was lower in RSH-VHL (8.04 ± 3.00) when compared with RSN (10.42 ± 2.55), p<0.01. Finally, RSH-VHL (31.12 ± 1.11 SE) induced greater V̇O2 when compared with the same exercise in normal breathing conditions (29.65 ± 0.87 SE), p=0.03. In conclusion this study revealed that although statistically significant the reduction of the arterial oxygen saturation with the utilization of ventilatory hypoventilation with low lung volume may not have been sufficient to induce significative levels of hypoxia. MPO and PPO were significantly affected by RSH-VHL but there was not a significant decrease in total work or RSAdecs. Blood lactate concentration and respiratory exchange ratio were lower in RSH-VHL when compared with RSN and V̇O2.was greater.