RESUMO
The effects of different resistance exercises on cardiovascular responses remain elusive. Therefore, the present study aimed to investigate acute cardiovascular responses to unilateral and bilateral upper and lower limb resistance exercise. Young healthy males (n = 22; 26.9 ± 5.4 years, 170.0 ± 6.0 cm, 77.0 ± 10.8 kg) participated in the present study. Four experimental sessions were carried out, each consisting of one of the four exercises: unilateral and bilateral knee extension, unilateral and bilateral biceps curl. Cardiovascular responses (heart rate; HR, systolic blood pressure; SBP, and rate-pressure product; RPP) were measured at rest and after each of the three sets in each resistance exercise. All sets were performed until concentric muscle failure with a rest interval of two min. The HR, SBP, and RPP progressively increased during all sessions with uni- and bilateral exercises of the lower and upper limbs. Importantly, bilateral exercises, mainly of the lower limbs, induced greater increases in HR, and RPP than unilateral exercises of the upper and lower limbs. Regarding SBP, bilateral knee extension exercise induced greater increases than unilateral biceps curl. From a practical standpoint, exercise professionals may consider prescribing unilateral upper and lower limb exercises to alleviate cardiovascular stress, because even when performed until concentric muscle failure, this exercise mode seems to induce lower cardiovascular demand during the resistance training session.
RESUMO
o estudo teve como objetivo verificar as adaptações geradas pelo treinamento de força (TF) nos parâmetros neuromusculares e na composição corporal de adolescentes. A amostra foi composta por 10 adolescentes do sexo masculino (16,4 ± 1,0 anos), o protocolo de treinamento de força teve duração de 10 semanas com 3 sessões semanais, divididos em treinos A e B. Para comparação do desempenho, foram avaliadas variáveis antropométricas e composição corporal (estatura, peso, índice de massa corporal e percentual de gordura), bem como, neuromusculares, por meio da resistência muscular de membros superiores (teste de flexão de braços), força explosiva de membros inferiores (teste de salto horizontal), flexibilidade (teste de sentar e alcançar), e força muscular (supino, puxada e leg press 45º). Para comparar os resultados pré e pós intervenção foram utilizadas as diferenças de médias estandardizadas e seus respectivos intervalos de confiança (IC= 90%) e as probabilidades (maior/similar/menor). Foram encontrados aumentos substanciais entre os períodos pré e pós intervenção, para a resistência muscular localizada de membros superiores (92/7/1, Likely), um impacto benéfico de força no supino (86/11/2, Likely), puxada (82/15/3, Likely) e leg press 45° (84/14/2, Likely), e redução em média de 3% na gordura corporal. Os resultados contribuem para uma reflexão crítica em relação ao incentivo a prática de TF em adolescentes, pois com supervisão adequada, planejamento, individualização das cargas de treino e educação técnica correta de cada exercício, os riscos foram suprimidos e os benefícios amplificados.(AU)
Our aim was to investigate the adaptations caused by strength training (ST) in neuromuscular parameters and body composition of adolescents. The sample consisted of 10 male adolescents (16.4 ± 1.0 years) and the strength training protocol lasted 10 weeks with 3 weekly sessions, divided into training sessions A and B. Anthropometric variables and body composition (height, weight, body mass index and percentage of fat) as well as neuromuscular performance (upper limb endurance strength, horizontal jump height, flexibility and muscle strength in bench-press, lat pull-down and 45º leg press exercises). Pre- and post-intervention results were compared using standardized mean differences and their respective confidence intervals (CI = 90%) and likelihood (greater / similar / lower). Substantial increases were found between the pre- and post-intervention periods for upper-limb muscle endurance (92/7/1, Likely) and bench press (86/11/2, Likely), lat pull-down (82 / 15/3, Likely) and leg press (84/14/2, Likely) strength, while a beneficial reduction of 3% in body fat was observed. The results contribute to a critical reflection regarding the incentive to practice ST in adolescents. With proper supervision, planning, individualization of training loads and correct technical education of each exercise, the potential risks were suppressed and the benefits amplified.(AU)
