Acute effect of different stretching methods on isometric muscle strength / Efeito agudo de diferentes métodos de alongamento sobre a força muscular isométrica

This study investigated the acute effect of static stretching methods (SS) and proprioceptive neuromuscular facilitation (PNF) on the static muscle strength (SMS). Eleven young male subjects with strength training experience, performed 3 tests with a 48h interval between them, randomly selected, where each one subject carried out all procedures: a) hand grip without stretching; b) hand grip preceded by static stretching of wrist flexors muscles; c) hand grip preceded by PNF stretching of wrist flexors muscles. The Shapiro-Wilk test verified the normality of data, and a one-way ANOVA with repeated measures, followed by Tukey's post hoc test, evaluated the differences between the groups. The significance was set at p < 0.05. Significant differences were detected between control and static stretching protocols (35.4±11.30 vs. 30.2±9.18 kg N-1; p < 0.05). The same was observed between control and PNF stretching protocols (35.4±11.30 vs. 29.1±10.05 kg N-1; p < 0.01). However, no statistical difference was found for static and FNP stretching protocols (30.2±9.18 vs. 29.1±10.05 kg N-1; p > 0.05). In conclusion, both stretching methods had caused negative effects on isometric strength, reducing its levels.

. O presente estudo objetivou investigar o efeito agudo dos métodos de alongamento estático (AE) e facilitação neuromuscular proprioceptiva (FNP) sobre a força muscular estática (FME). Foram realizados, em 11 homens jovens com experiência prévia em treinamento de força, três testes com intervalo de 48h entre a aplicação dos mesmos, selecionados aleatoriamente, fazendo com que cada sujeito realizasse todas as técnicas, em rodízio: a) teste de preensão manual sem alongamento; b) teste de preensão manual precedido por alongamento estático dos músculos flexores de punho; c) teste de preensão manual precedido por FNP dos músculos flexores de punho. O teste de Shapiro-Wilk foi realizado para avaliar a normalidade dos dados e a one-way Anova com medida repetida, seguida por post-hoc de Tukey para análise das diferenças entre grupos. A significância adotada foi alpha p < 0,05. Conforme os resultados, entre os protocolos SA e AE, foram encontradas diferenças significativas na produção de força isométrica (35,4±11,30 vs. 30,2±9,18 kg N-1; p < 0,05). Entre SA e FNP, também foram encontradas diferenças significativas (35,4±11,30 vs. 29,1±10,05 kg N-1; p < 0,001). Todavia, diferenças significativas não foram observadas entre AE e FNP (30,2±9,18 vs. 29,1±10,05 kg N-1; p > 0,05). Os métodos de AE e FNP provocam efeito agudo sobre a FME reduzindo os níveis desta capacidade física.

Is blood lactate removal during water immersed cycling faster than during cycling on land?

The aim of the present study was to compare lactate removal during active recovery performed during cycling in water immersion (CW) and during cycling on land (CL), after a similar exercise bout in male adults. Eleven healthy and physically active men, aged between 20 and 26 years old participated in the experiment. Before the experimental tests, the ventilatory threshold of the subjects was determined. Each subject completed the experimental tests twice, with one week separating the two periods of experiment. The subjects exercised on the treadmill during 6 min at a speed 10% above the speed corresponding to their ventilatory threshold. Subsequently, the subjects recovered from the exercise bout either on a stationary bike (CL) or on a aquatic-specific bike (CW). On the subsequent week the subjects performed the same protocol but with a different recovery condition. Recovery condition assignment for the first test was counterbalanced (six subjects started with one condition and five with the other). Capillary blood samples were collected after each test and during the recovery period (at 3, 6, 9 and 15 minutes) and blood lactate was measured. The blood lactate values during CW were lower than during CL and significant differences were observed at the 6(th) minute (p ≤ 0.05) and at the 15(th) minute of recovery (p ≤ 0.05). Therefore, we may conclude that active recovery using cycling in water immersion may be more efficient than cycling on land for blood lactate removal. Key pointsPrevious studies have found positive effects of half liquid environment on blood lactate removal.However, few studies have compared lactate removal in half liquid and in dry land conditions with the use of stationary bikes.We have compared the lactate removal during active recovery on half-liquid cycling and active recovery on dry land cycling after a similar exercise bout in male adults.The blood lactate values during the recovery were lower after half-liquid cycling when compared with dry land cycling and significant differences were observed at the 6(th) minute and at the 15(th) minute of recovery.We may conclude that active recovery using half-liquid cycling may be more efficient than dry land cycling for blood lactate removal.