OBJECTIVE: This study investigated the acute hemodynamic responses to multiple sets of passive stretching exercises performed with and without the Valsalva maneuver. METHODS: Fifteen healthy men aged 21 to 29 years with poor flexibility performed stretching protocols comprising 10 sets of maximal passive unilateral hip flexion, sustained for 30 seconds with equal intervals between sets. Protocols without and with the Valsalva maneuver were applied in a random counterbalanced order, separated by 48-hour intervals. Hemodynamic responses were measured by photoplethysmography pre-exercise, during the stretching sets, and post-exercise. RESULTS: The effects of stretching sets on systolic and diastolic blood pressure were cumulative until the fourth set in protocols performed with and without the Valsalva maneuver. The heart rate and rate pressure product increased in both protocols, but no additive effect was observed due to the number of sets. Hemodynamic responses were always higher when stretching was performed with the Valsalva maneuver, causing an additional elevation in the rate pressure product. CONCLUSIONS: Multiple sets of unilateral hip flexion stretching significantly increased blood pressure, heart rate, and rate pressure product values. A cumulative effect of the number of sets occurred only for systolic and diastolic blood pressure, at least in the initial sets of the stretching protocols. The performance of the Valsalva maneuver intensified all hemodynamic responses, which resulted in significant increases in cardiac work during stretching exercises.

Sabe-se pouco sobre os efeitos do envelhecimento na recuperação pós-esforço (RP). O estudo observou a RP em 15 idosos (GI, idade = 61 ± 1 anos) e 15 jovens (GJ, idade = 22 ± 2 anos) após atividades de três intensidades (IE) em cicloergômetro. Realizaram-se testes máximos, com incremento de 30W/min para GJ e de 25W/min após detecção de steady-state para GI. Posteriormente, os grupos pedalaram a 40% e 75% da carga máxima, respectivamente, 25 e 15 minutos. Foram acompanhados VO2, VCO2, V E e FC nos primeiros 15 minutos da RP nas três IE. O tratamento dos resultados compreendeu: a) teste de ajustamento das curvas experimentais a equações com uma ou duas exponenciais; b) cálculo do valor dos componentes para a equação mais ajustada; c) análise das constantes extraídas. Os desvios de ajustamento foram inferiores para uma curva de duas exponenciais, definida por integral de tempo na forma A/a +B/b. A/a designa a componente rápida da recuperação e B/b a lenta. Quando comparados os grupos, GI mostrou constantes maiores que GJ, evidenciando recuperação mais lenta nas duas fases. Subdividindo os componentes, em GI e GJ as constantes de velocidade de recuperação rápida (1/a) para VO2 e VCO2 foram semelhantes nas três IE, enquanto para a constante lenta (1/b), os valores para GI indicaram maior dependência em relação à carga. A recuperação da FC revelou-se extremamente dependente da IE para GJ. Para GI isso foi menos evidente, talvez por menor possibilidade de elevação da FC. A V E em GJ comportou-se de forma similar ao VO2 e VCO2. Porém, para GI as constantes de tempo foram mais lentas, mais associadas à IE que os demais parâmetros. Conclui-se: a) pode existir uma constante comum para a chamada 'fase alática' da curva de recuperação do VO2 e do VCO2, independentemente da IE e da idade; b) as diferenças entre GJ e GI podem dever-se às menores potência aeróbia máxima, termorregulação e eficácia do tampão respiratório nos idosos.

Few data are available about post-exercise recovery (PR) and the aging process. Recovery of VO2, VCO2, V E and HR was observed at different exercise loads (EL) on cyclo-ergometer. A group of 10 young (GJ, age = 22 ± 2 years) and 10 elderly subjects (GI, age = 61 ± 1 years) performed maximal tests. A 30 W/min load incremental was applied to GJ and a 25 W/min after steady-state for GI. Also, subjects performed exercise at 40% and 75% of peak VO2, during 25 and 15 minutes respectively. VO2, VCO2, V E and HR were measured during the first 15 minutes of PR for the three EL. Results analysis was made by: a) testing experimental data residuals for one and two exponential equations; b) determining the better equation components; c) analysis of extracted constants. Deviations were smaller for a two exponential function, defined by S = 0ò¥ x(t)dt = A/a + B/b. A/a designs PR fast component and B/b the slower one. When groups were compared, GI had higher constants than GJ, showing a slower recovery at both phases. GI and GJ constants for PR fast phase (1/a) were similar at all EI for VO2 and VCO2. Results suggested a greater dependence of exercise load for PR slower constant (1/b) in GI. HR recovery has shown to be very much associated to EL in GJ, with time course PR being directly affected by exercise load. The same results were not observed for GI, maybe because of elderly limited HR upward drift potential. Data for V E recovery were similar to those observed for VO2 and VCO2 in GJ. However, GI constants were slower, more associated to EL than the other parameters. The authors conclude that: a) there can be a common constant for the 'alatic phase' of PR for VO2 and VCO2, independent of EL and age; b) differences between GJ and GI can be due to lower maximal aerobic capacity, thermoregulation and age-related reduced CO2 chemosensitivity, delaying elimination of the exercise-induced CO2 load.