Rodrigo Celes

Effects of rest interval between exercise sets on blood pressure after resistance exercises

BACKGROUND Although studies have demonstrated the occurrence of postexercise hypotension (PEH) in resistance exercises, there is still no consensus on an ideal protocol. OBJECTIVE To evaluate the effects of different rest intervals (RI) between resistance exercise (RE) sets on postexercise blood pressure (BP). METHODS Sixteen sedentary non-hypertensive young men performed three RE protocols with RI of 1 (P1), 2 (2) and 3 (P3) minutes between the sets, as well as a control protocol (CON), in a counterbalanced manner. The RE protocols consisted of three sets of eight repetitions in six exercises. The loads used in the 1st, 2nd, and 3rd exercise sets were 80%, 70% and 60% of one repetition maximum (1RM), respectively. Measurements were taken at rest (RES), 15 (T15), 30 (T30), 45 (T45), 60 (T60), 75 (T75), and 90 (T90) minutes after the session. Factorial analysis of variance (Anova) was carried out, followed by post hoc LSD. RESULTS No significant change was found in systolic BP after the protocols. A significant increase in diastolic BP was verified after CON at timepoints T45 and T90. Significant reduction in diastolic BP occurred after P1 and P3, with duration of 30 and 15 minutes, respectively. No significant differences were found in the systolic and diastolic BP responses between the protocols with different RI. CONCLUSION RI does not seem to influence systolic BP reduction after an RE session. However, reductions in diastolic BP (P1 and P3) lasting up to 30 minutes were observed.FUNDAMENTO: Apesar de os estudos demonstrarem a ocorrencia da hipotensao pos-exercicio (HPE) em exercicios resistidos, ainda nao ha consenso sobre um protocolo ideal. OBJETIVO: Avaliar os efeitos de diferentes intervalos de recuperacao (IR) entre series de exercicio resistido (ER) na pressao arterial (PA) pos-exercicio. METODOS: Dezesseis homens jovens sedentarios e nao hipertensos realizaram, de forma contrabalanceada tres protocolos de ER com 1 (P1), 2 (P2) e 3 (P3) minutos de IR entre as series, e um protocolo controle (CON). Os protocolos de ER consistiram em tres series de oito repeticoes em seis exercicios. As cargas utilizadas na 1a, 2a e 3a serie dos exercicios foram respectivamente 80, 70 e 60% de 1 repeticao maxima (1RM). As medidas foram realizadas em repouso (REP), 15 (T15), 30 (T30), 45 (T45), 60 (T60), 75 (T75) e 90 (T90) minutos apos a sessao. Foi realizada uma analise de variância fatorial (ANOVA) com post hoc LSD. RESULTADOS: Nao foi encontrada alteracao significativa na PA sistolica apos os protocolos. Foi encontrado um aumento significativo da PA diastolica, apos o CON, nos momentos T45 e T90. Ocorreu reducao significativa na PA diastolica apos P1 e P3, com duracao de 30 e 15 minutos respectivamente. Nao foram encontradas diferencas significativas nas respostas da PA sistolica e diastolica entre os protocolos com diferentes IR. CONCLUSAO: Parece que o IR nao influencia a reducao da PA sistolica apos uma sessao de ER. No entanto, foi encontrada uma queda na PA diastolica (P1 e P3) com duracao de ate 30 minutos.

Efeitos de diferentes intervalos de recuperação no desempenho muscular isocinético em idosos

OBJECTIVE: To compare the effects of different rest intervals (RI) between sets of isokinetic contractions on muscle performance in older adults. METHODS: Twenty older participants (66.9±3.9 years; 76.1±13.4kg; 169±5.2cm) underwent three sessions of unilateral isokinetic training for the knee extensor muscles, with different RI (1 minute, 2 minutes and 3 minutes) at an angular velocity of 60°•s-1. Each session consisted of three sets of 10 repetitions, during which the peak torque (PT), total work (TW) and fatigue index (FI) were evaluated. Factorial ANOVA for repeated measurements, with Bonferroni post-hoc analysis, was used to identify possible differences between the RI. The statistical significance level was set at p 0.05). Although muscle performance was lower during the third sets with all RI, the greatest decreases in PT, TW and FI occurred with the 1 minute RI (p<0.05). CONCLUSIONS: The results showed that the RI variable has an important influence on isokinetic muscle performance in older adults, particularly from the third sets onwards, which suggests that RI should be increased as successive sets are performed within the same exercise session.

Avaliação muscular isocinética do quadríceps em indivíduos com doença pulmonar obstrutiva crónica

Rationale: Muscle debility has a significant impact on health-related quality of life in subjects with chronic obstructive pulmonary disease (COPD), and is correlated to exacerbation and even mortality. Assessing muscle strength is extremely relevant. Lack of standardisation in numbers of sets and rest interval in isokinetic test protocol can lead to distinct results, making comprehension and comparisons among studies difficult. Aim: To analyse the effect of two sets and three different rest intervals on isokinetic strength measurement of quadriceps tests, in order to define the adequate test protocol. Methods: Subjects with severe or very severe COPD underwent three isokinetic tests to evaluate knee extensor muscle strength, at an angular velocity of 60° · s− 1, with rest intervals of 30, 60 and 120 seconds. Each test consisted of two sets of five repetitions, during which peak torque, total work and fatigue index were measured. Results: In 20 studied subjects (66.1 ± 7.4 years, 70 ± 10.8 kg, 167.4 ± 6.2 cm, FEV1 36.5 ± 10.1%), there were no significant differences in peak torque, total work and fatigue index, independent of number of sets or rest interval between sets. Conclusion: In subjects with severe or very severe COPD, quadriceps muscle strength can be evaluated by an isokinetic protocol with one set of five repetitions. If two sets are performed, a rest interval of 30 seconds is enough to ensure muscle recovery between sets. Rev Port Pneumol 2010; XVI (5): 717-736

Efeitos do intervalo de recuperação entre as séries sobre a pressão arterial após exercícios resistidos

BACKGROUND Although studies have demonstrated the occurrence of postexercise hypotension (PEH) in resistance exercises, there is still no consensus on an ideal protocol. OBJECTIVE To evaluate the effects of different rest intervals (RI) between resistance exercise (RE) sets on postexercise blood pressure (BP). METHODS Sixteen sedentary non-hypertensive young men performed three RE protocols with RI of 1 (P1), 2 (2) and 3 (P3) minutes between the sets, as well as a control protocol (CON), in a counterbalanced manner. The RE protocols consisted of three sets of eight repetitions in six exercises. The loads used in the 1st, 2nd, and 3rd exercise sets were 80%, 70% and 60% of one repetition maximum (1RM), respectively. Measurements were taken at rest (RES), 15 (T15), 30 (T30), 45 (T45), 60 (T60), 75 (T75), and 90 (T90) minutes after the session. Factorial analysis of variance (Anova) was carried out, followed by post hoc LSD. RESULTS No significant change was found in systolic BP after the protocols. A significant increase in diastolic BP was verified after CON at timepoints T45 and T90. Significant reduction in diastolic BP occurred after P1 and P3, with duration of 30 and 15 minutes, respectively. No significant differences were found in the systolic and diastolic BP responses between the protocols with different RI. CONCLUSION RI does not seem to influence systolic BP reduction after an RE session. However, reductions in diastolic BP (P1 and P3) lasting up to 30 minutes were observed.FUNDAMENTO: Apesar de os estudos demonstrarem a ocorrencia da hipotensao pos-exercicio (HPE) em exercicios resistidos, ainda nao ha consenso sobre um protocolo ideal. OBJETIVO: Avaliar os efeitos de diferentes intervalos de recuperacao (IR) entre series de exercicio resistido (ER) na pressao arterial (PA) pos-exercicio. METODOS: Dezesseis homens jovens sedentarios e nao hipertensos realizaram, de forma contrabalanceada tres protocolos de ER com 1 (P1), 2 (P2) e 3 (P3) minutos de IR entre as series, e um protocolo controle (CON). Os protocolos de ER consistiram em tres series de oito repeticoes em seis exercicios. As cargas utilizadas na 1a, 2a e 3a serie dos exercicios foram respectivamente 80, 70 e 60% de 1 repeticao maxima (1RM). As medidas foram realizadas em repouso (REP), 15 (T15), 30 (T30), 45 (T45), 60 (T60), 75 (T75) e 90 (T90) minutos apos a sessao. Foi realizada uma analise de variância fatorial (ANOVA) com post hoc LSD. RESULTADOS: Nao foi encontrada alteracao significativa na PA sistolica apos os protocolos. Foi encontrado um aumento significativo da PA diastolica, apos o CON, nos momentos T45 e T90. Ocorreu reducao significativa na PA diastolica apos P1 e P3, com duracao de 30 e 15 minutos respectivamente. Nao foram encontradas diferencas significativas nas respostas da PA sistolica e diastolica entre os protocolos com diferentes IR. CONCLUSAO: Parece que o IR nao influencia a reducao da PA sistolica apos uma sessao de ER. No entanto, foi encontrada uma queda na PA diastolica (P1 e P3) com duracao de ate 30 minutos.

Isokinetic muscle evaluation of quadriceps in patients with chronic obstructive pulmonary disease

RATIONALE Muscle debility has a significant impact on health-related quality of life in subjects with chronic obstructive pulmonary disease (COPD), and is correlated to exacerbation and even mortality. Assessing muscle strength is extremely relevant. Lack of standardisation in numbers of sets and rest interval in isokinetic test protocol can lead to distinct results, making com- prehension and comparisons among studies difficult. AIM To analyse the effect of two sets and three different rest intervals on isokinetic strength measurement of quadriceps tests, in order to define the adequate test protocol. METHODS Subjects with severe or very severe COPD underwent three isokinetic tests to evaluate knee extensor muscle strength, at an angular velocity of 60°⋅s⁻¹, with rest intervals of 30, 60 and 120 seconds. Each test consisted of two sets of five repetitions, during which peak torque, total work and fatigue index were measured. RESULTS In 20 studied subjects (66.1 ± 7.4 years, 70 ± 10.8 kg, 167.4 ± 6.2 cm, FEV₁ 36.5 ± 10.1%), there were no significant differences in peak torque, total work and fatigue index, independent of number of sets or rest interval between sets. CONCLUSION In subjects with severe or very severe COPD, quadriceps muscle strength can be evaluated by an isokinetic protocol with one set of five repetitions. If two sets are performed, a rest interval of 30 seconds is enough to ensure muscle recovery between sets.

Early phase adaptations of single vs. multiple sets of strength training on upper and lower body strength gains

The purpose of this study was to determine the effect of single sets vs. multiple sets on different muscle groups peak torque (PT) in untrained subjects. Twenty four untrained males were randomly assigned into one of two groups: 1) knee extension three sets and elbow flexion single set (3K-1E; n = 11), or 2) knee extension single set and elbow flexion three sets (1K-3E; n = 13). Subjects trained 2 days/week for 6 weeks and each workout consisted of 1 leg press exercise and 1 barbell curl. Training intensity started at 8 repetition maximum (RM). Strength was expressed as a concentric PT at 60 ◦ /s. ANOVA revealed that the increase in PT of the knee extensors from week 0 to 6 was significantly greater in the 3K-1E group (11.5%) than in the 1K-3E (4.0%) group, while no difference existed in the PT gains of the elbow flexors between 3K-1E (9.2%) and 1K-3E (7.8%). It was concluded that performing three sets of strength training is superior to one set for increasing strength of the knee extensors while single-set training protocols for the elbow flexors might be sufficient for untrained individuals in the early phases of a strength-training program.

Strength training with repetitions to failure does not provide additional strength and muscle hypertrophy gains in young women

This study investigated the effects of a 10-week resistance training to failure on neuromuscular adaptations in young women. Eighty-nine active young women were randomly assigned to one of three groups: 1) repetitions to failure (RF; three sets of repetitions to failure); 2) repetitions not to failure with equalized volume (RNFV; four sets of 7 repetitions); and 3) repetitions not to failure (RNF; three sets of 7 repetitions). All groups performed the elbow flexor exercise (bilateral biceps curl) and trained 2 days per week using 70% of 1RM. There were significant increases (p<0.05) in muscle strength after 5 (15.9% for RF, 18.4% for RNF, and 19.9% for RNFV) and 10 (28.3% for RF, 26.8% for RNF, and 28.3% for RNFV) weeks of training, with no significant differences between groups. Additionally, muscular endurance increased after 5 and 10 weeks, with no differences between groups. However, peak torque (PT) increased significantly at 180°.s-1 in the RNFV (13.7%) and RNF (4.1%) groups (p<0.05), whereas no changes were observed in the RF group (-0.5%). Muscle thickness increased significantly (p<0.05) in the RF and RNFV groups after 5 (RF: 8.4% and RNFV: 2.3%) and 10 weeks of training (RF: 17.5%, and RNFV: 8.5%), whereas no significant changes were observed in the RNF group (3.9 and 2.1% after 5 and 10 weeks, respectively). These data suggest that short-term training of repetitions to failure do not yield additional overall neuromuscular improvements in young women.

Relationship between ventilatory threshold and muscle fiber conduction velocity responses in trained cyclists.

The relationship between surface electromyography (SEMG) amplitude and the ventilatory threshold has been extensively studied. However, previous studies of muscle fiber conduction velocity (MFCV) are scarce and present insufficient evidence concerning the relationship between MFCV and metabolic responses during cycling. Based on that fact, the purpose of this study is twofold: (1) to investigate the existence of a MFCV threshold (MFCVT) during cycling and (2) to verify if this possible breakpoint is correlated with the ventilatory threshold (VT) and the SEMG threshold (SEMGT). Eight trained male cyclists (age 36.0±9.7years) performed an incremental cycling test with initial workload of 150W gradually incremented by 20Wmin(-1) until the exhaustion. Gas analyses were conducted using a breath-by-breath open-circuit spirometry and SEMG were registered from vastus lateralis in each pedaling cycle with a linear array of electrodes. A bi-segmental linear regression computer algorithm was used to estimate VT, MFCVT and SEMGT respectively in the carbon dioxide production (VCO2), MFCV and electromyography root mean square (EMG RMS) curves. The one way ANOVA for repeated measures did not reveal any significant difference among VT (77.1±7.5% of VO2max), MFCVT (80.3±10.4% of VO2max) and SEMGT (81.9±11.7% of VO2max). The Bland and Altman procedure confirmed a good concordance between SEMGT and VT (Bias=5.5 of %VO2max) as well as MFCVT and VT (Bias=5.2 of %VO2max). The present findings suggest that muscle fiber conduction velocity threshold is a valid and reliable non-invasive tool to obtain information about ventilatory threshold in trained cyclists.

Isokinetic work-to-surface electromyographic signal energy ratios as a muscular fatigue indicator

Efficiency of muscular work is usually measured as the relationship between work load and maximum exercise duration. The present study analyzes the efficiency feature as a ratio between mechanical work (WK) and the energy (E) of the surface electromyographic signal (SEMG). This relation (WK/ESEMG) was compared with the most common electromyographic descriptors and its behavior was observed during muscle fatigue. A total of sixteen healthy men (26.8 ± 4.7 yrs, 175.7 ± 4.7 cm, and 79.2 ± 9.4 kg) performed three sets of ten maximal concentric repetitions of dominant knee extension at 60º/s on an isokinetic dynamometer, with 1 minute of rest interval between the sets. The SEMG signals were recorded during the exercises. With the view to minimize the factors other than fatigue that also influence the SEMG descriptors behavior, the only isokinetic repetition phase considered for measurements was the load range. Statistical analyses showed significant correlations between WK/ESEMG and the traditional electromyographic fatigue indicators.

Efeito do intervalo de recuperação entre séries de extensões isocinéticas de joelho em homens jovens destreinados

OBJECTIVE: To assess the effect of two recovery intervals (RIs) between sets of isokinetic knee extension exercises on peak torque (PT) and total work (TW), among untrained young men. METHODS: Eighteen men (24.22±2.58 years; 80.42±11.41 kg) performed three sets of ten isokinetic extensions of the right knee, at 60° and 180°/s. The RIs between the sets were one and two minutes long, spread over two test days separated by a minimum of 48 hours. The work-to-recovery ratio was 1:3 and 1:6 for 60°/s, and 1:6 and 1:12 for 180°/s. The subjects had not participated in any resistance training programs within the last six months. The statistical analysis consisted of 2 x 3 repeated-measures ANOVA [RI (one or two minutes) x set (1st, 2nd or 3rd)]. The significance level was a<0.05. RESULTS: Neither one minute nor two minutes RIs maintained the PT and TW throughout the three sets (p<0.05). However, at 60°/s, two minutes RIs enabled better PT and TW in the second and third sets than one minute RIs (p<0.05). At 180°/s, two minutes RIs were only better (p<0.05) than one minute RIs for TW in the third set. CONCLUSION: This study indicated that, during an isokinetic training protocol, young men require more than two minutes of RI for full PT recovery at 60°/s and full TW recovery at 60°/s and 180°/s. However, better PT recovery can be attained with a 1:12 work-to-recovery ratio at 180°/s.