Volume Load Rather Than Resting Interval Influences Muscle Hypertrophy During High-Intensity Resistance Training.

ABSTRACT: Longo, AR, Silva-Batista, C, Pedroso, K, de Salles Painelli, V, Lasevicius, T, Schoenfeld, BJ, Aihara, AY, de Almeida Peres, B, Tricoli, V, and Teixeira, EL. Volume load rather than resting interval influences muscle hypertrophy during high-intensity resistance training. J Strength Cond Res 36(6): 1554-1559, 2022-Interset rest interval has been proposed as an important variable for inducing muscle mass and strength increases during resistance training. However, its influence remains unclear, especially when protocols with differing intervals have equalized volume. We aimed to compare the effects of long (LI) vs. short rest interval (SI) on muscle strength (one repetition maximum [1RM]) and quadriceps cross-sectional area (QCSA), with or without equalized volume load (VL). Twenty-eight subjects trained twice a week for 10 weeks. Each subject's leg was allocated to 1 of 4 unilateral knee extension protocols: LI, SI, SI with VL -matched by LI (VLI-SI), and LI with VL-matched by SI (VSI-LI). A 3-minute rest interval was afforded in LI and VSI-LI protocols, while SI and VLI-SI employed a 1-minute interval. All subjects trained with a load corresponding to 80% 1RM. One repetition maximum and QCSA were measured before and after training. All protocols significantly increased 1RM values in post-training (p < 0.0001; LI: 27.6%, effect size [ES] = 0.90; VLI-SI: 31.1%, ES = 1.00; SI: 26.5%, ES = 1.11; and VSI-LI: 31.2%, ES = 1.28), with no significant differences between protocols. Quadriceps cross-sectional area increased significantly for all protocols in post-training (p < 0.0001). However, absolute changes in QCSA were significantly greater in LI and VLI-SI (13.1%, ES: 0.66 and 12.9%, ES: 0.63) than SI and VSI-LI (6.8%, ES: 0.38 and 6.6%, ES: 0.37) (both comparisons, p < 0.05). These data suggest that maintenance of high loads is more important for strength increases, while a greater VL plays a primary role for hypertrophy, regardless of interset rest interval.

Muscle Failure Promotes Greater Muscle Hypertrophy in Low-Load but Not in High-Load Resistance Training.

ABSTRACT: Lasevicius, T, Schoenfeld, BJ, Silva-Batista, C, Barros, TdS, Aihara, AY, Brendon, H, Longo, AR, Tricoli, V, Peres, BdA, and Teixeira, EL. Muscle failure promotes greater muscle hypertrophy in low-load but not in high-load resistance training. J Strength Cond Res 36(2): 346-351, 2022-The purpose of this study was to investigate the effects of an 8-week resistance training program at low and high loads performed with and without achieving muscle failure on muscle strength and hypertrophy. Twenty-five untrained men participated in the 8-week study. Each lower limb was allocated to 1 of 4 unilateral knee extension protocols: repetitions to failure with low load (LL-RF; ∼34.4 repetitions); repetitions to failure with high load (HL-RF; ∼12.4 repetitions); repetitions not to failure with low load (LL-RNF; ∼19.6 repetitions); and repetitions not to failure with high load (HL-RNF; ∼6.7 repetitions). All conditions performed 3 sets with total training volume equated between conditions. The HL-RF and HL-RNF protocols used a load corresponding to 80% 1 repetition maximum (RM), while LL-RF and LL-RNF trained at 30% 1RM. Muscle strength (1RM) and quadriceps cross-sectional area (CSA) were assessed before and after intervention. Results showed that 1RM changes were significantly higher for HL-RF (33.8%, effect size [ES]: 1.24) and HL-RNF (33.4%, ES: 1.25) in the post-test when compared with the LL-RF and LL-RNF protocols (17.7%, ES: 0.82 and 15.8%, ES: 0.89, respectively). Quadriceps CSA increased significantly for HL-RF (8.1%, ES: 0.57), HL-RNF (7.7%, ES: 0.60), and LL-RF (7.8%, ES: 0.45), whereas no significant changes were observed in the LL-RNF (2.8%, ES: 0.15). We conclude that when training with low loads, training with a high level of effort seems to have greater importance than total training volume in the accretion of muscle mass, whereas for high load training, muscle failure does not promote any additional benefits. Consistent with previous research, muscle strength gains are superior when using heavier loads.

Blood Flow Restriction Does Not Attenuate Short-Term Detraining-Induced Muscle Size and Strength Losses After Resistance Training With Blood Flow Restriction.

ABSTRACT: Teixeira, EL, de Salles Painelli, V, Silva-Batista, C, de Souza Barros, T, Longo, AR, Lasevicius, T, Schoenfeld, BJ, Aihara, AY, and de Almeida Peres, B. Blood flow restriction does not attenuate short-term detraining-induced muscle size and strength losses after resistance training with blood flow restriction. J Strength Cond Res 35(8): 2082-2088, 2021-After a short-term resistance training with blood flow restriction (BFR), we investigated the effects of 12 days of detraining (DET), without an exercise stimulus, on quadriceps cross-sectional area (QCSA) and muscle strength (1 repetition maximum [1RM]), with 1 leg receiving daily intermittent BFR during DET vs. the same nonexercise condition without BFR (CON) in the contralateral leg. Both subjects' legs were evaluated for QCSA and 1RM before (PRE) and after (POST) both legs being unilaterally submitted to 3 weeks (4 days per week) of low-load (3 sets of 15 repetitions, 30% 1RM) resistance training with BFR. The DET period started immediately after POST, where each leg was randomly submitted to a daily intermittent BFR protocol or CON, without any associated exercise stimulus. Quadriceps cross-sectional area and 1RM were reassessed after DET. Both legs at CON and BFR conditions increased QCSA (6.3 and 6.8%, respectively; both p < 0.0001) and 1RM (9.5 and 10.1%, respectively; both p < 0.05) from PRE to POST. Both legs at CON and BFR conditions reduced QCSA (-4.6 and 4.9%, respectively; both p < 0.0001) and 1RM (-9.0 and -8.2%, respectively; both p < 0.05) from POST to DET, with no significant differences between conditions (p > 0.05). We conclude that muscle strength and hypertrophy gains obtained in 3 weeks of resistance training with BFR are not maintained after 12 days of DET. Moreover, the application of BFR, without an associated exercise stimulus, does not attenuate such losses.

Varying the Order of Combinations of Single- and Multi-Joint Exercises Differentially Affects Resistance Training Adaptations.

Brandão, L, de Salles Painelli, V, Lasevicius, T, Silva-Batista, C, Brendon, H, Schoenfeld, BJ, Aihara, AY, Cardoso, FN, de Almeida Peres, B, and Teixeira, EL. Varying the order of combinations of single- and multi-joint exercises differentially affects resistance training adaptations. J Strength Cond Res 34(5): 1254-1263, 2020-Our study aimed to compare the effects of multi-joint (MJ) and single-joint (SJ) exercises, either isolated or in combination, and in different orders, on cross-sectional area (CSA) of the pectoralis major (PM) and different heads of the triceps brachii (TB), as well as on the one-repetition maximum (1-RM) in the bench press and lying barbell triceps press. Forty-three young men were randomly assigned to one of 4 possible RT protocols: barbell bench press plus lying barbell triceps press (MJ + SJ, n = 12); lying barbell triceps press plus barbell bench press (SJ + MJ, n = 10); barbell bench press (MJ, n = 10); or lying barbell triceps press (SJ, n = 11). Results showed significant within-group increases in 1-RM bench press for MJ, MJ + SJ, and SJ + MJ but not for SJ. Conversely, significantly greater within-group increases in elbow extension 1-RM were noted for SJ, MJ + SJ, and SJ + MJ but not for MJ. Significantly greater increases in PM CSA were observed for MJ, MJ + SJ, and SJ + MJ compared with SJ. Significant increases in TB CSA were noted for SJ, MJ + SJ, and SJ + MJ, but not for MJ, without observed between-group differences. Individual analysis of TB heads showed significantly greater CSA increases in the lateral head for MJ, MJ + SJ, and SJ + MJ compared with SJ. Alternatively, significantly greater increases in the long head were observed for SJ, MJ + SJ, and SJ + MJ compared with MJ. CSA increases for the medial head were statistically similar between conditions. Our findings indicate that muscular adaptations are differentially affected by performance of MJ and SJ exercises.

Differential muscle hypertrophy and edema responses between high-load and low-load exercise with blood flow restriction.

We sought to determine whether early increases in cross-sectional area (CSA) of different muscles composing the quadriceps with low-load resistance training with blood flow restriction (LL-BFR) were mainly driven by muscle hypertrophy or by edema-induced swelling. We also compared these changes to those promoted by high-load resistance training (HL-RT). In a randomized within-subject design, fifteen healthy, untrained men were submitted to magnetic resonance imaging (MRI) for CSA and edema-induced muscle swelling assessment (fast spin echo inversion recovery, FSE-STIR). MRI was performed in LL-BFR and HL-RT at baseline (W0) and after 3 weeks (W3), with a further measure after 6 weeks (W6) for HL-RT. Participants were also assessed at these time points for indirect muscle damage markers (range of motion, ROM; muscle soreness, SOR). CSA significantly increased for all the quadriceps muscles, for both LL-BFR and HL-RT at W3 (all P < .05) compared to W0. However, FSE-STIR was elevated at W3 for all the quadriceps muscles only for HL-RT (all P < .0001), not LL-BFR (all P > .05). Significant increases and decreases were shown in SOR and ROM, respectively, for HL-RT in W3 compared to W0 (both P < .05), while these changes were mitigated at W6 compared to W0 (both P > .05). No significant changes in SOR or ROM were demonstrated for LL-BFR across the study. Early increases in CSA with LL-BFR seem to occur without the presence of muscle edema, whereas initial gains obtained by HL-RT were influenced by muscle edema, in addition to muscle hypertrophy.

Similar Muscular Adaptations in Resistance Training Performed Two Versus Three Days Per Week.

The purpose of the present study was to compare changes in muscle strength and hypertrophy between volume-equated resistance training (RT) performed 2 versus 3 times per week in trained men. Thirty-six resistance-trained men were randomly assigned to one of the two experimental groups: a split-body training routine (SPLIT) with muscle groups trained twice per week (n = 18) over four weekly sessions, or a total-body routine (TOTAL), with muscle groups being trained three times per week (n = 18) over three weekly sessions. The training intervention lasted 10 weeks. Testing was carried out pre- and post-study to assess maximal muscular strength in the back squat and bench press, and hypertrophic adaptations were assessed by measuring muscle thickness of the elbow flexors, elbow extensors, and quadriceps femoris. Twenty-eight subjects completed the study. Significant pre-to-post intervention increases in upper and lower-body muscular strength occurred in both groups with no significant between-group differences. Furthermore, significant pre-to-post intervention increases in muscle size of the elbow extensors and quadriceps femoris occurred in both groups with no significant between-group differences. No significant pre-to-post changes were observed for the muscle size of elbow flexors both in the SPLIT or TOTAL group. In conclusion, a training frequency of 2 versus 3 days per week produces similar increases in muscular adaptations in trained men over a 10-week training period. Nonetheless, effect size differences favored SPLIT for all hypertrophy measures, indicating a potential benefit for training two versus three days a week when the goal is to maximize gains in muscle mass.

Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy.

The present study investigated the effects of different intensities of resistance training (RT) on elbow flexion and leg press one-repetition maximum (1RM) and muscle cross-sectional area (CSA). Thirty men volunteered to participate in an RT programme, performed twice a week for 12 weeks. The study employed a within-subject design, in which one leg and arm trained at 20% 1RM (G20) and the contralateral limb was randomly assigned to one of the three conditions: 40% (G40); 60% (G60), and 80% 1RM (G80). The G20 started RT session with three sets to failure. After G20 training, the number of sets was adjusted for the other contralateral limb conditions with volume-matched. CSA and 1RM were assessed at pre, post-6 weeks, and post-12 weeks. There was time effect for CSA for the vastus lateralis (VL) (8.9%, 20.5%, 20.4%, and 19.5%) and elbow flexors (EF) (11.4%, 25.3%, 25.1%, and 25%) in G20, G40, G60, and G80, respectively (p > .05). G80 showed higher CSA than G20 for VL (19.5% vs. 8.9%) and EF (25% vs. 11.4%) at post-12 weeks (p < .05). There was time effect for elbow flexion and unilateral leg press strength for all groups post-12 weeks (p < .05). However, the magnitude of increase was higher in G60 and G80. In conclusion, when low to high intensities of RT are performed with volume-matched, all intensities were effective for increasing muscle strength and size; however, 20% 1RM was suboptimal in this regard, and only the heavier RT intensity (80% 1RM) was shown superior for increasing strength and CSA compared to low intensities.

Efeito da ordem dos exercícios de força sobre o volume, o lactato e o desempenho / Effect of the order of strength exercises on volume, lactate and performance / Efecto de la orden de los ejercicios de fuerza en el volumen, lactato y rendimiento

RESUMO Introdução: A alternância entre segmentos corporais para prescrição do treinamento de força (TF) é amplamente utilizada, entretanto seus efeitos permanecem desconhecidos. Objetivo: Verificar o efeito agudo da manipulação da ordem dos exercícios do TF, alternando segmentos corporais, sobre a força dinâmica máxima (1 RM) de membros inferiores (MMII) e superiores (MMSS), a concentração de lactato sanguíneo [La], a percepção subjetiva de esforço (PSE) e o volume total de treino (VT). Métodos: Dezoito homens (23,1 ± 3,8 anos; 78,4 ± 8,6 kg; 1,72 ± 0,06 m) executaram três condições de TF: condição A (supino reto, desenvolvimento, rosca Scott, meio-agachamento, leg press, cadeira extensora); condição B (meio-agachamento, leg press, cadeira extensora, supino reto, desenvolvimento, rosca Scott) e condição C (supino reto, meio-agachamento, desenvolvimento, leg press, rosca Scott e cadeira extensora). Os exercícios foram executados com três séries de 10 RM. Os testes de 1 RM para MMII e MMSS foram realizados nas semanas iniciais e após as condições experimentais. As coletas de sangue foram feitas no repouso [T0], imediatamente após [IA], 3 [T3] e 5 minutos [T5] após cada condição. A PSE de MMSS, MMII e geral, e o VT foram mensurados ao final de cada condição. Resultados: A 1 RM foi reduzida depois da sessão em todas as condições tanto para MMSS (A = -19,4%; B = -23,0%; C = -22,8%) quanto para MMII (A = -16,2%; B = -15,3%; C = -16,1%) sem diferença entre condições. A PSE apresentou resultados similares entre as condições (Condição A = 8,4; Condição B = 8,7; Condição C = 8,7). Houve aumento significante no La no momento T3 da condição C comparado com as outras condições: (C = 7,29 mmol.L-1; A = 6,60 mmol.L -1; B = 6,51 mmol.L-1) (p < 0,0001). O VT na condição C (16.169,4 ± 2.562,5 kg) foi superior às condições A (13.222,2 ± 2.010,4 kg) e B (13.989,8 ± 2.223,4 kg) (p < 0,0001). Conclusão: Os resultados sugerem que somente o VT e a demanda metabólica foram mais afetados pela ordem dos exercícios.

ABSTRACT Introduction: The alternation between body segments for prescription of strength training (ST) is widely used; however, its effects remain unknown. Objective: To verify the acute effect of the manipulation of the order of ST exercises, alterna-ting body segments, on the maximum dynamic force (1 RM) of lower limbs (LL) and upper limbs (UL), blood lactate [La] concentration, subjective perception of effort (SPE) and the total training volume (TV). Methods: Eighteen men (23.1±3.8 years; 78.4±8.6 kg; 1.72±0.06 m) performed three ST conditions: condition A: (bench press, shoulder press, preacher arm curl, half squat, leg press, leg extension); condition B (half squat, leg press, leg extension, bench press, shoulder press, preacher arm curl) and condition C (bench press, half squat, shoulder press, leg press, preacher arm curl, leg extension). The exercises were performed in three sets of 10 RM. The 1 RM tests for LL and UL were performed in the initial weeks and after the experimental conditions. Blood samples were taken at rest [T0], immediately after [IA], 3 [T3], and 5 minutes [T5] after each condition. SPE of UL, LL, and general, and VT were measured at the end of each condition. Results: The 1 RM was reduced after the session in all conditions for both UL (A = -19.4%, B = -23.0%, C = -22.8%) and LL (A = -16.2 %, B = -15.3%, C = -16.1%) with no difference between conditions. The SPE presented similar results between the conditions (Condition A=8.4, Condition B=8.7, Condition C=8.7). There was a significant increase in La at time T3 of condition C compared to the other conditions: (C=7.29 mmol.L-1, A=6.60 mmol.L-1, B=6.51 mmol.L-1) (p<0.0001). The TV in condition C (16,169.4 ± 2,562.5 kg) was higher than conditions A (13,222.2 ± 2,010.4 kg) and B (13,989.8 ± 2223.4 kg) (p<0.0001). Conclusion: The results suggest that only TV and the metabolic demand were more affected by the order of exercises.

RESUMEN Introducción: La alternancia entre los segmentos del cuerpo para la prescripción de entrenamiento de fuerza (EF) es ampliamente utilizada, pero siguen desconocidos sus efectos. Objetivo: Evaluar el efecto agudo de la manipulación de la orden de los ejercicios de EF, alternando segmentos del cuerpo, en la fuerza máxima (1 RM) de las extremidades inferiores (EI) y superiores (ES), la concentración del lactato (La) en la sangre, la percepción subjetiva del esfuerzo (PSE) y el volumen de entrenamiento (VE). Métodos: Dieciocho hombres (23,1 ± 3,8 años; 78,4 ± 8,6 kg; 1,72 ± 0,06 m) realizaron tres condiciones de EF: Condición A (press de banca, press de hombros, rosca Scott, media sentadilla, prensa de piernas, extensión de la pierna); Condición B (media sentadilla, prensa de piernas, extensión de la pierna, press de banca, press de ombros, rosca Scott) y Condición C (press de banca, media sentadilla, press de hombros, prensa de piernas, rosca Scott, y extensión de la pierna). Los ejercicios se realizaron con tres series de 10 RM. Las pruebas de 1 RM de las EI y ES se llevaron a cabo en las primeras semanas y después de las condiciones experimentales. Las muestras de sangre fueron tomadas en reposo [T0] inmediatamente después [IA], 3 [T3] y 5 minutos [T5] después de cada condición. La PSE, de ES, EI y general y VE se midieron al final de cada condición. Resultados: La 1 RM se redujo después de la sesión en todas las condiciones para ES (A = -19,4%; B = -23,0%; C = -22,8%) y EI (A = -16,2%; B = -15,3%; C = -16,1%), sin diferencia entre las condiciones. La PSE mostró resultados similares entre las condiciones (Condición A = 8,4, Condición B = 8.7, Condición C = 8,7). Hubo un aumento significativo en La en el momento T3 de la condición C en comparación con las otras condiciones (C = 7,29 mmol.L-1; A = 6,60 mmol.L-1, B = 6,51 mmol.L-1) (p < 0,0001). El VE en la condición C (16.169,4 ± 2.562,5 kg) fue superior a las condiciones A (13.222,2 ± 2.010.4 kg) y B (13.989,8 ± 2.223,4 kg) (p < 0,0001). Conclusión: Los resultados sugieren que solamente el VE y las demandas metabólicas fueron afectados por el orden de los ejercicios.