Postactivation Potentiation Improves Acute Resistance Exercise Performance and Muscular Force in Trained Men.

ABSTRACT: Conrado de Freitas, M, Rossi, FE, Colognesi, LA, de Oliveira, JVNS, Zanchi, NE, Lira, FS, Cholewa, JM, and Gobbo, LA. Postactivation potentiation improves acute resistance exercise performance and muscular force in trained men. J Strength Cond Res 35(5): 1357-1363, 2021-The purpose of this study was to investigate the effects of heavy back squat (90% one repetition maximum [1RM]) postactivation potentiation (PAP) on acute resistance exercise performance and force production in recreationally trained men, and to verify the relationship between maximal strength and the PAP response. Ten resistance-trained men randomly completed 4 experimental trials: (a) back squats without PAP (No-PAP), (b) back squats with PAP, (c) maximum voluntary isometric contraction (MVIC) of the quadriceps without PAP, and (d) MVIC with PAP. Back squats were performed with 4 sets at 70% of 1 RM with 2 minutes of rest interval. The number of squats repetitions performed was recorded for each set, and a total number of repetitions were calculated to analyze performance. Maximum voluntary isometric contraction was measured using electronic dynamometer, and the peak force and mean force were recorded. Blood lactate concentration was analyzed presquat and postsquat exercise. Repetitions performed in the first set was significantly (p < 0.001) greater in the PAP condition (22.00 ± 5.14) compared with No-PAP (15.50 ± 5.10), which resulted in significantly (p = 0.001) more total repetitions performed in the PAP (56.20 ± 17.3) condition compared with No-PAP (48.80 ± 14.5). Maximum voluntary isometric contraction peak was higher in PAP than in No-PAP (PAP = 765.7 ± 147.8 vs. No-PAP = 696.8 ± 131.5 N, p = 0.006). No significant correlations were observed between back squat 1RM relative to body mass and the PAP response in squat and MVIC. There were no significant differences in lactate concentration between conditions. In conclusion, PAP resulting from a heavy load prior back squat exercise improved total volume during resistance exercise. In addition, PAP was effective to increase force production during MVIC, but there was no relationship between relative 1RM values and the PAP response in trained men.

Appetite Is Suppressed After Full-Body Resistance Exercise Compared With Split-Body Resistance Exercise: The Potential Influence of Lactate and Autonomic Modulation.

ABSTRACT: Conrado de Freitas, M, Ricci-Vitor, AL, de Oliveira, JVNS, Quizzini, GH, Vanderlei, LCM, Silva, BSA, Zanchi, NE, Cholewa, JM, Lira, FS, and Rossi, FE. Appetite is suppressed after full-body resistance exercise compared with split-body resistance exercise: the potential influence of lactate and autonomic modulation. J Strength Cond Res 35(9): 2532-2540, 2021-The purposes of this study were to investigate the effects of full- vs. split-body resistance training on appetite and leptin response and to verify the potential involvement of lactate and autonomic modulation during this response in trained men. Twelve recreationally resistance-trained men (age = 26.1 ± 5.5 years) performed 3 randomized trials in 3 conditions: upper body (UB), lower body (LB), and full body (FB). The subjective rating of hunger was obtained through a visual analog scale. Leptin and lactate concentration were evaluated at rest, immediately after exercise, and during recovery. Heart rate variability in the time and frequency domains was recorded at baseline and during recovery (until 60 minutes after exercise) to assess autonomic modulation. The FB condition induced lower subjective hunger ratings than the UB at Post-1 hour (p < 0.05) and a significant difference in the area under the curve between conditions (p = 0.028) with lower hunger sensation for FB in relation to UB (p = 0.041). The FB presented greater lactate concentration and induced slower heart rate variability recovery in relation to UB and LB conditions (p < 0.05), and heart rate variability remained lower until 60 minutes after exercise compared with rest only in the FB condition. There was a significant negative correlation between subjective hunger ratings and lactate concentration only for the FB condition (r = -0.72, p = 0.028). Full-body resistance exercise induced lower subjective hunger ratings after exercise in relation to UB resistance exercise. The FB also induced higher lactate production and slower recovery of autonomic modulation compared with the UB and LB conditions. Future research is necessary to investigate a mechanistic relationship between lactate concentrations and hunger suppression after resistance exercise.

Postexercise hypotension and autonomic modulation response after full versus split body resistance exercise in trained men.

To investigate the effects of full versus split body resistance exercise on postexercise hypotension and autonomic modulation in trained men. Sixteen resistance recreationally trained males (age, 24.9±5.3 years) performed three randomized trials: upper body (UB), lower body (LB), and full body (FB) conditions. Blood pressure and heart rate variability were collected at rest, immediately postexercise, post-10, and post-30 min during recovery. For systolic blood pressure, delta (30 min minus rest) was lower for the FB condition compared to the UB (-10.1±7.4 mmHg [FB] vs. -3.3±12.6 mmHg [LB] vs. -1.9±8.1 mmHg [UB], P=0.004). For diastolic blood pressure (-8.2±10.9 mmHg [FB] vs. -1.5±9.8 mmHg [LB] vs. -8.7±11.4 mmHg [UB], P=0.038) and mean blood pressure delta during recovery (-11.7±14 mmHg [FB] vs. -2.2±10.6 mmHg [LB] vs. -5.2±6.8 mmHg [UB], P=0.045), there were statistically significant lower values in the FB condition in relation to the LB condition. Regarding heart rate variability, there were no significant differences between conditions, however, the square root of the mean squared difference between adjacent RR intervals presented an increase until post-30 during recovery (P<0.001), and there was a higher values of low frequency and lower values of high frequency across time (P<0.001). Postexercise hypotension was influenced by the amount of muscle mass involved in a bout of resistance exercise, with the FB condition inducing lower systolic blood pressure in relation to the UB after exercise, as well as a great decrease in postexercise diastolic and mean blood pressure compared with the LB. The autonomic modulation response was similar between conditions during recovery.