João B. Ferreira-Junior

Dissociated Time Course of Muscle Damage Recovery Between Single- and Multi-Joint Exercises in Highly Resistance-Trained Men

Abstract Soares, S, Ferreira-Junior, JB, Pereira, MC, Cleto, VA, Castanheira, RP, Cadore, EL, Brown, LE, Gentil, P, Bemben, MG, and Bottaro, M. Dissociated time course of muscle damage recovery between single- and multi-joint exercises in highly resistance-trained men. J Strength Cond Res 29(9): 2594–2599, 2015—This study compared the time course of elbow flexor muscle recovery after multi- and single-joint exercises in highly resistance-trained men. Sixteen men (24.5 ± 5.5 years) performed, in a counterbalanced order, 8 sets of 10 repetition maximum (RM) unilateral seated row exercise and 8 sets of 10RM unilateral biceps preacher curl exercise using the contralateral arm. Maximum isometric peak torque (PT) and delayed onset muscle soreness (DOMS) were recorded at baseline (pre), 10 minutes, 24, 48, 72, and 96 hours after each exercise protocol. There was a significant decrease (p ⩽ 0.05) in elbow flexor PT 10 minutes after both the multi- and single-joint exercise sessions. However, PT decrease was greater after single-joint (26.8%) when compared with multi-joint (15.1%) exercise (p ⩽ 0.05). In addition, elbow flexor PT was lower (8.4%) than baseline 24 hours after the single-joint exercise (p < 0.01), whereas PT returned to baseline 24 hours after the multi-joint exercise. Compared with baseline, DOMS increased at 24, 48, and 72 hours after single-joint exercise (p ⩽ 0.05). However, DOMS returned to baseline levels after 72 hours after multi-joint exercise. In addition, DOMS after single-joint exercise was greater (p ⩽ 0.05) than after multi-joint exercise at 24, 48, and 72 hours after exercise. Our data suggest that after a resistance training session, highly resistance-trained men experience dissimilar elbow flexor strength recovery between single-joint and multi-joint exercises. Likewise, elbow flexor DOMS is greater and takes longer to recover after single-joint exercise.

Session rating of perceived exertion following resistance exercise with blood flow restriction.

Session ratings of perceived exertion (SRPE) provide a valid and reliable indicator of resistance exercise session intensity. However, there is a lack of studies on the effects of resistance exercise with blood flow restriction (BFR) on SRPE. Thus, the aim of this study is to compare the effects of resistance exercise at high intensity versus low intensity with BFR on internal training load measured by SRPE. Thirteen young (22·2 ± 3·8 years) resistance‐trained men (training experience 3·2 ± 2·4 years) participated in the study protocol. After determining one maximum repetition (1‐RM), the subjects were assigned to two groups in a counterbalanced design (i) high‐intensity exercise (HIE, performed one training session at 80% of 1‐RM) and (ii) low intensity with BFR (BFR, performed an exercise session at 50% of 1‐RM with BFR). During each session, subjects performed three sets of unilateral elbow flexion leading to concentric failure with a 1‐min rest interval between sets. A cuff around the arm, inflated at 110 mmHg, was used continuously for BFR. The SRPE was reported 30 min after the end of the session. The low intensity with BFR showed lower total work (197·13 ± 63·49 versus 300·92 ± 71·81 kg; P = 0·002) and higher SRPE (9 versus 6; P = 0·007) than high‐intensity resistance exercise. The present results indicate that BFR is an important factor to increase internal training load. Future studies should investigate the physiological stress imposed by different training methods rather than just quantify the external training load such as intensity or volume.

The Chronic Effects of Low- and High-Intensity Resistance Training on Muscular Fitness in Adolescents.

To compare the effects of high-load, low-repetition maximum (LRM) and low-load, high-repetition maximum (HRM) resistance training regimens on muscular fitness in untrained adolescents. Forty-five untrained adolescents of both sexes (13.7±0.8 years; 161.3±7.5 cm, 56.8±13.4 kg) were randomly assigned into one of three groups: 1) LRM (n = 17): volunteers performed three sets of 4-6-repetition maximum (RM); 2) HRM (n = 16): volunteers performed three sets of 12–15 RM; and 3) control (CON, n = 12). Training was performed two times a week for 9 weeks. After training, there were significant increases in 1 RM chest press (LRM = 14.8% and HRM = 14.2%, p<0.05) and squat (LRM = 26.4% and HRM = 25.7%, p<0.05), with no differences between the LRM and HRM groups (p>0.05). Additionally, muscular endurance increased significantly for the chest press (LRM = 14.5% and HRM = 21.8%, p<0.05) and squat test (LRM = 31.4% and HRM = 32.4%, p<0.05) following resistance training, with no difference between the LRM and HRM groups (p>0.05). These results suggest that both high-load, low-repetition and moderate-load, high-repetition resistance training can be prescribed to improve muscular fitness in untrained adolescents.

One session of partial-body cryotherapy (−110 °C) improves muscle damage recovery

To evaluate the effects of a single session of partial‐body cryotherapy (PBC) on muscle recovery, 26 young men performed a muscle‐damaging protocol that consisted of five sets of 20 drop jumps with 2‐min rest intervals between sets. After the exercise, the PBC group (n = 13) was exposed to 3 min of PBC at −110 °C, and the control group (n = 13) was exposed to 3 min at 21 °C. Anterior thigh muscle thickness, isometric peak torque, and muscle soreness of knee extensors were measured pre, post, 24, 48, 72, and 96 h following exercise. Peak torque did not return to baseline in control group (P < 0.05), whereas the PBC group recovered peak torques 96 h post exercise (P > 0.05). Peak torque was also higher after PBC at 72 and 96 h compared with control group (P < 0.05). Muscle thickness increased after 24 h in the control group (P < 0.05) and was significantly higher compared with the PBC group at 24 and 96 h (P < 0.05). Muscle soreness returned to baseline for the PBC group at 72 h compared with 96 h for controls. These results indicate that PBC after strenuous exercise may enhance recovery from muscle damage.

Does whole-body cryotherapy improve vertical jump recovery following a high-intensity exercise bout?

Whole-body cryotherapy (WBC) has been used as a recovery strategy following different sports activities. Thus, the aim of the study reported here was to examine the effect of WBC on vertical jump recovery following a high-intensity exercise (HIE) bout. Twelve trained men (mean ± standard deviation age = 23.9±5.9 years) were randomly exposed to two different conditions separated by 7 days: 1) WBC (3 minutes of WBC at −110°C immediately after the HIE) and 2) control (CON; no WBC after the HIE). The HIE consisted of six sets of ten repetitions of knee extensions at 60° · s−1 concentric and 180° · s−1 eccentric on an isokinetic dynamometer. The vertical jump test was used to evaluate the influence of HIE on lower extremity muscular performance. The vertical jump was performed on a force platform before HIE (T1) and 30 minutes after (T2) the WBC and CON conditions. As a result of HIE, jump height, muscle power, and maximal velocity (Vmax) had significant decreases between T1 and T2, however no significance was found between the WBC and CON conditions. The results indicate that one session of WBC had no effect on vertical jump following an HIE compared with a CON condition. WBC may not improve muscle-function (dependent on stretch-shortening cycle) recovery in very short periods (ie, 30 minutes) following HIE.

Effects of partial-body cryotherapy (− 110 °C) on muscle recovery between high-intensity exercise bouts.

The aim of this study was to evaluate the effects of a single partial-body cryotherapy bout between training sessions on strength recovery. 12 young men (23.9±5.9 years) were randomly exposed to 2 different conditions separated by 7 days: 1) Partial-body cryotherapy (subjects were exposed to 3 min of partial-body cryotherapy at - 110 °C between 2 high-intensity training sessions); 2) Control (subjects were not exposed to partial-body cryotherapy between 2 high-intensity training sessions). Subjects were exposed to partial-body cryotherapy after the first training session. The 2 knee extension high-intensity training sessions were separated by a 40-min rest interval. Knee extension training consisted of 6 sets of 10 repetitions at 60°.s(-1) for concentric actions and 6 sets of 10 at 180.s(-1) for eccentric actions. The decrease in eccentric peak torque and total work was significantly (p<0.05) less after partial-body cryotherapy (5.6 and 2%, respectively) when compared to control (16 and 11.6%, respectively). However, the decrease in concentric peak torque and total work was not different (p>0.05) between partial-body cryotherapy (9.4 and 6.5%, respectively) and control (7.5 and 5.2%, respectively). These results indicate that the use of partial-body cryotherapy between-training sessions can enhance eccentric muscle performance recovery.

Chest Press Exercises With Different Stability Requirements Result in Similar Muscle Damage Recovery in Resistance-Trained Men.

Abstract Ferreira, DV, Ferreira-Júnior, JB, Soares, SRS, Cadore, EL, Izquierdo, M, Brown, LE, and Bottaro, M. Chest press exercises with different stability requirements result in similar muscle damage recovery in resistance trained men. J Strength Cond Res 31(1): 71–79, 2017—This study investigated the time course of 96 hours of muscle recovery after 3 different chest press exercises with different stability requirements in resistance-trained men. Twenty-seven men (23.5 ± 3.8 years) were randomly assigned to one of the 3 groups: (a) Smith machine bench press; (b) barbell bench press; or (c) dumbbell bench press. Participants performed 8 sets of 10 repetition maximum with 2 minutes rest between sets. Muscle thickness, peak torque (PT), and soreness were measured pre, post, 24, 48, 72, and 96 hours after exercise. There were no differences in the time course of PT or muscle thickness values of the pectoralis major (p = 0.98 and p = 0.91, respectively) or elbow extensors (p = 0.07 and p = 0.86, respectively) between groups. Muscle soreness of the pectoralis major was also not different between groups (p > 0.05). However, the Smith machine and barbell groups recovered from triceps brachii muscle soreness by 72 hours after exercise (p > 0.05), whereas the dumbbell group did not present any triceps brachii muscle soreness after exercise (p > 0.05). In conclusion, resistance-trained men experience similar muscle damage recovery after Smith machine, barbell, and dumbbell chest press exercise. However, muscle soreness of the elbow extensors takes a longer time to recover after using a barbell chest press exercise.

Effects of rest interval on strength recovery in breast cancer survivors

The purpose of this study was to compare the acute effect of 2 different resting intervals (RI) between sets of isokinetic knee extension exercise on peak torque (PT) and total work (TW) in breast cancer survivors (BCS) and control group (CNT). 16 BCS (52±4 years) and 14 CNT (53±6 years) performed 3 sets of 10 unilateral isokinetic knee extension repetitions at 60°.s(- 1) on 2 separate days with 2 different RI between sets (1 and 2 min). There was a significant interaction between groups vs. exercise sets (p=0.03) and RI vs. exercise sets (p<0.001) for PT. PT was greater in CNT at 1(st) and 2(nd) sets compared to BCS group (CNT, 133.4±20.8 and BCS 107.6±19.9 Nm, p=0.012 and CNT, 118.9±19.6 and BCS, 97.1±15.9  Nm, p=0.045, respectively). The TW of the knee extensor was significant greater in CNT than BCS group for all 3 knee extension exercise sets. In conclusion, the present study suggests that Breast Cancer Survivors women may need a longer rest interval (longer than 2 min) to be able to fully recover during a 3 sets of isokinetic knee extension exercise training session.

Dissociated time course between peak torque and total work recovery following bench press training in resistance trained men

OBJECTIVE To evaluate the time course of peak torque and total work recovery after a resistance training session involving the bench press exercise. DESIGN Repeated measures with a within subject design. METHODS Twenty-six resistance-trained men (age: 23.7±3.7years; height: 176.0±5.7cm; mass: 79.65±7.61kg) performed one session involving eight sets of the bench press exercise performed to momentary muscle failure with 2-min rest between sets. Shoulder horizontal adductors peak torque (PT), total work (TW), delayed onset muscle soreness (DOMS) and subjective physical fitness were measured pre, immediately post, 24, 48, 72 and 96h following exercise. RESULTS The exercise protocol resulted in significant pectoralis major DOMS that lasted for 72h. Immediately after exercise, the reduction in shoulder horizontal adductors TW (25%) was greater than PT (17%). TW, as a percentage of baseline values, was also less than PT at 24, 48 and 96h after exercise. Additionally, PT returned to baseline at 96h, while TW did not. CONCLUSIONS Resistance trained men presented dissimilar PT and TW recovery following free weight bench press exercise. This indicates that recovery of maximal voluntary contraction does not reflect the capability to perform multiple contractions. Strength and conditioning professionals should be cautious when evaluating muscle recovery by peak torque, since it can lead to the repetition of a training session sooner than recommended.

Reliability of normalized surface electromyographic signals of maximal upper-body isokinetic strength

BACKGROUND: Normalization in surface electromyography (SEMG) has been the object of numerous investigations. OBJECTIVE: The purpose of this study was to evaluate the reliability of normalized SEMG amplitude, as well as the reliability of different normalization coefficients during isokinetic upper-body strength assessment. METHODS: Thirteen male subjects performed a maximal isokinetic elbow flexion test and test-retest separated by 5 to 7 days. Three normalization coefficients were extracted from the tests: 1) mean value of the rectified SEMG signal (MeanTask); 2) peak value of the rectified SEMG signal (PeakTask); 3) maximal value of the rectified SEMG signal of the peak torque repetition (Isokinetic-specMVC). These normalization coefficients, as well as the root mean square value (RMS) of the signal before and after normalization by described coefficients (RMS-MeanTask; RMS-PeakTask; RMS-Isokinetic-specMVC) were evaluated in terms of absolute and relative reliability. RESULTS: None of the normalization coefficients presented acceptable levels of absolute reliability (bias range in limits of agreement greater than 27%). However MeanTask and Isokinetic-specMVC presented good levels of relative reliability (ICC > 0.80). RMS-MeanTask was the only amplitude parameter that demonstrated satisfactory indices of absolute (bias range lower than 5% and CV 0.80) reliability. CONCLUSIONS: Normalizing SEMG amplitude by MeanTask is a reasonable strategy to reduce day-to-day amplitude discrepancies during isokinetic upper-body strength assessment.