Low-Load Resistance Training to Volitional Failure Induces Muscle Hypertrophy Similar to Volume-Matched, Velocity Fatigue.

ABSTRACT: Terada, K, Kikuchi, N, Burt, D, Voisin, S, and Nakazato, K. Full title: Low-load resistance training to volitional failure induces muscle hypertrophy similar to volume-matched, velocity fatigue. J Strength Cond Res 36(6): 1576-1581, 2022-We investigated how resistance training (RT) to failure at low load affects acute responses and chronic muscle adaptations compared with low-load RT to velocity fatigue at equal work volume. Twenty-seven subjects performed 8 weeks of bench press twice weekly. Subjects were randomly assigned to one of 3 groups: low-load volitional failure (LVoF, n = 9), low-load velocity fatigue (LVeF, n = 8), and high-load (HL, n = 10). Resistance training comprised 3 sets to failure at 40% one repetition maximum (1RM) in the LVoF group, 3 sets to velocity fatigue (20% lifting velocity loss) at 40% 1RM in the LVeF group, and 3 sets of 8 repetitions at 80% 1RM in the HL group. We measured muscle strength, hypertrophy, endurance, and power at baseline and after the RT program. We also measured muscle swelling and blood lactate after each RT bout to investigate the acute response. There were no differences in total work volume between the LVoF and LVeF groups. Responses to RT were similar between LVoF and LVeF, whether looking at acute muscle swelling, increase in blood lactate, chronic hypertrophy, and strength gain. However, LVoF and LVeF RT triggered different responses to muscle function in comparison with HL training: LVoF and LVeF showed enhanced acute responses and greater chronic endurance gains, but lower chronic strength gains than HL. In conclusion, low-load RT to volitional failure induces muscle hypertrophy similar to volume-matched velocity fatigue.

The acute effect of a multi-modal plyometric training session on field-specific performance measures.

BACKGROUND: Plyometric and resistance exercises are known to cause exercise-induced muscle damage (EIMD). Thus, this study examined the impact of EIMD on various field-specific performance measures following a training session that combined plyometric and resistance exercises. METHODS: Nine competitive Ultimate Frisbee players undertook a training session consisting of several modes of plyometric and resistance exercises. Indirect markers of muscle damage (i.e., creatine kinase [CK] and delayed onset of muscle soreness [DOMS]) and field-specific performance measures (i.e., run-up vertical jump, standing broad jump, linear sprint and repeated agility) were measured prior to, 24 hours (T24) and 48 hours (T48) post training. RESULTS: The combined plyometric and resistance training session significantly increased muscle damage markers at T24 (CK: 326.5±210.4% and DOMS: 343.3±181.6%) and T48 (CK: 969.2±1262.3% and DOMS: 371.1±179.3%). The jump performance measures were significantly reduced at T24 (run-up vertical jump -5.5±6.3% and standing broad jump -4.7±3.7%) and T48 (run-up vertical jump -4.2±5.1% and standing broad jump -5.0±4.4%). Furthermore, completion times for linear sprint performance was significantly increased at T24 (4.5±3.4%) and T48 (7.2±4.2%), whilst the average completion time for the repeated agility protocol was significantly increased at T24 (1.4±1.4%). CONCLUSIONS: Competitive team sport athletes may require at least 48 hours of recovery when implementing field-based conditioning sessions after a training session that combines plyometrics and resistance exercises, particular if unfamiliar with such training modalities.

Impact of Exercise-Induced Muscle Damage on Performance Test Outcomes in Elite Female Basketball Players.

Doma, K, Leicht, A, Sinclair, W, Schumann, M, Damas, F, Burt, D, and Woods, C. Impact of exercise-induced muscle damage on performance test outcomes in elite female basketball players. J Strength Cond Res 32(6): 1731-1738, 2018-The purpose of this study was 2-fold: first, to examine the impact of exercise-induced muscle damage (EIMD) on physical fitness qualities after a basketball-specific training session; second, to determine the reproducibility of the sport-specific performance measures in elite female basketball players. Ten elite female basketball players (age 25.6 ± 4.5 years; height 1.8 ± 0.7 m; and body mass 76.7 ± 8.3 kg) undertook a 90-minute training session involving repeated jumping, sprinting, and game-simulated training. Indirect muscle damage markers (i.e., countermovement jump, delayed onset of muscle soreness [DOMS], and creatine kinase [CK]) and sport-specific performances (i.e., change-of-direction [COD] test and suicide test [ST]) were measured before and 24 hours after training. These measures were also collected 1 week after training to determine the reproducibility of the basketball-specific performance measures. A significant reduction in lower-body power (-3.5 ± 3.6%; p ≤ 0.05), while a significant increase in DOMS (46.7 ± 26.3%; p ≤ 0.05) and CK (57.6 ± 23.1%; p ≤ 0.05) was observed 24 hours after exercise. The ST was also significantly increased (2.1 ± 1.8%; p ≤ 0.05), although no difference was observed for COD (0.1 ± 2.0%; p > 0.05). The intraclass correlation coefficient and coefficient of variation for the COD and ST were 0.81 and 0.90, respectively, and 1.9 and 1.5%, respectively. In conclusion, appropriate recovery should be considered the day after basketball-specific training sessions in elite basketball players. Furthermore, this study showed the usability of performance measures to detect changes during periods of EIMD, with acceptable reproducibility and minimal measurement error.

Using lactate threshold to predict 5-km treadmill running performance in veteran athletes.

Measuring lactate threshold to predict endurance performance is difficult among veteran athletes, due to age-related decreases in net lactate concentration. The objective of this study was to determine whether lactate threshold, as assessed using the maximal deviation method (Dmax), which is not dependent on net values of lactate, could be used as a more valid measure of 5-km treadmill running performance than other methods of determining lactate threshold. Veteran runners (18 male and 18 female, aged 47.3±6.7 years) performed an incremental exercise test to establish mean treadmill velocity at lactate threshold using Dmax, a log-log method, a visual method, and a 4-mmol·L-1 method, and, on a separate occasion, completed a 5-km time trial. Mean treadmill velocity at Dmax was 12.2±1.8 km·h-1, not being significantly different to mean treadmill velocity (12.1±1.8 km·h-1) attained during the 5-km time trial (p>0.05); velocities were also significantly correlated (r=0.92, p<0.001), and limits of agreement narrow (-1.61 to 1.35 km·h-1). Correlations were weaker and limits of agreement wider for the other methods of lactate threshold determination. Using a two-way, mixed-methods ANOVA, there was no significant effect of sex when using the different methods of determining Tlac (F4,136=3.70, p=0.15). Mean treadmill velocity, when using Dmax for determining lactate threshold, can be used to predict 5-km running performance among male and female veteran athletes.

The repeated bout effect of traditional resistance exercises on running performance across 3 bouts.

This study investigated the repeated bout effect of 3 typical lower body resistance-training sessions on maximal and submaximal effort running performance. Twelve resistance-untrained men (age, 24 ± 4 years; height, 1.81 ± 0.10 m; body mass, 79.3 ± 10.9 kg; peak oxygen uptake, 48.2 ± 6.5 mL·kg-1·min-1; 6-repetition maximum squat, 71.7 ± 12.2 kg) undertook 3 bouts of resistance-training sessions at 6-repetitions maximum. Countermovement jump (CMJ), lower-body range of motion (ROM), muscle soreness, and creatine kinase (CK) were examined prior to and immediately, 24 h (T24), and 48 h (T48) after each resistance-training bout. Submaximal (i.e., below anaerobic threshold (AT)) and maximal (i.e., above AT) running performances were also conducted at T24 and T48. Most indirect muscle damage markers (i.e., CMJ, ROM, and muscle soreness) and submaximal running performance were significantly improved (P < 0.05; 1.9%) following the third resistance-training bout compared with the second bout. Whilst maximal running performance was also improved following the third bout (P < 0.05; 9.8%) compared with other bouts, the measures were still reduced by 12%-20% versus baseline. However, the increase in CK was attenuated following the second bout (P < 0.05) with no further protection following the third bout (P > 0.05). In conclusion, the initial bout induced the greatest change in CK; however, at least 2 bouts were required to produce protective effects on other indirect muscle damage markers and submaximal running performance measures. This suggests that submaximal running sessions should be avoided for at least 48 h after resistance training until the third bout, although a greater recovery period may be required for maximal running sessions.

The effects of acute branched-chain amino acid supplementation on recovery from a single bout of hypertrophy exercise in resistance-trained athletes.

This study investigated the effects of acute branched-chain amino acid (BCAA) supplementation on recovery from exercise-induced muscle damage among experienced resistance-trained athletes. In a double-blind matched-pairs design, 16 resistance-trained participants, routinely performing hypertrophy training, were randomly assigned to a BCAA (n = 8) or placebo (n = 8) group. The BCAAs were administered at a dosage of 0.087 g/kg body mass, with a 2:1:1 ratio of leucine, isoleucine, and valine. The participants performed 6 sets of 10 full-squats at 70% 1-repetition maximum to induce muscle damage. All participants were diet-controlled across the study. Creatine kinase, peak isometric knee-extensor force, perceived muscle soreness, and countermovement jump (CMJ) height were measured immediately before (baseline) and at 1 h, 24 h, and 48 h postexercise. There were large to very large time effects for all measurements between baseline and 24-48 h. Between-group comparisons, expressed as a percentage of baseline, revealed differences in isometric strength at 24-h (placebo ∼87% vs. BCAA ∼92%; moderate, likely), CMJ at 24 h (placebo ∼93% vs. BCAA ∼96%; small, likely), and muscle soreness at both 24 h (placebo ∼685% vs. BCAA ∼531%; small, likely) and 48 h (placebo ∼468% vs. BCAA ∼350%; small, likely). Acute supplementation of BCAAs (0.087 g/kg) increased the rate of recovery in isometric strength, CMJ height, and perceived muscle soreness compared with placebo after a hypertrophy-based training session among diet-controlled, resistance-trained athletes. These findings question the need for longer BCAA loading phases and highlight the importance of dietary control in studies of this type.

Lower-volume muscle-damaging exercise protects against high-volume muscle-damaging exercise and the detrimental effects on endurance performance.

PURPOSE: This study examined whether lower-volume exercise-induced muscle damage (EIMD) performed 2 weeks before high-volume muscle-damaging exercise protects against its detrimental effect on running performance. METHODS: Sixteen male participants were randomly assigned to a lower-volume (five sets of ten squats, n = 8) or high-volume (ten sets of ten squats, n = 8) EIMD group and completed baseline measurements for muscle soreness, knee extensor torque, creatine kinase (CK), a 5-min fixed-intensity running bout and a 3-km running time-trial. Measurements were repeated 24 and 48 h after EIMD, and the running time-trial after 48 h. Two weeks later, both groups repeated the baseline measurements, ten sets of ten squats and the same follow-up testing (Bout 2). RESULTS: Data analysis revealed increases in muscle soreness and CK and decreases in knee extensor torque 24-48 h after the initial bouts of EIMD. Increases in oxygen uptake [Formula: see text], minute ventilation [Formula: see text] and rating of perceived exertion were observed during fixed-intensity running 24-48 h after EIMD Bout 1. Likewise, time increased and speed and [Formula: see text] decreased during a 3-km running time-trial 48 h after EIMD. Symptoms of EIMD, responses during fixed-intensity and running time-trial were attenuated in the days after the repeated bout of high-volume EIMD performed 2 weeks after the initial bout. CONCLUSIONS: This study demonstrates that the protective effect of lower-volume EIMD on subsequent high-volume EIMD is transferable to endurance running. Furthermore, time-trial performance was found to be preserved after a repeated bout of EIMD.

Effects of exercise-induced muscle damage on resting metabolic rate, sub-maximal running and post-exercise oxygen consumption.

Exercise-induced muscle damage (EIMD), described as the acute weakness of the musculature after unaccustomed eccentric exercise, increases oxidative metabolism at rest and during endurance exercise. However, it is not known whether oxygen uptake during recovery from endurance exercise is increased when experiencing symptoms of EIMD. Therefore, the purpose of this study was to investigate the effects of EIMD on physiological and metabolic responses before, during and after sub-maximal running. After a 12 h fast, eight healthy male participants completed baseline measurements comprising resting metabolic rate (RMR), indirect markers of EIMD, 10 min of sub-maximal running and 30 min of recovery to ascertain excess post-exercise oxygen consumption (EPOC). Measurements were then repeated at 24 and 48 h after 100 Smith-machine squats. Data analysis revealed significant (P<0.05) increases in muscle soreness and creatine kinase (CK) and decreases in peak knee extensor torque at 24 and 48 h after squatting exercise. Moreover, RMR, physiological, metabolic and perceptual responses during sub-maximal running and EPOC were increased in the two days after squatting exercise (P<0.05). It is suggested that the elevated RMR was a consequence of a raised energy requirement for the degradation and resynthesis of damaged muscle fibres. The increased oxygen demand during sub-maximal running after muscle damage was responsible for the increase in EPOC. Individuals engaging in unaccustomed resistance exercise that results in muscle damage should be mindful of the increases in resting energy expenditure and increased metabolic demand to exercise in the days that follow.

Effects of repeated bouts of squatting exercise on sub-maximal endurance running performance.

It is well established that exercise-induced muscle damage (EIMD) has a detrimental effect on endurance exercise performed in the days that follow. However, it is unknown whether such effects remain after a repeated bout of EIMD. Therefore, the purpose of this study was to examine the effects of repeated bouts of muscle-damaging exercise on sub-maximal running exercise. Nine male participants completed baseline measurements associated with a sub-maximal running bout at lactate turn point. These measurements were repeated 24-48 h after EIMD, comprising 100 squats (10 sets of 10 at 80 % body mass). Two weeks later, when symptoms from the first bout of EIMD had dissipated, all procedures performed at baseline were repeated. Results revealed significant increases in muscle soreness and creatine kinase activity and decreases in peak knee extensor torque and vertical jump performance at 24-48 h after the initial bout of EIMD. However, after the repeated bout, symptoms of EIMD were reduced from baseline at 24-48 h. Significant increases in oxygen uptake (.VO2), minute ventilation (.VE), blood lactate ([BLa]), rating of perceived exertion (RPE), stride frequency and decreases in stride length were observed during sub-maximal running at 24-48 h following the initial bout of EIMD. However, following the repeated bout of EIMD, .VO2, .VE, [BLa], RPE and stride pattern responses during sub-maximal running remained unchanged from baseline at all time points. These findings confirm that a single resistance session protects skeletal muscle against the detrimental effects of EIMD on sub-maximal running endurance exercise.

Neuromuscular, biochemical and perceptual post-match fatigue in professional rugby league forwards and backs.

In this study, we investigated changes in creatine kinase, perceptual and neuromuscular fatigue of professional rugby league players after match-play. Twenty-three male rugby league players (10 backs, 13 forwards) had their creatine kinase, perceptual ratings of fatigue, attitude to training, muscle soreness, and flight time in a countermovement jump measured before and 1 and 2 days after (day 1 and day 2 respectively) league matches. Total playing time, offensive and defensive contacts were also recorded for each player. Creatine kinase was higher both 1 and 2 days after than before matches (P < 0.05) in forwards and backs. Similarly, perceived fatigue and muscle soreness were higher than pre-match on both days 1 and 2 (P < 0.05), but did not differ between groups (P > 0.05). Jump performance was lower on day 1 but not day 2 for both groups (P < 0.05). While total playing time was longer in backs (P < 0.05), relative frequencies for all contacts were greater in forwards (P < 0.05). Contacts for forwards were correlated with all markers of fatigue (P < 0.05), but only flight time was correlated with offensive contacts in backs (P < 0.05). Despite the mechanisms of fatigue being different between forwards and backs, our results highlight the multidimensional nature of fatigue after a rugby league match and that these markers do not differ between positions.

The effects of exercise-induced muscle damage on cycling time-trial performance.

Previous research has advocated that plyometric training improves endurance performance. However, a consequence of such a training is the immediate and prolonged appearance of exercise-induced muscle damage (EIMD). This study examined whether a single bout of plyometric exercise, designed to elicit muscle damage, affected cycling endurance performance. Seventeen participants were randomly assigned to either a muscle damage (n = 7 men, 1 woman) or nonmuscle damage (n = 8 men, 1 woman) group. Before and at 48 hours, participants were measured for perceived muscle soreness, peak isokinetic strength, and physiological, metabolic, and perceptual responses during 5-minute submaximal cycling at ventilatory threshold (VT) and a 15-minute time trial. Perceived muscle soreness and isokinetic strength (p < 0.05) were significantly altered in the muscle damage group after EIMD. No changes in heart rate or blood lactate were evident during submaximal exercise (p > 0.05). However, VO2, V(E), and rating of perceived exertion (RPE) values were increased at VT in the muscle damage group at 48 hours after EIMD (p < 0.05). During the time trial, mean power output, distance covered, and VO2 were lower in the muscle damage group at 48 hours after EIMD (p < 0.05). However, there was no change in RPE (p > 0.05), suggesting effort perception was unchanged during time-trial performance after EIMD. In conclusion, individuals using concurrent plyometric and endurance training programs to improve endurance performance should be aware of the acute impact of muscle-damaging exercise on subsequent cycling performance.