Acute impact of blood flow restriction on strength-endurance performance during the bench press exercise

The main goal of the present study was to evaluate the acute effects of blood flow restriction (BFR) at 70% of full arterial occlusion pressure on strength-endurance performance during the bench press exercise. The study included 14 strength-trained male subjects (age = 25.6 ± 4.1 years; body mass = 81.7 ± 10.8 kg; bench press 1 repetition maximum (1RM) = 130.0 ± 22.1 kg), experienced in resistance training (3.9 ± 2.4 years). During the experimental sessions in a randomized crossover design, the subjects performed three sets of the bench press at 80% 1RM performed to failure with two different conditions: without BFR (CON); and with BFR (BFR). Friedman’s test showed significant differences between BFR and CON conditions for the number of repetitions performed (p < 0.001); for peak bar velocity (p < 0.001) and for mean bar velocity (p < 0.001). The pairwise comparisons showed a significant decrease for peak bar velocity and mean bar velocity in individual Set 1 for BFR when compared to CON conditions (p = 0.01 for both). The two-way repeated measures ANOVA showed a significant main effect for the time under tension (p = 0.02). A post-hoc comparisons for the main effect showed a significant increase in time under tension for BFR when compared to CON (p = 0.02). The results of the presented study indicate that BFR used during strength-endurance exercise generally does not decrease the level of endurance performance, while it causes a drop in bar velocity.     

Acute responses of muscle oxygen saturation during different cluster training configurations in resistance-trained individuals

This study compared the perceptual responses, physiological indicators and technical parameters between different training protocols focused on upper body exercises. A randomized crossover design was performed, and 12 trained individuals (age: 27.1 ± 5.7 years; height: 173.7 ± 10.7 cm; BMI: 23.9 ± 2.3) completed three resistance training sessions under different protocols separated by at least 72 h: traditional training (TT) (4 x 6 repetitions at 85% of 1RM with 120 s of rest between sets), cluster 1 (CL1) (4 x 2+2+2 repetitions at 85% of 1RM with 15 s of intra-rep rest and 80 s between sets), and cluster 2 (CL2) (24 repetitions at 85% of 1RM with 15 s of inter-set recovery). Before training, arterial blood pressure (BP) and repetitions to failure of pull-up and push-up (FT) were collected. Muscle oxygen saturation (SmO₂) in the chest and movement velocity were evaluated in barbell bench press during the training session. After finishing, lactate, BP, rate of perceived exertion and FT were assessed. The percentage of velocity loss (TT: 19.24%; CL1: 5.02% and CL2: 7.30%) in the bench press and lactate concentration (TT: 8.90 mmol·l^-1; CL1: 6.13 mmol·l^-1 and CL2: 5.48 mmol·l^-1) were significantly higher (p < 0.05) for TT compared to both CLs. RPE values were higher (p < 0.05) in TT compared to CL1 (7.95 a.u. vs. 6.91 a.u., respectively). No differences (p > 0.05) were found between protocols for SmO₂, BP, FT, pain or heart rate between set configurations. Cluster configurations allow one to maintain higher movement velocity and lower lactate and RPE values compared to a traditional configuration, but with similar concentrations of SmO₂.     

Effect of unilateral and bilateral resistance exercise on maximal voluntary strength,total volume of load lifted,and perceptual and metabolic responses

The present study investigated the effect of unilateral and bilateral resistance exercise (RE) on maximal voluntary strength, total volume of load lifted (TVLL), rating of perceived exertion (RPE) and blood lactate concentration of resistance-trained males. Twelve healthy men were assessed for the leg extension one-repetition maximum (1RM) strength using bilateral and unilateral contractions. Following this assessment, an RE session (3 sets of repetitions to failure) was conducted with bilateral and unilateral (both limbs) contractions using a load of 50% 1RM. The TVLL was calculated by the product of the number of repetitions and the load lifted per repetition. RPE and blood lactate were measured before, during and after each set. Session RPE was measured 30 minutes after RE sessions. There was a significant difference in the bilateral (120.0±11.9) and unilateral (135.0±20.2 kg) 1RM strength (p < 0.05). The TVLL was similar between both RE sessions. Although the repetitions decreased with each successive set, the total number of repetitions completed in the bilateral protocol (48) was superior to the unilateral (40) protocol (p < 0.05). In both bouts, RPE increased with each subsequent set whilst blood lactate increased after set 1 and thereafter remained stable (p < 0.05). The RPE and lactate responses were not significantly different between both sessions. In conclusion, a bilateral deficit in leg extension strength was confirmed, but the TVLL was similar between both RE sessions when exercising to voluntary fatigue. This outcome could be attributed to the number of repetitions completed in the unilateral RE bout. The equal TVLL would also explain the similar perceptual and metabolic responses across each RE session.     

Moderate volume of high relative training intensity produces greater strength gains compared with low and high volumes in competitive weightlifters

The purpose of this study was to examine the effect of 3 volumes of heavy resistance, average relative training intensity (expressed as a percentage of 1 repetition maximum that represented the absolute kilograms lifted divided by the number of repetitions performed) programs on maximal strength (1RM) in Snatch (Sn), Clean & Jerk (C&J), and Squat (Sq). Twenty-nine experienced (>3 years), trained junior weightlifters were randomly assigned into 1 of 3 groups: low-intensity group (LIG; n = 12), moderate-intensity group (MIG; n = 9), and high-intensity group (HIG; n = 8). All subjects trained for 10 weeks, 4-5 days a week, in a periodized routine using the same exercises and training volume (expressed as total number of repetitions performed at intensities equal to or greater than 60% of 1RM), but different programmed total repetitions at intensities of >90-100% of 1RM for the entire 10-week period: LIG (46 repetitions), MIG (93 repetitions), and HIG (184 repetitions). During the training period, MIG and LIG showed a significant increase (p < 0.01-0.05) for C&J (10.5% and 3% for MIG and LIG, respectively) and Sq (9.5% and 5.3% for MIG and LIG, respectively), whereas in HIG the increase took place only in Sq (6.9%, p < 0.05). A calculation of effect sizes revealed greater strength gains in the MIG than in HIG or LIG. There were no significant differences between LIG and HIG training volume-induced strength gains. All the subjects in HIG were unable to fully accomplish the repetitions programmed at relative intensities greater than 90% of 1RM. The present results indicate that short-term resistance training using moderate volumes of high relative intensity tended to produce higher enhancements in weightlifting performance compared with low and high volumes of high relative training intensities of equal total volume in experienced, trained young weightlifters. Therefore, for the present population of weightlifters, it may be beneficial to use the MIG training protocol to improve the weightlifting program at least in a short-term (10 weeks) cycle of training.     

Prediction of muscle fiber composition using multiple repetition testing

Direct determination of muscle fiber composition is invasive and expensive, with indirect methods also requiring specialist resources and expertise. Performing resistance exercises at 80% 1RM is suggested as a means of indirectly estimating muscle fiber composition, though this hypothesis has never been validated against a direct method. The aim of the study was to investigate the relationship between the number of completed repetitions at 80% 1RM of back squat exercise and muscle fiber composition. Thirty recreationally active participants’ (10 females, 20 males) 1RM back squat load was determined, before the number of consecutive repetitions at 80% 1RM was recorded. The relationship between the number of repetitions and the percentage of fast-twitch fibers from vastus lateralis was investigated. The number of completed repetitions ranged from 5 to 15 and was independent of sex, age, 1RM, training frequency, training type, training experience, BMI or muscle fiber cross-sectional area. The percentage of fast-twitch muscle fibers was inversely correlated with the number of repetitions completed (r = –0.38, P = 0.039). Participants achieving 5 to 8 repetitions (n = 10) had significantly more fast-twitch muscle fibers (57.5 ± 9.5 vs 44.4 ± 11.9%, P = 0.013) than those achieving 11–15 repetitions (n = 11). The remaining participants achieved 9 or 10 repetitions (n = 9) and on average had equal proportion of fast- and slow-twitch muscle fibers. In conclusion, the number of completed repetitions at 80% of 1RM is moderately correlated with muscle fiber composition.     

MUSCLE DAMAGE AFTER A TENNIS MATCH IN YOUNG PLAYERS

The present study investigated changes in indirect markers of muscle damage following a simulated tennis match play using nationally ranked young (17.6 ± 1.4 years) male tennis players. Ten young athletes played a 3-hour simulated match play on outdoor red clay courts following the International Tennis Federation rules. Muscle soreness, plasma creatine kinase activity (CK), serum myoglobin concentration (Mb), one repetition maximum (1RM) squat strength, and squat jump (SJ) and counter movement jump (CMJ) heights were assessed before, immediately after, and 24 and 48 h after the simulated match play. All parameters were also evaluated in a non-exercised group (control group). A small increase in the indirect markers of muscle damage (muscle soreness, CK and Mb) was detected at 24-48 hours post-match (p < 0.05). A marked acute decrement in neuromuscular performance (1RM squat strength: -35.2 ± 10.4%, SJ: -7.0 ± 6.0%, CMJ: -10.0 ± 6.3%) was observed immediately post-match (p < 0.05). At 24 h post-match, the 1RM strength and jump heights were not significantly different from the baseline values. However, several players showed a decrease of these measures at 24 h after the match play. The simulated tennis match play induced mild muscle damage in young players. Coaches could monitor changes in the indirect markers of muscle damage to assess athletes’ recovery status during training and competition.     

Effects of Heavy Strength Training on Running Performance and Determinants of Running Performance in Female Endurance Athletes

Purpose

The purpose of the current study was to investigate the effects of adding strength training to normal endurance training on running performance and running economy in well-trained female athletes. We hypothesized that the added strength training would improve performance and running economy through altered stiffness of the muscle-tendon complex of leg extensors.

Methods

Nineteen female endurance athletes [maximal oxygen consumption (VO_2max): 53±3 ml∙kg^-1∙min^-1, 5.8 h weekly endurance training] were randomly assigned to either normal endurance training (E, n = 8) or normal endurance training combined with strength training (E+S, n = 11). The strength training consisted of four leg exercises [3 x 4–10 repetition maximum (RM)], twice a week for 11 weeks. Muscle strength, 40 min all-out running distance, running performance determinants and patellar tendon stiffness were measured before and after the intervention.

Results

E+S increased 1RM in leg exercises (40 ± 15%) and maximal jumping height in counter movement jump (6 ± 6%) and squat jump (9 ± 7%, p < 0.05). This was accompanied by increased muscle fiber cross sectional area of both fiber type I (13 ± 7%) and fiber type II (31 ± 20%) in m. vastus lateralis (p < 0.05), with no change in capillary density in m. vastus lateralis or the stiffness of the patellar tendon. Neither E+S nor E changed running economy, fractional utilization of VO_2max or VO_2max. There were also no change in running distance during a 40 min all-out running test in neither of the groups.

Conclusion

Adding heavy strength training to endurance training did not affect 40 min all-out running performance or running economy compared to endurance training only.     

Effects of heavy barbell hip thrust vs back squat on subsequent sprint performance in rugby players

The objective of this research was to compare the effect of Post-Activation Performance Enhancement (PAPE) exerted on the back squat (BS) versus the barbell hip thrust (HT) on the sprint performance (5- and 10-m). 17 male amateur rugby players participated in the study (age 22.14 ± 2.52 years; body mass 81.06 ± 9.6 kg; height 1.78 ± 0.05 m). All participants performed a dynamic maximum strength test (3RM) in BS and HT at maximum speed. Two randomized sessions were performed inducing PAPE using BS or HT trough three series with three repetitions at 85% 1RM eight minutes before the sprint tests. An ANOVA of repeated measurement, found no differences in the time for 5-m (F = 0.398, P = 0.537, η²p = 0.024) or 10-m (F = 2.589, P = 0.127, η²p = 0.139). There were no significant differences in the Protocol effect between HT and BS in 5-m or 10-m (F = 2.963, P = 0.104, η²p = 0.156 and F = 1.472, P = 0.243 η²p = 0.084, respectively). There were also no differences in the Time x Protocol interaction at 5-m (F = 0.001, P = 0.976, η²p < 0.001) or 10-m (F = 4.174, P = 0.058, η²p = 0.207). The effect size obtained in the results of the sprint tests was small in both exercises (ES < 0.2). None of the BS or HT exercises performed with heavy load induced a significant PAPE phenomenon on the ability to sprint in rugby players.     

Determination of metabolic equivalents during low- and high-intensity resistance exercise in healthy young subjects and patients with type 2 diabetes

The purpose of this study was to quantify the metabolic equivalents (METs) of resistance exercise in obese patients with type 2 diabetes (T2DM) and healthy young subjects and to evaluate whether there were differences between sessions executed at low- versus high-intensity resistance exercise. Twenty obese patients with T2DM (62.9±6.1 years) and 22 young subjects (22.6±1.9 years) performed two training sessions: one at vigorous intensity (80% of 1-repetition maximum (1RM)) and one at moderate intensity (60% of 1RM). Both groups carried out three strength exercises with a 2-day recovery between sessions. Oxygen consumption was continuously measured 15 min before, during and after each training session. Obese T2DM patients showed lower METs values compared with young healthy participants at the baseline phase (F= 2043.86; P<0.01), during training (F=1140.59; P<0.01) and in the post-exercise phase (F=1012.71; P<0.01). No effects were detected in the group x intensity analysis of covariance. In this study, at both light-moderate and vigorous resistance exercise intensities, the METs value that best represented both sessions was 3 METs for the obese elderly T2DM patients and 5 METs for young subjects.     

Effects of resistance training on hypertrophy,strength and tensiomyography parameters of elbow flexors: role of eccentric phase duration

The aim of the study was to compare the effects of two different training protocols, which differ in the duration of the eccentric phase, on the one-repetition maximum (1RM), thickness and contractile properties of elbow flexors. Twenty untrained college students were randomly divided into two experimental groups, based on the training tempo: FEG (Faster Eccentric Group: 1/0/1/0) and SEG (Slower Eccentric Group: 4/0/1/0). Training intervention was a biceps bending exercise, conducted twice a week for 7 weeks. The intensity (60–70% RM), sets (3–4) and rest intervals (120 s) were held constant, while repetitions were performed until it was not possible to maintain a set duration. In the initial and final measurements, 1RM, muscle thickness and tensiomyography parameters – contraction time (Tc) and radial deformation (Dm) – were evaluated. An ANCOVA model (using baseline outcomes as covariates) was applied to determine between-group differences at post-test, while Pearson’s product-moment correlation coefficient was used to investigate the relationship between absolute changes in muscle thickness and Dm. Muscle strength increase was greater for SEG than for FEG (6.0 ± 1.76 vs. 3.30 ± 2.26 kg, p < 0.01). In both groups muscle thickness increased equally (FEG: 3.24 ± 2.01 vs. SEG: 3.57 ± 1.17 mm, p < 0.01), while an overall reduction in Dm was observed (FEG: 1.99 ± 1.20 vs. SEG: 2.26 ± 1.03 mm, p < 0.01). Values of Tc remained unchanged. A significant negative relationship was observed between changes in muscle thickness and Dm (r = -0.763, Adj.R² = 0.560, p < 0.01). These results indicate that the duration of the eccentric phase has no effect on muscle hypertrophy in untrained subjects, but that slower eccentric movement significantly increases 1RM.     

Effects of resistance training intensity on sleep quality and strength recovery in trained men: a randomized cross-over study

Resistance training (RT) variables can affect sleep quality, strength recovery and performance. The aim of this study was to examine the acute effect of RT leading to failure vs. non-failure on sleep quality (SQ), heart rate variability (HRV) overnight and one-repetition maximum (1-RM) performance 24 hours after training. Fifteen resistance-trained male athletes (age: 23.4 ± 2.4 years; height 178.0 ± 7.6 cm; weight: 78.2 ± 10.6 kg) performed two training sessions in a randomized order, leading to failure (4x10) or non-failure (5x8(10) repetitions), with 90 seconds for resting between sets at 75% 1-RM in bench press (BP) and half squat (HS). The day after, the participants completed the predicted 1-RM test for both exercises. In addition, the subjective and actigraphic SQ and HRV during sleep were measured after each training session. The day after the training protocol leading to failure, the 1-RM of BP (MD = 7.24 kg; -7.2%; p < 0.001) and HS (MD = 20.20 kg; -11.1%; p < 0.001) decreased. However, this parameter did not decrease after a non-failure RT session. No differences were observed between failure and non-failure training sessions on SQ and HRV; therefore, both types of training sessions similarly affected the SQ and the autonomic modulation during the night after the training session. This study provides an insight into the influence of different training strategies on SQ, strength performance and recovery after moderate- to high-demand training. This information could be useful especially for professional coaches, weightlifters and bodybuilders, due to the potential influence on the programming processes.     

Accuracy of prediction equations for determining one repetition maximum bench press in women before and after resistance training

Repetitions to fatigue (RTF) using less than a 1 repetition maximum (1RM) load (RepWt) have been shown to be a good predictor of 1RM strength in men, but such information is scarce in women. The purpose of this study was to evaluate the accuracy of current prediction equations to estimate 1RM bench press performance and to determine whether resistance training changes the capability to predict 1RM from muscular endurance repetitions in young women. Members (n = 103) of a required wellness course were measured for 1RM bench press and RTF using randomly assigned percentages between 60% and 90% of the 1RM (RepWt) before and after 12 weeks of progressive resistance training. The %1RM used to perform RTF remained the same for each individual after training (75.6% +/- 10.3%) as before. One repetition maximum bench press increased significantly after training (28% +/- 21%). Although the change in the group average for RTF (0.6 +/- 6.1) was not significant, the correlation between pretraining and posttraining RTF was moderate (r = 0.66; p < 0.01), and individual differences in percentage change in RTF were substantial (27% +/- 99%). The percentage change in 1RM was not significantly related to initial 1RM (r = -0.05), but it was negatively related to the change in RTF (r = -0.40; p < 0.01). Prediction equations were more accurate in the pretraining and posttraining conditions, in which fewer than 10 RTF were used. Resistance training may alter the relationship between strength and muscle endurance across a wide range of RTF in young women without compromising the accuracy of predicting maximal strength.     

ACUTE EFFECTS OF MOVEMENT VELOCITY ON BLOOD LACTATE AND GROWTH HORMONE RESPONSES AFTER ECCENTRIC BENCH PRESS EXERCISE IN RESISTANCE-TRAINED MEN

This study aimed to compare the effects of different velocities of eccentric muscle actions on acute blood lactate and serum growth hormone (GH) concentrations following free weight bench press exercises performed by resistance-trained men. Sixteen healthy men were divided into two groups: slow eccentric velocity (SEV; n = 8) and fast eccentric velocity (FEV; n = 8). Both groups performed four sets of eight eccentric repetitions at an intensity of 70% of their one repetition maximum eccentric (1RMecc) test, with 2-minute rest intervals between sets. The eccentric velocity was controlled to 3 seconds per range of motion for SEV and 0.5 seconds for the FEV group. There was a significant difference (P < 0.001) in the kinetics of blood lactate removal (at 3, 6, 9, 15, and 20 min) and higher mean values for peak blood lactate (P = 0.001) for the SEV group (9.1 ± 0.5 mM) compared to the FEV group (6.1 ± 0.4 mM). Additionally, serum GH concentrations were significantly higher (P < 0.001) at 15 minutes after bench press exercise in the SEV group (1.7 ± 0.6 ng · mL⁻¹) relative to the FEV group (0.1 ± 0.0 ng · mL⁻¹). In conclusion, the velocity of eccentric muscle action influences acute responses following bench press exercises performed by resistance-trained men using a slow velocity resulting in a greater metabolic stress and hormone response.     

Impact of testing strategy on expression of upper-body work capacity and one-repetition maximum prediction after resistance training in college-aged men and women

The purpose of this study was to assess the effect of resistance training on upper-body muscular strength and the expression of work capacity and muscular endurance. In addition, a training-induced change in the relationship between muscular strength and endurance was assessed by testing changes in the accuracy of using endurance repetitions to predict 1 repetition maximum (1RM) bench press before and after training. College-aged men (n = 85) and women (n = 62) completed a 12-week linear periodization resistance training program. Before and after training, the subjects were assessed for 1RM and repetitions to fatigue (RTFs) with a submaximal load. After pretraining 1RM determination, the subjects were randomly assigned to perform RTFs at 65% 1RM (n = 74) or 90% 1RM (n = 73). Pretraining and posttraining RTFs were conducted at the same respective % 1RM. Work capacity was determined from repetition weight × RTF. After training, there was a significant increase in 1RM in both men (～14%) and women (～23%). Posttraining RTF was not different from pretraining RTF at 65 %1RM (18.2 ± 5.1 and 19.0 ± 6.0, respectively) but was significantly reduced in the 90% 1RM group (6.1 ± 3.6 vs. 4.5 ± 2.7, respectively). Likewise, there was a differential effect of training on the expression of work capacity, which increased in the 65 % 1RM group (123 ± 155 kg-reps) but decreased in the 90% 1RM group (-62 ± 208 kg-reps); the effect was independent of gender within each testing group. In conclusion, the changes in muscular strength associated with resistance training produced an increase in work capacity when tested with a 65 % 1RM load without a change in endurance. In contrast, both work capacity and endurance decreased when tested with 90% 1RM. Thus, the impact of strength training on work capacity and muscle endurance is specific to the load at which endurance testing is performed.     

Changes in fitness and shipboard task performance following circuit weight training programs featuring continuous or interval running

Pre- and post-physiological data were collected on 57 Navy men (mean age = 19.5 years) who participated in either circuit weight training/continuous run (CWT/CR) (N = 31) or circuit weight training/interval run (CWT/IR) (N = 26) programs. Measured variables included 4 measures of upper torso dynamic strength (one repetition maximum [1 RM] for arm curl, bench press, shoulder press, and lat pull-down); two measures of lower torso dynamic strength (1 RM) for knee extension and leg press); one measure of power (number of revolutions completed on an arm ergometer (Monark) at maximum drag); three measures of muscular endurance (number of repetitions at 60% 1 RM for bench press and leg press and maximal number of bent-knee sit-ups in 120 s); one stamina measure (time to exhaustion on a cycle ergometer (Monark) maximal work capacity [MWC] test; and three simulated shipboard tasks: manikin shoulder drag, open/secure a water tight door and paint bucket carry. Composite shipboard performance derived from the summed time (s) required to complete the three tasks was also calculated. Results show performance on the manikin shoulder drag and majority of evaluative fitness measures was significantly (p less than 0.05) enhanced following both circuit weight training/run formats. Significantly (p less than 0.05) higher values for shoulder press (F = 7.2), arm ergometer (F = 5.3), and sit-ups (F = 6.8) and lower values for leg press muscular endurance (F = 5.1) were observed in CWT/IR when compared to CWT/CR.(ABSTRACT TRUNCATED AT 250 WORDS)     

EFFECT OF THE NUMBER OF SPRINT REPETITIONS ON THE VARIATION OF BLOOD LACTATE CONCENTRATION IN REPEATED SPRINT SESSIONS

The aim of the present study was to examine the effect of number of sprint repetitions on the variation of blood lactate concentration (blood [La]) during different repeated-sprint sessions in order to find the appropriate number of sprint repetitions that properly simulates the physiological demands of team sport competitions. Twenty male team-sport players (age, 22.2 ± 2.9 years) performed several repeated-sprint sessions (RSS) consisting of 1, 2, 3, 4, 5, 9, or 10 repetitions of 30 m shuttle sprints (2 × 15 m) with 30 s recovery in between. The blood [La] was obtained after 3 min of recovery at the end of each RSS. The present study showed that for RSS of 3 sprints (RSS3) there was a high increase (p<0.001) in blood [La], which reached approximately fivefold resting values (9.4±1.7 mmol · l⁻¹) and then remained unchanged for the RSS of 4 and 5 sprints (9.6±1.4 and 10.5±1.9 mmol · l⁻¹, p=0.96 and 0.26, respectively). After RSS9 and RSS10 blood [La] further significantly increased to 12.6 and 12.7 mmol · l⁻¹, p<0.001, respectively. No significant difference was found between RSS3, RSS4 and RSS5 for the percentage of sprint speed decrement (Sdec) (1.5±1.2; 2.0±1.1 and 2.6±1.4%, respectively). There was also no significant difference between RSS9 and RSS10 for Sdec (3.9±1.3% and 4.5±1.4%, respectively). In conclusion, the repeated-sprint protocol composed of 5 shuttle sprint repetitions is more representative of the blood lactate demands of the team sports game intensity.     

The effects of training volume and competition on the salivary cortisol concentrations of Olympic weightlifters

This study examined the effects of training volume and competition on the salivary cortisol (Sal-C) concentrations of Olympic weightlifters. Male (n = 5) and female (n = 4) Olympic weightlifters provided saliva samples across a 5-week experimental = period. The first aim was to assess the weekly effects of high (≥ 200 sets) and low (≤ 100 sets) training volume on Sal-C. The second aim was to compare Sal-C concentrations and 1 repetition maximum (1RM) performance during 2 simulated and 2 actual competitions. Performance was assessed using the snatch, clean and jerk, and the Olympic total lift. Data from each competition setting were pooled before analysis. There were no significant weekly changes in Sal-C levels (p > 0.05). The actual competitions produced higher (128-130%) Sal-C concentrations (p < 0.001) and superior 1RM lifts (1.9-2.6%) for the clean and jerk, and the Olympic total, than the simulated competitions (p < 0.05). Individual Sal-C concentrations before the simulated competitions were positively correlated to all of the 1RM lifts (r = 0.48-0.49, p < 0.05). In conclusion, actual competitions produced greater Sal-C responses than simulated competitions, and this appeared to benefit the 1RM performance of Olympic weightlifters. Individuals with higher Sal-C concentrations also tended to exhibit superior 1RM lifts during the simulated competitions. Given these findings, greater emphasis should be placed upon the monitoring of C to establish normative values, training standards and to assist with performance prediction.     

Occurrence of fatigue during sets of static squat jumps performed at a variety of loads

Research has identified that the optimal power load for static squat jumps (with no countermovement) is lower than the loads usually recommended for power training. Lower loads may permit the performance of additional repetitions before the onset of fatigue compared with heavier loads; therefore, the aim of this study was to determine the point of fatigue during squat jumps at various loads (0, 20, 40, 60% 1-repetition maximum [1RM]). Seventeen professional rugby league players performed sets of 6 squat jumps (with no countermovement), using 4 loading conditions (0, 20, 40, and 60% of 1RM back squat). Repeated measures analysis of variance revealed no significant differences (p > 0.05) in force, velocity, power, and displacement between repetitions, for the 0, 20, and 40% loading conditions. The 60% condition showed no significant difference (p > 0.05) in peak force between repetitions; however, velocity (1.12 + 0.10 and 1.18 + 0.11 m·s(-1)), power (3,385 + 343 and 3,617 + 396 W) and displacement (11.13 + 2.31 and 11.85 + 2.16 cm) were significantly (p < 0.02) lower during repetition 6 compared with repetition 2. These findings indicate that when performing squat jumps (with no countermovement) with a load <40% 1RM back squat, up to >6 repetitions can be completed without inducing fatigue and a minimum of 4-6 repetitions should be performed to achieve peak power output. When performing squat jumps (with no countermovement) with a load equal to the 60% 1RM only, 5 repetitions should be performed to minimize fatigue and ensure maintenance of velocity and power.     

Similar hypotensive responses to resistance exercise with and without blood flow restriction

Low intensity resistance exercise (RE) with blood flow restriction (BFR) has gained attention in the literature due to the beneficial effects on functional and morphological variables, similar to those observed during traditional RE without BFR, while the effects of BFR on post-exercise hypotension remain unclear. The aim of the present study was to compare the blood pressure (BP) response of trained normotensive individuals to RE with and without BFR. In this cross-over randomized trial, eight male subjects (23.8 ± 4 years, 74 ± 3 kg, 174 ± 4 cm) completed two exercise protocols: traditional RE (3 x 10 repetitions at 70% one-repetition maximum [1-RM]) and low intensity RE (3 x 15 repetitions at 20% 1-RM) with BFR. Blood pressure measurements were performed after 15 min of seated rest (0), immediately after and 10 min, 20 min, 30 min, 40 min, 50 min and 60 min after the experimental sessions. Similar hypotensive effects for systolic BP (SBP) were observed for both protocols (P < 0.05) after exercise, with no differences between groups (P > 0.05) and no statistically significant difference for diastolic BP (P > 0.05). These results suggest that in normotensive trained individuals, both traditional RE and RE with BFR induce hypotension for SBP, which is important to prevent cardiovascular disturbances.     

The relationship between maximal repetition performance and muscle fiber type as estimated by noninvasive technique in the quadriceps of untrained women

The purpose of this investigation was to establish a relationship between the number of repetitions an individual can complete at a predetermined load and their percentage of type II muscle fibers in their quadriceps. Subjects included 22 untrained women between the ages of 18 and 35. Day 1 consisted of noninvasive anthropologic testing, 1 repetition maximum (1RM) testing, and recording repetition performance at 70% 1RM. Day 2 consisted of isokinetic dynamometry to determine muscle fiber composition. Results were obtained and analyzed using the Pearson product correlation coefficient (r). The results demonstrated a fair-to-moderate relationship (Pearson r = -0.48, p = 0.02) that individuals with greater percentages of type II muscle fibers performed fewer repetitions at 70% 1RM. The results of this study demonstrate that muscle fiber type composition is an important variable to consider when designing training or rehabilitation programs.