Effects of Load and Focus of Attention on Mechanical Parameters During Bench-Press Throw in Resistance-Trained Men.

PURPOSE: Power output is dependent on the load used during exercise such as bench-press throw (BPT). Attentional focus (external [EXT] vs internal [INT]) during exercise significantly modulates power performance. The purpose of the present study was to examine the effects of load and attentional focus on mechanical parameters during BPT. METHODS: In a crossover study, 31 resistance-trained men (mean age 23.5 [3.0] y) performed BPT at 30% (light), 50% (moderate), and 70% (heavy) of 1-repetition maximum (1-RM) using an INT or EXT focus of attention in randomized order. A linear encoder was used to identify barbell vertical displacement, throw time, peak/average velocity, force, and power during the concentric lifting phase. RESULTS: Statistical analysis revealed significant load × focus interaction effects for velocity and vertical displacement (P ≤ .045; 0.66 ≤ d ≤ 0.89). Post hoc analyses indicated significantly larger velocities and displacements at 30% and 70% of 1-RM in favor of EXT (P ≤ .038; 0.79 ≤ d ≤ 1.13) but similar values at 50% of 1-RM (P > .05). Furthermore, significant main effects of load were found for throw time, force, and power (P < .001; 4.20 ≤ d ≤ 14.0). While time and force gradually increased with higher loads (P < .001; 1.45 ≤ d ≤ 14.0), power output was larger at 50% compared with 30% and 70% 1-RM (P < .001; 3.09 ≤ d ≤ 7.07), irrespective of attentional focus. CONCLUSIONS: The present findings indicated that practitioners may use EXT over INT attentional focus to enhance velocity and vertical displacement during BPT at light and heavy loads (ie, 30% and 70% 1-RM). At moderate loads (ie, 50% 1-RM), mechanical bench-press parameters appear to be less affected by attentional focus.

Effects of climbing- and resistance-training on climbing-specific performance: a systematic review and meta-analysis.

The objective of this systematic review and meta-analysis was to examine the effects of climbing and climbing-and-resistance-training on climbing performance, and strength and endurance tests. We systematically searched three databases (SPORTDiscus, SCOPUS, and PubMed) for records published until January 2021. The search was limited to randomized-controlled trials using active climbers and measuring climbing performance or performance in climbing-specific tests. Data from the meta-analysis are presented as standardized difference in mean (SDM) with 95% confidence intervals (95% CI). Eleven studies are included in the systematic review and five studies compared training to a control group and could be meta-analyzed. The overall meta-analysis displayed an improvement in climbing-related test performance following climbing-specific resistance training compared to only climbing (SDM = 0.57, 95%CI = 0.24-0.91). Further analyses revealed that finger strength (SDM = 0.41, 95%CI 0.03-0.80), rate of force development (SDM = 0.91, 95%CI = 0.21-1.61), and forearm endurance (SDM = 1.23, 95%CI = 0.69-1.77) were improved by resistance-training of the finger flexors compared to climbing training. The systematic review showed that climbing performance may be improved by specific resistance-training or interval-style bouldering. However, resistance-training of the finger flexors showed no improvements in strength or endurance in climbing-specific tests. The available evidence suggests that resistance-training may be more effective than just climbing-training for improving performance outcomes. Importantly, interventional studies including climbers is limited and more research is needed to confirm these findings.

Comparing the effects of variable and traditional resistance training on maximal strength and muscle power in healthy adults: A systematic review and meta-analysis.

OBJECTIVES: The aim of the study was to aggregate different effects between variable resistance training and traditional resistance training on maximal muscle strength and muscle power and identify potential sex- and training program-related moderator variables. DESIGN: Meta-analysis. METHODS: A systematic literature search was conducted in SPORTDiscus, PubMed, and Web of Science. Interventions were included if they compared variable resistance training and traditional resistance training in healthy adults and examined the effects on measures of maximal muscle strength and/or muscle power of the lower and/or upper body. A random-effects model was used to calculate weighted and averaged standardized mean differences. Additionally, univariate sub-group analyses were independently computed for sex and training-related moderator variables. RESULTS: Seventeen studies comprising a total of 491 participants (341 men and 150 women, age 18-37 years) were included in the analyses. In terms of maximal muscle strength, there were no statistically significant differences between variable resistance training and traditional resistance training for the lower (p = 0.46, standardized mean difference = -0.10) or the upper body (p = 0.14, standardized mean difference = -0.17). Additionally, there were no significant training-related differences in muscle power for the lower (p = 0.16, standardized mean difference = 0.21) or upper body (p = 0.81, standardized mean difference = 0.05). Sub-group analyses showed a significant moderator effect for training period and repetitions per set for maximal muscle strength in the lower body (p = 0.03-0.04) with larger strength gains following traditional resistance training when performing more repetitions per set (p = 0.02, standardized mean difference = 0.43). No other significant sub-group effects were found (p = 0.18-0.82). CONCLUSIONS: Our results suggest that variable resistance training and traditional resistance training are equally effective in improving maximal muscle strength and muscle power in healthy adults.

Associations between biological maturity level, match locomotion, and physical capacities in youth male soccer players.

INTRODUCTION: Biological maturity level has shown to affect sport performance in youths. However, most previous studies have used noninvasive methods to estimate maturity level. Thus, the main aim of the present study was to investigate the association between skeletal age (SA) as a measure of biological maturation level, match locomotion, and physical capacity in male youth soccer players. METHOD: Thirty-eight Norwegian players were followed during two consecutive seasons (U14 and U15). Match locomotion was assessed with GPS-tracking in matches. SA, assessed by x-ray, physical capacities (speed, strength and endurance) and anthropometrics were measured in the middle of each season. Analysis of associations between SA, match locomotion, and physical capacities were adjusted for the potential confounding effect of body height and weight. RESULTS: In matches, positive associations were found between SA and maximal speed and running distance in the highest speed zones. Further, SA was associated with 40 m sprint time and countermovement jump (CMJ) height, and with intermittent-endurance capacity after adjusting for body height (U14). Associations between SA and leg strength and power, and between SA and absolute VO2max were not significant after adjusting for body weight. There was no association between SA and total distance covered in matches. CONCLUSION: Biological maturity level influence match locomotion and performance on physical capacity tests. It is important that players, parents and coaches are aware of the advantages more mature players have during puberty, and that less mature players also are given attention, appropriate training and match competition to ensure proper development.

The Effects of 10 Weeks Hangboard Training on Climbing Specific Maximal Strength, Explosive Strength, and Finger Endurance.

The aim of this study was to investigate the effects of 10 weeks of hangboard training (HBT) on climbing-specific maximal strength, explosive strength, and muscular endurance. In total, 35 intermediate- to advanced-level climbers (8 women and 27 men) were randomized into a hangboard training group (HBT) or a control group (CON). The HBT program consisted of two sessions of 48 min per week using the Beastmaker 1000 series hangboard, and the following application to smartphone. Both groups continued their normal climbing training routines. Pre- and post-intervention, maximal peak force, maximal average force, and rate of force development (RFD) were measured while performing an isometric pull-up on a 23 mm deep campus rung and jug holds. In addition, finger endurance was measured by performing a sustained dead-hang test on the same rung. The HBT increased peak force and average force in 23 mm rung condition, average force in jug condition, and utilization rate øl,.- in peak force to a greater extent than CON (p = 0.001-0.031, ES = 0.29-0.66), whereas no differences were detected between groups in RFD (jug or 23 mm), peak force in jug condition, utilization rate in RFD, average force or in dead-hang duration (p = 0.056-0.303). At post-test, the HBT group demonstrated 17, 18, 28, 10, 11, and 12% improvement in peak force, average force, RFD in 23 mm rung condition, average force in jug condition, utilization rate in peak force, and dead-hang duration, respectively [p = 0.001-0.006, effect size (ES) = 0.73-1.12] whereas no change was observed in CON (p = 0.213-0.396). In conclusion, 10 weeks of HBT in addition to regular climbing was highly effective for increasing maximal finger strength compared with continuing regular climbing training for intermediate and advanced climbers.

The Effects of Trunk Muscle Training on Physical Fitness and Sport-Specific Performance in Young and Adult Athletes: A Systematic Review and Meta-Analysis.

BACKGROUND: The role of trunk muscle training (TMT) for physical fitness (e.g., muscle power) and sport-specific performance measures (e.g., swimming time) in athletic populations has been extensively examined over the last decades. However, a recent systematic review and meta-analysis on the effects of TMT on measures of physical fitness and sport-specific performance in young and adult athletes is lacking. OBJECTIVE: To aggregate the effects of TMT on measures of physical fitness and sport-specific performance in young and adult athletes and identify potential subject-related moderator variables (e.g., age, sex, expertise level) and training-related programming parameters (e.g., frequency, study length, session duration, and number of training sessions) for TMT effects. DATA SOURCES: A systematic literature search was conducted with PubMed, Web of Science, and SPORTDiscus, with no date restrictions, up to June 2021. STUDY ELIGIBILITY CRITERIA: Only controlled trials with baseline and follow-up measures were included if they examined the effects of TMT on at least one measure of physical fitness (e.g., maximal muscle strength, change-of-direction speed (CODS)/agility, linear sprint speed) and sport-specific performance (e.g., throwing velocity, swimming time) in young or adult competitive athletes at a regional, national, or international level. The expertise level was classified as either elite (competing at national and/or international level) or regional (i.e., recreational and sub-elite). STUDY APPRAISAL AND SYNTHESIS METHODS: The methodological quality of TMT studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. A random-effects model was used to calculate weighted standardized mean differences (SMDs) between intervention and active control groups. Additionally, univariate sub-group analyses were independently computed for subject-related moderator variables and training-related programming parameters. RESULTS: Overall, 31 studies with 693 participants aged 11-37 years were eligible for inclusion. The methodological quality of the included studies was 5 on the PEDro scale. In terms of physical fitness, there were significant, small-to-large effects of TMT on maximal muscle strength (SMD = 0.39), local muscular endurance (SMD = 1.29), lower limb muscle power (SMD = 0.30), linear sprint speed (SMD = 0.66), and CODS/agility (SMD = 0.70). Furthermore, a significant and moderate TMT effect was found for sport-specific performance (SMD = 0.64). Univariate sub-group analyses for subject-related moderator variables revealed significant effects of age on CODS/agility (p = 0.04), with significantly large effects for children (SMD = 1.53, p = 0.002). Further, there was a significant effect of number of training sessions on muscle power and linear sprint speed (p ≤ 0.03), with significant, small-to-large effects of TMT for > 18 sessions compared to ≤ 18 sessions (0.45 ≤ SMD ≤ 0.84, p ≤ 0.003). Additionally, session duration significantly modulated TMT effects on linear sprint speed, CODS/agility, and sport-specific performance (p ≤ 0.05). TMT with session durations ≤ 30 min resulted in significant, large effects on linear sprint speed and CODS/agility (1.66 ≤ SMD ≤ 2.42, p ≤ 0.002), whereas session durations > 30 min resulted in significant, large effects on sport-specific performance (SMD = 1.22, p = 0.008). CONCLUSIONS: Our findings indicate that TMT is an effective means to improve selected measures of physical fitness and sport-specific performance in young and adult athletes. Independent sub-group analyses suggest that TMT has the potential to improve CODS/agility, but only in children. Additionally, more (> 18) and/or shorter duration (≤ 30 min) TMT sessions appear to be more effective for improving lower limb muscle power, linear sprint speed, and CODS/agility in young or adult competitive athletes.

Contemporary Training Practices of Norwegian Powerlifters.

ABSTRACT: Shaw, MP, Andersen, V, Sæterbakken, AH, Paulsen, G, Samnøy, LE, and Solstad, TEJ. Contemporary training practices of Norwegian powerlifters. J Strength Cond Res 36(9): 2544-2551, 2022-The aim of this study was to explore the contemporary training practices of Norwegian powerlifters. One hundred twenty-four Norwegian powerlifters completed an electronic questionnaire that surveyed their current training practices with a focus on 2 areas: (a) training content and (b) training design and monitoring. One hundred seventeen respondents met the inclusion criteria, and the sample included World, European, and Norwegian champions. Where data were dichotomized, chi-square tests were used. The most frequently reported (58.1%) category of training was 5-6 times per week, with no statistically significant associations between levels of competitors (international vs. noninternational) (X 2 (1) = 0.414, p = 0.52). The most frequently reported load used in training was 71-80% 1 repetition maximum. The majority of Norwegian (76.9%) powerlifters train with variable resistance, with those competing internationally more likely to use elastic bands (X 2 (1) = 4.473, p = 0.034). 32.5% of respondents reported that they included strength training exercises in their training. Norwegian powerlifters' training differs from practices previously identified in the literature, with a higher prevalence of elastic resistance, particularly for those competing internationally, and a decreased use of strength training exercises at all levels. Norwegian powerlifters train frequently (5 or more times per week) and with submaximal loads.

Core Muscle Activation in Three Lower Extremity Exercises With Different Stability Requirements.

ABSTRACT: Saeterbakken, AH, Stien, N, Pedersen, H, and Andersen, V. Core muscle activation in three lower extremity exercises with different stability requirements. J Strength Cond Res 36(2): 304-309, 2022-The aim of the study was to compare core muscle surface electromyography (sEMG) during 3-repetition maximum (3RM) and the sEMG amplitude in the turnover from the descending to ascending phase in leg press, free-weight squats, and squats using the Smith machine. Nineteen women with 4.5 (±2.0) years of resistance training were recruited. After one familiarization session, the subjects performed 3RM in randomized order measuring electromyographic activity in the rectus abdominis, external oblique, and erector spinae. The exercises with the lowest stability requirements (leg press) demonstrated 17-59% and 17-42% lower core muscle sEMG amplitude than free weights and the Smith machine, respectively. No statistically significant differences were observed between the Smith machine and free weights. No statistically significant differences in turnover sEMG amplitude in the rectus abdominis between the exercises was observed, but lower sEMG amplitude was observed in external oblique and erector spinae in leg press compared with the other exercises. The 3RM loads in leg press were 54 and 47% greater than squats using the Smith machine and free weights, with 5% greater loads with the Smith machine than with free weights. In conclusion, lower mean and turnover core muscle sEMG amplitude were observed with the leg press but greater 3RM loads compared with squats with the Smith machine and free weights. The authors recommend that resistance-trained individuals use squats to include the core muscles in the kinetic chain, but there is no evidence that greater stability requirements (free weights instead of the Smith machine) will result in greater core muscle sEMG amplitude.

Effects of Two vs. Four Weekly Campus Board Training Sessions on Bouldering Performance and Climbing-Specific Tests in Advanced and Elite Climbers.

This study examined the effects of two or four weekly campus board training sessions among highly accomplished lead climbers. Sixteen advanced-to-elite climbers were randomly allocated to two (TG2), or four weekly campus board training sessions (TG4), or a control group (CG). All groups continued their normal climbing routines. Pre- and post-intervention measures included bouldering performance, maximal isometric pull-up strength using a shallow rung and a large hold (jug), and maximal reach and moves to failure. Rate of force development (RFD; absolute and 100ms) was calculated in the rung condition. TG4 improved maximal force in the jug condition (effect size (ES) = 0.40, p = 0.043), and absolute RFD more than CG (ES = 2.92, p = 0.025), whereas TG2 improved bouldering performance (ES = 2.59, p = 0.016) and maximal moves to failure on the campus board more than CG (ES = 1.65, p = 0.008). No differences between the training groups were found (p = 0.107-1.000). When merging the training groups, the training improved strength in the rung condition (ES = 0.87, p = 0.002), bouldering performance (ES = 2.37, p = 0.006), maximal reach (ES = 1.66, p = 0.006) and moves to failure (ES = 1.43, p = 0.040) more than CG. In conclusion, a five-week campus board training-block is sufficient for improving climbing-specific attributes among advanced-to-elite climbers. Sessions should be divided over four days to improve RFD or divided over two days to improve bouldering performance, compared to regular climbing training.

Electromyographic comparison of the barbell deadlift using constant versus variable resistance in healthy, trained men.

Variable, external resistance is proposed to increasingly augment the muscular stress throughout a dynamic movement. However, it is uncertain how different levels of variable resistance affect the activation in the deadlift. The aim of the study was to compare the electromyographic activity of the gluteus maximus, biceps femoris, semitendinosus, vastus lateralis and erector spinae muscles during the barbell deadlift with free weights (FW) alone, with two (FW-2EB), and four elastic bands (FW-4EB) to deload some of the constant external resistance. Fifteen resistance-trained men participated in a cross-over design where resistance loadings were matched using two-repetition maximum loadings in the three different conditions. For the whole movement, both repetitions were analyzed. For the phase-specific analysis, the last repetition was divided into six parts, i.e. the lower, middle and upper phase in both the ascending and descending phase of the movement. The mean deloading contributions from FW-2EB and FW-4EB were 21% and 41%, respectively. In FW-4EB, the erector spinae was activated more in the whole movement (8%, ES = 0.31, p = 0.002) compared to FW-2EB. There was also a tendency towards higher activation in FW-4EB versus FW for the whole movement (5%, ES = 0.18, p = 0.072). There were no significant differences between the conditions in any of the other phases or muscles (p = 0.106-0.926). In summary, a high contribution from variable, external resistance seems to activate the back extensors more than a low contribution.

Electromyographic Comparison of Barbell Deadlift, Hex Bar Deadlift, and Hip Thrust Exercises: A Cross-Over Study.

Andersen, V, Fimland, MS, Mo, D-A, Iversen, VM, Vederhus, T, Rockland Hellebø, LR, Nordaune, KI, and Saeterbakken, AH. Electromyographic comparison of barbell deadlift, hex bar deadlift, and hip thrust exercises: a cross-over study. J Strength Cond Res 32(3): 587-593, 2018-The aim of the study was to compare the muscle activation level of the gluteus maximus, biceps femoris, and erector spinae in the hip thrust, barbell deadlift, and hex bar deadlift; each of which are compound resisted hip extension exercises. After 2 familiarization sessions, 13 resistance-trained men performed a 1 repetition maximum in all 3 exercises in 1 session, in randomized and counterbalanced order. The whole ascending movement (concentric phase), as well as its lower and upper parts (whole movement divided in 2), were analyzed. The hip thrust induced greater activation of the gluteus maximus compared with the hex bar deadlift in the whole (16%, p = 0.025) and the upper part (26%, p = 0.015) of the movement. For the whole movement, the biceps femoris was more activated during barbell deadlift compared with both the hex bar deadlift (28%, p < 0.001) and hip thrust (20%, p = 0.005). In the lower part of the movement, the biceps femoris activation was, respectively, 48% and 26% higher for the barbell deadlift (p < 0.001) and hex bar deadlift (p = 0.049) compared with hip thrust. Biceps femoris activation in the upper part of the movement was 39% higher for the barbell deadlift compared with the hex bar deadlift (p = 0.001) and 34% higher for the hip thrust compared with the hex bar deadlift (p = 0.002). No differences were displayed for the erector spinae activation (p = 0.312-0.859). In conclusion, the barbell deadlift was clearly superior in activating the biceps femoris compared with the hex bar deadlift and hip thrust, whereas the hip thrust provided the highest gluteus maximus activation.

Nordic walking and specific strength training for neck- and shoulder pain in office workers: a pilot-study.

BACKGROUND: More than half of all adults have experienced neck pain during the last six months. Studies have demonstrated reduced pain in the neck-and shoulder region after specific strength training of the affected muscles, but specific endurance training of neck and shoulder muscles has not been properly examined. AIM: To examine the impact of Nordic walking (NW) compared to specific strength training (ST) and a non-training control group (Con) on self-reported neck-and shoulder pain among office workers. DESIGN: Randomized intervention trial with a stratified control group. SETTINGS: University research laboratory. POPULATION: Thirty-four female office workers with neck- and shoulder pain. METHODS: The participants were allocated to NW, ST or Con. Pain intensity (0-100 mm Visual Analog Scale), isometric abduction strength and a Six-Minute Walk Test (6MWT) were assessed pre, post and 10 weeks postintervention. Both training groups attended the training programs twice per week for ten weeks (30 minutes per session). RESULTS: Both training groups demonstrated a similar (P=0.421-0.802), but significant reduction in pain intensity (P=0.014-0.018). Between post-test and the 10 weeks postintervention test, similar pain intensity was observed in the NW (P=0.932) while the ST demonstrated an increase (P=0.136). Throughout the testing period, no difference in pain was observed for the Con (P=0.724-1.000) or between the Con and the training groups (P=0.421-0.802). No changes in strength and 6MWT were observed between or within the groups (P=0.184-0.870). CONCLUSIONS: Both NW and ST reduced pain for office workers with low neck-and shoulder pain and appear to be useful exercise modalities for this group. CLINICAL REHABILITATION IMPACT: Both interventions reduced pain, but larger randomized studies should verify these findings.

Core Muscle Activation in One-Armed and Two-Armed Kettlebell Swing.

The aim of the study was to compare the electromyographic activity of rectus abdominis, oblique external, and lower and upper erector spinae at both sides of the truncus in 1-armed and 2-armed kettlebell swing. Sixteen healthy men performed 10 repetitions of both exercises using a 16-kg kettlebell in randomized order. For the upper erector spinae, the activation of the contralateral side during 1-armed swing was 24% greater than that of the ipsilateral side during 1-armed swing (p < 0.001) and 11% greater during 2-armed swing (p = 0.026). Furthermore, the activation in 2-armed swing was 12-16% greater than for the ipsilateral side in 1-armed swing (p < 0.001). For rectus abdominis, however, 42% lower activation of the contralateral side was observed during 1-armed swing compared with ipsilateral sides during 2-armed swing (p = 0.038) and 48% compared with the ipsilateral side during 1-armed swing (p = 0.044). Comparing the different phases of the swing, most differences in the upper erector spinae were found in the lower parts of the movement, whereas for the rectus abdominis, the differences were found during the hip extension. In contrast, similar muscle activity in the lower erector spinae and external oblique between the different conditions was observed (p = 0.055-0.969). In conclusion, performing the kettlebell swing with 1 arm resulted in greater neuromuscular activity for the contralateral side of the upper erector spinae and ipsilateral side of the rectus abdominis, and lower activation of the opposite side of the respective muscles.

Comparison of Kinematics and Muscle Activation in Free-Weight Back Squat With and Without Elastic Bands.

The purpose of the study was to compare kinematic muscle activation when performing 6 repetition maximum (6RM) squats using constant (free weights) or variable resistance (free weights + elastic bands). Twenty recreationally trained women were recruited with 4.6 ± 2.1 years of resistance training experience and a relative strength (6RM/body mass) of 1.1. After a familiarization session identifying the 6RM loads, the participants performed 6RM squats using constant and variable resistance in a randomized order. The total resistance in the variable resistance group was similar to the constant resistance in the presticking region (98%), but greater in the sticking region (105%) and the poststicking region (113%). In addition, the presticking barbell velocity was 21.0% greater using variable than constant resistance, but 22.8% lower in the poststicking region. No significant differences in muscle electromyographic activity, time occurrence, and vertical displacement between the squat modalities were observed, except for higher barbell displacement poststicking using variable resistance. It was concluded that, due to differences in total resistance in the different regions performing variable compared with constant resistance, greater barbell velocity was observed in the presticking region and lower resistance was observed in the poststicking region. However, the extra resistance in the sticking and poststicking regions during the variable resistance modality did not cause increased muscle activity. When performing squats with heavy resistance, the authors recommend using variable resistance, but we suggest increasing the percentage resistance from the elastic bands or using chains.

Elastic Bands in Combination With Free Weights in Strength Training: Neuromuscular Effects.

This study compared the effects of a variable vs. a constant lower limb resistance training program on muscle strength, muscle activation, and ballistic muscle performance at different knee angles. Thirty-two females were randomized to a constant resistance training free-weight group (FWG) or a variable resistance training group using free weights in combination with elastic bands (EBG). Two variations of the squat exercise (back squat and split) were performed 2 days per week for 10 weeks. Knee extensor maximal voluntary isometric contraction (MVC) and countermovement jump were assessed at knee angles of 60, 90, and 120° before and after the intervention. During the MVCs, muscle activation of the superficial knee extensor muscles was measured using surface electromyography. The FWG increased their MVCs at 60 and 90° (24 and 15%, respectively), whereas the EBG only increased significantly at 60° (15%). The FWG increased their jump height significantly at all angles (12-16%), whereas the EBG only improved significantly at 60 and 90° (15 and 10%, respectively). Both groups improved their 6-repetition maximum free-weight squat performance (EBG: 25% and FWG: 23%). There were no significant changes in muscle activation. In conclusion, constant and variable resistance training provided similar increases in dynamic and isometric strength, and ballistic muscle performance, albeit most consistently for the group training only with free weights.

Effects of BOSU ball(s) during sit-ups with body weight and added resistance on core muscle activation.

The objective of this study was to assess the electromyographic activity of the rectus abdominis (upper and lower part) and external oblique during sit-ups performed on BOSU ball(s). Twenty-four men participated in a familiarization session, and in the next session, they performed the experimental tests in randomized order. The sit-ups were performed with 10 repetitions with body weight and with 10 repetition maximum (10RM) using elastic bands as external resistance under 4 different conditions: (a) on a stable surface, (b) with the BOSU ball under their feet (dome side down, lower-body instability), (c) BOSU ball under the low back (dome side up, upper-body instability), and (d) with BOSU balls under both feet and the low back (dual instability). The feet were not attached to the surface. We observed that with body weight, external oblique activation was decreased by upper-body instability and dual instability by 22-24% (p = 0.002-0.006), whereas the rectus abdominis was not affected by the surface. Using 10RM loads, the upper and lower rectus abdominis activities were increased by upper body and dual instability by 21-24% compared with that for a stable surface (P ≤ 0.001-0.036). Further, lower-body instability did not affect muscle activities significantly with either load for any condition. Hence, BOSU balls under the low back can increase and decrease abdominal muscle activation depending on the load, whereas placing a BOSU ball under the feet with the dome side down had little impact.

Effects of replacing free weights with elastic band resistance in squats on trunk muscle activation.

The purpose of this study was to assess the effects of adding elastic bands to free-weight squats on the neuromuscular activation of core muscles. Twenty-five resistance trained women with 4.6 ± 2.1 years of resistance training experience participated in the study. In randomized order, the participants performed 6 repetition maximum in free-weight squats, with and without elastic bands (i.e., matched relative intensity between exercises). During free-weight squats with elastic bands, some of the free weights were replaced with 2 elastic bands attached to the lowest part of the squat rack. Surface electromyography (EMG) activity was measured from the erector spinae, external oblique, and rectus abdominis, whereas a linear encoder measured the vertical displacement. The EMG activities were compared between the 2 lifting modalities for the whole repetition and separately for the eccentric, concentric, and upper and lower eccentric and concentric phases. In the upper (greatest stretch of the elastic band), middle, and lower positions in squats with elastic bands, the resistance values were approximately 117, 105, and 93% of the free weight-only trial. Similar EMG activities were observed for the 2 lifting modalities for the erector spinae (p = 0.112-0.782), external oblique (p = 0.225-0.977), and rectus abdominis (p = 0.315-0.729) in all analyzed phases. In conclusion, there were no effects on the muscle activity of trunk muscles of substituting some resistance from free weights with elastic bands in the free-weight squat.

Effects of grip width on muscle strength and activation in the lat pull-down.

The lat pull-down is one of the most popular compound back exercises. Still, it is a general belief that a wider grip activates the latissimus dorsi more than a narrow one, but without any broad scientific support. The aim of the study was to compare 6 repetition maximum (6RM) load and electromyographic (EMG) activity in the lat pull-down using 3 different pronated grip widths. Fifteen men performed 6RM in the lat pull-down with narrow, medium, and wide grips (1, 1.5, and 2 times the biacromial distance) in a randomized and counterbalanced order. The 6RM strengths with narrow (80.3 ± 7.2 kg) and medium grip (80 ± 7.1 kg) were higher than wide grip (77.3 ± 6.3 kg; p = 0.02). There was similar EMG activation between grip widths for latissimus, trapezius, or infraspinatus, but a tendency for biceps brachii activation to be greater for medium vs. narrow (p = 0.09), when the entire movement was analyzed. Analyzing the concentric phase separately revealed greater biceps brachii activation using the medium vs. narrow grip (p = 0.03). In the eccentric phase, there was greater activation using wide vs. narrow grip for latissimus and infraspinatus (p ≤ 0.04), and tendencies for medium greater than narrow for latissimus, and medium greater than wide for biceps (both p = 0.08), was observed. Collectively, a medium grip may have some minor advantages over small and wide grips; however, athletes and others engaged in resistance training can generally expect similar muscle activation which in turn should result in similar hypertrophy gains with a grip width that is 1-2 times the biacromial distance.

Electromyographic activity and 6RM strength in bench press on stable and unstable surfaces.

The purpose of the study was to compare 6-repetition maximum (6RM) loads and muscle activity in bench press on 3 surfaces, namely, stable bench, balance cushion, and Swiss ball. Sixteen healthy, resistance-trained men (age 22.5 ± 2.0 years, stature 1.82 ± 6.6 m, and body mass 82.0 ± 7.8 kg) volunteered for 3 habituation/strength testing sessions and 1 experimental session. In randomized order on the 3 surfaces, 6RM strength and electromyographic activity of pectoralis major, deltoid anterior, biceps brachii, triceps brachii, rectus abdominis, oblique external and erector spinae were assessed. Relative to stable bench, the 6RM strength was approximately 93% for balance cushion (p ≤ 0.001) and approximately 92% for Swiss ball (p = 0.008); the pectoralis major electromyographic (EMG) activity was approximately 90% using the balance cushion (p = 0.080) and approximately 81% using Swiss ball (p = 0.006); the triceps EMG was approximately 79% using the balance cushion (p = 0.028) and approximately 69% using the Swiss ball (p = 0.002). Relative to balance cushion, the EMG activity in pectoralis, triceps, and erector spinae using Swiss ball was approximately 89% (p = 0.016), approximately 88% (p = 0.014) and approximately 80% (p = 0.020), respectively. In rectus abdominis, the EMG activity relative to Swiss ball was approximately 69% using stable bench (p = 0.042) and approximately 65% using the balance cushion (p = 0.046). Similar EMG activities between stable and unstable surfaces were observed for deltoid anterior, biceps brachii, and oblique external. In conclusion, stable bench press had greater 6RM strength and triceps and pectoralis EMG activity compared with the unstable surfaces. These findings have implications for athletic training and rehabilitation, because they demonstrate an inferior effect of unstable surfaces on muscle activation of prime movers and strength in bench press. If an unstable surface in bench press is desirable, a balance cushion should be chosen instead of a Swiss ball.