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Background Despite extensive research, the effects of L-carnitine supplementation in treating obesity are still unclear and equivocal. L-carnitine transports fatty acids into mitochondria for oxidation and is marketed as a weight loss supplement. The purpose of the present research is to investigate the efficacy of L-carnitine during concurrent training on the functional capacities and body composition in obese men. Methods Thirty nonactive, obese males (age = 37.2 ± 1.5 years; body mass index = 33.8 ± 2.5 kg/m 2) participated in this research. The participants were randomly divided into three groups: experimental group 1 (EXP1)—concurrent training with L-carnitine supplementation; experimental group 2 (EXP2)—L-carnitine supplementation without training; and control group—without training or L-carnitine supplementation. Concurrent training was performed for 8 weeks, three sessions per week, with a training intensity ranging from 60 to 75% of the maximum heart rate reserve and one-repetition maximum. Both experimental groups were supplemented with 35 mg L-carnitine supplement per kilogram body weight. Various functional and body composition variables were collected at three time points (pre-test, mid-test, and post-test). Results A number of variables were significantly improved in EXP1 after 4 and 8 weeks (systolic blood pressure, maximal oxygen consumption, weight, body mass index, and one-repetition maximum) and only after 8-weeks (diastolic blood pressure, resting heart rate, percentage of body fat, and fat-free mass). No significant changes were observed for EXP2 and the control group. Conclusion L-carnitine supplementation, in conjunction with concurrent training, emerges as a highly effective approach for enhancing body composition and boosting functional capacities in obese adult men. Therefore, it is recommended that overweight male individuals integrate concurrent training into their regimen while taking L-carnitine. [ABSTRACT FROM AUTHOR]

Background: The perception of bar velocity loss (PVL) can be used as an alternative method for autoregulating intraset repetitions during velocity-based training. This study analyzed the accuracy and reliability of the PVL as a method to autoregulate the intraset repetitions using a moderate velocity loss (VL) threshold (15–30%). Methods: A total of 22 resistance-trained men were familiarized with the PVL in a single session. Test–retest was performed in two sessions 1 week apart, in which participants completed three sets of bench press and back squat at 40, 60, and 80% 1 repetition maximum (1RM). Participants stopped the sets when they reached a moderate VL zone using their PVL. Accuracy was assessed by analyzing whether the mean VL (actual) and the lower and upper limits of the confidence interval (CI) (95%) of each set were within the established VL range and quantifying the relative frequency of correctly interrupted sets. Test–retest reliability was examined by the intraclass correlation coefficient and coefficient of variation. Results: PVL showed acceptable accuracy in both exercises at 60 and 80% 1RM (50–65% success rate) and retest for all loads (53–76% success rate). Similar PVL percentages were observed between most of the sets for the test and retest (p > 0.05). Accuracy improved during the retest, especially for bench press (40% 1RM) and back squat (40 and 80% 1RM). PVL was not reliable in the test–retest comparison. Conclusion: PVL can be a strategy with acceptable accuracy to autoregulate the intraset repetitions in a moderate zone (VL15–30%), but its reliability does not appear satisfactory after one familiarization session. [ABSTRACT FROM AUTHOR]

The aims of this repeated measures study were (I) to determine the reliability of single-leg squat 1RM and inter-limb asymmetries in pre-pubertal athletes, and (II) to assess associations between bilateral and/or unilateral squat 1RM performance, inter-limb asymmetries, and participants’ chronological and biological age. Thirty-one soccer players (age [mean ± standard deviation] = 8.48 ± 0.47 years; body mass = 28.32 ± 3.47 kg; body height = 121.70 ± 4.11 cm) practiced two familiarization and two experimental sessions. Bilateral and unilateral squat 1RM and asymmetries between both legs were assessed. Biological age was obtained through the age at peak height velocity (12.87 ± 0.38 years) and maturity offset (3.92 ± 0.44 years). Absolute and relative reliability and Pearson's correlations were calculated. Right and left leg 1RM and asymmetries presented good relative reliability (ICCrange = 0.84–0.85) levels, but non-acceptable absolute reliability (CV ~ 12 %). Asymmetries presented trivial to small correlations with strength (Range = 0.01–0.11). Similarly, chronological, and biological age presented small correlations with strength and asymmetries (Range = 0.01–0.22). Considering the good reliability, the bilateral and unilateral 1RM back half squat test can be considered in youth soccer players. Finally, lower-body mechanical performance and asymmetry between legs show trivial to small correlations, with maturation not affecting asymmetry in male youth soccer players. In conclusion, strength and power activities and training should be placed on younger soccer players with high asymmetry scores regardless of their stage of maturation.

Resistance training intensity is commonly quantified as the load lifted relative to an individual's maximal dynamic strength. This approach, known as percent-based training, necessitates evaluating the one-repetition maximum (1RM) for the core exercises incorporated in a resistance training program. However, a major limitation of rigid percent-based training lies in the demanding nature of directly testing the 1RM from technical, physical, and psychological perspectives. A potential solution that has gained popularity in the last two decades to facilitate the implementation of percent-based training involves the estimation of the 1RM by recording the lifting velocity against submaximal loads. This review examines the three main methods for prescribing relative loads (%1RM) based on lifting velocity monitoring: (i) velocity zones, (ii) generalized load-velocity relationships, and (iii) individualized load-velocity relationships. The article concludes by discussing a number of factors that should be considered for simplifying the testing procedures while maintaining the accuracy of individualized L-V relationships to predict the 1RM and establish the resultant individualized %1RM-velocity relationship: (i) exercise selection, (ii) type of velocity variable, (iii) regression model, (iv) number of loads, (v) location of experimental points on the load-velocity relationship, (vi) minimal velocity threshold, (vii) provision of velocity feedback, and (viii) velocity monitoring device. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the variables determining performance in a simulated on-snow Skimo sprint competition, and how their relationship with performance evolves from the individual time trial to the final. Fifteen national-level junior Skimo athletes (mean ± SD: age, 17.8 ± 2.5 years; maximal oxygen uptake, 66.8 mL·kg−1·min−1) underwent a comprehensive assessment, involving submaximal and maximal endurance tests, maximal strength assessments, and a maximal sprint to determine maximal glycolytic capacity. Subsequently, a simulated sprint competition, comprising an individual time-trial and three heats (quarterfinal, semifinal, final), was conducted. Whole-body and upper body aerobic power (r = 0.69–0.93), maximal speed and power (r = 0.82–0.85) during the maximal performance test, as well as fat-free mass (r = 0.62–0.77) and body fat (r = −0.67–−0.77), exhibited significant correlations with performance in the time-trial, quarterfinal and semifinal. Moreover, maximal strength (r = 0.39–0.95) and transition duration (r = 0.52–0.85) showed moderate to large correlations with sprint performance. Overall, aerobic power, maximal speed and power, as well as fat-free mass, and body fat emerged as crucial determinants of Skimo sprint performance, while dynamic strength and the ability to transition quickly between sections also proved to be relevant factors. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare the effects of free-weight andmachine-based resistance training on strength, hypertrophy, and joint discomfort. Methods: Thirty-eight resistance-trained men participated in an 8-wk resistance program allocated into free-weight (n = 19) or machine-based (n = 19) groups. Training variables were identical for both modalities, so they only differed in the use of barbells or machines to execute the full squat, bench press, prone bench pull, and shoulder press exercises. The velocity-based method was implemented to accurately adjust the intensity throughout the program. Strength changes were evaluated using eight velocity-monitored loading tests (four exercises two modalities) and included the relative one-repetition maximum (1RMRel), as well as the mean propulsive velocity against low (MPVLow) and high (MPVHigh) loads. Ultrasound-derived cross-sectional area of quadriceps (proximal and distal regions), pectoralis major, and rectus abdominis was measured to examine hypertrophy. Complementarily, Western Ontario and McMaster Universities and Disabilities of the Arm, Shoulder and Hand questionnaires were administrated to assess changes in lower- and upper-limb joint discomfort. Outcomes were compared using ANCOVA and percentage of change (Δ) statistics. Results: Each group significantly ( P < 0.001) increased 1RMRel, MPVLow, and MPVHigh for both modalities tested, but especially in the one they trained.When considering together the eight exercises tested, strength changes for both modalities were similar (Δ differences ≤1.8%, P ≥ 0.216). Likewise, the cross-sectional area of all the muscles evaluated was significantly increased by both modalities, with no significant differences between them (Δ difference ≤2.0%, P ≥ 0.208). No between-group differences ( P ≥ 0.144) were found for changes in stiffness, pain, and functional disability levels, which were reduced by both modalities. Conclusions: Free-weight and machine-based modalities are similarly effective to promote strength and hypertrophy without increasing joint discomfort. [ABSTRACT FROM AUTHOR]

The present systematic review with meta-analysis summarized studies that investigated the effect of carbohydrate (CHO) mouth rinse on muscle strength and muscular endurance. The search was performed in six databases. Thirteen randomized clinical trials were selected and the standardized mean difference between CHO mouth rinse and placebo for maximal strength and muscular endurance was determined via a random-effects model using Review Manager 5.4 software. Meta-regression was also performed to explore the influence of load, number of sets, number of exercises, fasting time, CHO concentration, and number of mouth rinses on the main outcomes. There was no significant effect of CHO mouth rinse on maximal strength (mean difference= 0.25 kg, 95%CI − 1.81 to 2.32 kg, z = 0.24, p = 0.810). However, there was a significant positive effect of CHO mouth rinse on muscular endurance (mean difference = 1.24 repetitions, 95%CI 0.70 to 1.77 repetitions, z = 4.55, p < 0.001). Meta-regression identified that CHO mouth rinse has greater benefits on muscular endurance when using high workloads, multiple exercises, and a smaller number of mouth rinses (p = 0.001). In conclusion, CHO mouth rinse has no effect on maximal muscle strength but has a positive effect on muscular endurance and seems to optimize when fewer mouth rinses, high workloads and numbers of exercises are used. Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2057417 [ABSTRACT FROM AUTHOR]

This study aimed to evaluate whether lifting velocity can be used to estimate the overhead press one repetition maximum (1RM) and to explore the differences in the accuracy of the 1RM between three velocity-based methods. Twenty-seven weightlifters (16 men and 11 women) participated. The first session was used to test the overhead press 1RM. The second session consisted of an incremental loading test during the overhead press. The mean velocity was registered using a transducer attached to the barbell. A 1-way repeated-measures analysis of variance (ANOVA) with Bonferroni post hoc corrections was applied to the absolute differences between the actual and predicted 1RMs. Raw differences with 95% limits of agreement and ordinary least-products regressions were used to test the concurrent validity of the 1RM prediction methods with respect to the actual 1RM. The ANOVA did not reveal significant differences for the absolute differences respect to the actual 1RM between the three 1RM prediction methods (F = 3.2, p =.073). The absolute errors were moderate for the Multiple-Point (6.1 ± 3.7%), Two-Point45−75 (8.6 ± 6.2%), and Two-Point45−90 methods (5.7 ± 4.0%). The validity analysis showed that all the 1RM prediction methods underestimated the actual 1RM (1.0–2.2 kg), but ordinary least-products regressions failed to show fixed or proportional bias. These results suggest that the Multiple-Point and Two-Point45−90 velocity-based methods might be viable tools to predict the overhead press 1RM in weightlifters, but practitioners are encouraged to use the direct 1RM for a more accurate prescription of the training loads. [ABSTRACT FROM AUTHOR]

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We examined the accuracy of twelve different velocity-based methods for predicting the bilateral leg-press exercise one-repetition maximum (1RM) in breast cancer survivors. Twenty-one female breast cancer survivors (age 50.2 ± 10.8 years) performed an incremental loading test up to the 1RM. Individual load-velocity relationships were modeled by linear and quadratic polynomial regression models considering the mean velocity (MV) and peak velocity (PV) values recorded at five incremental loads (~45-55-65-75-85% of 1RM) (multiple-point methods) and by a linear regression model considering only the two distant loads (~45-85% of 1RM) (two-point method). The 1RM was always estimated through these load-velocity relationships as the load associated with a general (MV: 0.24 m/s; PV: 0.60 m/s) and an individual (MV and PV of the 1RM trial) minimal velocity threshold (MVT). Compared to the actual 1RM, the 1RMs estimated by all linear regression models showed trivial differences (Hedge's g ranged from 0.08 to 0.17), very large to nearly perfect correlations (r ranged from 0.87 to 0.95), and no heteroscedasticity of the errors (coefficient of determination (r2) < 0.10 obtained from the relationship of the raw differences between the actual and predicted 1RMs with their average value). Given the acceptable and comparable accuracy for all 1RM linear prediction methods, the two-point method and a general MVT could be recommended to simplify the testing procedure of the bilateral leg-press 1RM in breast cancer survivors. [ABSTRACT FROM AUTHOR]

We examined the accuracy of twelve different velocity-based methods for predicting the bilateral leg-press exercise one-repetition maximum (1RM) in breast cancer survivors. Twenty-one female breast cancer survivors (age 50.2 ± 10.8 years) performed an incremental loading test up to the 1RM. Individual load-velocity relationships were modeled by linear and quadratic polynomial regression models considering the mean velocity (MV) and peak velocity (PV) values recorded at five incremental loads (~45-55-65-75-85% of 1RM) (multiple-point methods) and by a linear regression model considering only the two distant loads (~45–85% of 1RM) (two-point method). The 1RM was always estimated through these load-velocity relationships as the load associated with a general (MV: 0.24 m/s; PV: 0.60 m/s) and an individual (MV and PV of the 1RM trial) minimal velocity threshold (MVT). Compared to the actual 1RM, the 1RMs estimated by all linear regression models showed trivial differences (Hedge’s g ranged from 0.08 to 0.17), very large to nearly perfect correlations (r ranged from 0.87 to 0.95), and no heteroscedasticity of the errors (coefficient of determination (r2) < 0.10 obtained from the relationship of the raw differences between the actual and predicted 1RMs with their average value). Given the acceptable and comparable accuracy for all 1RM linear prediction methods, the two-point method and a general MVT could be recommended to simplify the testing procedure of the bilateral leg-press 1RM in breast cancer survivors.

Purpose: Recent evidence indicates that low‐load blood flow restriction (LL‐BFR) training elicits an anabolic response in tendinous tissue. The purpose of the present study was to investigate the hypertrophic pattern induced in the Achilles tendon by LL‐BFR, in comparison with the regional hypertrophy typically observed with conventional high‐load (HL) resistance training. Methods: N = 40 male participants were randomly and concealed allocated to one of two groups: LL‐BFR training (20–35% one‐repetition maximum/1RM) or HL training (70–85% 1RM). The training was completed three times per week for a total of 14 weeks. Before and after the training period, Achilles tendon morphology was assessed using magnetic resonance imaging along the entire tendon length. Additionally, dynamic strength measures of the plantar flexors were evaluated. Results: In line with previous findings, dynamic plantar flexion strength was improved to a comparable extent in both groups (LL‐BFR: 43.6%; HL: 43.5%). The results also confirmed significant increases in Achilles tendon cross‐sectional area with LL‐BFR (+5.2%). Moreover, they revealed that the hypertrophic pattern obtained with LL‐BFR was similar to regional changes seen with conventional HL training. Conclusion: The present findings point towards the notion that despite the low loads being applied, LL‐BFR training induces Achilles tendon hypertrophy by potentiating anabolic responses in the same regions as with conventional high‐load training. Future studies are needed to (i) focus on the potential mechanisms underlying these tendon morphology changes and (ii) apply and evaluate LL‐BFR training in clinical populations to validate these results in rehabilitative settings. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the variables determining performance in a simulated on-snow Skimo sprint competition, and how their relationship with performance evolves from the individual time trial to the final. Fifteen national-level junior Skimo athletes (mean ± SD: age, 17.8 ± 2.5 years; maximal oxygen uptake, 66.8 mL·kg−1·min−1) underwent a comprehensive assessment, involving submaximal and maximal endurance tests, maximal strength assessments, and a maximal sprint to determine maximal glycolytic capacity. Subsequently, a simulated sprint competition, comprising an individual time-trial and three heats (quarterfinal, semifinal, final), was conducted. Whole-body and upper body aerobic power (r = 0.69–0.93), maximal speed and power (r = 0.82–0.85) during the maximal performance test, as well as fat-free mass (r = 0.62–0.77) and body fat (r = −0.67–−0.77), exhibited significant correlations with performance in the time-trial, quarterfinal and semifinal. Moreover, maximal strength (r = 0.39–0.95) and transition duration (r = 0.52–0.85) showed moderate to large correlations with sprint performance. Overall, aerobic power, maximal speed and power, as well as fat-free mass, and body fat emerged as crucial determinants of Skimo sprint performance, while dynamic strength and the ability to transition quickly between sections also proved to be relevant factors.

The velocity loss method is often used in velocity–based training (VBT) to dynamically regulate training loads. However, the effects of velocity loss on maximum strength development and training efficiency are still unclear. Therefore, we conducted a dose–response meta–analysis aiming to fill this research gap. A systematic literature search was performed to identify studies on VBT with the velocity loss method via PubMed, Web of Science, Embase, EBSCO, and Cochrane. Controlled trials that compared the effects of different velocity losses on maximum strength were considered. One–repetition maximum (1RM) gain and 1RM gain per repetition were the selected outcomes to indicate the maximum strength development and its training efficiency. Eventually, nine studies with a total of 336 trained males (training experience/history ≥ 1 year) were included for analysis. We found a non–linear dose–response relationship (reverse U–shaped) between velocity loss and 1RM gain (pdose–response relationship < 0.05, pnon–linear relationship < 0.05). Additionally, a negative linear dose–response relationship was observed between velocity loss and 1RM gain per repetition (pdose–response relationship < 0.05, pnon–linear relationship = 0.23). Based on our findings, a velocity loss between 20 and 30% may be beneficial for maximum strength development, and a lower velocity loss may be more efficient for developing and maintaining maximum strength. Future research is warranted to focus on female athletes and the interaction of other parameters. [ABSTRACT FROM AUTHOR]

Resistance bands are widely used nowadays to enhance muscle strength due to their high portability, but the relationship between resistance band workouts and conventional dumbbell weight training is still unclear. Thus, this study suggests a convolutional neural network model that identifies the type of band workout and counts the number of repetitions and a regression model that deduces the band force that corresponds to the one-repetition maximum. Thirty subjects performed five different exercises using resistance bands and dumbbells. Joint movements during each exercise were collected using a camera and an inertial measurement unit. By using different types of input data, several models were created and compared. As a result, the accuracy of the convolutional neural network model using inertial measurement units and joint position is 98.83%. The mean absolute error of the repetition counting algorithm ranges from 0.88 (seated row) to 3.21 (overhead triceps extension). Lastly, the values of adjusted r-square for the 5 exercises are 0.8415 (chest press), 0.9202 (shoulder press), 0.8429 (seated row), 0.8778 (biceps curl), and 0.9232 (overhead triceps extension). In conclusion, the model using 10-channel inertial measurement unit data and joint position data has the best accuracy. However, the model needs to improve the inaccuracies resulting from non-linear movements and one-time performance. [ABSTRACT FROM AUTHOR]

Relatively few investigations have examined the transfer effects of multiple-joint isokinetic eccentric only (MJIE) resistance training on non-specific measures of muscle strength. This study investigated the transfer effects of a short-term MJIE leg press (Eccentron) resistance training program on several non-specific measures of lower-body strength. Fifteen participants performed Eccentron training three times/week for four weeks and were evaluated on training-specific Eccentron peak force (EccPF), nontraining-specific leg press DCER one-repetition maximum (LP 1 RM), and peak torques of the knee extensors during isokinetic eccentric (Ecc30), isokinetic concentric (Con150) and isometric (IsomPT) tasks before and after the training period. The training elicited a large improvement in EccPF (37.9%; Cohen's d effect size [ES] = 0.86). A moderate transfer effect was observed on LP 1 RM gains (19.0%; ES = 0.48) with the magnitude of the strength improvement being about one-half that of EccPF. A small effect was observed on IsomPT and Ecc30 (ES = 0.29 and 0.20, respectively), however, pre-post changes of these measures were not significant. Con150 testing showed no effect (ES = 0.04). These results suggest a short term MJIE training program elicits a large strength improvement in training-specific measures, a moderate strength gain transfer effect to DCER concentric-based strength of a similar movement (i.e., LP 1 RM), and poor transfer to single-joint knee extension measures. [ABSTRACT FROM AUTHOR]

We aimed to investigate the effects of 8-week circuit weight training by intensity on blood stress hormones and antioxidant capacity in high-school wrestlers. This study involved 27 male wrestlers with >2 years of wrestling experience who were randomly assigned to either a low intensity (n=13) or a high-intensity circuit weight training group (n=14). The participants performed circuit weight training for 60 min per session, 3 times per week for 8 weeks. The low- and high-intensity circuit weight training exercises were performed at 50%-60% and 70%-80% of one-repetition maximum for 10 stations, respectively, and 8-15 repeated sessions per station were performed in order. No changes were observed in adrenocorticotropic hormone (ACTH), cortisol, epinephrine, and norepinephrine levels between the two training groups. When compared to levels before the training, ACTH and epinephrine levels decreased, whereas cortisol levels increased. However, no difference was observed in norepinephrine levels. Further, no differences were observed in malondialdehyde (MDA) and glutathione peroxidase (GPX) levels between the two groups. However, MDA and GPX levels were increased from those before training. Changes in superoxide dismutase levels were observed between the two groups, but the change was significant only in the high-intensity circuit weight training group. Long-term training did not increase lipid peroxidation, but increased the activity of antioxidant enzymes that defend against oxidative stress. The antioxidant defense system in tissues can be regulated by exercise intensity as well as physical training status., Competing Interests: CONFLICT OF INTEREST No potential conflict of interest relevant to this article was reported., (Copyright © 2024 Korean Society of Exercise Rehabilitation.)

The aims of this repeated measures study were (I) to determine the reliability of single-leg squat 1RM and inter-limb asymmetries in pre-pubertal athletes, and (II) to assess associations between bilateral and/or unilateral squat 1RM performance, inter-limb asymmetries, and participants' chronological and biological age. Thirty-one soccer players (age [mean ± standard deviation] = 8.48 ± 0.47 years; body mass = 28.32 ± 3.47 kg; body height = 121.70 ± 4.11 cm) practiced two familiarization and two experimental sessions. Bilateral and unilateral squat 1RM and asymmetries between both legs were assessed. Biological age was obtained through the age at peak height velocity (12.87 ± 0.38 years) and maturity offset (3.92 ± 0.44 years). Absolute and relative reliability and Pearson's correlations were calculated. Right and left leg 1RM and asymmetries presented good relative reliability (ICCrange = 0.84-0.85) levels, but non-acceptable absolute reliability (CV ~ 12 %). Asymmetries presented trivial to small correlations with strength (Range = 0.01-0.11). Similarly, chronological, and biological age presented small correlations with strength and asymmetries (Range = 0.01-0.22). Considering the good reliability, the bilateral and unilateral 1RM back half squat test can be considered in youth soccer players. Finally, lower-body mechanical performance and asymmetry between legs show trivial to small correlations, with maturation not affecting asymmetry in male youth soccer players. In conclusion, strength and power activities and training should be placed on younger soccer players with high asymmetry scores regardless of their stage of maturation., Competing Interests: This study was approved by the Local Clinical Research Ethics Committee “Personal Protection Committee” under the following code (CPP SUD N° O221/2022). Amador Garcia-Ramos is an Academic Editor for Heliyon. All data generated or analyzed during this study are included in this published article. The databases are available upon reasonable request to the corresponding author., (© 2024 The Authors.)

Abstract Background Unilateral resistance training increases the strength of the contralateral non-trained homologous muscles known as the cross-education effect. We tested the hypothesis that unilateral eccentric resistance training (ET) would induce greater and longer-lasting cross-education effect when compared with concentric resistance training (CT). Methods Young (20–23 y) participants were allocated to ET (5 males, 4 females) or CT (5 males, 4 females) group that performed unilateral progressive ET or CT of the elbow flexors, twice a week for 5 weeks (10 sessions) followed by a 5-week detraining, and control group (7 males, 6 females) that did not perform any training. Maximum voluntary isometric contraction torque of the elbow flexors (MVIC), one-repetition maximum of concentric dumbbell curl (1-RM), and biceps brachii and brachialis muscle thickness (MT) were measured from the trained and non-trained arms before, several days after the last training session, and 5 weeks later. A ratio between the trained and non-trained arms for the change in MVIC or 1-RM from pre- to post-training (cross-body transfer ratio) was compared between ET and CT groups. Results The control group did not show significant changes in any variables. Both ET and CT increased (P 0.05) after ET and CT, and MVIC returned to the baseline after detraining, but 1-RM was maintained for both groups. An increase (P

Muscular strength is critical for adults with an intellectual disability (ID) to promote their mobility, cardiovascular capacity, and performance of daily living/recreational/vocational activities. This article reports the results of the first systematic review and meta-analysis of peer-reviewed clinical trials that evaluated the effects of resistance training (RT) interventions on muscular strength in adults with ID. The protocol was registered with PROSPERO (CRD42020184905). The review focuses on clinical trials that recorded quantitative measures of maximum muscular strength. Eleven electronic databases were searched from their earliest available record up to May 2020. After screening 1996 search records, 11 clinical trials were reviewed. The RT interventions, while heterogeneous, had an overall significant (p ≤ 0.05) effect on muscular strength in adults with ID, ages 25–58 years. The findings were more significant and less heterogeneous for non-combined RT interventions than for interventions that combined RT exercises with aerobic or balance exercises. The TESTEX overall score was 8.3 ± 3.6. RT interventions (particularly when not combined with other exercises) are effective in promoting muscular strength in adults with ID. The limited number of studies and the low study quality scores indicate a potential risk of bias, which limits the interpretation of the findings and warrants further investigation. Muscular strength is critical for adults with an intellectual disability (ID) to promote their mobility, cardiovascular capacity, and performance of daily living/recreational/vocational activities. RT interventions are an effective means of improving muscular strength in adults with ID, especially when not combined with other forms of exercise. Testing and assessment protocols used in RT programs should be individualized for adults with ID to accommodate their characteristics and should be implemented under conditions similar to those experienced during the training regimen. It is important to implement familiarization sessions before carrying out muscular strength testing or initiating an RT program to ensure safety, accuracy, and effectiveness of the program for adults with ID. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to examine whether cardiorespiratory fitness and leg strength can be estimated based on their relationship with physical performance tests in Japanese breast cancer survivors. Methods: Participants were 50 sedentary women aged 20 to 59 years who have received breast surgery in the past 2 to 13 months after diagnosis of invasive breast cancer (stage I-IIa). Cardiorespiratory fitness and leg strength were measured by peak oxygen consumption (VO2peak), and one-repetition maximum for leg press (leg press 1RM). Physical performance tests were performed 6-min walk test, chair stand test, and grip strength. Using multiple regression analysis, we developed prediction equations for VO2peak and leg strength based on their associations with the physical performance tests. The validity of the estimation equations was assessed using Bland–Altman plots. Results: Mean age, VO2peak, and leg press 1RM were 48 ± 6 years, 25.0 ± 3.6 mL/kg/min, and 95 ± 32 kg, respectively. Multiple regression analysis yielded 6-min walk test distance, age, height, and body weight as predictors of VO2peak. Measured VO2peak and predicted VO2peak showed a moderate positive correlation (r = 0.463, p < 0.001). Chair stand test, grip strength, age, height, and body weight were selected as predictors of leg press 1RM. There was a strong positive correlation between predicted and measured leg press 1RM (r = 0.754, p < 0.001). Conclusion: The results suggest that leg strength can be predicted using physical performance tests. However, further examination may be needed to determine whether cardiorespiratory fitness can be predicted based on 6-min walk test. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the effects of three different unilateral isoinertial resistance training protocols with eccentric overload on changes in lean mass and muscle function of trained (TL) and contralateral non-trained (NTL) legs. Methods: Physically active university students were randomly assigned to one of three training groups or a control group (n = 10/group). Participants in the training groups performed dominant leg isoinertial squat training twice a week for 6 weeks (4 sets of 7 repetitions) using either an electric-motor device with an eccentric phase velocity of 100% (EM100) or 150% (EM150) of concentric phase velocity or a conventional flywheel device (FW) with the same relative inertial load. Changes in thigh lean mass, unilateral leg-press one-repetition maximum (1-RM), muscle power at 40–80% 1-RM, and unilateral vertical jump height before and after training were compared between the groups and between TL and NTL. Results: No changes in any variable were found for the control group. In TL, all training groups showed similar increases (p < 0.05) in 1-RM strength (22.4–30.2%), lean tissue mass (2.5–5.8%), muscle power (8.8–21.7%), and vertical jump height (9.1–32.9%). In NTL, 1-RM strength increased 22.0–27.8% without significant differences between groups; however, increases in lean mass (p < 0.001) were observed for EM150 (3.5%) and FW (3.8%) only. Unilateral vertical jump height (6.0–32.9%) and muscle power (6.8–17.5%) also increased in NTL without significant differences between training groups. Conclusion: The three eccentric-overload resistance training modalities produced similar neuromuscular changes in both the trained and non-trained legs, suggesting that strong cross-education effects were induced by the eccentric-overload training. [ABSTRACT FROM AUTHOR]

Using a within-subject design we compared the individual responses between drop-set (DS) vs. traditional resistance training (TRAD) (n=16) and crescent pyramid (CP) vs. TRAD (n=15). Muscle cross-sectional area (CSA), leg press and leg extension 1 repetition maximum (1-RM) were assessed pre and post training. At group level, CSA increased from pre to post (DS: 7.8% vs. TRAD: 7.5%, P =0.02; CP: 7.5% vs. TRAD: 7.8%, P =0.02). All protocols increased the 1-RM from pre to post for leg press (DS: 24.9% vs. TRAD: 26.8%, P < 0.0001; CP: 27.3% vs. TRAD:2 6.3%, P < 0.0001) and leg extension (DS: 17.1% vs. TRAD: 17.3%, P < 0.0001; CP: 17.0% vs. TRAD: 16.6%, P < 0.0001). Individual analysis for CSA demonstrated no differences between protocols in 15 subjects. For leg press 1-RM, 5 subjects responded more to TRAD, 2 to DS and 9 similarly between protocols. In TRAD vs. CP, 4 subjects responded more to CP, 1 to TRAD and 10 similarly between protocols. For leg extension 1-RM 2 subjects responded more to DS, 3 to TRAD and 11 similarly between protocols. Additionally, 2 subjects responded more to CP, 2 to TRAD and 11 similarly between protocols. In conclusion, all protocols induced similar individual responses for CSA. For 1-RM, some subjects experience greater gains for the protocol performed with higher loads, such as CP. [ABSTRACT FROM AUTHOR]

The velocity loss method is often used in velocity–based training (VBT) to dynamically regulate training loads. However, the effects of velocity loss on maximum strength development and training efficiency are still unclear. Therefore, we conducted a dose–response meta–analysis aiming to fill this research gap. A systematic literature search was performed to identify studies on VBT with the velocity loss method via PubMed, Web of Science, Embase, EBSCO, and Cochrane. Controlled trials that compared the effects of different velocity losses on maximum strength were considered. One–repetition maximum (1RM) gain and 1RM gain per repetition were the selected outcomes to indicate the maximum strength development and its training efficiency. Eventually, nine studies with a total of 336 trained males (training experience/history ≥ 1 year) were included for analysis. We found a non–linear dose–response relationship (reverse U–shaped) between velocity loss and 1RM gain (pdose–response relationship < 0.05, pnon–linear relationship < 0.05). Additionally, a negative linear dose–response relationship was observed between velocity loss and 1RM gain per repetition (pdose–response relationship < 0.05, pnon–linear relationship = 0.23). Based on our findings, a velocity loss between 20 and 30% may be beneficial for maximum strength development, and a lower velocity loss may be more efficient for developing and maintaining maximum strength. Future research is warranted to focus on female athletes and the interaction of other parameters.

Resistance bands are widely used nowadays to enhance muscle strength due to their high portability, but the relationship between resistance band workouts and conventional dumbbell weight training is still unclear. Thus, this study suggests a convolutional neural network model that identifies the type of band workout and counts the number of repetitions and a regression model that deduces the band force that corresponds to the one-repetition maximum. Thirty subjects performed five different exercises using resistance bands and dumbbells. Joint movements during each exercise were collected using a camera and an inertial measurement unit. By using different types of input data, several models were created and compared. As a result, the accuracy of the convolutional neural network model using inertial measurement units and joint position is 98.83%. The mean absolute error of the repetition counting algorithm ranges from 0.88 (seated row) to 3.21 (overhead triceps extension). Lastly, the values of adjusted r-square for the 5 exercises are 0.8415 (chest press), 0.9202 (shoulder press), 0.8429 (seated row), 0.8778 (biceps curl), and 0.9232 (overhead triceps extension). In conclusion, the model using 10-channel inertial measurement unit data and joint position data has the best accuracy. However, the model needs to improve the inaccuracies resulting from non-linear movements and one-time performance.

Relatively few investigations have examined the transfer effects of multiple-joint isokinetic eccentric only (MJIE) resistance training on non-specific measures of muscle strength. This study investigated the transfer effects of a short-term MJIE leg press (Eccentron) resistance training program on several non-specific measures of lower-body strength. Fifteen participants performed Eccentron training three times/week for four weeks and were evaluated on training-specific Eccentron peak force (EccPF), nontraining-specific leg press DCER one-repetition maximum (LP 1 RM), and peak torques of the knee extensors during isokinetic eccentric (Ecc30), isokinetic concentric (Con150) and isometric (IsomPT) tasks before and after the training period. The training elicited a large improvement in EccPF (37.9%; Cohen’s d effect size [ES] = 0.86). A moderate transfer effect was observed on LP 1 RM gains (19.0%; ES = 0.48) with the magnitude of the strength improvement being about one-half that of EccPF. A small effect was observed on IsomPT and Ecc30 (ES = 0.29 and 0.20, respectively), however, pre-post changes of these measures were not significant. Con150 testing showed no effect (ES = 0.04). These results suggest a short term MJIE training program elicits a large strength improvement in training-specific measures, a moderate strength gain transfer effect to DCER concentric-based strength of a similar movement (i.e., LP 1 RM), and poor transfer to single-joint knee extension measures.

Background: Unilateral resistance training increases the strength of the contralateral non-trained homologous muscles known as the cross-education effect. We tested the hypothesis that unilateral eccentric resistance training (ET) would induce greater and longer-lasting cross-education effect when compared with concentric resistance training (CT). Methods: Young (20–23 y) participants were allocated to ET (5 males, 4 females) or CT (5 males, 4 females) group that performed unilateral progressive ET or CT of the elbow flexors, twice a week for 5 weeks (10 sessions) followed by a 5-week detraining, and control group (7 males, 6 females) that did not perform any training. Maximum voluntary isometric contraction torque of the elbow flexors (MVIC), one-repetition maximum of concentric dumbbell curl (1-RM), and biceps brachii and brachialis muscle thickness (MT) were measured from the trained and non-trained arms before, several days after the last training session, and 5 weeks later. A ratio between the trained and non-trained arms for the change in MVIC or 1-RM from pre- to post-training (cross-body transfer ratio) was compared between ET and CT groups. Results: The control group did not show significant changes in any variables. Both ET and CT increased (P < 0.05) MVIC (22.5 ± 12.3 % vs. 26.0 ± 11.9 %) and 1-RM (28.8 ± 6.6 % vs. 35.4 ± 12.9 %) of the trained arm without a significant difference between groups. MVIC was maintained after detraining for ET but returned to the baseline for CT, and 1-RM was maintained after detraining for both ET and CT. For the non-trained arm, MVIC (22.7 ± 17.9 % vs. 12.2 ± 10.2 %) and 1-RM (19.9 ± 14.6 % vs. 24.0 ± 10.6 %) increased similarly (P > 0.05) after ET and CT, and MVIC returned to the baseline after detraining, but 1-RM was maintained for both groups. An increase (P < 0.05) in MT was found only after ET for the trained arm (7.1 ± 6.1 %). The cross-body transfer ratio for MVIC was greater (P < 0.05) for ET (90.9 ± 46.7 %) than CT (49.0 ± 30.0 %). Conclusions: These results did not support the hypothesis and showed similar changes in the most of the variables between ET and CT for the trained and non-trained arms, and strong cross-education effects on MVIC and 1-RM, but less detraining effect after ET than CT on MVIC of the trained arm. Trial registration: University Hospital Medical Information Network Clinical Trials Registry (UMIN000044477; Jun 09, 2021). [ABSTRACT FROM AUTHOR]

The purpose of this study was to quantify the effect of an overload microcycle and taper on bench press velocity and to determine if the load-velocity relationship could accurately predict 1-repetition maximum (1RM). Twelve male powerlifters participated in resistance training structured into an introduction microcycle, overload microcycle (PostOL), and taper (PostTP). At the end of each microcycle, subjects completed a bench press for 1RM assessment consisting of warm-up sets at 40, 55, 70, and 85% of a previously established 1RM. The mean concentric velocity (MCV) was recorded during each warm-up set. A predicted 1RM (p1RM) was calculated using an individualized load-velocity profile (LVP). The average MCV decreased after PostOL (0.66 ± 0.07 m·s-1) compared with baseline (BL) (p = 0.003; 0.60 ± 0.11 m·s-1) but increased after PostTP (0.67 ± 0.09 m·s-1). One-repetition maximum increased from PostOL (146.7 ± 19.8 kg) to PostTP (p = 0.002; 156.1 ± 21.0 kg), with no differences observed between other test sessions (p > 0.05). Bland-Altman analysis indicated that p1RM was consistently higher than measured 1RM (3.4-7.8 kg), and the limits of agreement were extremely wide. However, very large to near perfect correlations (r = 0.89 to 0.96) were observed between p1RM and 1RM during BL, PostOL, and PostTP. The load-velocity relationship established from submaximal sets did not accurately predict 1RM, but MCV was affected by changes in weekly training loads. Velocity-based measurements seem to be more sensitive to changes in training loads than maximal strength. [ABSTRACT FROM AUTHOR]

This study aimed to examine the validity of using bar velocity to estimate relative load in squat and bench-press exercises for both young men and women. Twenty-five men and 25 women performed a progressive loading test up to 1-RM in the squat and bench-press exercises, which were repeated after 2-weeks. Relationships between mean propulsive velocity and%1-RM were analysed. A second-order polynomial equation for predicting the corresponding velocity of each percentage of 1-RM was developed for men (validation). This equation was then applied in women (cross-validation). Moreover, a specific equation for women was developed (validation) and was also applied in a sub-sample of women (cross-validation). Close relationships (R2 : 0.91–0.95) between bar velocity and relative load were observed in both sexes for squat and bench press. Men's equation applied to women showed a high level of agreement, although lower bias and higher level of agreement was observed when a sex-specific equation was applied in women, both validation and cross-validation samples. In conclusion, lifting velocity can be used to accurately prescribe the relative load regardless of sex in both upper-body and lower-body exercises, although when estimating load from velocity measures it will be necessary to use the sex-specific equation for each exercise. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the relationship between movement velocity and relative load (%1RM) in the deadlift exercise. Fifty men (age = 23.8 ± 3.6 years, body mass = 78.2 ± 8.3 kg, height = 1.78 ± 0.06 m) performed a first evaluation (T1) consisting of a one-repetition maximum (1RM) test. Forty-two subjects performed a second evaluation (T2) after 6 weeks. Mean (MV), mean propulsive (MPV) and peak (PV) velocity measures of the concentric phase were analyzed. Load-velocity relationships were studied by fitting first order equations to the data using loads from 30-100% of 1RM. A comprehensive set of statistics for assessing bias and level of agreement to estimate the 1RM value from the different models was used. Stability of these relationships was assessed using the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). General load-velocity equations provided good adjustments (R² ~ 0.91-0.93), however individual load-velocity regressions provided better adjustments (R² ~ 0.97). Individual estimations also showed higher agreement and more regular variation than general equations. Moreover, MPV showed smaller bias than the other velocity parameters (MV and PV). The stability analysis of the load-velocity relationships resulted in ICC values higher than 0.82 and CV lower than 3.0%. Monitoring repetition velocity allows estimation of the %1RM in the deadlift exercise. More accurate predictions of relative load can be obtained when using individualized regression equations instead of general equations. [ABSTRACT FROM AUTHOR]

This study investigated the return to baseline of movement velocity and maximal strength following a strength-orientated session and power-orientated session in the free-weight back-squat performed with maximal concentric velocity. Fourteen strength-trained males completed a strength-orientated session (five sets of five repetitions @80% of a one-repetition maximum) and a power-orientated session (three sets of six repetitions @50% one-repetition maximum) in a randomised order over two weeks (e.g. strength week 1, power week 2). The back-squat was then performed with loads of 20%, 40%, 60%, 80%, 90% and 100% one-repetition maximum at 24, 48, 72 and 96 h following the strength and power exercise sessions to assess return to baseline of squat velocity and maximal strength. Dependent variables included one-repetition maximum, back-squat mean velocity and peak velocity and countermovement jump peak velocity. Meaningful changes ((effect size) ≥ −0.60) were reported for mean velocity and peak velocity at loads ≥ 60% one-repetition maximum at 24 and 48 h after the strength-orientated session. Trivial to small (effect size ≤ −0.59) differences were reported for squat velocities following the power-orientated session. Only trivial to small effect size differences were observed for countermovement jump peak velocity and one-repetition maximum at all time points following both sessions. Squat velocity (mean velocity and peak velocity) across the load–velocity profile had recovered at 72 h following the strength-orientated session. However, the return to baseline of squat velocity (mean velocity and peak velocity) did not coincide with the return to baseline of one-repetition maximum or countermovement jump peak velocity. Therefore, measuring and monitoring meaningful changes in velocity may be a more valid and practical alternative in determining full recovery and readiness to train. [ABSTRACT FROM AUTHOR]

This study aimed to compare the goodness of fit and the reliability of different regression models for fitting the force-velocity relationship (FV) of bench press (BP) and squat (SQ). Additionally, the reliability of the position on FV of the velocity (V1RM) and the force performed with the 1RM (F1RM) was explored. Nine rugby players and 12 judokas participated in this study. The FV of BP and SQ were obtained twice by a protocol performed until the 1RM. Individual FV were fitted by linear (LM), quadratic polynomial (PM), and exponential models (EM). Adjusted coefficients of determination of LM and PM (medians higher than 0.919) were higher than for EM. The reliability was higher for LM in comparison with PM. The reliability of V1RM was not acceptable (CV% = 19 and 18% for BP and SQ). High reliability was observed for F1RM (CV% = 3 and 2% for BP and SQ) and for the ratio between F1RM and the force-axis intercept of FV (CV% = 2 and 4% for BP and SQ). The reliability of the relative values of F1RM around 92 and 87% of F0 for BP and SQ suggests the use of these values for monitoring resistance training programmes. [ABSTRACT FROM AUTHOR]

We investigated the effects of sling-based, suspended push-up training on muscle size and function of upper limb and abdominal muscles. Eight men conducted suspended push-ups to failure 3 sets/session, 3 sessions/week, for 8 weeks. The maximum number of push-ups during training gradually and significantly increased from the first to last training session (+92%), suggesting improved muscle endurance. After the training, muscle thickness of the elbow extensors (+16%) and flexors (+3%), as well as abdominal muscles (rectus abdominis: RA,+27%; external oblique: EO,+14%) significantly increased. No changes occurred in maximum isometric strength of elbow extension or flexion, nor in 1-repetition maximum bench press. In a follow-up experiment, electromyograms (EMGs) of RA, EO and internal oblique (IO) during suspended push-ups to failure were measured and normalized to those during maximum voluntary contraction of each muscle (% EMGmvc) in six men. EMG significantly increased when reaching failure in all muscles (RA: 46–88%, EO: 32–50%, IO: 19–52%, start-end), and was particularly high in RA. These results suggest that suspended push-up training can augment size of not only upper limb but also abdominal muscles, likely attributable to high muscle activities during exercise; however, this does not necessarily improve maximum strength after training thus warrants careful interpretation/application. [ABSTRACT FROM AUTHOR]

Purpose: Evaluate intra-rater and inter-rater reliability of the one-repetition maximum strength test in people with chronic heart failure. Design: Intra-rater and inter-rater reliability study. Setting: A public tertiary hospital in northern metropolitan Melbourne. Participants: Twenty-four participants (nine female, mean age 71.8 ± 13.1 years) with mild to moderate heart failure of any aetiology. Methods: Lower limb strength was assessed by determining the maximum weight that could be lifted using a leg press. Intra-rater reliability was tested by one assessor on two separate occasions. Inter-rater reliability was tested by two assessors in random order. Statistical analyses: Intra-class correlation coefficients and 95% confidence intervals were calculated. Bland and Altman analyses were also conducted, including calculation of mean differences between measures () and limits of agreement. Results: Ten intra-rater and 21 inter-rater assessments were completed. Excellent intra-rater (intra-class correlation coefficient2,1 0.96) and inter-rater (intra-class correlation coefficient2,1 0.93) reliability was found. Intra-rater assessment showed less variability (mean difference 4.5 kg, limits of agreement −8.11 to 17.11 kg) than inter-rater agreement (mean difference −3.81 kg, limits of agreement −23.39 to 15.77 kg). Conclusion: One-repetition maximum determined using a leg press is a reliable measure in people with heart failure. Given its smaller limits of agreement, intra-rater testing is recommended. Using a leg press to determine a one-repetition maximum we were able to demonstrate excellent inter-rater and intra-rater reliability using an intra-class correlation coefficient. The Bland and Altman levels of agreement were wide for inter-rater reliability and so we recommend using one assessor if measuring change in strength within an individual over time. [ABSTRACT FROM AUTHOR]

This study aimed to determine the suitability of the load-velocity relationship to prescribe the relative load (%1RM) in women, as well as to compare the load-velocity profile between sexes and participants with different strength levels. The load-velocity relationship of 14 men (1RM: 1.17 ± 0.19) and 14 women (1RM: 0.66 ± 0.13) were evaluated in the bench press exercise. The main findings revealed that: (I) the load-velocity relationship was always strong and linear (R2 range: 0.987–0.993), (II) a steeper load-velocity profile was observed in men compared to women (Effect size [ES]: 1.09), with men showing higher velocities for light loads (ES: − 0.81 and − 0.40 for the y-intercept and 30%1RM, respectively), but women reporting higher velocities for the heavy loads (ES: 1.14 and 1.50 at 90%1RM and 100%1RM, respectively); and (III) while the slope of the load-velocity profile was moderately steeper for weak men compared to their strong counterpart (ES: 1.02), small differences were observed between strong and weak women (ES: − 0.39). While these results support the use of the individual load-velocity relationship to prescribe the %1RM in the bench press exercise for women, they also highlight the large disparities in their load-velocity profile compared to men. [ABSTRACT FROM AUTHOR]