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The aim of this study was to assess the agreement of three different automated methods of identifying force-onset (40 N, 5 SDs, and 3 SDs) with manual identification, during the isometric mid-thigh pull (IMTP). Fourteen resistance-trained participants with >6 months experience training with the power clean volunteered to take part. After three familiarisation sessions, the participants performed five maximal IMTPs separated by 1 min of rest. Fixed bias was found between 40 N and manual identification for time at force-onset. No proportional bias was present between manual identification and any automated threshold. Fixed bias between manual identification and automated was present for force at onset and F150. Proportional but not fixed bias was found for F50 between manual identification and all automated thresholds. Small to moderate differences (Hedges g = −0.487- −0.692) were found for F90 between all automated thresholds and manual identification, while trivial to small differences (Hedges g = −0.122—−0.279) were found between methods for F200 and F250. Based on these results, strength and conditioning practitioners should not use a 40 N, 5 SDs, or 3 SDs threshold interchangeably with manual identification of force-onset when analysing IMTP force–time curve data. [ABSTRACT FROM AUTHOR]

The prediction of one-repetition maximum (1RM) using the submaximal load–velocity relationship (LVR) is highly relevant for the field of strength and conditioning. The optimal minimum velocity threshold (MVT) was recently proposed to increase the accuracy of 1RM predictions. However, using the average optimal MVT would allow for more practical estimations. LVRs of the free-weight back squat were obtained in 53 participants, throughout 2 sessions. LVRs were obtained using the multi- and two-point methods. Estimations of 1RM were made based on the average actual MVT (1RM velocity) and the average optimal MVT. The accuracy of 1RM predictions was examined using absolute-percent error and Bland-Altman plots. Cross-validation was performed using a leave-one-out approach. The number of selected loads did not affect the slope, y-intercept, optimal MVT or the accuracy of 1RM predictions. Predictions based on the average optimal MVT displayed greater accuracy than those obtained with the average actual MVT (~6% vs. ~8% absolute-percent error, respectively). However, wide 95% limits of agreement (LoA) were found between actual and estimated 1RM using both approaches (~13%1RM). The average optimal MVT offers more accurate 1RM estimations than the average actual MVT. However, errors prove substantial, making it challenging to precisely track minor changes in 1RM. [ABSTRACT FROM AUTHOR]

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recently, a Schwarz crystal structure with curved grain boundaries (GBs) constrained by twin-boundary (TB) networks was discovered in nanocrystalline Cu through experiments and atomistic simulations. Nanocrystalline Cu with nanosized Schwarz crystals exhibited high strength and excellent thermal stability. However, the grain-size effect and associated deformation mechanisms of Schwarz nanocrystals remain unknown. Here, we performed large-scale atomistic simulations to investigate the deformation behaviors and grain-size effect of nanocrystalline Cu with Schwarz crystals. Our simulations showed that similar to regular nanocrystals, Schwarz nanocrystals exhibit a strengthening-softening transition with decreasing grain size. The critical grain size in Schwarz nanocrystals is smaller than that in regular nanocrystals, leading to a maximum strength higher than that of regular nanocrystals. Our simulations revealed that the softening in Schwarz nanocrystals mainly originates from TB migration (or detwinning) and annihilation of GBs, rather than GB-mediated processes (including GB migration, sliding and diffusion) dominating the softening in regular nanocrystals. Quantitative analyses of simulation data further showed that compared with those in regular nanocrystals, the GB-mediated processes in Schwarz nanocrystals are suppressed, which is related to the low volume fraction of amorphous-like GBs and constraints of TB networks. The smaller critical grain size arises from the suppression of GB-mediated processes.

The aim of this study was to determine the associations between the front and back squat, countermovement jump (CMJ) and deep squat jump (DSJ) force–time metrics, and weightlifting performance in top-level weightlifters. Thirteen top-level weightlifters who classified for the World Championship 2023 participated. The heaviest successful snatch and clean and jerk were recorded within a preparation session as performance indicators. The front and back squat one-repetition maximums (1RMs) were evaluated in separate training sessions. The average of three maximum CMJs and DSJs were recorded using a force plate, and jump height, propulsive net impulse, and peak power were calculated for further analysis. Pearson's correlation coefficients were used to determine the associations between variables. Statistical significance was set at p ≤ 0.05. The front and back squat 1RMs were significant and nearly perfectly associated with weightlifting performance (p < 0.001, r = 0.98–0.99). CMJ and DSJ propulsive net impulse displayed nearly perfect associations with weightlifting performance (p < 0.001, r = 0.96–0.99), while jump height is a less promising metric to assess the weightlifters' ballistic capabilities. This study reinforces that lower body maximum strength and ballistic capabilities are closely associated with top-level weightlifters' performance and are of practical importance to monitor their neuromuscular function. [ABSTRACT FROM AUTHOR]

Abstract Background Increases in maximal strength and muscle volume represent central aims of training interventions. Recent research suggested that the chronic application of stretch may be effective in inducing hypertrophy. The present systematic review therefore aimed to syntheisize the evidence on changes of strength and muscle volume following chronic static stretching. Methods Three data bases were sceened to conduct a systematic review with meta-analysis. Studies using randomized, controlled trials with longitudinal (≥ 2 weeks) design, investigating strength and muscle volume following static stretching in humans, were included. Study quality was rated by two examiners using the PEDro scale. Results A total of 42 studies with 1318 cumulative participants were identified. Meta-analyses using robust variance estimation showed small stretch-mediated maximal strength increases (d = 0.30 p

Background: Increases in maximal strength and muscle volume represent central aims of training interventions. Recent research suggested that the chronic application of stretch may be effective in inducing hypertrophy. The present systematic review therefore aimed to syntheisize the evidence on changes of strength and muscle volume following chronic static stretching. Methods: Three data bases were sceened to conduct a systematic review with meta-analysis. Studies using randomized, controlled trials with longitudinal (≥ 2 weeks) design, investigating strength and muscle volume following static stretching in humans, were included. Study quality was rated by two examiners using the PEDro scale. Results: A total of 42 studies with 1318 cumulative participants were identified. Meta-analyses using robust variance estimation showed small stretch-mediated maximal strength increases (d = 0.30 p < 0.001) with stretching duration and intervention time as significant moderators. Including all studies, stretching induced small magnitude, but significant hypertrophy effects (d = 0.20). Longer stretching durations and intervention periods as well as higher training frequencies revealed small (d = 0.26–0.28), but significant effects (p < 0.001–0.005), while lower dosage did not reach the level of significance (p = 0.13–0.39). Conclusions: While of minor effectiveness, chronic static stretching represents a possible alternative to resistance training when aiming to improve strength and increase muscle size. As a dose-response relationship may exist, higher stretch durations and frequencies as well as long program durations should be further elaborated. Key Points: •While animal research consistently showed chronic stretch-mediated hypertrophy and strength increases, literature in humans draws an inconclusive picture, possibly due to lack of comparability of stretching parameters, such as duration and frequency. •Our systematic review is the first that included studies using comparable stretching durations of up to two hours in humans, which showed small magnitude maximal strength increases and muscle hypertrophy. •Even though less effective, high volume stretching might provide a sufficient alternative to strength training when aiming to induce muscle hypertrophy and strength increases. It must be noted that comparatively high training effort is opposed by comparatively small adaptations, suggesting a preference for the more efficient strength training if applicable. [ABSTRACT FROM AUTHOR]

The mechanical properties of cementitious sand and gravel damming material have been experimentally determined by means of microscopic SEM (Scanning Electron Microscopy) image analysis. The results show that the combination of fly ash and water can fill the voids in cemented sand and gravel test blocks because of the presence of hydrated calcium silicate and other substances; thereby, the compactness and mechanical properties of these materials can be greatly improved. For every 10 kg/m³ increase in the amount of cementitious material, the density increases by about 2%, and the water content decreases by 0.2%. The amount of cementitious material used in the sand and gravel in these tests was 80-110 kg/m³, the water-binder ratio was 1-1.50. Moreover, the splitting tensile strength was 1/10 of the compressive strength, and the maximum strength was 7.42 MPa at 90 d. The optimal mix ratio has been found to be 50 kg of cement, 60 kg of fly ash and 120 kg of water (C50F60W120). The related dry density was 2.6 g/cm³, the water content was 6%, and the water-binder ratio was 1.09. [ABSTRACT FROM AUTHOR]

Traditional insurance's earthquake contingency costs are insufficient for earthquake funding due to extreme differences from actual losses. The earthquake bond (EB) links insurance to capital market bonds, enabling higher and more sustainable earthquake funding, but challenges persist in pricing EBs. This paper presents zero-coupon and coupon-paying EB pricing models involving the inconstant event intensity and maximum strength of extreme earthquakes under the risk-neutral pricing measure. Focusing on extreme earthquakes simplifies the modeling and data processing time compared to considering infinite earthquake frequency occurring over a continuous time interval. The intensity is accommodated using the inhomogeneous Poisson process, while the maximum strength is modeled using extreme value theory (EVT). Furthermore, we conducted model experiments and variable sensitivity analyses on EB prices using earthquake data from Indonesia's National Disaster Management Authority from 2008 to 2021. The sensitivity analysis results show that choosing inconstant intensity rather than a constant one implies significant EB price differences, and the maximum strength distribution based on EVT matches the data distribution. The presented model and its experiments can guide EB issuers in setting EB prices. Then, the variable sensitivities to EB prices can be used by investors to choose EB according to their risk tolerance. [ABSTRACT FROM AUTHOR]

Isometric strength training has been reported to benefit various sport-related dynamic performances. However, it is still unknown whether performing isometric strength training at single or multiple joint angles would elicit greater benefit. Purpose: To compare the effects of isometric bench press performed at single (SIBP) and multiple (MIBP) joint angles on dynamic strength and overhead throwing performance. Methods: Sixteen male softball and baseball athletes performed overhead throwing, 1-repetition-maximum (1RM) bench press, and ballistic push-up during pretest and posttest. They were then randomly assigned to either SIBP or MIBP to undergo 12 strength training sessions. During the training, isometric bench press was performed at only 90° elbow angle for SIBP but at 60°, 90°, and 120° elbow angles for MIBP. Results: A significant main time effect was observed for bench press 1RM (P =.003) and relative 1RM (P <.001). Similarly, a significant main time effect was observed for ballistic push-up peak power only (P =.037). There was no significant change in overhead throwing velocity in either group. There was also no significant difference in change in all measures between groups. However, a moderate effect in favor of MIBP was observed for change in ballistic push-up peak power (P =.180, g = 0.67). Conclusions: Based on the current findings, the inclusion of both SIBP and MIBP were equally beneficial to maximal strength development. However, performing MIBP had a greater effect on power development. [ABSTRACT FROM AUTHOR]

Study purpose. The purpose of this study was to determine the effect of reverse grip barbell curls and barbell triceps extension exercises on increasing the maximum strength of the arm muscles of wrestling athletes. Materials and methods. This type of research is quasi-experimental. The population in the study was 24 wrestling athletes. Sampling was carried out using purposive sampling techniques, namely 10 male wrestling athletes. The research instrument was carried out by lifting a load that was only able to be lifted 1 time or expressed ability (maximum strength) using a barbell. The data analysis technique used is hypothesis testing using the t-test formula. Results. The results of this study showed that the exercises of reverse grip barbell curls and barbell triceps extension have an effect on the increase in the maximum strength of the arm muscles of wrestling athletes; from the initial test and the final test results, there was an increase with a difference of 1.04, namely from an average score of 29.9 kg in the pre-test to 32.3 kg in the post-test. Conclusions. The conclusion in this study is that there is a significant influence of the reverse grip form of barbell curls and barbell triceps extension on the increase in maximum strength of the arm muscles in wrestling athletes.

IntroductionBased on the assumption of maximal strength as a basic ability, several studies show a high influence of maximum strength on jumping performance in several sport athletes. However, there is a wide range of correlations from r = 0.17–0.9 between squat 1RM and jumping performance in different sports. Additionally, there are only a few studies investigating the influence of deadlift one repetition maximum (1RM) on jumping performance. Thus, this study aimed to investigate the correlations between 1RM in the deadlift on jumping performance using the countermovement jump height (CMJ) and squat jump height (SJ) considering different sports.Methods103 athletes with experience in the deadlift from soccer, basketball, American football, powerlifting as well as participants from different sports without any deadlift experience (control group) were included to this study.ResultsOverall statistics showed a significant moderate influence of deadlift 1RM (r = 0.301–0.472) on jumping performance. However, subgroup analysis showed no significant correlation between deadlift 1RM and jumping performance in control participants, while moderate correlations could be detected in powerlifters (r = 0.34–0.39), soccer players (r = 0.437–0.46), American football players (0.584–0.62) and high correlations in basketball players (r = 0.809–0.848) showing significant influence of type of sport on correlations between deadlift maximum strength and jumping performance.DiscussionPresented results underline movement velocity- and task specificity of strength training routines which is discussed in the light of the respective sports.

The study aimed at the possibility of breaking the adjustment in the body muscles that are relevant to the volleyball player in terms of connectivity in the development of motor velocity through extreme and ultra-maximum force exercises. The researchers used the experimental method to solve the search problem. (24) A player in deliberate style, and the two researchers used several tools and methods, and this vocabulary was sunk for a period of.(4) weeks, 3 modules per week and 12 modules, 1 module time.(90 minutes) Motor speed measurement tests were used because of their importance in achieving the player's goal of exercise and the overwhelming strike test, which measures the performance level of offensive skills in volleyball. Tests were conducted before and after the use of extreme and super-maximum force exercises

Copyright of Journal of Physical Education (20736452) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Using standard tests to assess maximum strength is very important where resistance training planning is based individually. This study aimed to estimate 1 repetition maximum of active women based on the Rating of Perceived and to provide a special predictive equation. 30 healthy women (20-35 years; BMI: 26.32 ± 3.34 kg/m2) performed one repetition of chest press with eyes close and then chose a number to determine the intensity by Rating of Perceived Exertion scale of 6-20. In order to evaluate the validity of the designed equation, one repetition of the maximum number of subjects was calculated by Brzycki equation, and correlation was determined by Pearson's correlation method. There was a high correlation between the present study equation and the Brzycki method (r=0.89) and also after cross validations (r=0.91). No significant difference was observed between the results of the present equation and the results of Berzyski's equation. It seems that the equation of the present study” 1RM={(20-RPE" /" 40) +1 }× weight/2 " can provide a reliable estimate for 1 repetition maximum of chest press in healthy women. [ABSTRACT FROM AUTHOR]

Maximal strength measured via maximal voluntary contraction is known as a key factor in competitive sports performance as well as injury risk reduction and rehabilitation. Maximal strength and hypertrophy are commonly trained by performing resistance training programs. However, literature shows that long-term, long-lasting static stretching interventions can also produce significant improvements in maximal voluntary contraction. The aim of this study is to compare increases in maximal voluntary contraction, muscle thickness and flexibility after 6 weeks of stretch training and conventional hypertrophy training. Sixty-nine (69) active participants (f = 30, m = 39; age 27.4 ± 4.4 years, height 175.8 ± 2.1 cm, and weight 79.5 ± 5.9 kg) were divided into three groups: IG1 stretched the plantar flexors continuously for one hour per day, IG2 performed hypertrophy training for the plantar flexors (5 × 10–12 reps, three days per week), while CG did not undergo any intervention. Maximal voluntary contraction, muscle thickness, pennation angle and flexibility were the dependent variables. The results of a series of two-way ANOVAs show significant interaction effects (p < 0.05) for maximal voluntary contraction (ƞ2 = 0.143–0.32, p < 0.006), muscle thickness (ƞ2 = 0.11–0.14, p < 0.021), pennation angle (ƞ2 = 0.002–0.08, p = 0.077–0.625) and flexibility (ƞ2 = 0.089–0.21, p < 0.046) for both the stretch and hypertrophy training group without significant differences (p = 0.37–0.99, d = 0.03–0.4) between both intervention groups. Thus, it can be hypothesized that mechanical tension plays a crucial role in improving maximal voluntary contraction and muscle thickness irrespective whether long-lasting stretching or hypertrophy training is used. Results show that for the calf muscle, the use of long-lasting stretching interventions can be deemed an alternative to conventional resistance training if the aim is to increase maximal voluntary contraction, muscle thickness and flexibility. However, the practical application seems to be strongly limited as a weekly stretching duration of up to 7 h a week is opposed by 3 × 15 min of common resistance training. [ABSTRACT FROM AUTHOR]

Study purpose. The purpose of this study was to determine the effect of reverse grip barbell curls and barbell triceps extension exercises on increasing the maximum strength of the arm muscles of wrestling athletes. Materials and methods. This type of research is quasi-experimental. The population in the study was 24 wrestling athletes. Sampling was carried out using purposive sampling techniques, namely 10 male wrestling athletes. The research instrument was carried out by lifting a load that was only able to be lifted 1 time or expressed ability (maximum strength) using a barbell. The data analysis technique used is hypothesis testing using the t-test formula. Results. The results of this study showed that the exercises of reverse grip barbell curls and barbell triceps extension have an effect on the increase in the maximum strength of the arm muscles of wrestling athletes; from the initial test and the final test results, there was an increase with a difference of 1.04, namely from an average score of 29.9 kg in the pre-test to 32.3 kg in the post-test. Conclusions. The conclusion in this study is that there is a significant influence of the reverse grip form of barbell curls and barbell triceps extension on the increase in maximum strength of the arm muscles in wrestling athletes. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the associations between the front and back squat, countermovement jump (CMJ) and deep squat jump (DSJ) force–time metrics, and weightlifting performance in top-level weightlifters. Thirteen top-level weightlifters who classified for the World Championship 2023 participated. The heaviest successful snatch and clean and jerk were recorded within a preparation session as performance indicators. The front and back squat one-repetition maximums (1RMs) were evaluated in separate training sessions. The average of three maximum CMJs and DSJs were recorded using a force plate, and jump height, propulsive net impulse, and peak power were calculated for further analysis. Pearson’s correlation coefficients were used to determine the associations between variables. Statistical significance was set at p ≤ 0.05. The front and back squat 1RMs were significant and nearly perfectly associated with weightlifting performance (p < 0.001, r = 0.98–0.99). CMJ and DSJ propulsive net impulse displayed nearly perfect associations with weightlifting performance (p < 0.001, r = 0.96–0.99), while jump height is a less promising metric to assess the weightlifters’ ballistic capabilities. This study reinforces that lower body maximum strength and ballistic capabilities are closely associated with top-level weightlifters’ performance and are of practical importance to monitor their neuromuscular function.

Traditional insurance’s earthquake contingency costs are insufficient for earthquake funding due to extreme differences from actual losses. The earthquake bond (EB) links insurance to capital market bonds, enabling higher and more sustainable earthquake funding, but challenges persist in pricing EBs. This paper presents zero-coupon and coupon-paying EB pricing models involving the inconstant event intensity and maximum strength of extreme earthquakes under the risk-neutral pricing measure. Focusing on extreme earthquakes simplifies the modeling and data processing time compared to considering infinite earthquake frequency occurring over a continuous time interval. The intensity is accommodated using the inhomogeneous Poisson process, while the maximum strength is modeled using extreme value theory (EVT). Furthermore, we conducted model experiments and variable sensitivity analyses on EB prices using earthquake data from Indonesia’s National Disaster Management Authority from 2008 to 2021. The sensitivity analysis results show that choosing inconstant intensity rather than a constant one implies significant EB price differences, and the maximum strength distribution based on EVT matches the data distribution. The presented model and its experiments can guide EB issuers in setting EB prices. Then, the variable sensitivities to EB prices can be used by investors to choose EB according to their risk tolerance.

This study investigated the predictive validity and reliability of the load-velocity relationship with the one-repetition maximum test (1RM) in power clean from the knee exercise (PC). Initially, 12 healthy young males, with no PC experience, underwent eight sessions to learn the PC technique. After the learning period, the participants visited the laboratory on four more occasions with intervals between the visits from 72 to 96 h. The first two sessions were dedicated to the actual 1RM tests, while the last two sessions were performed to measure the barbell's load-velocity relationship at 30%, 45%, 60%, 75%, and 90% of PC 1RM. The highest peak velocity recorded at each load was used to establish the linear regression equation and, consequently, to predict 1RM values. As a result, a low validity was observed between the highest actual 1RM value and the predicted 1RM in sessions 1 and 2 (typical errors = 3.6 to 5.0 kg, coefficients of variation = 6.03 to 8.21%, effect sizes = -1.23 to -1.00, and Bland-Altman bias = 8.5 to 11.7 kg). For reliability, higher measurement errors (intraclass correlation coefficient, typical error, coefficient of variation, and width of limits of agreement at 95%) were observed for the predicted 1RM compared to the actual 1RM test. In conclusion, the load-velocity relationship was not able to predict the 1RM value with high accuracy in the PC from the knee. Moreover, the predicted 1RM presented inferior reliability than the actual 1RM test. [ABSTRACT FROM AUTHOR]

The main objective of this research was to evaluate the behavior of composite sections of different configurations subjected to bending, considering the parameters established by ANSI/AISC, NSR-10, ACI-18 and laboratory tests such as the four-point bending test. Theoretical studies were used to evaluate the stiffness, strength and stresses of the sections in order to categorize and compare them with reinforced concrete sections and structural steel sections. Laboratory tests verified the effectiveness of the theoretical calculation and the real behavior of the materials. The test results showed a close theoretical validation and a ductile and favorable bending behavior due to the isolation of the compressed and tensioned parts. [ABSTRACT FROM AUTHOR]

Vertical jumping performance is of high importance for various individual and team sports. Movement patterns utilizing a stretch shortening cycle are of particular interest. Despite their involvement in every vertical jump variation, the importance of the plantar flexors' dynamic maximum strength for jumping performance has not been investigated yet. Therefore, the aim of this study is to examine the relationship between plantar flexion strength and different vertical jump variations. The present study examines the correlation of maximum strength in the standing calf raise and in the squat with performance in the vertical jumping forms squat jump (SJ), countermovement jump (CMJ), and drop jump (DJ) from different heights in 56 physical education students. The one-repetition maximum (1 RM) in the standing calf raise shows moderate to high (p < 0.01) correlations for SJ and CMJ (r = 0.575–0.659, and r = 0.565–0.708, respectively). The DJ revealed weak to medium correlations (p < 0.01) with the dynamic maximum strength of the plantar flexors (r = 0.362–0.573). A comparison of the strongest and weakest subjects revealed significant differences between groups with the stronger participants displaying greater jumping performance in all tests. In addition, squat 1 RM was significantly correlated (p < 0.05) with DJ performance. It can be concluded that the strength of the plantar flexors displays a relevant factor for vertical jumping performance in SJ, CMJ, and DJ that supports the main propulsive mechanisms. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the peak force (PF), peak power (PP), and peak velocity (PV) outputs produced during half-squat (HS) and jump squat (JS) exercises executed at 20, 40, 60, and 80% of 1 repetition maximum (1RM) in the HS (HS 1RM) and to compute and compare the strength deficit (SDef) achieved in these exercises across these loads. Twenty-four national rugby union players (age: 25.7 ± 3.6 years) performed HS 1RM and a progressive loading test in the HS and JS exercises. The PF, PP, and PV values were obtained in all loads for both exercises, and the SDef was calculated as the percentage difference between the PF at distinct relative intensities and the PF at HS 1RM. The differences in HS and JS variables were determined using an analysis of variance with repeated measures. Higher PF, PP, and PV outputs were generated in the JS in comparison with the HS exercise (p < 0.05); moreover, the SDef magnitudes were significantly lower in the JS (p < 0.01), for all loading conditions. Importantly, the differences in SDef, and as a consequence, PF, PP, and PV decreased progressively with increasing load. Overall, the loaded JS exhibited increased levels of PF, PP, and PV and reduced levels of SDef when compared to the traditional HS performed across a range of loads. The JS is indicated to reduce the SDef and improve the athletes’ ability to apply force at higher velocities. Nevertheless, with heavier loads (i.e.,≥80% HS 1RM), its potential advantages and effectiveness may be seriously compromised. [ABSTRACT FROM AUTHOR]

BACKGROUND: An advantage that deadlift (DL) has over back squat (BSQ) is that the latter requires additional equipment (i.e., squat rack). Accordingly, if DL can lead to positive effects on jumping, acceleration, and change of direction, DL could present as a more practical training exercise than that of BSQ. OBJECTIVE: This study aimed to compare the effects of DL and BSQ on jumping, acceleration, and change of direction. METHODS: Twenty-three men (12 in the DL group [age: 20.3 ± 1.4 years old, height: 169.6 ± 6.7 cm, body weight: 65.7 ± 11.2 kg] and 11 in the BSQ group [age: 20.2 ± 1.9 years old, height: 171.5 ± 4.8 cm, body weight: 70.1 ± 6.8 kg]) participated in this study. The participants performed five repetitions maximum (RM) of DL and BSQ, and the isokinetic strength of hip joint extension, muscle thickness of the gluteus maximus and hamstrings, countermovement jump (CMJ) height, 10 m sprint time, and T-test results were measured. The 1RM was estimated using the 5RM and normalized to body weight (BW). Both groups performed supervised DL and BSQ training for eight sessions. RESULTS: There were significant improvements on 1RM DL/BW (p < 0.01), 1RM BSQ/BW (p < 0.01), and 10 m sprint (p < 0.01) in the two groups. The effect sizes (d) of the DL and BSQ groups were 2.01 and 1.04 for 1RM DL/BW, 1.08 and 2.08 for 1RM BSQ/BW, 0.35 and 0.11 for CMJ height, and - 0.94 and - 0.54 for 10 m sprint, respectively. CONCLUSIONS: DL training might improve jumping and acceleration compared to those of BSQ training. [ABSTRACT FROM AUTHOR]

Background: Strength and speed are two major factors that determine performance in basketball players especially sprinting, jumping and change of direction. This study examined relationships of maximal strength in the front squat and the deadlift with basketball-specific sprint and jump performance tests that are commonly used in test batteries of athletic diagnostics. Materials and methods: In all, 42 youth male elite basketball players (age: 14.7 ± 2.4 years, age range: 13–18 years, height: 179.1 ± 15.3 cm, weight: 69.8 ± 19.2 kg) volunteered to take part in the present study. The one repetition maximum (1 RM) in the front squat and deadlift were used to determine maximum strength. Countermovement jump (CMJ) and standing long jump were evaluated to determine jump performance and 5, 10, and 20 m linear sprint as well as agility T‑test were performed to determine sprint performance. Pearson correlation analysis was used to assess the relationships between strength and jump and sprint performance. Results: Strong positive correlations were found between maximal strength and jump heights (r = 0.85–0.91, p < 0.001) and strong negative correlations were determined between maximal strength and measured sprint times r = (−0.71 to −0.85, p < 0.001). Conclusion: The measured maximal strength in the front squat and deadlift seem to be good predictors for basketball-specific jump and sprint performance. From this, it seems to be beneficial to include training of maximal strength via front squat and deadlift into training routines as well as performance diagnostics. [ABSTRACT FROM AUTHOR]

The purposes of this study were to investigate the acute effects of resistance training protocol on kinetic changes in squat jump (SJ), shortened isometric mid-thigh pull (IMTP), and isometric squat (ISQ) and to examine the relationship of dynamic maximum strength with performance changes over 48 hours in resistance-trained individuals. Participants completed performance tests at pre-, post-24 hours, and post-48 hours resistance training protocol (Baseline, Post24, and Post48). The training protocol consisted of 5 sets of 10 repetitions of back squat (BSQ) at 60% of 1 repetition maximum (1RM). SJ variables included jump height (JH), peak power (PP), and relative PP. For the IMTP and ISQ, isometric peak force (IPF), relative IPF, rate of force development at 250 milliseconds (RFD250), and impulse at 250 milliseconds (IMP250) were calculated. Significant decreases were observed from Baseline to Post24 (p = 0.023, Cohen's dz effect size [dz] = 1.00) and Post48 (p = 0.032, dz = 0.94) in SJ JH. IMTP IMP250 significantly decreased from Baseline to Post48 (p = 0.046, dz = 0.88). Significant negative correlation was found between relative 1RM BSQ and the changes from Baseline to Post48 in ISQ RFD250 (p = 0.046,r = −0.61). Acute performance decreases might remain until 48 hours after resistance training in explosive strength and impulse regardless of isometric testing type. [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. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the association between hamstring muscle peak torque and rapid force capacity (rate of torque development, RTD) vs sprint performance in elite youth football players. Methods: Thirty elite academy youth football players (16.75 [1.1] y, 176.9 [6.7] cm, 67.1 [6.9] kg) were included. Isometric peak torque (in Newton meters per kilogram) and early- (0–100 ms) and late- (0–200 ms) phase RTD (RTD100, RTD200) (in Newton meters per second per kilogram) of the hamstring muscles were obtained as independent predictor variables. Sprint performance was assessed during a 30-m-sprint trial. Mechanical sprint variables (maximal horizontal force production [FH0, in Newtons per kilogram], maximal theoretical velocity [V0, in meters per second], maximal horizontal power output [Pmax, in watts per kilogram]) and sprint split times (0–5, 0–15, 0–30, and 15–30 m, in seconds) were derived as dependent variables. Subsequently, linear-regression analysis was conducted for each pair of dependent and independent variables. Results: Positive associations were observed between hamstring RTD100 and FH0 (r2 =.241, P =.006) and Pmax (r2 =.227, P =.008). Furthermore, negative associations were observed between hamstring RTD100 and 0- to 5-m (r2 =.206, P =.012), 0- to 15-m (r2 =.217, P =.009), and 0- to 30-m sprint time (r2 =.169, P =.024). No other associations were observed. Conclusions: The present data indicate that early-phase (0–100 ms) rapid force capacity of the hamstring muscles plays an important role for acceleration capacity in elite youth football players. In contrast, no associations were observed between hamstring muscle function and maximal sprint velocity. This indicates that strength training focusing on improving early-phase hamstring rate of force development may contribute to enhance sprint acceleration performance in this athlete population. [ABSTRACT FROM AUTHOR]

Purpose: To compare the associations between optimum power loads and 1-repetition-maximum (1RM) values (assessed in half-squat and jump-squat exercises) and multiple performance measures in elite athletes. Methods: Sixty-one elite athletes (15 Olympians) from 4 different sports (track and field [sprinters and jumpers], rugby sevens, bobsled, and soccer) performed squat and countermovement jumps, half-squat exercise (to assess 1RM), half-squat and jump-squat exercises (to assess bar-power output), and sprint tests (60 m for sprinters and jumpers and 40 m for the other athletes). Pearson product–moment correlation test was used to determine relationships between 1RM and bar-power outputs with vertical jumps and sprint times in both exercises. Results: Overall, both measurements were moderately to near perfectly related to speed performance (r values varying from −.35 to −.69 for correlations between 1RM and sprint times, and from −.36 to −.91 for correlations between bar-power outputs and sprint times; P <.05). However, on average, the magnitude of these correlations was stronger for power-related variables, and only the bar-power outputs were significantly related to vertical jump height. Conclusions: The bar-power outputs were more strongly associated with sprint-speed and power performance than the 1RM measures. Therefore, coaches and researchers can use the bar-power approach for athlete testing and monitoring. Due to the strong correlations presented, it is possible to infer that meaningful variations in bar-power production may also represent substantial changes in actual sport performance. [ABSTRACT FROM AUTHOR]

The purposes of this study were to investigate intrasession and intersession reliability of variables obtained from squat jump (SJ), shortened isometric midthigh pull (IMTP), and isometric squat (ISQ) protocols and to evaluate relationships between isometric and dynamic performance and 1 repetition maximum (1RM) back squat (BSQ). Eleven moderately resistance-trained men participated (27.8 ± 3.9 years; 175.0 ± 7.2 cm; 87.2 ± 11.4 kg). Subjects completed familiarization in the IMTP and ISQ, followed by 1RM BSQ at least 48 hours before the first performance test. Two performance tests occurred at 7-day intervals including SJ, IMTP, and ISQ. SJ variables included jump height (SJH), body mass (BM), peak force (PF), and peak power (PP). Isometric midthigh pull and ISQ variables included isometric peak force (IPF); relative IPF; rate of force development at 90, 200, and 250 milliseconds; and impulse at 90, 200, and 250 milliseconds. SJ, IMTP, and ISQ kinetic variables were considered reliable if intraclass correlations (ICCs) and coefficients of variations (CVs) were >0.80 and <10%. Intrasession and intersession reliability criteria were met for SJH, BM, PF, and PP (ICC = 0.91-1.00, CV = 0.5-9.1%). Isometric peak force and impulse at 200 and 250 milliseconds met intrasession and intersession reliability criteria for IMTP and ISQ (ICC = 0.90-0.99, CV = 2.1-8.1%). Significant large correlation was observed between 1RM BSQ and ISQ peak force (p = 0.038, r = 0.63), but not between 1RM BSQ and shortened IMTP peak force (p = 0.11, r = 0.50). Shortened IMTP and ISQ peak force and impulse are reliable kinetic variables, and ISQ peak force is indicative of 1RM BSQ in moderately resistance-trained men. [ABSTRACT FROM AUTHOR]

Copyright of Actividad Fisica & Deporte is the property of Universidad de Ciencias Aplicadas & Ambientales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Al.Qadisiya journal for the Sciences of Physical Education is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Kotani, Y, Lake, J, Guppy, SN, Poon, W, Nosaka, K, Hori, N, and Haff, GG. The reliability of the squat jump force-velocity and load-velocity profiles. J Strength Cond Res 36(11): 3000–3007, 2022—The purpose of this study was to investigate the between-session reliability of the squat jump force-velocity (FV) and load-velocity (LV) profiles. Eighteen subjects (age = 28.1 ± 4.8 years; height = 1.7 ± 9.7; body mass = 74.7 ± 12.8) who could back squat >1.5 times body mass participated in this study. Each subject completed a familiarization session, followed by 2 experimental sessions each separated by 72 hours. Subjects performed a series of squat jumps on a force plate against external loads between 0 and 100% of their body mass in a quasi-randomized block order. Intraclass correlation coefficient (ICC) and coefficient of variation (CV) were used to examine the between-session reliability. Peak velocity (PV) and mean velocity (MV) at each load were highly reliable (ICC >0.80, CV% <7.41, SEM <0.13 m·s−1, smallest detectable difference [SDD] <0.31 m·s−1, ES <0.21). Force-velocity profiles created with peak force and relative peak force resulted in poor to excellent reliability (ICC = 0.34–0.92, CV% = 11.9–26.3). When mean and relative mean forces were used to create FV profiles, there was poor to good reliability (ICC = 0.03–0.85, CV% = 18.1–39.4). When the LV profile was calculated with PV (ICC = 0.60–0.90, CV% = 7.9–16.9) or MV (ICC = 0.49–0.91, CV% = 11.1–23.4), there was poor to excellent reliability. There was no time effect found between sessions for both FV and LV profiles. The squat jump FV and LV profiles established with a force plate are not reliable. Therefore, these profiles are not recommended to be used to inform programming decisions. [ABSTRACT FROM AUTHOR]

Purpose: To examine the reliability and usefulness of the isometric midthigh pull (IMTP) and isometric squat (ISqT) performed at the same knee and hip angles. The scores produced in each test were compared to determine the magnitude of differences between tests. Methods: Twenty-six male and female athletes (age, 23.6 [4.3] y; height, 1.75 [0.07] m; and body mass, 68.8 [9.7] kg) performed 2 maximal repetitions of the IMTP and ISqT following a specific warm-up. Results: Maximum force, absolute peak force (PF), relative PF, allometrically scaled PF, rate of force development (0–200 and 0–250 ms), and impulse (0–300 ms) were deemed reliable (intraclass correlation coefficient [ICC] ≥.86 and coefficient of variation [CV] ≤9.4%) in the IMTP and ISqT based on predetermined criteria (ICC ≥.8 and CV ≤10%). Impulse (0–200 and 0–250 ms) was reliable in the ISqT (ICC ≥.92 and CV ≤9.9%). Participants produced significantly (P <.05) greater PF and impulse (0–300 ms) during the ISqT compared with the IMTP. When split by sex, female participants produced significantly greater PF (P =.042) during the ISqT, with no significant differences among male participants (P =.245). Both tests are capable of detecting changes in performance in maximum force and absolute PF. Conclusions: Both tests are reliable for non-time-dependent maximal strength measures when measured at the same knee and hip angles. The ISqT may be preferred when coaches want to test an athlete’s true maximum lower-limb strength, especially female athletes. [ABSTRACT FROM AUTHOR]

Purpose: This study compared the concurrent validity and reliability of previously proposed generalized group equations for estimating the bench press (BP) 1-repetition maximum (1RM) with the individualized load--velocity relationship modeled with a 2-point method. Methods: Thirty men (BP 1RM relative to body mass: 1.08 [0.18] kg⋅kg-1) performed 2 incremental loading tests in the concentric-only BP exercise and another 2 in the eccentric--concentric BP exercise to assess their actual 1RM and load--velocity relationships. A high velocity (≈1 m⋅s-1) and a low velocity (≈0.5 m⋅s-1) were selected from their load--velocity relationships to estimate the 1RM from generalized group equations and through an individual linear model obtained from the 2 velocities. Results: The directly measured 1RM was highly correlated with all predicted 1RMs (r = .847-.977). The generalized group equations systematically underestimated the actual 1RM when predicted from the concentric-only BP (P < .001; effect size = 0.15-0.94) but overestimated it when predicted from the eccentric--concentric BP (P < .001; effect size = 0.36--0.98). Conversely, a low systematic bias (range: -2.3 to 0.5 kg) and random errors (range: 3.0-3.8 kg), no heteroscedasticity of errors (r² = .053-.082), and trivial effect size (range: -0.17 to 0.04) were observed when the prediction was based on the 2-point method. Although all examined methods reported the 1RM with high reliability (coefficient of variation ≤ 5.1%; intraclass correlation coefficient ≥ .89), the direct method was the most reliable (coefficient of variation < 2.0%; intraclass correlation coefficient ≥ .98). Conclusions: The quick, fatigue-free, and practical 2-point method was able to predict the BP 1RM with high reliability and practically perfect validity, and therefore, the authors recommend its use over generalized group equations. [ABSTRACT FROM AUTHOR]

Background: Chronic obstructive pulmonary disease (COPD) is one of the world's most common diseases and reasons for death. Systemic consequences, especially reduced muscle strength, muscle mass and muscle function, are common and contribute to worsening prognosis and increasing morbidity and mortality. There is strong evidence that physical activity and strength training are effective in prolonging life and lead to better quality of life. Numerous studies have shown that ingestion of protein and carbohydrates after strength training can increase regeneration of strength in young athletes. Recently, we demonstrated that the same effect can be achieved with these macronutrients administered in a meal. Until now, it is not clear if patients with COPD, integrated in regular physical training, respond similarly. Methods: Prescribed strength training, consisting of two sets circular training with machines for big muscle groups was supplemented with a meal rich in protein and carbohydrates. Changes in maximum strength after 24 h were investigated to find out about the impact of this meal on physical capacity. A pilot study was conducted with pragmatic cross-over design. Results: With nutritive intervention, strength in both knee extensor and chest press were significantly higher than in control training. Conclusion: The study showed beneficial effects for the intake of protein and carbohydrates in changes in maximum strength. For now, the underlying mechanism remains unclear. Clinical relevance needs further research. The study design and study protocol can be used for further studies with only small adaptions. [ABSTRACT FROM AUTHOR]

This network meta-analysis aimed at evaluating the effectiveness of different velocity-based (VBT) and traditional 1RM-based resistance training (TRT) interventions on strength and power indices in healthy participants. The research was conducted until December 2021 using the online electronic databases PubMed, Web of Science, PsycNet, and SPORTDiscus for studies with the following inclusion criteria: 1) controlled VBT trials, 2) strength and/or jump and/or sprint parameters as outcomes (c), participants aged between 18 and 40 years, and 4) peer-reviewed and published in English. Standardized mean differences (SMD) using a random effects models were calculated. Fourteen studies with 311 healthy participants were selected and 3 networks (strength, jump, and sprint) were achieved. VBT, TRT, repetitions in reserve (RIR), low velocity loss (lowVL), and high velocity loss (highVL) were ranked for each network. Based on P-score rankings, lowVL (P-score ≥ 0.59; SMD ≥ 0.33) and highVL (P-score ≥ 0.50; SMD ≥ 0.12) revealed favorable effects on strength, jump, and sprint performance compared to VBT (P-score ≤ 0.47; SMD ≤0.01), TRT (P-score ≤0.46; SMD ≤ 0.00), and RIR (P-score ≤ 0.46; SMD ≤ 0.12). In conclusion, lowVL and highVL showed notable effects on strength, jump, and sprint performance. In particular for jump performance, lowVL induced favorable improvements compared to all other resistance training approaches. [ABSTRACT FROM AUTHOR]

Loturco, I, McGuigan, MR, Rodríguez-Rosell, D, Pereira, LA, and Pareja-Blanco, F. A novel strategy to determine the 1-repetition maximum in the jump squat exercise. J Strength Cond Res 36(8): 2330–2334, 2022—This study aimed to determine the maximum relative load of the half-squat (HS; i.e., % HS 1-repetition maximum [1RM]) that can be used in its ballistic variation, namely, the jump squat (JS) exercise, and to examine whether this reference value varies in subjects with different strength levels. In total, 186 elite athletes from 10 distinct sport disciplines participated in this study. A progressive loading test up to HS 1RM was performed during the competitive phase of the season for all athletes. Mean propulsive velocity and propulsive phase duration were also assessed during the 1RM test. Athletes were divided into 3 distinct subgroups: "low," "middle," and "high" strength levels, based on their relative HS 1RM values (kg·kg−1). A 1-way analysis of variance was used to compare the variables assessed between the groups. Significance level was set at p < 0.05. The high group demonstrated the highest relative HS 1RM values, followed by the middle and low groups (all p < 0.05). No significant differences were observed between the groups for the remaining variables (p > 0.05). It was observed that at 86.0 ± 5.4% 1RM, the full concentric action can already be considered as entirely propulsive in the HS exercise for all subjects, independent of their strength levels. Therefore, this relative strength value may be used as a reference for the 1RM in the JS exercise. [ABSTRACT FROM AUTHOR]

Consumption of protein in weight training when adjusted to the needs will result in perfect muscle growth and development, especially in increasing maximum strength. In fact, many Fitness Members consume protein without paying attention to the dose, so that increasing maximum strength is not realized properly. This study aims to provide high-protein supplements and high-protein foods in weight training to increase maximum muscle strength. The design used in this study is a three group pre test and post test, consisting of a group consuming high protein supplements, a group consuming a high protein diet and a control group. The population in this study are FIK UNP students, with a total sample of 39 people. The instrument used in this study is a maximum strength test (leg & Hand Dynamo Meter test). The data obtained in this study are analyzed by analysis of variance (ANOVA) with = 0.05. The results showed: (1) There was a difference in effect between the group given high protein supplements, high protein die,t and the control group, (2) The group given high protein supplements had a difference from the average of the other two groups, (3) The group given high protein supplements high-protein supplements had a difference from the average of the other two groups, (4) The high-protein diet group did not have a mean difference with the control group. The limitation in this study is that the researcher was not able to control aspects that were outside the research activities such as other high protein contamination consumed by the research food samples. The next stage, this research will look at the effects of consuming high-protein supplements on a sustainable basis on human health.

This network meta-analysis aimed at evaluating the effectiveness of different velocity-based (VBT) and traditional 1RM-based resistance training (TRT) interventions on strength and power indices in healthy participants. The research was conducted until December 2021 using the online electronic databases PubMed, Web of Science, PsycNet, and SPORTDiscus for studies with the following inclusion criteria: 1) controlled VBT trials, 2) strength and/or jump and/or sprint parameters as outcomes (c), participants aged between 18 and 40 years, and 4) peer-reviewed and published in English. Standardized mean differences (SMD) using a random effects models were calculated. Fourteen studies with 311 healthy participants were selected and 3 networks (strength, jump, and sprint) were achieved. VBT, TRT, repetitions in reserve (RIR), low velocity loss (lowVL), and high velocity loss (highVL) were ranked for each network. Based on P-score rankings, lowVL (P-score ≥ 0.59; SMD ≥ 0.33) and highVL (P-score ≥ 0.50; SMD ≥ 0.12) revealed favorable effects on strength, jump, and sprint performance compared to VBT (P-score ≤ 0.47; SMD ≤0.01), TRT (P-score ≤0.46; SMD ≤ 0.00), and RIR (P-score ≤ 0.46; SMD ≤ 0.12). In conclusion, lowVL and highVL showed notable effects on strength, jump, and sprint performance. In particular for jump performance, lowVL induced favorable improvements compared to all other resistance training approaches.

Abstract Aim: Assess the effect of the performance order in the Concurrent Training (CT), Aerobic-Strength (AS), and Strength-Aerobic (SA), in the static balance, dynamic balance, and muscle strength in elderly people. Methods: The study involved 38 elderly people (men and women) aged 60 to 75 years old, divided into SA (n = 19) and AS (n = 19). Within 12 weeks, the aerobic training consisted of walking with intensity prescribed by the Borg's Rating of Perceived Exertion (6-20) and the strength training consisted of six exercises, with intensity controlled by Repetition Maximum training zones. Static balance (plantar pressure center area and displacement in bipedal support with eyes closed and open), dynamic balance (Timed Up and Go and Tandem Gait), and maximum dynamic strength of knee extension and bench press have been evaluated. For data analysis, Generalized Estimating Equations with Bonferroni's complimentary test have been used (α = 0.05). Results: For static and dynamic balance there hasn't been an effect on the 12 weeks of combined training, regardless of the performance order. Both groups maintained the balance variables within the intervention period. When it comes to strength, there has been a noticeable improvement in lower limbs (SA: 16%; AS: 11%; p < 0,001) and upper (SA: 22.0%; AS: 8.7%; p < 0.001), without any differences between the groups. Conclusion: So there is no difference between the order of performance of the CT in the variables of static and dynamic balance and strength of upper and lower limbs. Furthermore, after training, there have been significant improvements in the variables of strength and maintenance of static and dynamic balance.

This review analyzes relevant variables involved in acute interference effects of concurrent training (CT) sessions of aerobic exercise followed by strength exercises. The aerobic exercise intensity, mode, volume, duration of recovery interval between exercises, muscle groups involved, and utilization of ergogenic aids are the variables identified in this review. High-intensity interval aerobic exercises result in more pronounced negative effects on strength-endurance exercise but not in maximal strength. Cycling results in more negative effects on strength-endurance performance exercise than running. A 4-hour to 8-hour recovery interval seems to be enough to avoid interference on strength-endurance performance. Reduction in strength-endurance performance is located in muscle groups involved in both exercises. Low aerobic exercise volume (3 km) with ∼18 minutes of duration does not diminish strength endurance, whereas higher volumes (5 and 7 km) with ∼30 and ∼42 minutes of duration, respectively, generate impairments. Caffeine, carbohydrate, and beta-alanine are not able to revert the deleterious effect on strength-endurance performance, whereas creatine and capsaicin analog supplementation are. Thus, these variables must be taken into consideration to prescribe and organize a CT session. This information may help coaches to organize exercise sessions that minimize or avoid the impairment in strength performance after aerobic exercises. [ABSTRACT FROM AUTHOR]

Introduction: In recent years, music has been used as an ergogenic aid in different sports, especially in the training of muscular strength. Objetive: Determinate the ergogenic effect of music on the performance of muscle strength. Method: A systematic review was carried out under the PRISMA guidelines, for which the following Web of Science, Pubmed and Ebsco database were searched as well as Google Schoolar. The terms music AND muscular strength were used. 1975 papers were identified in the database from which 12 were selected that met the inclusion criteria, one more that was found in Google Scholar to include a total of 13 articles in this study. Results: In three articles muscular power was evaluated in wich all of them were improved with music. Also in seven studies the maximum strength was assessed in wichin which two presentes positive results. Finally, muscula endurance was evaluated in eigth articles, of which seven were positively influenced by music. Conclusion: Music has ergogenic effects on muscular endurance, but no on maximum strength. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Capital Institute of Physical Education is the property of Shoudu Tiyu Xueyuan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Maximum- and reactive-strength qualities both have important roles in athletic movements and sporting performance. Very little research has investigated the relationship between maximum strength and reactive strength. The aim of this study was to investigate the relationship between maximum-strength (isometric midthigh-pull peak force [IMTP PF]) and reactive-strength (drop-jump reactive-strength index [DJ-RSI]) variables at 0.3-m, 0.4-m, 0.5-m, and 0.6-m box heights. A secondary aim was to investigate the between- and within-group differences in reactive-strength characteristics between relatively stronger athletes (n = 11) and weaker athletes (n = 11). Forty-five college athletes across various sports were recruited to participate in the study (age, 23.7 ± 4.0 y; mass, 87.5 ±16.1 kg; height, 1.80 ± 0.08 m). Pearson correlation results showed that there was a moderate association (r = .302-431) between maximum-strength variables (absolute, relative, and allometric scaled PF) and RSI at 0.3, 0.4, 0.5 and 0.6 m (P < .05). In addition, 2-tailed independent-samples t tests showed that the RSIs for relatively stronger athletes (49.59 ± 2.57 N/kg) were significantly larger than those of weaker athletes (33.06 ± 2.76 N/kg) at 0.4 m (Cohen d = 1.02), 3.5 m (d = 1.21 ), and 0.6 m (d = 1.39) (P < .05). Weaker athletes also demonstrated significant decrements in RSI as eccentric stretch loads increased at 0.3-m through 0.6-m box heights, whereas stronger athletes were able to maintain their reactive-strength ability. This research highlights that in specific sporting scenarios, when there are high eccentric stretch loads and fast stretch-shortening-cycle demands, athletes' reactive-strength ability may be dictated by their relative maximal strength, specifically eccentric strength. [ABSTRACT FROM AUTHOR]

• Compiled an experimental database for PR steel joints with T-stub connections. • Developed a reliable envelope model for PR steel joints with T-stub connections. • Addressed limitations in existing methods and compared the developed model with existing models. The utilization of partially-restrained (PR) steel beam-to-column bolted T-stub connections offers a promising avenue for enhancing the efficiency and resilience of steel structural systems by reducing material consumption and facilitating post-hazard rehabilitation of connection components. However, the practical application of PR T-stub connections faces challenges due to the lack of comprehensive design guidelines. Specifically, in the context of performance-based seismic design for structural systems featuring PR T-stub connections, the accurate characterization of the cyclic envelope is pivotal. Presently, the availability of dependable cyclic envelope models tailored to PR T-stub connections is limited, with existing models facing various limitations. In response to these challenges, this study aims to pioneer a more dependable envelope model capable of mitigating the shortcomings of existing models. To achieve this objective, a comprehensive database comprising experimental data from steel beam-to-column assemblages with T-stub connections subjected to cyclic loading is compiled. These assemblages feature T-stubs either cut from hot-rolled sections or fabricated by welding plates, while the connected beams and columns are hot-rolled members. A four-stage multi-linear cyclic envelope is then developed. Particular attention is given to determining the two key characteristics of PR T-stub connections: maximum strength and initial rotational stiffness. The accuracy and robustness of the developed envelope model are rigorously assessed through comparisons with both experimental results and predictions from existing envelope models. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Physical Education (20736452) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aube, D, Wadhi, T, Rauch, J, Anand, A, Barakat, C, Pearson, J, Bradshaw, J, Zazzo, S, Ugrinowitsch, C, and De Souza, EO. Progressive resistance training volume: effects on muscle thickness, mass, and strength adaptations in resistance-trained individuals. J Strength Cond Res 36(3): 600-607, 2022-This study investigated the effects of 12-SET, 18-SET, and 24-SET lower-body weekly sets on muscle strength and mass accretion. Thirty-five resistance-trained individuals (one repetition maximum [1RM] squat: body mass ratio [1RM: BM] = 2.09) were randomly divided into 12-SET: n = 13, 18-SET: n = 12, and 24-SET: n = 10. Subjects underwent an 8-week resistance-training (RT) program consisting of 2 weekly sessions. Muscle strength (1RM), repetitions to failure (RTF) at 70% of 1RM, anterior thigh muscle thickness (MT), at the medial MT (MMT) and distal MT (DMT) points, as well as the sum of both sites ([SIGMA]MT), along with region of interest for fat-free mass (ROI-FFM) were measured at baseline and post-testing. For the 1RM, there was a main time effect (p <= 0.0001). However, there was a strong trend toward significance (p = 0.052) for group-by-time interaction, suggesting that 18-SET increased 1RM back squat to a greater extent compared with 24-SET (24-SET: 9.5 kg, 5.4%; 18-SET: 25.5 kg, 16.2%; 12-SET: 18.3 kg, 11.3%). For RTF, only a main time-effect (p <= 0.0003) was observed (24-SET: 5.7 reps, 33.1%; 18-SET: 2.4 reps, 14.5%; 12-SET: 5.0 reps, 34.8%). For the MMT, DMT, [SIGMA]MT, and ROI-FFM, there was only main time-effect (p <= 0.0001) (MMT: 24-SET: 0.15 cm, 2.7%; 18-SET: 0.32 cm, 5.7%; 12-SET: 0.38 cm, 6.4%-DMT: 24-SET: 0.39 cm, 13.1%; 18-SET: 0.28 cm, 8.9%; 12-SET: 0.34 cm, 9.7%-[SIGMA]MT: 24-SET: 0.54 cm, 6.1%; 18-SET: 0.60 cm, 6.7%; 12-SET: 0.72 cm, 7.7%, and ROI-FFM: 24-SET: 0.70 kg, 2.6%; 18-SET: 1.09 kg, 4.2%; 12-SET: 1.20 kg, 4.6%, respectively). Although all of the groups increased maximum strength, our results suggest that the middle dose range may optimize the gains in back squat 1RM. Our findings also support that differences in weekly set number did not impact in MT and ROI-FFM adaptations in subjects who can squat more than twice their body mass. /=>/p> [ABSTRACT FROM AUTHOR]