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Purpose: This study aimed to (1) evaluate the acute effects of different interrepetition rest full-squat protocols on countermovement jump (CMJ) height, velocity loss (VL), and skin temperature (Tsk) and (2) determine whether the VL, the changes in Tsk, or the individual strength level is associated with the change in CMJ height. Methods: Sixteen resistance-trained men randomly performed 3 squat protocols at maximal intended velocity with 60% of the 1-repetition maximum (sets × repetitions [interrepetition rest]): traditional (2 × 6 [0 s]), cluster 2 (2 × 6 [30 s every 2 repetitions]), and cluster 1 (1 × 12; [36 s every repetition]), plus a control session. CMJ height was assessed before and 2, 4, and 8 minutes after the protocols. Results: There was a significant main effect of protocol for the VL (F = 20.54, P <.001) and loss in mean power (F = 12.85, P <.001; traditional > cluster 2 > cluster 1). However, we found a comparable reduction of CMJ height after 8 minutes: traditional (−3.4% [4.2%]), cluster 2 (−5.3% [4.9%]), cluster 1 (−5.4% [2.9%]), and control (−4.2% [3.6%]). Overall, mean Tsk acutely decreased after all the protocols. Higher individual strength level (but not VL or the changes in Tsk) was associated with lower CMJ-height loss (P <.05). Conclusions: Although different interrepetition rest full-squat protocols may alter the loss in velocity and power, they result in a similar decrease in Tsk and CMJ height, which could be more influenced by individual strength level than VL or changes in Tsk. [ABSTRACT FROM AUTHOR]

This study investigated how equipment and sex affect the prediction accuracy of the maximum number of repetitions performed to failure (RTF) using the fastest mean velocity of the set (MVfastest). Sixteen men and twelve women completed four sessions (two using free-weight equipment and two sessions using the Smith machine). Each session involved three sets of repetitions to failure against the 65%, 75%, and 85% of the one-repetition maximum, interspersed by 10-min of rest. The goodness-of-fit of the individualized RTF-MVfastest relationships was comparable between both equipment types and sexes (P ≥0.510). Moreover, there were not significant differences in the MVfastest associated with RTF between equipment types (P ≥0.258). However, the MVfastest associated with RTF was higher for men than for women in repetitions 6 to 15 (P ≤0.043; ES≥0.69). In addition, the absolute errors when predicting RTF showed no significant differences between equipment types and loads (P <0.444). Specifically, these RTF estimates were within an acceptable range for men (<2 repetitions), but not for women (≥2 repetitions) (main effect of sex: P ≤0.018; ES≥0.58). These findings suggest that individualized RTF-MVfastest equations estimate the RTF with an acceptable precision in men during bench press exercises in both equipment types but exhibit lower precision for women. [ABSTRACT FROM AUTHOR]

Background: Physical testing is crucial for athlete monitoring, talent identification, optimizing training, and tailoring programs to enhance game-performance in elite competitions. Hypothesis: Load-velocity (L-V) relationship variables discriminate between elite and junior volleyball players, correlate with volleyball-specific performance, and are generalizable across lower- and upper-body exercises. Study Design: Cross-sectional study. Level of Evidence: Level 3. Methods: A total of 9 elite and 11 junior volleyball players were assessed for the L-V relationship (load-axis intercept [ L 0], velocity-axis intercept [ v 0], and area under the L-V relationship line [ A line]) during the countermovement jump (CMJ) and bench press throw (BPT) exercises. Block and spike jump height, as well as standing and jumping spike speed were assessed 24 hours later. Results: Elite players presented greater magnitude in the L-V variables (P ≤ 0.03; effect size [ES] ≥ 1.06) and higher volleyball-specific performance (P ≤ 0.03; ES ≥ 1.09) than juniors (except for CMJ v 0 and A line). The L-V relationship variables were significantly associated with the block and spike jump height and jumping spike speed only in elite players (r ≥ 0.703 and P ≤ 0.04 in 11 out of 18 correlations). No significant associations were observed between CMJ and BPT for any L-V relationship variable (r ≤ 581; P ≥ 0.08, except for A line in junior players). Conclusion: The L-V relationship is a practical procedure to assess volleyball players' maximal mechanical capacities, which are associated with volleyball-specific performance in elite players. However, these data should not be used interchangeably between playing standards or exercises. Clinical Relevance: This information might help strength and conditioning coaches to prescribe more effective training programs that focus on developing the specific physical capacities necessary for players to potentially advance to elite status. [ABSTRACT FROM AUTHOR]

The aims of this study were to assess (i) the load–velocity relationship during the box squat exercise in women survivors of breast cancer, (ii) which velocity variable (mean velocity [MV], mean propulsive velocity [MPV], or peak velocity [PV]) shows stronger relationship with the relative load (%1RM), and (iii) which regression model (linear [LA] or polynomic [PA]) provides a greater fit for predicting the velocities associated with each %1RM. Nineteen women survivors of breast cancer (age: 53.2 ± 6.9 years, weight: 70.9 ± 13.1 kg, and height: 163.5 ± 7.4 cm) completed an incremental load test up to one‐repetition maximum in the box squat exercise. The MV, MPV, and the PV were measured during the concentric phase of each repetition with a linear velocity transducer. These measurements were analyzed by regression models using LA and PA. Strong correlations of MV with %1RM (R2 = 0.903/0.904; the standard error of the estimate (SEE) = 0.05 m.s−1 by LA/PA) and MPV (R2 = 0.900; SEE = 0.06 m.s−1 by LA and PA) were observed. In contrast, PV showed a weaker association with %1RM (R2 = 0.704; SEE = 0.15 m.s−1 by LA and PA). The MV and MPV of 1RM was 0.22 ± 0.04 m·s−1, whereas the PV at 1RM was 0.63 ± 0.18 m.s−1. These findings suggest that the use of MV to prescribe relative loads during resistance training, as well as LA and PA regression models, accurately predicted velocities for each %1RM. Assessing and prescribing resistance exercises during breast cancer rehabilitation can be facilitated through the monitoring of movement velocity. Highlights: Movement velocity allows to precisely determine the relative load during the box squat exercise without submitting the patient to excessive mechanical and metabolic stress.From a practical perspective, we suggest using the mean velocity and a linear adjustment.This approach could provide an advantage over traditional assessment methods, enabling the efficient evaluation and prescription of resistance training intensity in exercise rehabilitation programs for women survivors of breast cancer. [ABSTRACT FROM AUTHOR]

This study examined the impact of different inter-repetition rest (IRR) configurations (zero seconds [IRR0], three seconds [IRR3], and self-selected less than five seconds [SSIRR]) on estimating the number of repetitions (Nrep) and the percentage of completed repetitions relative to the maximum number of repetitions possible to failure (%rep) after reaching 10%, 20%, and 30% velocity loss thresholds (VLT). Eighteen men completed three sessions, each with a different IRR configuration, separated by 48–72 hours. Single sets of repetitions to momentary muscular failure were performed against 65%, 75%, and 85% of the one-repetition maximum during free-weight back squat and bench press exercises. No significant differences were reported between IRR configurations for the Nrep (P ≥0.089) and %rep (P ≥0.061), except for %rep after reaching the 20–30%VLT against 65%1RM and the 10–20%VLT against 75%1RM in the bench press exercise (P ≤0.048). Additionally, both Nrep and %rep exhibited high interindividual variability (between-subject CV=14–79%) across the different IRR configurations. The individual %rep-%VLT relationships were slightly stronger than the general %rep-%VLT relationships (median R2 =0.914–0.971 vs. 0.698–0.900). Overall, regardless of the IRR configuration, this novel velocity-based approach does not guarantee the same effort levels across subjects in the free-weight back squat and bench press sets. [ABSTRACT FROM AUTHOR]

This study aimed to examine the load-velocity (L-V) relationship in the bench-press (BP) and leg-press (LP) exercises performed unilaterally, and compared this unilateral L-V relationship with the bilateral variants. Nineteen men (age=23.5±2.1 years) completed two incremental tests in BP and LP, performed bilaterally and unilaterally, across two sessions with a 48-hour rest period. We found a close relationship between medium propulsive velocity (MPV) and %1RM in unilateral BP (R2 =0.97, SEE=0.06 m·s-1) and LP (R2 =0.96, SEE=0.06 m·s-1). No significant differences were observed between the preferred and non-preferred sides in the L-V relationship for either exercise. Additionally, higher velocities were achieved in unilateral exercises compared to bilateral exercises, particularly with light and moderate loads (30–70%1RM) in BP (p<0.05) and with light loads (30–45%1RM) in LP (p<0.05). Close L-V relationships were observed in unilateral exercises, without differences in the L-V relationships between preferred and non-preferred sides despite the interlimb asymmetries in the absolute strength values. Interestingly, lower velocities were observed at light loads (~30–45% 1RM) for bilateral compared to unilateral exercises, which could be explained by different strength deficits for these exercises. [ABSTRACT FROM AUTHOR]

Introduction: White castings with a high Cr content of the hypoeutectic type are one of the most used in hardfacing to reduce wear by abrasion, in parts used in mineral processing, and in the sugar industry. Objective: To know the effect of a peripheral coating with a high C content, applied to a commercial AWS E FeCr-A8 electrode, on the microstructure of the deposited metal, as well as the behavior of resistance to abrasive wear. Materials and methods: Specimens were prepared for the characterization of the metal deposited with the original electrode (EO) and the modified one (EM) by means of hardness, optical metallography (OM), and analysis of the chemical composition using scanning electron microscopy (SEM). Using the test proposed by the ASTM G65, (2017) standard the resistance to abrasive wear was determined. Results and Discussion: The hardness of the metal deposited with the original electrode is 560 HV, while the hardness reached with the modified electrode reaches 750 HV, which is due to the fact that the morphology of the austenite and the eutectic zone is different for both deposits. The test of resistance to abrasive wear for the deposit obtained with the modified electrode showed a volume loss of 0.0531 mm3, lower than that manifested by the deposit made with the original electrode (0.0669 mm3). Conclusions: By applying a peripheral coating to the AWS FeCr-A8 electrode, the volumetric fraction of carbides in the eutectic zone of the deposit microstructure increases, improving the resistance to abrasive wear. [ABSTRACT FROM AUTHOR]

Purpose: This study assessed the effects of 12-week supervised resistance training combined with home-based physical activity on physical fitness, cancer-related fatigue, depressive symptoms, health-related quality of life (HRQoL), and life satisfaction in female breast cancer survivors. Methods: A parallel-group, outcome assessor-blinded, randomized controlled trial included 60 female breast cancer survivors who had completed their core treatments within the previous 10 years. Through computer-generated simple randomization, participants were assigned to resistance training (RTG; two sessions/week for 12 weeks plus instructions to undertake ≥ 10,000 steps/d) or control (CG; ≥ 10,000 steps/d only). Outcomes were evaluated at baseline and week 12. Muscular strength was assessed with electromechanical dynamometry. A standardized full-body muscular strength score was the primary outcome. Secondary outcomes included cardiorespiratory fitness, shoulder mobility, cancer-related fatigue, depressive symptoms, HRQoL, and life satisfaction. Results: Thirty-two participants were assigned to RTG (29 achieved ≥ 75% attendance) and 28 to CG (all completed the trial). Intention-to-treat analyses revealed that the standardized full-body muscular strength score increased significantly in the RTG compared to the CG (0.718; 95% CI 0.361–1.074, P < 0.001, Cohen's d = 1.04). This increase was consistent for the standardized scores of upper-body (0.727; 95% CI 0.294–1.160, P = 0.001, d = 0.87) and lower-body (0.709; 95% CI 0.324–1.094, P = 0.001, d = 0.96) strength. There was no effect on cardiorespiratory fitness, shoulder flexion, cancer-related fatigue, depressive symptoms, HRQoL, or life satisfaction. The sensitivity analyses confirmed these results. Conclusion: and implication for cancer survivors. In female breast cancer survivors who had completed their core treatments within the past 10 years, adding two weekly sessions of supervised resistance training to a prescription of home-based physical activity for 12 weeks produced a large increase in upper-, lower-, and full-body muscular strength, while other fitness components and patient-reported outcomes did not improve. Trial registration number. ISRCTN14601208. [ABSTRACT FROM AUTHOR]