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Purpose: To compare the effects of 6-week barbell weighted-jump-squat (WJS) training with and without eccentric load reduction on explosive performance. Methods: Twenty well-trained male athletes were randomly assigned to either an experimental group (n = 10) or a control group (n = 10). Participants completed 12 WJS training sessions (6 sets of 5 repetitions of barbell back squat at 30% of 1-repetition maximum [1RM]) twice a week over a 6-week period. While the control group used 0% eccentric loading (ie, traditional WJS), the experimental group utilized a 50% eccentric loading reduction with a mechanical braking unit (ie, eccentric load set at 15% of 1RM). Performance assessments, including countermovement jump, 20-m sprint, standing long jump, and 1RM barbell back squat, were conducted both before (pretests) and after (posttests) the intervention. Results: Both the experimental group and the control group demonstrated a significant increase in countermovement-jump height (+6.4% [4.0%] vs +4.9% [5.7%]; P <.001) and peak power output (+2.3% [2.7%] vs +1.9% [5.1%]; P =.017), faster 20-m sprint times (+9.4% [4.8%] vs +9.2% [5.5%]; P <.001), longer standing long jump (+3.1% [2.5%] vs +3.0% [3.3%]; P <.001), and higher 1RM back squat (+6.4% [4.0%] vs +4.9% [5.7%]; P <.001) from pretests to posttests. However, there was no significant condition × time interaction for any variable (all P ≥.294). Conclusions: Both WJS training methods, with and without load reduction in the eccentric phase, effectively enhance explosive performance. Nevertheless, athletes in later stages of injury rehabilitation or intense training may find reducing eccentric load a more tolerable strategy for achieving similar performance gains compared with traditional isoinertial loading. [ABSTRACT FROM AUTHOR]

Purpose: This study explored the effects of 4 bench-press (BP) training programs with different velocity-loss (VL) thresholds (0%, 15%, 25%, and 50%) on strength gains and neuromuscular adaptations. Methods: Forty-six resistance-trained men (22.8 [4.4] y) were randomly assigned into 4 groups that differed in the VL allowed within the set: 0% (VL0), 15% (VL15), 25% (VL25), and 50% (VL50). Training loads (40%–55% 1-repetition maximum), frequency (2 sessions/wk), number of sets (3), and interset recovery (4 min) were identical for all groups. Participants completed the following tests before and after an 8-week (16-session) BP training program: (1) maximal isometric test, (2) progressive loading test, and (3) fatigue test in the BP exercise. During all tests, triceps brachii muscle electromyography was assessed. Results: After completing the resistance-training program, no significant group × time interactions were noticed for isometric and dynamic BP strength variables. The dose–response relationship exhibited an inverted U-shaped relationship pattern, with VL25 showing the greatest effect sizes for almost all strength variables analyzed. The total number of repetitions performed during the training program increased as the VL magnitude increased. Conclusions: The group that trained with high VL threshold (50%), which performed a total of 876 repetitions, did not experience additional strength gains compared with those experienced by the 0%, 15%, and 25% of VL groups, which performed significantly fewer repetitions (48, 357, and 547, respectively). These findings suggest that when light loads (40%–55% 1-repetition maximum) are used, low and moderate VL thresholds (0%–25%) provide a higher training efficiency. [ABSTRACT FROM AUTHOR]

Introduction: Unlike the most common training approaches for bodybuilding, powerlifting programs are generally based on maximum and submaximal loads, putting enormous stresses on the lumbar spine. The flexion relaxation phenomenon evaluation is a clinical tool used for low back pain (LBP) assessment. This study aimed to evaluate the role of the flexion relaxation phenomenon in the analysis of LBP in the powerlifters. Methods: Healthy professional powerlifters participated in the study. In fact, we divided the participants into a LBP-low-risk group and a LBP-high-risk group, based on a prior history of LBP. Outcome measures included flexion relaxation ratio (FRR) and trough surface electromyography collected during trunk maximum voluntary flexion; furthermore, during a bench press lifting, we measured the height of the arched back (ARCH), using a camera and the Kinovea video editing software, to consider a potential correlation with the risk of LBP. Results: We included a group of 18 male (aged 24–39 y) powerlifters of 93 kg category. We measured a nonsignificant mean difference of ARCH between low-risk LBP group and high-risk LBP subjects. Curiously, maximum voluntary flexions were both above the threshold of 3.2 μV; therefore, with an absence of appropriate myoelectric silence, on the contrary, the FRR ratios were higher than 9.5, considering the presence of the phenomenon, exclusively for the low-risk group. The lumbar arched back measurement data did not report any association with the LBP risk, regarding the maximum voluntary flexion value, and even more than the FRR there is a relationship with the presence or the absence of LBP risk. Conclusions: FRR could be considered as a useful parameter for studying the risk of LBP in powerlifting. The FRR index not only refers to the possible myoelectric silence of the lumbar muscles in trunk maximum forward flexion but also takes into account the energy value delivered by the lumbar muscles during the flexion. Furthermore, we can indicate that the size of the powerlifter ARCH may not be a determining factor in the occurrence of LBP. [ABSTRACT FROM AUTHOR]

This case study assessed body composition, muscle strength, cardiorespiratory fitness, and metabolic health of the present female world champion powerlifter in the 70+ age category who started resistance exercise training at 63 years of age with no prior experience with structured exercise training. Measures of body composition (magnetic resonance imaging, computed tomography, and dual-energy X-ray absorptiometry scanning, leg volume); strength (one-repetition maximum leg press and extension, maximum voluntary contraction, and handgrip strength); physical function (short physical performance battery); cardiorespiratory fitness (peak oxygen consumption); and metabolic health (oral glucose tolerance test) were assessed. In addition, a muscle biopsy was collected to assess muscle fiber type distribution and cross-sectional area (CSA). Where possible, data were compared with previously (un)published sex- and age-matched data using z scores. Skeletal muscle mass index was calculated by dividing limb muscle mass by height squared. Data from the control groups are expressed as mean ± 95% confidence interval. Our participant (age: 71 years; body mass: 64.5 kg; body mass index: 27.6 kg/m2) reported a good bone mineral density of 1.09 g/cm2 (T score between −1 and +1) and very low values of abdominal and organ body fat (i.e., between 20% and 70% lower compared with a reference group of postmenopausal women). In addition, she showed a 33% greater skeletal muscle mass index when compared with healthy, older female control subjects (7.9 vs. 5.9 [5.7–6.2] kg/m2; n = 61) as well as 37% greater muscle quadriceps CSA (63.8 vs. 46.6 [44.5–48.7] cm2; n = 48) and 46% greater Type II muscle fiber CSA (4,536 vs. 3,097 [2,707–3,488] μm2; n = 19). Absolute leg press muscle strength was 36% greater (190 vs. 140 [132–147] kg; n = 30) and handgrip strength was 33% greater (33 vs. 25 [23–26] kg; n = 48) when compared with healthy, age-matched controls. In conclusion, even for resistance exercise naïve individuals, starting exercise at an advanced age can lead to improvements in body composition and muscle strength allowing older adults to reduce the risk for developing metabolic syndrome, live independently, and even compete at a world class level. [ABSTRACT FROM AUTHOR]

There has been an increase in the use of commercially available multi-ingredient preworkout supplements (MIPS); however, there are inconsistencies regarding the efficacy of MIPS in resistance-trained women. Purpose: To determine the effect of varying doses of MIPS compared with caffeine only (C) and a placebo (PL) on resistance-training performance in trained women. Methods: Ten women (21.5 [2.3] y) completed 1-repetition-maximum tests at baseline for leg press and bench press. A within-group, double-blind, and randomized design was used to assign supplement drinks (ie, PL, C, MIPS half scoop [MIPS-H], and MIPS full scoop [MIPS-F]). Repetitions to failure were assessed at 75% and 80% to 85% of 1-repetition maximum for bench and leg press, respectively. Total performance volume was calculated as load × sets × repetitions for each session. Data were analyzed using a 1-way repeated-measures analysis of variance and reported as means and SDs. Results: There were no differences in repetitions to failure for bench press (PL: 14.4 [3.2] repetitions, C: 14.4 [2.9] repetitions, MIPS-H: 14.2 [2.6] repetitions, MIPS-F: 15.1 [3.1] repetitions; P =.54) or leg press (PL: 13.9 [7.8] repetitions, C: 10.8 [5.9] repetitions, MIPS-H: 13.1 [7.1] repetitions, MIPS-F: 12.4 [10.7] repetitions; P =.44). Furthermore, there were no differences in total performance volume across supplements for bench press (PL: 911.2 [212.8] kg, C: 910.7 [205.5] kg, MIPS-H: 913.6 [249.3] kg, MIPS-F: 951.6 [289.6] kg; P =.39) or leg press (PL: 4318.4 [1633.6] kg, C: 3730.0 [1032.5] kg, MIPS-H: 4223.0 [1630.0] kg, MIPS-F: 4085.5 [2098.3] kg; P =.34). Conclusions: Overall, our findings suggest that caffeine and MIPS do not provide ergogenic benefits for resistance-trained women in delaying muscular failure. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare a number of variables derived from the vertical and horizontal force components between loaded countermovement jumps performed in a Smith machine (SM modality; vertically restrained jumps) and with free weights (FW modality; unrestrained jumps). Twenty-three recreationally trained individuals, 6 women and 17 men, performed on a 3D force platform 5 maximal countermovement jump trials against 3 external loads (30%, 50%, and 70% of the SM 1-repetition maximum) using the SM and FW jumping modalities on separate sessions. The SM modality promoted greater values for virtually all the variables derived from the vertical force component (maximal force, maximal and minimum velocity, and impulse) and also shorter durations of the braking and propulsive phases. Regardless of the countermovement jump phase (braking or propulsive), the impulse directed toward the backward direction was always considerably greater for the SM compared with the FW modality. These results evidence that for recreationally trained individuals, the SM modality could be more effective to increase the general force capacity of the leg muscles due to increased external stability, while the FW modality is preferable when the orientation of force application is a crucial consideration, as it reduces the horizontal force component. [ABSTRACT FROM AUTHOR]

Background: The current physical activity guidelines recommend engagement in strength activities at least 2 days per week. Currently, there is a lack of literature examining strength activities among people with disabilities. The purpose of this study is to estimate and compare the prevalence of engagement in strength activities and adherence to strength activity guidelines among adults with and without disabilities in the United States. Methods: A total of 1,005,644 adults (18–80 y old) with and without disabilities from the 2013 to 2017 Behavioral Risk Factor Surveillance System were included in this secondary data analysis. Descriptive analyses were performed to describe the prevalence of strength activity behaviors of adults with and without disabilities. Logistic and Poisson regression models were performed to evaluate the relative contribution of disability status on strength activity behaviors. Results: A higher proportion of participants without disabilities (46.42%, 95% CI, 46.18–46.65) reported engaging in strength activities compared with participants with disabilities (30.68%, 95% CI, 30.29–31.08; P <.01). Participants with disabilities were less likely to engage in strength activities (odds ratio = 0.51, 95% CI, 0.50–0.52; adjusted odds ratio = 0.75, 95% CI, 0.73–0.77) and meet strength activity guidelines (odds ratio = 0.56, 95% CI, 0.54–0.57; adjusted odds ratio = 0.75, 95% CI, 0.73–0.77) than participants without disabilities. Conclusion: Experiencing a disability is associated with lower engagement in strength activities; thus, it is important to identify effective and efficient approaches to promoting strength activities among people with disabilities. [ABSTRACT FROM AUTHOR]

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

Purpose: The aim of the present study was to analyze the effect of different eccentric tempos on eccentric kinetics and kinematics and the subsequent concentric performance when performing countermovement jumps against different loads. Methods: After 1-repetition-maximum assessment and 2 familiarization sessions, 13 well-trained participants performed, in randomized order, 12 sets (4 tempos × 3 loads) of 4 repetitions of the loaded countermovement-jump exercise. The eccentric tempos analyzed were 5 and 2 seconds, as fast as possible, and accelerated (ie, without pause between repetitions), while the loads used were 30%, 50%, and 70% of 1-repetition maximum. Several kinetic and kinematic variables during both phases were recorded by linking a linear position transducer to the barbell. Results: The eccentric work was greater in the accelerated condition despite no changes in the eccentric depth. The peak and mean propulsive velocities were greater in the as-fast-as-possible and accelerated conditions. Correlation analysis showed that, compared with the 5-second condition, the increased concentric performance in the accelerated condition was related to the difference in eccentric work performed in the last 100 milliseconds of the eccentric phase (r >.770). Conclusions: Contrary to current practices, the current study highlights the need for performing the eccentric phase of loaded countermovement jumps, a common exercise performed by athletes for both training and evaluation purposes, as fast as possible. This allows not only a greater eccentric work but also improved concentric performance. [ABSTRACT FROM AUTHOR]

Adaptations to resistance training and subsequent performance can be undermined by inadequate interset recovery. Methods typically used to monitor recovery were developed for longitudinal use, making them time-inefficient within singular exercise bouts. If valid, perceptual recovery status (PRS) may be used as an efficient and inexpensive assessment tool to monitor individual recovery. Purpose: The aim of this study was to assess the validity of PRS on monitoring recovery during a high-intensity back-squat session. Methods: Ten healthy men participated in the 2-session study (separated by at least 48 h). Session 1 included anthropometrics, PRS familiarization, and a 1-repetition-maximum back squat. Session 2 included a high-intensity protocol (5 sets of 5 repetitions; 5-min interset recovery; 85% of 1-repetition maximum). PRS was obtained before the first set and during the last 30 seconds of each 5-minute recovery; rating of perceived exertion (RPE) was also collected. A linear position transducer collected mean barbell velocity (MBV). Repeated-measures correlations assessed the common intraindividual relationships of PRS scores to intraset MBV and RPE, respectively. Results: A very large, positive correlation appeared between PRS and MBV (r [95% CI] =.778 [.613 to.878]; P <.0001). A large, negative correlation emerged between PRS and RPE (r [95% CI] = −.549 [−.737 to −.282]; P <.001). Conclusions: Results indicate that PRS can be a means for practitioners to monitor individualized recovery. PRS tracked well with RPE, strengthening its utility in a practitioner-based setting. Findings provide insight into the practicality of PRS for recovery monitoring. It could be used alongside other measures (eg, MBV and countermovement jump) to individually program and maintain performance. [ABSTRACT FROM AUTHOR]

Most people with intellectual disabilities have comorbid health conditions, which will impact optimization of sporting performance. Classification is used in Paralympic events to ensure that those with similar levels of functional ability compete fairly against each other. An evidence-based approach needs to be developed for athletes with intellectual disabilities to be classified in relation to their overall functional capacity into competition groups of similar ability. This research builds on previous work using the taxonomy of The International Classification of Functioning, Disability and Health (ICF) to group athletes with intellectual disabilities into comparable competition groups as an approach to Paralympic classification. Three groups of athletes—Virtus, Special Olympics, and Down syndrome—are compared using the ICF questionnaire indicating functional health status in relation to sporting performance. The questionnaire was found to discriminate between athletes with Down syndrome and other athletes, and an approach to using a cutoff score to develop competition classes is explored. [ABSTRACT FROM AUTHOR]

Background: Understanding postural control in low back pain (LBP) subgroups can help develop targeted interventions to improve postural control. The studies on this topic are limited. Therefore, the primary purpose of this study was to compare the postural control of LBP subgroups with healthy individuals during overhead load lifting and lowering. Methods: In this cross-sectional study, the participants were 52 with LBP and 20 healthy. The LBP patients were classified based on the O'Sullivan classification system into 21 flexion patterns and 31 active extension patterns. The participants lifted the box from their waists to their overheads and lowered it to their waists. Changes in postural control parameters were measured with a force plate system. Results: The results of the analysis of variance showed that during load lifting, the mediolateral phase plane (p =.044) and the mean total velocity (p =.029) had significant differences between flexion patterns and healthy. Also, the load-lowering results showed that active extension patterns, compared with healthy, had significant differences in the anteroposterior–mediolateral phase plane (p =.042). The patients showed less postural sway than the healthy. Conclusions: The results in this work highlight the importance of identifying the homogenous subgroups in LBP and support the classification of heterogeneous LBP. Different subgroups exhibit different postural control behaviors. These behaviors can be due to the loading of various tissues during different tasks. [ABSTRACT FROM AUTHOR]

Purpose: The study examined the longitudinal interplay of anthropometric, metabolic, and neuromuscular development related to performance in adolescent national-level swimmers over 12 months. Methods: Seven male and 12 female swimmers (14.8 [1.3] y, FINA [International Swimming Federation] points 716 [51]) were tested before (T0) and after the preparation period (T1), at the season's peak (T2), and before the next season (T3). Anthropometric (eg, fat percentage) and neuromuscular parameters (squat and bench-press load-velocity profile) were assessed on dry land. Metabolic (cost of swimming [C], maximal oxygen uptake [ V ˙ O 2 peak ], and peak blood lactate [bLapeak]) and performance (sprinting speed [vsprint] and lactate thresholds [LT1 and 2]) factors were determined using a 500-m submaximal, 200-m all-out, 20-second sprint, and incremental test (+0.03 m·s−1, 3 min), respectively, in front-crawl swimming. Results: vsprint (+0.6%) and LT1 and 2 (+1.9–2.4%) increased trivially and slightly, respectively, from T0 to T2 following small to moderate strength increases (≥+10.2%) from T0 to T1 and V ˙ O 2 peak (+6.0%) from T1 to T2. Bench-press maximal strength and peak power correlated with vsprint from T0 to T2 (r ≥.54, P <.05) and LT2 at T1 (r ≥.47, P <.05). Changes in fat percentage and V ˙ O 2 peak (T2–T1 and T3–T2, r ≤ −.67, P <.01) and C and LT2 (T2–T0, r = −.52, P =.047) were also correlated. Conclusions: Increases in strength and V ˙ O 2 peak from preparation to the competition period resulted in improved sprint and endurance performance. Across the season, upper-body strength was associated with vsprint and LT2, although their changes were unrelated. [ABSTRACT FROM AUTHOR]

Studies on postactivation performance enhancement (PAPE) have used different exercises as a conditioning activity to investigate potentiation, but exclusively in upper limbs (UL) or lower (LL) limbs, or contralateral potentiation. A single exercise capable of inducing PAPE in both UL and LL is currently unknown. The present study explored the effect of the clean and jerk (C&J) as a conditioning activity for simultaneously producing PAPE interlimbs at the fourth, seventh, and 12th minutes postintervention. Twelve male weightlifters with 1-repetition maximum (1RM) in the C&J equivalent to ≥1.15 × body mass were randomly submitted to 2 experimental conditions (C&J and control [CON]). The C&J condition consisted of general warm-up (running on a treadmill and self-selected preparatory exercises) and 4 sets of 3 repetitions of C&J with 2 minutes between them (30%1RM, 50%1RM, 65%1RM, and 80%1RM) followed by a countermovement jump and a bench-press throw on a Smith machine after 4, 7, and 12 minutes, to measure the magnitude of PAPE in UL and LL. No previous exercise preceded countermovement-jump and bench-press-throw tests in the CON besides general warm-up. The main finding was that, regardless of time, the C&J resulted in greater height on countermovement jump and Smith machine bench-press throw when compared with the CON, presenting a similar effect size between UL and LL (34.6 [3.9] vs 33.4 [4.1] cm [+3.66%]; P =.038; effect size = 0.30 and 30.3 [4.7] vs 29.0 [5.1] cm [+4.44%]; P =.039; effect size = 0.26), respectively. Thus, C&J can be useful to produce PAPE simultaneously among members. [ABSTRACT FROM AUTHOR]

Weightlifting has become an increasingly popular form of exercise that has been shown to have many health benefits but can be dangerous if performed improperly. The objective of this study was to describe the epidemiology of lower body weightlifting injuries in the United States. The National Electronic Injury Surveillance System database was queried from January 1, 2012, to December 31, 2021, for lower body injuries related to using weightlifting equipment. Demographics, diagnosis, disposition, and mechanism of injury (MOI) were analyzed. There were 7,773 lower extremity weightlifting injuries identified from 2012–2021, giving a national estimate of 311,842 injuries. The most common MOI was dropped weight (n=1785, 22.96%). Deadlifts were the most cited exercise that led to lower extremity injury (n=503, 6.47%). Males were more likely than females to be injured (76% males vs. 24% females; p<0.001), especially by compound movements with free weights including squats (79.63% males vs. 19.96% females, p<0.03) and deadlifts (83.89% males vs. 16.10% females, p<0.001). Nearly all injuries were treated as outpatient but those admitted to the hospital were significantly older than those treated as outpatients (38.0 years vs. 31.2 years, p<0.05). Weightlifting carries a high risk of injury due to the intensity and technique required for the different movements involved. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether the optimal minimal velocity threshold (MVT) provides more precise estimates of one-repetition maximum (1RM) in the hexagonal barbell deadlift (HBD) than the general and individual MVTs. The 1RMs of 27 resistance-trained males were predicted using three types of MVT: (i) General MVT: averaged across subjects' velocity of the 1RM trial (0.25 m·s-1), (ii) individual MVT: velocity attained during the 1RM trial, and (iii) Optimal MVT: MVT that eliminated the differences between the actual and predicted 1RM. Two individual load-velocity relationships were modelled considering five (30-50-70-80%1RM) or six (30-50-70-80-90%1RM) loading conditions. Negligible differences (Effect size<0.20), low absolute errors (<5% of the actual 1RM), and extremely high correlations (r >0.90) were observed between the actual and six predicted 1RMs. The only significant difference was the lower raw errors for the 90%1RM condition (0.60±7.34 kg) compared to the 80%1RM condition (2.27±7.54 kg; p =0.013). These results suggest that the individual load-velocity relationship offers an accurate estimation of the HBD 1RM in resistance-trained males, and these estimates could maintain similar levels of precision across different types of MVT (general, individual, and optimal) and final tested loads (80%1RM and 90%1RM). [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the acute metabolic response, neuromuscular activity, and mechanical performance of different set configurations in bench-press (BP). Twenty-two resistance-trained men performed three resistance exercise protocols consisting of 3 x 12 BP repetitions at 60% 1RM, with 4 minutes of rest between sets, but with different set configurations: (a) traditional set (TS), without rest within the set; (b) cluster-6 (CS6), with 30-second intraset rest after the sixth repetition in each set; and (c) cluster-2 (CS2), with 30-second intraset rest every two repetitions. Mean propulsive force (MPF), velocity (MPV), power (MPP), and electromyography (EMG) values were recorded for each repetition. Blood lactate, maximal voluntary isometric BP contraction, and dynamic strength in BP were assessed pre- and post-exercise. The CS2 protocol resulted in greater mechanical performance (i. e. MPF, MPV, and MPP) and lower alterations of EMG parameters (i. e. root mean square and median frequency) during the exercise compared to CS6 and TS (TS

Returning to recreational sporting activities after adult spinal deformity (ASD) correction may significantly impact the patient's perceived quality of life. This study sought to characterize participation in sporting activities before and after ASD surgery, and to identify factors associated with impaired return to sports. Cross-sectional survey and retrospective review of prospectively collected data. Patients who underwent posterior-only thoracolumbar ASD surgery between 2016 and 2021 with ≥1 year follow-up and ≥3 levels of fusion to the pelvis were included. Preoperative and postoperative participation in sports, timing of return to these activities, and reasons for limited sports participation postoperatively were assessed. A survey was used to evaluate outcome measures. Differences in demographic, surgical, and perioperative variables between patients who reported improved, unchanged, or worsened activity tolerance were evaluated. Ninety-five patients were included (mean age: 64.3±10.1 years; BMI: 27.3±6.1 kg/m2; median levels fused: 7). The survey was completed at an average of 43.5±15.9 months after surgery. Sixty-eight (72%) patients participated in sports preoperatively. The most common sports were swimming (n=33, 34.7%), yoga (n=23, 24.2%), weightlifting (n=20, 21.1%), elliptical (n=19, 20.0%), and golf (n=11, 11.6%). Fifty-seven (83.8%) returned to at least one sport postoperatively, most commonly 6-12 months after surgery (45%). Elliptical had the highest rate of equal or improved participation (53%). Patients generally returned below their preoperative level to all other sports. Reasons for reduced sporting activities included physical limitation (51.4%), fear (20.0%), pain (17.1%), and surgeon advice (8.6%). There were no differences in the demographic, surgical, or perioperative characteristics between those who returned to sports at the same or better level compared with those who returned at a lower level. About 84% of patients successfully resumed sporting activities after undergoing fusion to the sacrum/pelvis for ASD. However, this return is typically at a lower level of participation than their preoperative participation, particularly in higher demand sports. Understanding trends in sporting activity may be valuable for counseling patients and setting expectations. [ABSTRACT FROM AUTHOR]

Background: CrossFit® combines different types of activities (weightlifting, gymnastics, and cardiovascular training) that challenge aerobic and anaerobic pathways. Over the last few years, the scientific interest in CrossFit® has increased considerably. However, there have been no published reviews characterizing the physical demands and physiological responses to CrossFit®. The present study synthesizes current evidence on the physical demands and physiological responses to CrossFit®. Methods: The search was performed in three electronic databases (PubMed, Scopus, and Web of Science). Manuscripts related to the physical and physiological performance of adult CrossFit® participants written in English, Portuguese, and Spanish were retrieved for the analysis. Results: In addition, a meta-correlation was conducted to examine the predictors of CrossFit® performance. A total of 68 papers were included in the review. Physical and physiological markers differed between the different workouts analyzed. In addition, 48 to 72 h are needed to recover from a CrossFit® challenge. Specific tests that involve CrossFit® movements were more related to CrossFit® performance than non-specific. Conclusion: Although the characterization of CrossFit® is dependent on the workout examined, the benefits of muscle hypertrophy are aligned with the recent findings of concurrent training. The characterization of CrossFit® entire sessions and appropriate recovery strategies should be considered in future studies to help coaches manipulate and adjust the training load. [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]

Background: Our systematic review aimed to critically evaluate empirical literature describing the association of muscle-strengthening exercise (MSE) with recurrence and/or mortality among breast cancer survivors. Methods: We included English-language empirical research studies examining the association between MSE and recurrence and/or mortality among females diagnosed with breast cancer. Seven databases (MEDLINE, PsycINFO, Embase, Scopus, Web of Science, Cochrane CENTRAL, and CINAHL) were searched in September 2023. Quality was appraised using the Mixed Methods Appraisal Tool. Results are summarized descriptively. Results: Five sources were identified. MSE measurement differed in relation to the description of the MSE (i.e., muscle-strengthening vs. strength training), examples of activities (e.g., sit-ups or push-ups vs. calisthenics vs. circuit training), and exercise frequency (i.e., days vs. times/week). Findings offer provisional evidence that some MSE may lower the hazards of recurrence and mortality. This association may vary by race, weight status, and menopausal status. Conclusions: In summary, limited available evidence suggests that MSE may lower the hazards of recurrence and mortality. More consistent measurement and analyses would help generate findings that are more readily comparable and applicable to inform clinical practice. Further research is needed to improve understanding of the strength and differences of these associations among underserved and underrepresented women. [ABSTRACT FROM AUTHOR]

This study aimed to discuss the differences in technical characteristics between the lunge-style and squat-style jerk techniques and to reveal the adaptability of these techniques for individual weightlifters. A total of 52 attempts by 32 male weightlifters were selected, and the video data were digitized manually using the SIMI Motion 7.50 three-dimensional analysis system. The technical characteristics of the lunge split and squat jerk were fundamentally consistent during the pre-squat, force exertion, and inertia ascent phases. The primary differences between the lunge split and squat jerk techniques were observed during the squatting and support phases, including the vertical descent velocity of the barbell at the end of the squat shoulder-locking phase and the stability angles in the sagittal and coronal axes. The vertical velocity of the barbell at the end of the squat shoulder-locking phase was significantly greater in the squat style (−0.41 ± 0.17 vs. −0.88 ± 0.14) compared to the lunge style (t = 6.393, p < 0.05). The stability angle on the sagittal axis at the end of the squat-supporting phase in the lunge style was significantly greater (46.99 ± 3.23 vs. 13.64 ± 0.51) than that of the squat style (t = 45.639, p < 0.05). [ABSTRACT FROM AUTHOR]

This study aimed to analyze the intersubject variability in the relationship between percentage of velocity loss (%VL) and percentage of repetitions performed out of maximum possible (%MNR) in postmenopausal women. Thirty-five postmenopausal active women (58 ± 3 years) performed sets leading to muscular failure, completing 10-13 repetitions, in both leg press (LP) and bench press (BP). Mean lift velocity of each repetition was expressed as a percentage of the fastest repetition, and repetitions were quantified as a percentage of the maximum number of repetitions completed in the set. Given the hierarchical structure of the data, %VL-%MNR relationships were fitted by linear mixed model regressions. A significant intersubject variability in the intercept (i.e., %MNR associated with 0%VL) was detected (p < 0.001 in both LP and BP), even when centered values of the completed repetitions were included in the models. The estimated variance in the intercept for LP (117.39; SE: 45.41) was almost double that for BP (67.47; SE: 20.27). The variability observed in the intercept entailed variability in the estimated %MNR for specific %VL values. The use of velocity loss thresholds for estimating the intensity of effort in active postmenopausal women does not overcome uncertainty of more traditional methods. [ABSTRACT FROM AUTHOR]

Mental fatigue can impair resistance exercise performance. Brain endurance training (BET)--the addition of demanding cognitive tasks to standard exercise training--improves endurance exercise performance more than standard training. Although BET has yet to be evaluated with resistance exercise, it is expected to improve performance, particularly when the performer feels mentally fatigued. The study employed a pretest (week 0), midtest (week 3), posttest (week 6), and follow-up (week 9) design, with subjects randomized to BET (n = 46) or control (exercise training) (n = 45) groups. In testing sessions, subjects performed chest press and squat jump exercises to failure before (feeling fresh) and after (feeling tired) a 30-minute cognitively demanding Stroop task. Training comprised 5 BET or control training sessions per week for 6 weeks. In each training session, subjects completed 4 sets of each exercise to failure, with each exercise set preceded by a 3-minute cognitive task (BET) or rest (control). Exercise performance (number of repetitions to failure) and mental fatigue markers were assessed. In pretesting, exercise performance did not differ between the groups. In midtesting and posttesting, BET performed more chest press and squat jump repetitions when fatigued by the 30-minute Stroop than control. The mental fatigue elicited by the Stroop task gradually declined with training in BET compared with control. In conclusion, BET enhanced resistance exercise performance compared with standard training when tested sub-sequent to a mentally fatiguing cognitive task. These benefits were maintained weeks after training ended. Brain endurance training is an effective method to mitigate the deleterious effects of mental fatigue on resistance exercise performance. [ABSTRACT FROM AUTHOR]

Relationships between force-generating capabilities and weightlifting performance (e.g., snatch, clean and jerk [C&J], and combined total) have previously been explored in adult weightlifters; however, associations in young athletes are unknown. The purpose of this study was twofold: (a) to examine the relationships between countermovement jump (CMJ) and isometric midthigh pull (IMTP) kinetics and weightlifting performance in young weightlifters and (b) to determine the proportion of weightlifting performance that could be accounted for by CMJ and IMTP kinetics using principal component analysis (PCA). Thirty-seven young weightlifters (12-18 years of age) completed 3 trials of CMJ and 2 trials of the IMTP assessments on dual force plates. Recent competition maximum loads, obtained within 2 weeks of the data collection, for the C&J and snatch were also recorded. Pearson's zero-order correlation coefficients demonstrated moderate to very high correlations (r = 0.359-0.801; all p ≤ Benjamini-Hochberg critical values [B-Hα]) between CMJ kinetic variables, including jump height, average braking force, average braking velocity, absolute and relative braking net impulse, absolute and relative force at minimum displacement, absolute and relative propulsive force, absolute and relative propulsive net impulse and average propulsive velocity, and weightlifting performance. High to very high correlations were evident between IMTP peak force and relative peak force and all weightlifting performance metrics (snatch, C&J, combined total, combined total [kg]/body mass [kg-0.67], and Sinclair's total; r = 0.538-0.796; p ≤ B-Hα). Components from the PCA were used to conduct stepwise, multiple, linear regression analyses. Moderate (45.8-52.9%) and large percentages (79.1-81.3%) of variance in absolute measures of weightlifting performance were explained by IMTP peak force variables and CMJ propulsive variables, respectively. These novel findings indicate that IMTP peak force variables and CMJ propulsive variables could provide valuable insight for talent identification and long-term athletic development in junior weightlifting pathways. [ABSTRACT FROM AUTHOR]

Mind Body Connect is a charity that delivers community-based physical exercise (PE) classes to people in recovery from substance use disorders. This study aimed to identify the contribution that strength training played in the development of positive short- and long-term psychological attributes for people recovering from substance use disorders by assessing (a) the short-term associations between participation in group exercise classes (N = 43, t = 2,940) and (b) the prospective long-term association between strength development and individuals' self-assessed level of "grit" among participants for whom strength training became a habitual activity (N = 13, median 8 weeks supported training). Participants completed demographic, Profile of Mood States—Adapted Short Form, and Short Grit Scale questionnaires before and after each strength training session over a period of 45 noncompulsory training sessions between February 2020 and March 2021. Weekly training logs recording the weight lifted were normalized into a measure of physical capital development. Short-term associations were tested using multilevel regression models predicting change in mean Grit score with interactions for gender; long-term associations were assessed through the use of latent growth models. We found that training sessions were associated with weak to moderate reductions (β = −0.112 to −0.533) in many negative mood states but elevated fatigue ( β MEN = 1.071, β WOMEN = 0.397). Latent growth in recorded strength was strongly associated with latent growth in self-assessed grit (β = 0.674). The findings suggest that PE classes and supported long-term strength training may assist with the development of recovery capital. [ABSTRACT FROM AUTHOR]

Purpose: To examine whether local blue and green space access was associated with weekly physical activity frequency during the COVID-19 pandemic. Design: Cross-sectional. Setting: Population-based, nationally representative sample of U.S. adults (May and June 2021). Sample: Adults, ages 18-94 (N = 1,771). Measures: Self-reported data included the presence of blue spaces (e.g., lakes, outdoor swimming pools, riverside trails) and green spaces (e.g., parks, forests, or natural trails) in their neighborhoods, and days of physical activity per week (e.g., running, swimming, bicycling, lifting weights, playing sports, or doing yoga). Analysis: Multiple Poisson regression assessed relationships between blue and green spaces and physical activity, with coefficients transformed into incidence risk ratios (IRR). Results: Among participants, 67.2% reported living near a blue space and 86.1% reported living near a green space. Racial/ethnic and socioeconomic disparities in access to blue and green spaces were observed, with less access among non-Hispanic Black participants and those with lower income and educational attainment. Living near blue (IRR = 1.23, 95% CI = 1.10, 1.39) or green space (IRR = 1.25, 95% CI = 1.02, 1.54) was significantly associated with more frequent weekly physical activity. Conclusion: Proximity to blue or green spaces is associated with more frequent physical activity during the COVID-19 pandemic. Health promotion efforts should include equitable strategies to improve accessibility to blue and green spaces. [ABSTRACT FROM AUTHOR]

This study was to ivestigated effects of adult fitness literacy programme (AFLP) in promoting physical activities among adults in Oye-Ekiti, Nigeria. Specifically, it determined effectiveness of AFLP in increasing participation in aerobic, strength, flexibility, and balance activities. Population was made up of adult 124 participants The study used a quasi-experimental pre-test post-test design. Data were collected with questionnaire. Data were analyzed using mean, standard deviation and t-test at 0.05 level of significance. Results show that for aerobic activities, the mean scores increased significantly from pre-test to post-test. For vigorous activities, the mean rose from 3.5 (SD = 0.82) to 4.2 (SD = 0.63), while for moderate aerobic activities, the mean increased from 2.9 (SD = 0.65) to 3.5 (SD = 0.74). Similarly, self-rated current aerobic fitness improved from a mean of 3.2 (SD = 0.87) to 3.8 (SD = 0.69). Paired t-tests revealed these improvements were statistically significant, with t-statistics ranging from 2.47 to 7.69 and corresponding p-values less than 0.001, except for session duration where p = 0.004 (t = 3.08). For strength-based activities, participants also showed significant increases, with the mean for weight lifting, push-ups, or sit-ups rising from 3.57 to 4.21, and the mean for activities involving resistance bands or free weights increasing from 2.95 to 3.52, both at the p<0.001 level. [ABSTRACT FROM AUTHOR]

This research explains how unexpected and uncontrollable chance events can facilitate or constrain competitive advantage in sport, through a study of Iran in five weight division-specific sports (i.e. weightlifting, wrestling, taekwondo, judo and boxing). The analysis relied on data collected from 25 semi-structured interviews. The study identifies six types of chance events impacting elite sport – economic crises, sport-specific crises, diplomatic tensions with foreign countries, political decisions by foreign governments, technological discontinuities, and new policies and rules of international governing bodies. The contributions of this paper to the literature reside in the identification of crises as a major type of chance events and the discovery of some chance events specific to elite sport. [ABSTRACT FROM AUTHOR]

Background: As interest in health increases, the number of people engaging in weight training to enhance muscle strength and muscle mass is on the rise. High-intensity weight training has been reported to induce tooth clenching habits, leading to tooth damage and temporomandibular joint (TMJ) abnormalities. Consequently, it is essential to investigate the impact of weight training accompanied by tooth clenching on oral health and to develop guidelines based on these findings. Methods: The study included male participants aged 25 years and older, comprising 15 non-exercisers and 15 professional fitness trainers who have been engaged in weight training for over 5 years. Data were collected using a self-administered questionnaire to gather information on age, exercise experience, total weight lifted in three major weight training exercises (deadlift, bench press, and squat), and teeth clenching habits. Additionally, examinations for tooth cracks and fractures, TMJ noise and pain, maximum mouth opening, occlusal force, and occlusal contact area were conducted. Results: Compared to non-exercisers, professional fitness trainers who have been engaged in weight training for over 5 years exhibited a higher prevalence of teeth clenching habits. While there were no significant differences between the two groups in occlusal contact area and the extent of tooth fractures, there were significant differences in occlusal force and the degree of tooth cracks. Furthermore, unlike joint noise and TMJ pain, the maximum mouth opening was significantly reduced in professional fitness trainers compared to non-exercisers. Conclusion: Our study suggests that the continuation of high-intensity exercise, which induces teeth clenching habits, may cause tooth damage and TMJ disorders.

Abstract Background Our systematic review aimed to critically evaluate empirical literature describing the association of muscle-strengthening exercise (MSE) with recurrence and/or mortality among breast cancer survivors. Methods We included English-language empirical research studies examining the association between MSE and recurrence and/or mortality among females diagnosed with breast cancer. Seven databases (MEDLINE, PsycINFO, Embase, Scopus, Web of Science, Cochrane CENTRAL, and CINAHL) were searched in September 2023. Quality was appraised using the Mixed Methods Appraisal Tool. Results are summarized descriptively. Results Five sources were identified. MSE measurement differed in relation to the description of the MSE (i.e., muscle-strengthening vs. strength training), examples of activities (e.g., sit-ups or push-ups vs. calisthenics vs. circuit training), and exercise frequency (i.e., days vs. times/week). Findings offer provisional evidence that some MSE may lower the hazards of recurrence and mortality. This association may vary by race, weight status, and menopausal status. Conclusions In summary, limited available evidence suggests that MSE may lower the hazards of recurrence and mortality. More consistent measurement and analyses would help generate findings that are more readily comparable and applicable to inform clinical practice. Further research is needed to improve understanding of the strength and differences of these associations among underserved and underrepresented women.

Background: The development and influence of physical capabilities and game action performance over the course of the season are a big challenge for coaches and players. Purpose: The aims of the present study were to examine (1) the seasonal changes in the physical capabilities (mechanical and kinematic) and game-performance indicators in top-level men volleyball players and (2) the relationship between these physical capabilities and game-performance indicators in official matches. Methods: Eleven top-level players participated. Players were physically tested 3 times during the season. Before each test, players' match performance (11 sets) was analyzed according to the level of opposition and match location. The percentage of change, statistical differences over the season (Friedman and Wilcoxon tests), and associations between variables (Spearman r) were calculated (P <.05) among mechanical (force–velocity profile during vertical jump and bench press), kinematic (jump height and spike ball speed), and game action performance features (coefficient, efficacy, and percentage of errors in serve, attack, and block). Results: The theoretical maximal force and velocity during vertical jump and bench press, respectively; the peak spike ball speed; and the serve efficacy significantly increased over the season. Moreover, there was a significant reduction in serve errors as the jump height increased (r = −.44; P =.026), as well as a significant increase in serve errors as the peak spike ball speed increased (r = −.62; P =.001). Conclusion: These findings reveal how the physical and game action performance variables evolve and interact during the season. This may help coaches and trainers to monitor and analyze the most relevant volleyball performance factors. [ABSTRACT FROM AUTHOR]

Purpose: During Ramadan month, Muslims often continue training to maintain their muscle performance. However, trainers should stress the importance of the time of day chosen for practicing resistance training (RT) during Ramadan fasting to avoid health and performance alteration. Thus, this study aimed to investigate the effects of the timing of RT during Ramadan intermittent fasting (RIF) on muscle strength and hypertrophy in healthy male adults. Methods: Forty men were randomly allocated to 2 matched groups: 20 practicing whole-body RT in the late afternoon in a fasted state and 20 training in the late evening in a fed state (FED). Both groups performed 4 days per week of whole-body RT (∼75%–85% 1-repetition maximum, 12 repetitions/3–4 sets) during RIF. Anthropometric measurements and 1-repetition-maximum test for the squats, deadlift, and bench press were measured. A cross-sectional area of the quadriceps and biceps brachii was examined using ultrasound scans. All measurements were taken at 4 time points: 24 hours before the start of Ramadan, on the 15th day of Ramadan, on the 29th day of Ramadan, and 21 days after Ramadan. Results: Post hoc tests indicated significant preimprovement to postimprovement in FED at the 29th day of Ramadan for the 1-repetition-maximum test for the squats (P =.02; effect size = 0.21) and deadlift (P =.03; effect size = 0.24) when compared to 24 hours before the start of Ramadan. No significant changes were observed in the fasted-state group or for cross-sectional area for both groups. Conclusions: Practicing RT during RIF appears not to have adverse effects on muscle hypertrophy and strength no matter whether it is practiced in FED or fasted state. However, RT had greater effects on muscle strength when applied in FED. Our findings suggest that training sessions should be scheduled after breaking the fast during Ramadan. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to explore whether offset loading in the barbell squat altered ground-reaction force (GRF) and muscle activation in the dominant (D) and nondominant (ND) lower limb compared to traditional squats. Methods: Twelve well-trained men (age 26.4 [3.2] y; 10.3 [1.9] y experience) performed 3 sets of 10 repetitions at 60% of their previously measured 1-repetition maximum. Sets were quasi-randomized between traditional loading (TDL), dominant-side offset loading (OS-D), and nondominant-side offset loading (OS-ND). All repetitions were performed on a dual force plate with electromyography sensors on the prime mover muscles of the squat. GRF symmetry was assessed using the symmetry index (SI) to determine the direction (D [+] or ND [−]) and magnitude (%) of the asymmetry. Finally, the first 3 and final 3 repetitions of each set were compared for compensatory changes in symmetry. Results: OS-D induced a significant change in limb SI relative to TDL (5.21% vs 1.44%; P =.011); however, no significant difference in limb SI was seen between TDL and OS-ND (−0.66% vs 1.44%; P =.278). No asymmetries between D and ND muscle activation were present in any condition. TDL and OS-D squats exhibited significant improvements in limb SI between the first 3 and final 3 repetitions (P =.035 and.011, respectively); however, no such improvement was seen in OS-ND. Conclusions: OS-D is capable of significantly altering GRF limb SI in a bilateral squat; however, OS-ND appears to exhibit no GRF or electromyography effects relative to TDL. Thus, the results of this study do not support the use of OS-ND in the pursuit of strengthening a weaker limb, suggesting that unilateral training may be a preferred mode of exercise for this desired outcome. [ABSTRACT FROM AUTHOR]

Purpose: Mental fatigue (MF) can impair physical performance in sport. We tested the hypothesis that cognitive load alone, and intermixed with standard resistance training, would induce MF, increase rating of perceived exertion (RPE), alter perception of weight lifting and training, and impair cycling time-trial performance. Methods: This 2-part study employed a within-participant design. In part 1, after establishing leg-extension 1-repetition maximum (1RM), 16 participants lifted and briefly held weights at 20%, 40%, 60%, and 80% of 1RM. RPE and electromyography (EMG) were measured for each lift. During the testing sessions, participants completed cognitive tasks (MF condition) or watched neutral videos (control condition) for 90 minutes before lifting the weights. In part 2, they completed submaximal resistance training comprising 6 weight training exercises followed by a 20-minute cycling time trial. In the MF condition, they completed cognitive tasks before and between weight training exercises. In the control condition, they watched neutral videos. Mood (Brunel Mood Scale), workload (National Aeronautics and Space Administration Task Load Index), MF-visual analogue scale (MF-VAS), RPE, psychomotor vigilance, distance cycled, power output, heart rate, and blood lactate were measured. Results: In part 1, the cognitive task increased lift-induced RPE (P =.011), increased MF-VAS (P =.002), and altered mood (P <.001) compared with control. EMG did not differ between conditions. In part 2, the cognitive tasks increased RPE (P <.001), MF-VAS (P <.001), and mental workload (P <.001), but reduced cycling time-trial power (P =.032) and distance (P =.023) compared with control. Heart rate and blood lactate did not differ between conditions. Conclusion: A state of MF induced by cognitive load, alone or intermixed with physical load, increased RPE during weight lifting and training and impaired subsequent cycling performance. [ABSTRACT FROM AUTHOR]

Purpose: Velocity-based training is used to prescribe and monitor resistance training based on velocity outputs measured with tracking devices. When tracking devices are unavailable or impractical to use, perceived velocity loss (PVL) can be used as a substitute, assuming sufficient accuracy. Here, we investigated the accuracy of PVL equal to 20% and 40% relative to the first repetition in the bench-press exercise. Methods: Following a familiarization session, 26 resistance-trained men performed 4 sets of the bench-press exercise using 4 different loads based on their individual load–velocity relationships (∼40%–90% of 1-repetition maximum [1RM]), completed in a randomized order. Participants verbally reported their PVL at 20% and 40% velocity loss during the sets. PVL accuracy was calculated as the absolute difference between the timing of reporting PVL and the actual repetition number corresponding to 20% and 40% velocity loss measured with a linear encoder. Results: Linear mixed-effects model analysis revealed 4 main findings. First, across all conditions, the absolute average PVL error was 1 repetition. Second, the PVL accuracy was not significantly different between the PVL thresholds (β = 0.16, P =.267). Third, greater accuracy was observed in loads corresponding to the midportion of the individual load–velocity relationships (∼50%–60% 1RM) compared with lighter (<50% 1RM, β = 0.89, P <.001) and heavier loads (>60% 1RM, 0.63 ≤ β ≤ 0.84, all P values <.001). Fourth, PVL accuracy decreased with consecutive repetitions (β = 0.05, P =.017). Conclusions: PVL can be implemented as a monitoring and prescription method when velocity-tracking devices are impractical or absent. [ABSTRACT FROM AUTHOR]

Purpose: To compare predetermined and autoregulated resistance training sessions on velocity loss and perceived fatigue. Methods: Twenty-six resistance-trained men completed 3 sessions including the back-squat and bench-press exercises matched for load (75% of 1-repetition maximum), volume (24 repetitions), and total rest (240 s). Sessions were randomly performed as traditional set (TRA), 3 sets of 8 repetitions with 120-second interset rests; cluster interset-rest redistribution (IRR), 6 clusters of 4 repetitions with 48-second between-clusters rests; and autoregulation cluster training (ACT), a personalized combination of clusters, repetitions per cluster, and between-clusters rest regulated on a velocity loss threshold. The comparative effects were evaluated on velocity loss outputs measured with a linear encoder and perceived fatigue responses reported using a single-item scale. Results: IRR and ACT induced less velocity loss than TRA (b = −2.09, P <.001). ACT also mitigated velocity loss more than IRR (b = −2.31, P <.001). The back squat resulted in greater velocity loss compared to the bench press (b = 1.83, P <.001). Perceived fatigue responses mirrored the pattern observed for the velocity loss outputs (IRR and ACT vs TRA: b = −0.64, P <.001; ACT vs IRR: b = −1.05, P <.001; back squat vs bench press: b = 0.46, P =.005). Conclusions: IRR and ACT reduced neuromuscular and perceived fatigue, likely due to their cluster-set structures' embedding frequent windows of interset rest. However, the ACT was overall more effective, presumably given its personalized structure. [ABSTRACT FROM AUTHOR]

Purpose: We aimed at investigating the acute effects of lower-body high-intensity interval training (HIIT) on upper- and lower-body explosive strength assessed by mean propulsive velocity (MPV) in naturally menstruating women. In addition, we assessed the combination of lower-body HIIT and squat, as well as lower-body HIIT and bench press, on bench press and squat MPV. Methods: Thirteen women (age: 23 [2] y, menstrual cycle length: 28.4 [2.0] d) completed 2 training modalities on separate days (separated by 30 [4.2] d) consisting of HIIT followed by lower-body (HIIT + LBS) or upper-body (HIIT + UBS) strength loading. Squat and bench press MPV were assessed before HIIT (T0), after HIIT (T1), after the strength loading (T2), and 24 hours postloading (T3). Results: Mixed factorial analysis of variance indicated a significant effect for time in bench press and squat (P <.001) but not for interaction. Pairwise comparison showed that bench press MPV remained unchanged (P = 1.000) at T1 but was reduced at T2 compared with T0 (HIIT + LBS: −8.2% [3.9%], HIIT + UBS: −13.8% [12.1%], P <.001) and T1 (HIIT + LBS: −7.1% [3.2%], HIIT + UBS: −12.7% [8.7%], P <.001). Squat MPV decreased at T1 (HIIT + LBS: −6.0% [8.8%], HIIT + UBS: −4.8% [5.4%], P =.009) and was found to be decreased at T2 compared with T0 in both conditions (HIIT + LBS: −6.9% [3.3%], HIIT + UBS: −7.4% [6.1%], P <.001) but not compared with T1 (P = 1.000). Bench press and squat MPV returned to baseline at T3 compared with T0 (P >.050). Conclusion: Lower- but not upper-body explosive strength was reduced by HIIT. HIIT combined with upper- or lower-body strength loading resulted in a reduction of squat and bench press explosive strength. [ABSTRACT FROM AUTHOR]

Purpose: To compare the accuracy in the estimation of the Smith machine bench press 1-repetition maximum (1RM) when using a novel minimum velocity threshold (MVT) called optimal MVT (MVT that minimizes the differences between the actual and predicted 1RM in a preliminary session) with respect to using the 2 standard MVTs (general and individual MVTs). Methods: A total of 126 young men (Smith machine bench press 1RM = 80.7 [13.6] kg) completed 2 identical sessions consisting of an incremental loading test until reaching the 1RM load. Four individual load–velocity relationships were modeled in each session considering all loading conditions until reaching the load that showed the closest mean velocity to 0.60, 0.50, 0.40, and 0.30 m·s−1. The first testing session was used to determine the preindividual MVT and 4 optimal MVTs (1 for each final test velocity), while the second testing session was used to estimate the 1RM using 4 types of MVT (general MVT, preindividual MVT, actual-individual MVT, and optimal MVT). Results: The absolute errors in the prediction of the 1RM were significantly lower for the optimal MVT (2.94 [2.40] kg) compared to the general MVT (3.66 [2.99] kg), preindividual MVT (3.80 [3.15] kg), and actual-individual MVT (4.02 [3.21] kg). The optimal MVT (intraclass correlation coefficient [ICC] ranged from.56 to.62) was always more reliable than the individual MVT (ICC =.34). Conclusions: The optimal MVT provides more accurate estimates of the Smith machine bench press 1RM than the standard MVTs previously used in scientific research (general and individual MVTs). [ABSTRACT FROM AUTHOR]

Purpose: To assess the variations in power performance and perceptual training responses and compare the physical performance of national boxing athletes qualified or not qualified for the Tokyo Olympic Games over a 7-month training period. Methods: Twelve amateur boxers from the Brazilian national team were tested 6 times across 7 months. In the first assessment, boxers performed squat and countermovement jumps and bench press, prone bench pull, half squat, and jump squat power tests. In the following testing sessions, only countermovement jump and bench press power were assessed. In addition, the rating of perceived exertion and total quality recovery status were assessed in 106 training sessions across the study. Independent t test and repeated-measures analysis of variance were used for data analysis purposes. Results: No significant differences (P >.05) were observed between Olympic and non-Olympic groups for any test variables (effect size [95% CI] ranging from 0.01 [−1.13 to 1.13] to 0.69 [−0.53 to 1.79]). No significant changes (P >.05) were detected throughout the study for countermovement jump height and bench press power in either group (effect size [95% CI] ranging from 0.01 [−1.13 to 1.13] to 1.03 [−0.25 to 2.14]). Overall, both groups exhibited similar variations in both rating of perceived exertion and total quality recovery over the 7-month period. Conclusions: Within the same national team, power-related performance was similar between Olympic and non-Olympic boxers. The maintenance of power abilities and optimization of technical and tactical skills seem to be key issues to consider during the final stages of preparation for international boxing competitions. [ABSTRACT FROM AUTHOR]

Aims: In the present intervention study, low-velocity-loss (LVL) versus high-velocity-loss (HVL) thresholds in the squat and bench press were compared for changes in muscle strength, power, and hypertrophy. Methods: Strength-trained volunteers (7♀ and 9♂; age: 27.2 [3.4] y; height: 174.6 [8.0] cm; body mass: 75.3 [10.1] kg) were randomized into an LVL or HVL threshold group (LVL n = 3♀ + 5♂, and HVL n = 4♀ + 4♂). Training took place 3 times per week over 6 weeks (loads: ∼75%–90% of 1-repetition maximum [1RM]). The thresholds of LVLs and HVLs were set at 20% and 40% of maximal velocity, respectively, for the squat, and at 30% and 60%, respectively, for the bench press. Before and after the intervention, 1RM, leg press power, and squat jump were tested. The load (∼45% of 1RM) corresponding to 1-m/s velocity was assessed in all sessions for both exercises. In addition, the thickness of the vastus lateralis and triceps brachii and body composition (dual-energy X-ray absorptiometry [DEXA]) were measured. Results: Squat and bench-press 1RM increased similarly in both groups by 7% to 11% (SD: 4%–6%, P <.05). No group differences were observed for changes in jump height, leg press power, or DEXA lean mass. However, HVL showed a small increase in muscle thickness of the vastus lateralis compared with LVL (6 ± 6% [95% CI] group difference, P <.05). Conclusion: For strength-trained individuals, high-volume lower-velocity-loss thresholds were as effective as higher thresholds for improvements in 1RM strength; but local hypertrophy was seemingly elicited faster with higher velocity-loss thresholds. [ABSTRACT FROM AUTHOR]

A cross-sectional study on severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) seroprevalence among unvaccinated people living with HIV (PLWH) was conducted in Kampala, Uganda, in 2022. Data collection was done using a structured questionnaire. SARS-CoV-2 serologies were done using the Roche Elecsys Anti-SARS-CoV-2 S immunoassay, which assesses the adaptive humoral immune response to the SARS-CoV-2 Spike protein. A total of 575 PLWH (female n=355, 61.7%) with a median age of 49 years (IQR 39-55) were included. SARS-CoV-2 seroprevalence was 93%. The majority had antibody concentration levels ὅ 250 U/ml (n=383, 66.6%). Participants aged >55 years were significantly more likely to have lower antibody concentrations compared to younger participants (p-value < 0.001). A high BMI (= 30 kg/m2) was significantly associated with higher antibody concentrations (p-value 0.001). Concerning COVID-19 history, a small proportion of participants (n=79, 13.6%) reported contact with a known COVID-19 patient. Only 8.1% (n=47) had ever had a nasopharyngeal swab for SARS-CoV-2 RT-PCR done, and 3.1% (n=18) actually had a laboratory-confirmed SARS-CoV-2 infection in the past. SARS-CoV-2 seroprevalence was high among our study population, which may be attributed to the fact that the study took place right after all restrictions were lifted and the population was exposed to the dominant Omicron variant. Interestingly, only a small proportion of infections had been laboratory-confirmed. [ABSTRACT FROM AUTHOR]

This study aimed to assess the validity and reliability of a commercially available inertial measurement unit (Enode) for measuring barbell kinematics and kinetics during a snatch. In order to assess validity and within- and between-session reliability, thirteen competitive weightlifters conducted two snatches on two separate occasions at 85% of their one-repetition maximum. The Enode sensor was attached to the barbell, with each lift recorded via the device's native application concurrently with an 11-camera motion capture system. Passing–Bablok regression indicated fixed and proportional bias in some horizontal measures of barbell mechanics but showed no bias in all but one vertical variable. Collectively, this suggests that the Enode is a valid tool in the measurement of vertically derived, but not horizontally derived, variables from barbell kinematics. Within- and between-session reliability showed moderate to excellent ICCs, with trivial to small differences between repetitions and between sessions. However, between-session reliability showed lower levels of variability and, thus, may help coaches identify changes in technique over time (between sessions) with good accuracy. Overall the Enode offers a practical and affordable option for coaches seeking to monitor weightlifting technique in training environments. [ABSTRACT FROM AUTHOR]