Repetition Maximum Research Articles

Abstract 6290: Effects of a circuit, interval-based exercise program on vascular function among cancer survivors

Abstract Background: Cancer survivors are at an increased risk of cardiovascular comorbidity, including atherosclerosis, hypertension, and heart failure, due to negative impacts of cancer treatments on vascular function. Exercise is recommended in recent cardio-oncology rehabilitation guidelines and has been shown to improve vascular function in clinical populations; however, its effects on vascular function are understudied in clinical oncology settings. Purpose: This pilot study examined whether a circuit, interval-based exercise intervention can improve vascular function, assessed by brachial artery flow-mediated dilation (baFMD) and carotid intima media thickness (cIMT) in breast, prostate, and colorectal cancer survivors. Methods: Overweight or obese (BMI>25.0 kg/m2), sedentary breast, prostate or colorectal cancer survivors were randomized to exercise (n=60) or usual care (n=30). Survivors in the 4-month exercise intervention trained three times/week, in a circuit, interval-based supervised moderate-vigorous aerobic (65-85% of VO2max) and resistance (65-85% of 1-repetition maximum) program. cIMT and baFMD were measured at baseline and post-intervention via an ultrasound. Paired t-tests and repeated-measures analysis of variance were run to assess within- and between-group differences. Results: The study sample included breast (n=38), prostate (n=24), colorectal (n=28) cancer survivors who were 63.2 ± 10.8 years old, completed chemotherapy and/or radiation (75%) and were obese (87%). Post-intervention, baFMD significantly increased in the exercise group compared to the control group (between-group mean difference: 6.3%; 95% CI: [1.9 to 9.3], p=0.001). There was also a significant reduction in cIMT in the exercise group compared to the control group (between-group mean difference: -0.039mm, 95% CI: [-0.080 to -0.009], p=0.002). Conclusions: Our findings in this pilot study support that a circuit, interval-based aerobic and resistance exercise intervention may improve vascular function in breast, prostate, and colorectal cancer survivors. Future studies are recommended to understand how exercise interventions can be utilized clinically to improve cardiovascular disease risk and co-morbidity among cancer survivors. Citation Format: Cami N. Christopher, Dong-Woo Kang, Paola Gonzalo-Encabo, Rebekah L. Wilson, Amber J. Normann, Mary K. Norris, Christina M. Dieli-Conwright. Effects of a circuit, interval-based exercise program on vascular function among cancer survivors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6290.

The development of an automated assessment system for resistance training movement

ABSTRACT Portable data collection devices and machine learning (ML) have been combined in autonomous movement analysis models for resistance training (RT) movements. However, input features for these models were mostly extracted empirically and subsequent models demonstrated limited interpretability and generalisability to real-world settings. This study aimed to investigate the utility of interpretable and generalisable modelling techniques and several data-driven feature extraction (FE) methods. This was achieved by developing machine learning movement analysis models for the barbell back squat and deadlift using markerless motion capture. 61 participants performed submaximal and maximal repetitions of both RT movements. Movement data was collected using two Azure Kinect cameras. Joint and segment kinematic variables were calculated from the collected depth imaging, and input features were extracted using traditional, manual FE methods and novel data-driven techniques. Classifiers were developed for several predefined technical deviations for both movements. Many of the addressed technical deviations could be classified with good levels of accuracy (≥70%) while the remainder were poor (55%–60%). Additionally, data-driven FE techniques were comparable to previous, traditional FE methods. Interpretable and generalisable modelling techniques can be utilised to good effect for certain classification tasks while data-driven FE techniques did not provide a consistent advantage over traditional FE methods.

Resistance Exercise Minimal Dose Strategies for Increasing Muscle Strength in the General Population: an Overview.

Many individuals do not participate in resistance exercise, with perceived lack of time being a key barrier. Minimal dose strategies, which generally reduce weekly exercise volumes to less than recommended guidelines, might improve muscle strength with minimal time investment. However, minimal dose strategies and their effects on muscle strength are still unclear. Here our aims are to define and characterize minimal dose resistance exercise strategies and summarize their effects on muscle strength in individuals who are not currently engaged in resistance exercise. The minimal dosestrategies overviewed were: "Weekend Warrior," single-set resistance exercise, resistance exercise "snacking," practicing the strength test, and eccentric minimal doses. "Weekend Warrior," which minimizes training frequency, is resistance exercise performed in one weekly session. Single-set resistance exercise, which minimizes set number and session duration, is one set of multiple exercises performed multiple times per week. "Snacks," which minimize exercise number and session duration, are brief bouts (few minutes) of resistance exercise performed once or more daily. Practicing the strength test, which minimizes repetition number and session duration, is one maximal repetition performed in one or more sets, multiple days per week. Eccentric minimal doses, which eliminate or minimize concentric phase muscle actions, are low weekly volumes of submaximal or maximal eccentric-only repetitions. All approaches increase muscle strength, and some approaches improve other outcomes of health and fitness. "Weekend Warrior" and single-set resistance exercise are the approaches most strongly supported by current research, while snacking and eccentric minimal doses are emerging concepts with promising results. Public health programs can promote small volumes of resistance exercise as being better for muscle strength than no resistance exercise at all.

Assessing Motor Variability during Squat: The Reliability of Inertial Devices in Resistance Training.

Movement control can be an indicator of how challenging a task is for the athlete, and can provide useful information to improve training efficiency and prevent injuries. This study was carried out to determine whether inertial measurement units (IMU) can provide reliable information on motion variability during strength exercises, focusing on the squat. Sixty-six healthy, strength-trained young adults completed a two-day protocol, where the variability in the squat movement was analyzed at two different loads (30% and 70% of one repetition maximum) using inertial measurement units and a force platform. The time series from IMUs and force platforms were analyzed using linear (standard deviation) and non-linear (detrended fluctuation analysis, sample entropy and fuzzy entropy) measures. Reliability was analyzed for both IMU and force platform using the intraclass correlation coefficient and the standard error of measurement. Standard deviation, detrended fluctuation analysis, sample entropy, and fuzzy entropy from the IMUs time series showed moderate to good reliability values (ICC: 0.50-0.85) and an acceptable error. The study concludes that IMUs are reliable tools for analyzing movement variability in strength exercises, providing accessible options for performance monitoring and training optimization. These findings have implications for the design of more effective strength training programs, emphasizing the importance of movement control in enhancing athletic performance and reducing injury risks.

Distinct adaptations of muscle endurance but not strength or hypertrophy to low-load resistance training with and without blood flow restriction.

Low-load resistance training promotes muscle strength and hypertrophic adaptations when combined with blood flow restriction (BFR). However, the effect of BFR on muscle endurance remains unclear. The aim of this study was to clarify the effects of BFR on muscle performance and adaptation, with special reference to local muscle endurance. In experiment1, eight healthy men performed unilateral elbow flexion exercise to failure at 30% of one-repetition maximum with BFR (at 40% of estimated arterial occlusion pressure) and free blood flow (FBF). During the exercise, muscle activity and tissue oxygenation were measured from the biceps brachii. In experiment 2, another eight healthy men completed 6weeks of elbow flexion training with BFR and FBF. The number of repetitions to failure at submaximal load (Rmax), the estimated time for peak torque output to decay by 50% during repetitive maximum voluntary contractions (half-time), one-repetition maximum, isometric strength and muscle thickness of elbow flexors were measured pre- and post-training. Blood flow restriction resulted in fewer repetitions and lower muscle tissue oxygenation at the end of exercise than FBF, while the muscle activity increased similarly to repetition failure. Blood flow restriction also resulted in a smaller post-training Rmax, which was strongly correlated with the total exercise volume over the 6week period. Despite the smaller exercise volume, BFR resulted in similar improvements in half-time, muscle strength and thickness compared with FBF. These results suggest that the application of BFR can attenuate muscle endurance adaptations to low-load resistance training by decreasing the number of repetitions during exercise, both acutely and chronically.

Passively harmonic mode-locked erbium-doped fiber lasers based on PbSnS2 saturable absorbers

The two-dimensional (2D) material PbSnS2, a type of transition metal dichalcogenides (TMD), is a highly anisotropic layered compound with potential applications in ultrafast optics. We prepared PbSnS2 nanosheets by liquid phase exfoliation, attached them to microfibers to fabricate saturable absorbers (SAs) by optical deposition method, and successfully applied them to a passive erbium-doped fiber laser (EDFL). In addition, the saturable absorption properties of PbSnS2-based SA were confirmed using a balanced two-detector measurement system. The results demonstrate that the PbSnS2-based SA can realize different stable mode-locked states in the same EDFL cavity, including fundamental frequency conventional soliton and 15th harmonic mode-locked states. Among them, the laser produced fundamental frequency mode-locked state with a signal-to-noise ratio of 59.51 dB (6.58 MHz repetition frequency). The HML pulse with a maximum repetition frequency of 98.71 MHz (corresponding to the 15th harmonic) was obtained. The results demonstrate that PbSnS2 is a candidate material for generating ultrafast pulses and has excellent potential for application in ultrafast lasers.

Porous nano-grained cuprous selenide (Cu2Se) for mid-infrared photonics

Recently, mid-infrared photonics has attracted tremendous attention for various applications. To address the dilemma of the limited variety of materials for mid-infrared photonics, the mid-infrared optical modulation characteristics of the porous nano-grained cuprous selenide (Cu2Se) were investigated for the first time. The large effective nonlinear absorption coefficient, large modulation depth, and low saturation absorption intensity at 2.3 μm indicate that the porous nano-grained Cu2Se were promising saturable absorbers for the generation of Q-switched pulsed laser in the mid-infrared regime. As an application, the Tm:GdVO4 passively Q-switched laser operating on the 3H4 → 3H5 Tm3+ transition was achieved for the first time by using the prepared porous nano-grained Cu2Se as the saturable absorber. The minimum pulse duration and the maximum repetition rate of the stable Q-switched pulse train were 440 ns and 76.9 kHz, respectively. Our results demonstrated that the porous nano-grained Cu2Se was a promising candidate for the mid-infrared photonic applications.

Optimization of Cardiorespiratory Fitness and Quality of Life in Women with Chronic Heart Failure after a Cardiac Rehabilitation Program

Introduction: Women with heart failure (HF) tend to experience a greater symptom burden and lower quality of life, possibly due to phenotypic differences and unique gender-associated risk factors. Despite evidence on the effects of cardiac rehabilitation programs (CRP) in the general population, there is underrepresentation of women in these programs. Additionally, the impact of CRP on cardiorespiratory variables obtained through cardiopulmonary exercise testing (CPET) and health-related quality of life (HRQoL) in women with HF remains unknown. Objective: To assess the impact of a CRP on cardiorespiratory fitness (CRF) in cardiorespiratory variables obtained through CPET and HRQoL in women with HF. Methods: A quasi-experimental study included HF patients who completed a CRP from June 2019 to December 2023. The CRP involved nutritional assessment, psychosocial evaluation, educational sessions, and concurrent training. It comprised 30 minutes of aerobic resistance training at 65-80% of heart rate reserve (HRR) and 30 minutes of strength training at 30-50% of 1-repetition maximum (1RM), with a frequency of 3 sessions per week for 4 to 6 weeks. CPET was conducted at the beginning and end of the program, analyzing cardiorespiratory variables. HRQoL was assessed using the SF-36 questionnaire. Gains in CRF and HRQoL at the end of the program in both men and women were analyzed. Results: Out of 217 included patients, 29.9% were women. At the program's onset, women showed lower exercise tolerance than men (workload 5.4±2.57 METs vs. 6.62±2.53 METs) and worse HRQoL (62.03%±18.37 vs. 68.38%±18.37). However, post-intervention, they optimized their CRF (%predicted VO2 [%VO2p] initial 56.62%±20.11 vs final 80.12%±30.32, p=<0.001). Significant improvements in cardiorespiratory variables were observed in both cases: delta METs-load 3.02, p=<0.001, delta peak oxygen consumption (VO2peak) 1.83 ml/kg/min, p=<0.001, delta oxygen pulse (PO2) 1.21, p=0.021, delta cardiac power output (CPO) 1917, p=0.004, with a rightward shift in ventilatory thresholds and improvement in HRQoL (62.03%±18.37 vs. 78.81%±12.9, p=<0.001) post-CRP. The only variable with no significant changes in either case was VE/VCO2 slope (delta -0.51, p=0.736). Additionally, in women with reduced left ventricular ejection fraction (<50%), variables with no significant improvement included CPO (delta 959.22, p=0.283) and time to recovery of VO2 kinetics (TRCVO2) (delta -0.74, p=0.957). In patients with preserved left ventricular ejection fraction (≥50%), variables with no significant change included PO2 (delta 1.08, p=0.173), TRCVO2 (delta 26.82, p=0.099), and the first ventilatory threshold (VT1) (delta 0.09, p=0.504). Program attendance was 87.5% in both groups. Conclusion: Implementing a CRP in women with HF resulted in significant improvements in all evaluated cardiorespiratory variables (except for VE/VCO2 slope) and quality of life. These findings support the importance of ensuring women's access and participation in cardiac rehabilitation programs. Addressing existing barriers is crucial to maximize the long-term benefits of CRP in the female population with HF.

A high stability and low noise passively Q-switched yellow-green laser with a Ti3C2Tx-PVA saturable absorber

An 808 nm laser diode (LD) end-pumped passively Q-switched Nd: YAG ceramic yellow green laser at 561 nm with high stability and low noise has been demonstrated, for the first time to our knowledge based on passively Q-switching with a Ti3C2Tx-polyvinyl alcohol (Ti3C2Tx-PVA) film, frequency selection and filtering with a Brewster polarizer (BP) and a birefringent crystal (BC), and intracavity frequency doubling with a LiB3O5 (LBO) crystal. The 1112 nm and 1116 nm wavelengths from the Nd: YAG ceramic and the number of longitudinal modes of 1123 nm fundamental frequency light were effectively suppressed by adopting BP and BC. At 5.1 W of the 808 nm LD pump power, the 561 nm-PQYG laser with a maximum average power of 75.5 mW, a maximum repetition rate of 610 kHz, and a narrowest pulse width of 41 ns were obtained, corresponding to an average power instability of ±0.29%, a repetition rate instability ±7.08%, a pulse width instability of ±4.67%, and a laser noise of 0.49% over a period of 4 h.

The Impact of Velocity-Based Training on Load-Velocity Relationships in Leg Press and Chest Press for Older Persons.

Calaway, C, Mishra, S, Parrino, R, Martinez, KJ, Mann, JB, and Signorile, JF. Velocity-based training affects the load-velocity relationship in leg press and chest press for older persons. J Strength Cond Res 38(6): 1136-1143, 2024-This study examined the impact of 3 months of velocity-based training (VBT) on chest press (CP) and leg press (LP) maximal strength (1 repetition maximum [1RM]), peak power (PP), and percentage load where PP was achieved (%1RMPP) in older adults. Twenty-nine subjects were assigned to either a velocity-deficit (VD) group or a force-deficit (FD) group for each exercise depending on their load-velocity (LV) curves. Changes in load were determined by the ability to maintain either 90% (VD) or 70% (FD) of their PP during training. Subjects' powers were tested before and after the training intervention at loads between 40 and 80%1RM. Separate 2 (group) × 2 (time) ANOVA was used to examine changes in each variable by group for each exercise. Wilcoxon signed-rank tests were used to determine whether significant changes in %1RMPP for each exercise and group. For chest press 1 repetition maximum, there were no significant main effects or interaction. Significant main effects for time were observed for leg press 1 repetition maximum ( p < 0 .001, η2 = 0.547) and chest press peak power ( p = 0.009, η2 = 0.243). For LPPP, there were no significant main effects or interactions. For %1RMPP, CP median scores revealed no significant changes for either group. Significant declines in %1RMPP were observed for leg press velocity-deficit and leg press force-deficit ( p < 0.03) groups. Velocity-based training was effective at improving 1RM, PP, and shifting %1RMPP in the LP groups. These results have implications for targeting power improvements at specific areas of the LV curve. Health care providers and trainers should consider these findings when constructing exercise programs to counter age-related declines in older adults.

The Effect of Oral Adenosine Triphosphate (ATP) Supplementation on Anaerobic Exercise in Healthy Resistance-Trained Individuals: A Systematic Review and Meta-Analysis.

Adenosine triphosphate (ATP) is an energy and signaling molecule. It is synthesized endogenously and can be taken as an oral supplement. This review aimed to identify the effects of oral ATP supplementation on anaerobic exercise in healthy resistance-trained adults. A systematic review and meta-analysis were performed based on the Preferred Reporting Items of Systematic Reviews and Meta-Analysis (PRISMA) criteria. The inclusion criteria were articles published from 2000 to 2022, with anaerobic variables (maximal strength, maximum repetitions, and maximum anaerobic power) measurable in healthy adults with experience in resistance training, only randomized placebo-controlled clinical trials (RCTs), and with the acute (a single dose 30 min to 24 h before the tests) and/or chronic (>1 day) oral supplementation of ATP. A total of five RCTs with 121 adult men were included. The oral ATP supplementation achieved significantly greater gains in maximal strength compared with the placebo (PL) (MD = 8.13 kg, 95%CI [3.36-12.90], p < 0.001). Still, no differences were observed in the maximum number of repetitions or the maximum anaerobic power. Furthermore, 400 mg of ATP showed improvement in anaerobic exercise regardless of the duration of the supplementation protocol. In conclusion, supplementation with 400 mg of ATP doses can improve maximal muscle strength in resistance-trained men.

Usability of the novel ankle training equipment with spring resistance-based plantar press exercises in the standing position: A focus on chronic stroke patients with hemiplegic gait.

To improve gait disability in patients with chronic stroke, ankle muscle strengthening and calf muscle stretching exercises are required. However, currently available ankle training equipment limit ankle exercises based on the position. Recently developed ankle training equipment enables spring resistance-based plantar press exercises to be performed in the standing position with weight support. To conduct a usability test of the ankle training equipment in the standing position by stroke patients with hemiplegic gait and verify its effects on ankle movements. The ankle training equipment was applied to five patients with chronic stroke and hemiplegic gait. In the standing position, the patients performed forefoot and rearfoot press exercises in the affected side with a day's interval at 20 repetitions maximum (RM). During the exercises, surface electromyography (sEMG) was used to measure the maximum voluntary isometric contraction (%MVIC) of the leg muscles. The System Usability Scale (SUS) was used to assess the ankle training equipment. Wilcoxon signed-rank test was used to evaluate the differences in muscle activity between the two exercises. Forefoot and rearfoot press exercises increased the %MVIC in the biceps femoris. Additionally, the tibialis anterior and medial gastrocnemius activity was significantly different between the two exercises. The SUS was 78.75% (SD 12.7). The usability test of the passive-control foot press trainer (PFPT) that with improvements in the structure and functions for convenience, it could be commercialized. PFPT could be an alternative to the ankle rehabilitation robot that necessitates a sitting position.

Effects of Resistance Training Overload Progression Protocols on Strength and Muscle Mass.

The aim of this study was to compare the effects of progressive overload in resistance training on muscle strength and cross-sectional area (CSA) by specifically comparing the impact of increasing load (LOADprog) versus an increase in repetitions (REPSprog). We used a within-subject experimental design in which 39 previously untrained young persons (20 men and 19 women) had their legs randomized to LOADprog and REPSprog. Outcomes were assessed before and after 10 weeks of training. Muscle strength was assessed using the one repetition maximum (1RM) test on the leg extension exercise, and the CSA of the vastus lateralis was assessed by ultrasonography. Both protocols increased 1RM values from pre (LOADprog: 52.90±16.32 kg; REPSprog: 51.67±15.84 kg) to post (LOADprog: 69.05±18.55 kg, REPSprog: 66.82±17.95 kg), with no difference between them (P+>+0.05). Similarly, both protocols also increased in CSA values from pre (LOADprog: 21.34±4.71 cm²; REPSprog: 21.08±4.62 cm²) to post (LOADprog: 23.53±5.41 cm², REPSprog: 23.39±5.19 cm²), with no difference between them (P+>+0.05). In conclusion, our findings indicate that the progression of overload through load or repetitions can be used to promote gains in strength and muscle hypertrophy in young men and women in the early stages of training.

Glucose ingestion before and after resistance training sessions does not augment ribosome biogenesis in healthy moderately trained young adults

PurposeResistance training-induced skeletal muscle hypertrophy seems to depend on ribosome biogenesis and content. High glucose treatment may augment ribosome biogenesis through potentiating resistance training-induced adaptations. This was investigated with total RNA and ribosomal RNA abundances as main outcomes, with relevant transcriptional/translational regulators (c-Myc/UBF/rpS6) as a secondary outcome.MethodsSixteen healthy, moderately trained individuals [male/female, n = 9/7; age, 24.1 (3.3)] participated in a within-participant crossover trial with unilateral resistance training (leg press and knee extension, 3 sets of 10 repetitions maximum) and pre- and post-exercise ingestion of either glucose (3 × 30 g, 90 g total) or placebo supplements (Stevia rebaudiana, 3 × 0.3 g, 0.9 g total), together with protein (2 × 25 g, 50 g total), on alternating days for 12 days. Six morning resistance exercise sessions were conducted per condition, and the sessions were performed in an otherwise fasted state. Micro-biopsies were sampled from m. vastus lateralis before and after the intervention.ResultsGlucose ingestion did not have beneficial effects on resistance training-induced increases of ribosomal content (mean difference 7.6% [− 7.2, 24.9], p = 0.34; ribosomal RNA, 47S/18S/28S/5.8S/5S, range 7.6–37.9%, p = 0.40–0.98) or levels of relevant transcriptional or translational regulators (c-MYK/UBF/rpS6, p = 0.094–0.292). Of note, both baseline and trained state data of total RNA showed a linear relationship with UBF; a ∼14% increase in total RNA corresponded to 1 SD unit increase in UBF (p = 0.003).ConclusionGlucose ingestion before and after resistance training sessions did not augment ribosomal RNA accumulation during twelve days of heavy-load resistance training in moderately trained young adults.

Age-Related Differences in Physical Fitness and Performance of an “Ability Test” among Firefighters

This study’s primary objective was to examine the differences in body composition, abdominal strength, absolute and relative power, handgrip strength, one repetition maximum for squat and bench press, and the maximum count of push-up and sit-up repetitions executed within a minute across different age cohorts of firefighters. Furthermore, this study aimed to evaluate the age-related differences in firefighters’ completion times of six firefighting tasks. Eighty-four male volunteer firefighters (age 33.79 ± 6.97 years) were grouped into three age categories, 20–30 years, 31–40 years, and 41–50 years, and underwent the aforementioned evaluations. One-way analysis of variance (MANOVA) revealed that age exerts a statistically significant influence (p &lt; 0.001) on body fat percentage, waist circumference, and waist-to-hip ratio. Furthermore, age significantly affected the overall time of the ability test (p &lt; 0.001) and the duration required to accomplish each individual task (p &lt; 0.001). Additionally, age significantly affected abdominal strength, relative power (as measured by the step test), and the maximum count of push-up and sit-up repetitions performed within a minute. These outcomes support earlier research indicating an age-associated decrement in physical fitness parameters among firefighters. It is recommended that firefighters prioritize maintaining strength and endurance of the abdominal muscles, upper body muscular endurance, and a healthy body weight. The emphasis on specific muscular groups is essential for improving task performance within this profession.

Hypoxia matters: comparison of external and internal training load markers during an 8-week resistance training program in normoxia, normobaric hypoxia and hypobaric hypoxia

PurposeTo compare external and internal training load markers during resistance training (RT) in normoxia (N), intermittent hypobaric hypoxia (HH), and intermittent normobaric hypoxia (NH).MethodsThirty-three volunteers were assigned an 8-week RT program in either N (690 m, n = 10), HH (2320 m, n = 10), or NH (inspired fraction of oxygen = 15.9%; ~ 2320 m, n = 13). The RT program (3x/week) consisted of six exercises, with three sets of six to 12 repetitions at ~ 70% of one repetition maximum (1RM) with the first session of each week used for analysis. 1RM in back squat and bench press was used to evaluate muscle strength before and after the program. External load was assessed by the volume load relative to body mass (RVL, kg·kg−1). Internal load was assessed by the ratings of perceived exertion (RPE) and heart rate (HR).ResultsSmaller relative improvements were found for the back squat in the N group (11.5 ± 8.8%) when compared to the NH group (22.2 ± 8.2%, P = 0.01) and the HH group (22 ± 8.1%, P = 0.02). All groups showed similar RVL, HR responses and RPE across the program (P˃0.05). However, reduced HR recovery values, calculated as the difference between the highest HR value (HRpeak) and the resting heart rate after a two min rest, were seen in the N and NH groups across the program (P<\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$<$$\\end{document} 0.05).ConclusionIt seems that 8 weeks of intermittent RT in hypoxic environments could maximize time-efficiency when aiming to improve strength levels in back squat without evoking higher levels of physiological stress. Performing RT at hypobaric hypoxia may improve the cardiorespiratory response, which in turn could speed recovery.

Sex differences in fatiguability during single-joint resistance exercise in a resistance-trained population.

The primary aim of this study was to compare the fatiguability and acute recovery from a session of unilateral biceps curl exercise between habitually resistance-trained males and females. Twenty participants performed biceps curl one repetition maximum (1RM) and maximal voluntary contraction (MVC) testing of the elbow flexors. The exercise protocol consisted of four sets of unilateral biceps curls at 50% of the measured 1RM to volitional failure. MVC force and EMG activity of the elbow flexors were assessed following each set and during the recovery phase. The outcome variables compare the repetition volume, MVC strength loss, and EMG responses between males and females during the exercise and recovery phases. Across the exercise protocol, females completed significantly more repetitions compared to males (p < 0.01, d = 1.7) and lost significantly less strength across time (76% versus 69%, d = 0.48, p = 0.046). Additionally, females maintained a higher level of normalized EMG amplitude compared to males across the protocol (p = 0.035; d = 0.510). However, there were no sex differences in the strength (p = 0.562) or EMG (p = 0.607) responses during the recovery phase. In a resistance-trained population, females were able to perform a greater number of repetitions during the biceps curl exercise compared to their male counterparts at the same relative intensity of exercise. The ability of females to maintain a greater proportion of their maximal elbow flexor strength and muscle excitation during exercise suggests females can tolerate greater upper-body resistance exercise volume than males.

The Use of Acute Exercise Interventions as Priming Strategies to Improve Physical Performance During Track-and-Field Competitions: A Systematic Review

ABSTRACT The use of exercise interventions to maximize athletes' performance is a common practice in competitions. This systematic review aimed to compile research that explored the effectiveness of priming strategies to maximize physical performance in track and field. The literature search was conducted from PubMed and Scopus. One hundred eighty-two studies were assessed against the inclusion criteria: (a) minimum 1-year participation/competition experience; (b) randomized controlled trials with pre-post intervention outcomes; and (c) studies involving exercise interventions applied ≤6 hours before outcome measures were collected. Fifteen studies satisfied the criteria and were categorized according to the exercise interventions used (i.e., resistance training, plyometric/ballistic training, resisted sprints, and modified warm-ups). Heavy-loaded resistance training (i.e., &gt;85% 1 repetition maximum) and resisted sprints increased subsequent sprint performance. Plyometrics/ballistic training also positively impacted subsequent jumping (i.e., long jump) and throwing performance (i.e., shot put). Modified warm-ups (i.e., high-intensity sprints and heavier throwing implements) also improved subsequent running and throwing performance. Overall, exercise interventions performed at high intensity and low volume augment subsequent physical performance as close to 4 minutes before the event. However, a sufficient recovery interval must be considered for a positive performance response.

Effects of unilateral, bilateral, and combined unilateral+bilateral complex resistance training on bench press and squat strength in adolescent boxers.

Objective: To assess the effects of 8weeks of unilateral (UNI), bilateral (BI), and combined unilateral + bilateral (UNI + BI) resistance training on bench press and squat strength in adolescent boxers. Methods: Using the Gym Aware linear accelerometer, free-weight squat and bench press strength exercises were evaluated after an 8-week training intervention. Thirty adolescent boxers were randomly assigned to three groups: UNI, height: 1.73 ± 0.08m, weight: 55.42 ± 5.85kg; UNI + BI, height: 1.7 ± 0.06m, weight: 54.73 ± 5.33kg; and BI, height: 1.74 ± 0.06m, weight: 59.67 ± 8.39kg. Each group followed their designated UNI/BI/UNI + BI compound resistance training protocols, and the effects of 8 weeks of single-sided and bilateral intervention training on the performance of free-weight squat and bench press exercises at 30%, 50%, and 80% of 1-repetition maximum (1RM) were evaluated. Results: Significant improvements were observed in the 30% 1RM, 50% 1RM, and 80% 1RM outcomes for both squat and bench press exercises before and after the interventions (p < 0.05, p < 0.01). In the intergroup comparison, GymAware measurements revealed that the UNI and UNI + BI groups exhibited superior peak power values for squat and bench press exercises at 30% 1RM compared to the BI group. Discussion: UNI and UNI + BI training led to significantly higher output power values in bench press and squat exercises at 30% 1RM compared to the BI training group.

Resistance training status detection via local muscular endurance adaptation maximum repetition strategy

Aim: The strength-endurance maximum repetition strategy is local muscular endurance development via unprompted fatigue to voluntary contraction adaptation. Brief review aimed to maximum repetition developing on exercise selection and maximal repetition strategy of resistance training constant set workload. Multiple set and endurance maximum repetition strategy must be planned according to purposing resistance training science. Methods: The local muscular endurance periodic session and periodization detected to strength-endurance maximum repetition strategy including loading change and constant repetition set set-ups respectively, 102.3%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40% and 30%1RM. The population of resistance training formed on local muscular endurance adaptation to date below of 2023 yr. to trained or untrained resistance individuals obtained from PubMed and Web of Science databases, specifically in S&amp;C Journal investigation. Results: Primarily analysis of LME strategy used to absolute endurance and relative endurance performance uncommon without this critical literature search. Again, strength-endurance loading resistance session have been performed to develop absolute endurance provided high load low repetition strategy commonly used to performance detection and relative endurance detected low load high repetition strategy detected to neurofatigue detection using strength-endurance maximum repetition periodization in researches. Conclusion: Resistance training population may be detecting time-dependent strength and endurance maximum repetition periodic periodization session local muscular endurance adaptation to develop neuromuscular adaptation and strength gain. In conclusion, actual exercise and resistance training can be dependent to LME strategy.