Intensity Resistance Exercise Research Articles

Go with the Flow? Considerations for Blood Flow Restriction Training in People with Neurologic Conditions.

Blood flow restriction training (BFRT) with low intensity resistance or aerobic exercise can improve muscle strength and aerobic capacity, respectively. Furthermore, low intensity BFRT with resistance or aerobic exercise can be as effective as training at higher intensities without BFR in healthy adult populations. The clinical use of BFRT is therefore becoming increasingly common, particularly in otherwise healthy adults recovering from musculoskeletal injury or orthopedic surgery, for whom training at high intensities is not indicated. People with neurologic conditions may also benefit from training at lower intensities, as many individuals with neurologic conditions may not tolerate higher intensities for a variety of reasons, including advanced mobility restrictions, extreme weakness, severe fatigue, and/or pain. Indeed, more and more rehabilitation clinicians are beginning to use BFRT with their patients who have neurologic conditions even though there is very little evidence to support its safety, feasibility, or efficacy in those populations. In this perspective, we propose that BFRT can be an important alternative to conventional exercise training approaches for some individuals with neurologic conditions, and in the right circumstances can be delivered both safely and effectively. This perspective will also provide considerations and decision-making strategies that can help inform clinical decisions for rehabilitation practitioners considering the use of BFRT in their patients with neurologic conditions.

Effects of different intensity resistance training on fat level, energy intake, and appetite among overweight and obese female college students

This study examines how different intensity resistance exercises impact fat, energy intake, and appetite regulation in overweight and obese female college students in Jiangsu Province, China. This study used a randomized controlled trial (RCT) design that investigates resistance training intensity-target result causation. The study determines the impact of High-Intensity Interval Training (HIIT) and Moderate-Intensity Resistance Training (MIRT) on body composition, fat level/body composition, and muscle mass them. In Jiangsu Province, China, 515 overweight and obese female college students aged 18–25 were sampled. Intervention groups were assigned randomly to campus recruits based on demographic and anthropometric. This study demonstrated significant correlations between resistance training intensity, body composition, diet, and appetite regulation in overweight and obese colleagues. MIRT and HIIT outperformed Control in weight loss and diet and used valid measures like DEXA (Dual-Energy X-ray Absorptiometry), blood tests and food diaries to regulate appetite hormones. Increased protein and muscle mass minimize resistance exercise intensity-metabolic consequences. The study analyzes these impacts to show how exercise intensity, food, and metabolic health are interconnected. These findings help build evidence-based obesity prevention and treatment strategies for this demographic. Healthcare providers, legislators, and university stakeholders use this study to tackle college student obesity. The results suggest that campus wellness initiatives should focus on resistance exercise and diet to combat obesity. This research promotes exercise science and health behavior change theory for cross-cultural lifestyle interventions.

Perspectives of Healthcare Professionals and People with a Spinal Cord Injury on Resistance Exercise Intensity in Japan, Indonesia, Korea and Thailand

(1) Background: This study aims to investigate differences in the perspectives of healthcare professionals (HCPs) and adults with spinal cord injury (SCI) on resistance exercise intensity in Asian countries in association with knowledge translation (KT). Also, it verifies the appropriateness of the conventional indicators for resistance exercise intensity in an Asian context. (2) Methods: 121 certified HCPs and 107 adults with SCI participated in a survey conducted in Indonesian, Japanese, Korean and Thai languages. The survey asked what principles are important for prescribing resistance exercise, and if ‘moderate’ and ‘vigorous’ were appropriate terms for indicating an intensity level. Perspective differences were examined between both groups and, further, between countries from a psychosocial perspective. (3) Results: Of the HCPs, 92% perceived that resistance exercise intensity was far more important than frequency, time or type of exercise while frequency (61%) followed by intensity (58%) was perceived as important by respondents with SCI. Only Japanese respondents with SCI agreed with the HCPs’ perception of intensity. Both HCPs and respondents with SCI showed unfavorable responses to the usage of ‘moderate’ and ‘vigorous’ for describing resistance exercise intensity, especially Japanese HCPs and respondents with SCI from Indonesia. (4) Conclusions: Our findings suggest that non-HCPs must improve their perceptions of exercise intensity. Our findings also suggest the need for more explicit and user-friendly terms or expressions indicating the level of intensity in a local (Asian) context.

Fetal Heart Rate During Moderate To High Intensity Resistance Exercise In Pregnant Individuals

Fetal Heart Rate During Moderate To High Intensity Resistance Exercise In Pregnant Individuals

‘Just because I have prostate cancer doesn’t mean that I can’t do things’ – men’s experiences of the acceptability of an exercise intervention for prostate cancer during treatment

BackgroundStructured exercise has an important role in mitigating the extensive side effects caused by ongoing prostate cancer treatments, specifically androgen deprivation therapy (ADT) and radiation therapy (RT). Little is known about men’s experiences of, and preferences for, structured exercise programmes during active cancer treatment. This study aimed to inform the acceptability of a 6-month supervised intervention that emphasised increasing and varied intensities of aerobic and resistance exercise, by exploring the experiences of men who participated.MethodsIndividual semi-structured interviews were conducted with an interviewer independent of the exercise study and data was analysed using a descriptive qualitative design.ResultsTwelve prostate cancer patients were interviewed including participants who completed (n = 9) and withdrew from (n = 3) the intervention. Four main themes captured how men experienced the intervention: (1) Navigating the Unknown: Building confidence amidst vulnerability (subtheme- pushing the limits), (2) Building Trust: The credibility and approach of the exercise instructor (subtheme- appropriateness of supervised vs. independent exercise), (3) Flexibility in Delivery, (4) Finding Purpose: Exercise as a means of escapism and regaining control during treatment.ConclusionWhile an initial lack of self-confidence can be a barrier to exercise participation, exercise programmes have the potential to provide psychosocial benefits, rebuild confidence and empower men throughout their cancer treatment and into recovery. Structured exercise is acceptable during treatment including RT and can offer a form of escapism and sense of control for men navigating their cancer journey. Trust building, flexible delivery and credibility alongside a challenging exercise prescription are important facilitators of acceptability for men. Strategies to embed exercise from the point of diagnosis through ADT and RT should reflect men’s experiences of exercise during treatment.Trial registrationThe trial has been registered on ClinicalTrials.gov as of the 14th of December 2021 (NCT05156424).

Collagen Peptide Supplementation during Training Does Not Further Increase Connective Tissue Protein Synthesis Rates.

Protein supplementation increases post-exercise muscle protein synthesis rates and, as such, supports exercise-induced muscle conditioning. Collagen protein has been suggested as the preferred protein source to stimulate muscle connective protein synthesis rates during recovery from exercise. Here we assessed the effects of hydrolyzed collagen peptide supplementation on both myofibrillar as well as muscle connective protein synthesis rates during one week of strenuous resistance exercise training. In a randomized, double-blind, parallel design, 25 young men (24 ± 3 y, 76.9 ± 6.4 kg) were selected to perform one week of intense resistance-type exercise training. Subjects were randomly assigned into two groups receiving either 15 g hydrolyzed collagen peptides (COL) or a non-caloric placebo (PLA) twice daily during the intervention. Subjects were administered deuterated water (2H2O) daily, with blood and skeletal muscle tissue samples being collected prior to and after the intervention to determine daily myofibrillar and muscle connective protein synthesis rates. Post-absorptive plasma glycine, proline, and hydroxyproline concentrations increased following collagen peptide supplementation (p < 0.05) and showed higher levels when compared to the placebo group (p < 0.05). Daily muscle connective protein synthesis rates during the intervention period exceeded myofibrillar protein synthesis rates (1.99 ± 0.38 versus 1.34 ± 0.23 %/d, respectively; p < 0.001). Collagen peptide supplementation did not result in higher myofibrillar or muscle connective protein synthesis rates (1.34 ± 0.19 and 1.97 ± 0.47 %/d, respectively) when compared to the placebo group (1.34 ± 0.27 and 2.00 ± 0.27 %/d, respectively; p > 0.05). Collagen peptide supplementation (2 x 15 g daily) does not increase myofibrillar or muscle connective protein synthesis rates during one week of intense resistance exercise training in young, recreational athletes.

A study on the impact of acute exercise on cognitive function in Alzheimer's disease or mild cognitive impairment patients: A narrative review

This narrative review follows the JBI approach and comprehensively explores the effects and mechanisms of acute exercise on cognitive function in Alzheimer's disease (AD) and Mild cognitive impairment (MCI) patients. The results showed that the combination of acute exercise and cognitive training improved the cognitive function of AD patients better than aerobic exercise or resistance training alone. For patients with MCI, moderate intensity acute aerobic exercise and resistance exercise were beneficial to enhance Inhibitory control (IC), but high-intensity acute exercise was adverse to improve IC; Brain-derived neurotrophic factor (BDNF) and Insulin-like growth factor 1 (IGF-1) may assume the potential mediating mechanism of acute exercise on cognitive function in AD and MCI patients, but more research is needed to further confirm this mechanism.

Increased Neuromuscular Activity, Force Output, and Resistance Exercise Volume When Using 5-Minute Compared with 2-Minute Rest Intervals Between the Sets.

McMahon, G, Best, N, Coulter, T, and Erskine, RM. Increased neuromuscular activation, force output and resistance exercise volume when using 5-minute compared with 2-minute rest intervals between the sets. J Strength Cond Res 38(9): 1527-1534, 2024-Longer rest intervals between resistance exercise (RE) sets may promote greater muscle hypertrophy and strength gains over time by facilitating the completion of greater training volume and intensity. However, little is known about the acute neuromuscular responses to RE sets incorporating longer vs. shorter rest intervals. Using a within-subject, crossover design, 8 healthy, young subjects completed 2 separate acute bouts of 4 sets of 8 × 3-s maximal isometric contractions using either a 2-minute (REST-2) or 5-minute (REST-5) rest interval between sets. Peak torque (PT) and electromyography (EMG) were measured pre and 5 minutes postexercise. Peak torque and mean torque (MT), EMG, mean, and median frequencies were measured during each set, whereas blood lactate (BLa), heart rate (HR), and rating of perceived exertion (RPE) were measured following each set. Peak torque and MT were lower ( p < 0.05) in sets 3 and 4, and sets 2-4 in REST-2 compared with REST-5, respectively. Electromyography and BL were lower and higher, respectively, in REST-2 vs. REST-5. There was no main effect of condition on HR or RPE. Pre-to-post exercise reductions in PT (-17 ± 9% vs. -4 ± 7%) and EMG (-29 ± 14% vs. -10 ± 7%) were greater ( p < 0.001) in REST-2 vs. REST-5. Total exercise volume was less in REST-2 vs. REST-5 (9,748 ± 2296 N·m -1 vs. 11,212 ± 2513 N·m -1 , p < 0.001). These results suggest that incorporating 5-minute between-set rest intervals into a resistance exercise session facilitates improved neuromuscular function, increased exercise volume, and less metabolic stress compared with 2-minute rest intervals. Thus, 5-minute rest intervals may be more efficacious for promoting muscle hypertrophy and strength gains in a chronic resistance training program.

Muscle activity and hypoalgesia in blood flow restricted versus unrestricted effort-matched resistance exercise in healthy adults.

This study assessed muscle activity (root mean square, RMS, and median frequency, MDF) to evaluate the acute response to blood flow restriction (BFR) resistance exercise (RE) and conventional moderate intensity (MI) RE. We also performed exploratory analyses of differences based on sex and exercise-induced hypoalgesia (EIH). Fourteen asymptomatic individuals performed four sets of unilateral leg press with their dominant leg to volitional fatigue under two exercise conditions: BFR RE and MI RE. Dominant side rectus femoris (RF) and vastus lateralis (VL) muscle activity were measured using surface electromyography (sEMG) through exercise. RMS and MDF were calculated and compared between conditions and timepoints using a linear mixed model. Pressure pain thresholds (PPT) were tested before and immediately after exercise and used to quantify EIH. Participants were then divided into EIH responders and nonresponders, and the differences on RMS and MDF were compared between the two groups using Hedges' g. RMS significantly increased over time (RF: p = 0.0039; VL: p = 0.001) but not between conditions (RF: p = 0.4; VL: p = 0.67). MDF decreased over time (RF: p = 0.042; VL: p < 0.001) but not between conditions (RF: p = 0.74; VL: p = 0.77). Consistently lower muscle activation was found in females compared with males (BRF, RF: g = 0.63; VL, g = 0.5. MI, RF: g = 0.72; VL: g = 1.56), with more heterogeneous findings in MDF changes. For BFR, EIH responders showed greater RMS changes (Δ RMS) (RF: g = 0.90; VL: g = 1.21) but similar MDF changes (Δ MDF) (RF: g = 0.45; VL: g = 0.28) compared to nonresponders. For MI, EIH responders demonstrated greater increase on Δ RMS (g = 0.61) and decrease on Δ MDF (g = 0.68) in RF but similar changes in VL (Δ RMS: g = 0.40; Δ MDF: g = 0.39). These results indicate that when exercising to fatigue, no statistically significant difference was observed between BFR RE and conventional MI RE in Δ RMS and Δ MDF. Lower muscle activity was noticed in females. While exercising to volitional fatigue, muscle activity may contribute to EIH.

Effects of Resistance Exercise with and without Blood Flow Restriction on Acute Hemodynamic Responses: A Systematic Review and Meta-Analysis.

Low-load intensity resistance exercise with blood flow restriction (BFR) is an alternative method for enhancing strength and muscle mass. However, acute cardiovascular responses to a complete training session remain uncertain compared to high-load intensity resistance exercise (HI). Therefore, the objective of this study to examine acute and post-exercise hemodynamic responses to low-load BFR and HI protocols. This systematic review and meta-analysis (RD42022308697) followed PRISMA guidelines to investigate whether the responses of heart rate (HR), blood systolic (SBP), blood diastolic pressure (DBP), and rate pressure product (RPP) immediately after and up to 60 min post-exercise from BFR were consistent with those reported after resistance exercises performed at HI in healthy individuals. Searches using PICO descriptors were conducted in databases from January 2011 to December 2023, and effect sizes were determined by Hedge's g. The selected studies involved 160 participants in nine articles, for which the responses immediately after BFR and HI exercises showed no differences in HR (p = 0.23) or SBP (p = 0.57), but significantly higher DBP (p < 0.01) and lower RPP (p < 0.01) responses were found when comparing BFR to HI. Furthermore, the BFR and HI protocols showed no differences regarding SBP (p = 0.21) or DBP (p = 0.68) responses during a 15 to 60 min post-exercise period. Thus, these results indicated that hemodynamic responses are similar between BFR and HI, with a similar hypotensive effect up to 60 min following exercise.

Sex-Specific Sarcopenia Prevalence and Risk Factors in the Korean Population: A Cross-Sectional Epidemiological Study.

Background and Objective: This study aimed to identify the incidence of sarcopenia and disease risk factors in Korean adults and to provide data for sarcopenia prevention. Materials and Methods: Based on the Korea National Health and Nutrition Survey, 2008-2011, we selected 14,185 adults over the age of 20 who participated in sarcopenia diagnostic tests and health surveys. We analyzed sarcopenia risk factors using complex sample multi-logistic regression analysis. Results: The prevalence of sarcopenia in Korea was 31.3%, with 20.2% in men and 40.4% in women. In men, there was a higher risk of sarcopenia in those of older age, without a spouse, with a low body mass index (BMI), who never engage in resistance exercise, or who do mid-level intensity resistance exercises. In women, sarcopenia risk was higher in those in their 20s compared to those in their 60s, and risk factors included a low BMI, high-density lipoprotein cholesterol and waist circumference measurements, alcohol consumption, aerobic exercise, and resistance exercise. Conclusions: Interventions and lifestyle improvements will help prevent the onset of sarcopenia in elderly men and young women with risk factors such as a low BMI.

The biphasic activity of autophagy and heat shock protein response in peripheral blood mononuclear cells following acute resistance exercise in resistance-trained males.

Autophagy and heat shock protein (HSP) response are proteostatic systems involved in the acute and adaptive responses to exercise. These systems may upregulate sequentially following cellular stress including acute exercise, however, currently few data exist in humans. This study investigated the autophagic and HSP responses to acute intense lower body resistance exercise in peripheral blood mononuclear cells (PBMCs) with and without branched-chain amino acids (BCAA) supplementation. Twenty resistance-trained males (22.3 ± 1.5yr; 175.4 ± .7cm; 86.4 ± 15.6kg) performed a bout of intense lower body resistance exercise and markers of autophagy and HSP70 were measured immediately post- (IPE) and 2, 4, 24, 48, and 72h post-exercise. Prior to resistance exercise, 10 subjects were randomly assigned to BCAA supplementation of 0.22g/kg/d for 5days pre-exercise and up to 72h following exercise while the other 10 subjects consumed a placebo (PLCB). There were no difference in autophagy markers or HSP70 expression between BCAA and PLCB groups. LC3II protein expression was significantly lower 2 and 4h post-exercise compared to pre-exercise. LC3II: I ratio was not different at any time point compared to pre-exercise. Protein expression of p62 was lower IPE, 2, and 4h post-exercise and elevated 24h post-exercise. HSP70 expression was elevated 48 and 72h post-exercise. Autophagy and HSP70 are upregulated in PBMCs following intense resistance exercise with autophagy increasing initially post-exercise and HSP response in the latter period. Moreover, BCAA supplementation did not affect this response.

Exercise interventions for the effect of endothelial function in hypertensive patients: A systematic review and meta-analysis.

Endothelial dysfunction is crucial factor to the hypertension occurrence, and controversy remains regarding the effect of exercise on improving endothelial function in hypertensive patients. The authors used meta-analysis to evaluate the intervention effect of exercise on endothelial function in hypertensive patients and to investigate exercise protocols that may have a greater intervention effect. A total of 37 studies and a total of 2801 participants were included. The results were as follows: endogenous nitric oxide (NO)[SMD=.89, 95% CI (.48, 1.30), p<.0001], endothelin-1 (ET-1): [SMD=-.94, 95% CI (-1.15, -.73), p<.0001], flow-mediated dilation (FMD) [SMD=-.57, 95% CI (.36,.79), p<.000001]. In subgroup analysis, high-intensity aerobic exercise, with a single exercise duration of 35-50min, 3-4 times/week for a total of 10-12weeks, had the largest amount of intervention effect on NO, and moderate-intensity resistance exercise, with a single exercise duration of ≥60min, 6 times/week for a total of 15-18weeks, had the largest amount of intervention effect on ET-1. In conclusion, exercise can improve NO levels, FDM levels, and reduce ET-1 secretion of hypertension patients, thereby improve their endothelial function. The ideal intervention effect of improving NO level was more likely to be obtained by taking the exercise prescription of high-intensity aerobic exercise with a single exercise duration of 35-50min, 3-4 times/week for 10-12weeks; the ideal intervention effect of improving ET-1 was more likely to be obtained by taking the exercise prescription of oderate -intensity resistance exercise with a single exercise duration of ≥60min, 6 times/week for 15-18weeks.

Dehydration Decreases Slow Wave Sleep After Heavy Resistance Exercise

Purpose: The purpose of this study was to examine the effects of hydration status on sleep and recovery measurement before and after high volume resistance exercise. It was hypothesized that dehydration decreases sleep and recovery measurements following exercise. Methods: Eight resistance-trained men (age, 21±2 years; weight, 82.0±12.6 kg; height, 177.3±6.9 cm) performed a series of bilateral leg press and knee extensions (RE, 5 sets of 10 repetitions at 80% of 1 repetition maximum). Participants completed one trial in a euhydrated state (EUH; urine specific gravity (USG) &lt; 1.020) and the other in a dehydrated state (DEH: USG ≥ 1.020) which was separated by 2 weeks. For the DEH trial, participants were restricted from consuming fluids for 24 hours prior to the RE and were only permitted to drink 1.5 L of water post-exercise for the remainder of the day. For the EUH trial, participants were instructed to consume fluid for 24 hours prior to and 24 hours post RE to maintain euhydration. Sleep and recovery measurements were collected from a wearable sleep device that participants wore the night before (PRE) and after RE (POST). Repeated measures ANOVAs were used to identify the differences between EUH and DEH. Effect size (ES) was calculated with resulting effects identified as either small (0.2-0.49), medium (0.5-0.79), or large (&gt;0.8) effects. Results: Slow wave sleep (SWS) (POST EUH, 1.4±0.5 hr; POST DEH, 1.0±0.5 hr; ES=0.8; p=0.028) and %SWS (POST EUH, 21.8±3.7 %; POST DEH, 14.3±6.4 %; ES=1.4; p=0.016) were greater in DEH compared to EUH at the night following RE. Also, SWS decreased at POST compared to PRE in DEH (PRE DEH, 1.4±0.3hr; ES=1.0; p=0.028), but not in EUH (PRE EUH, 1.2±0.6 hr; p=0.061). Sleep duration, sleep effciency, sleep disturbance, sleep deprivation, rapid eye movement sleep (REM), %REM, light sleep, resting heart rate, and heart rate variability were not different between EUH and DEH ( p&gt;0.05). Conclusion: Dehydration decreases slow wave sleep following heavy RE, which potentially impairs recovery from exercise as SWS is important for physiological recovery. Therefore, it is critical to maintain euhydration to maximize recovery following an acute bout of RE. This study was funded by National Strength and Conditioning Association (NSCA). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 2238: Reducing cardiovascular disease risk in cancer survivors: Impact of a 16-week circuit-based interval exercise intervention

Abstract Introduction: Obesity and physical inactivity pose a significant health concern for cancer survivors in developing comorbid conditions such as type 2 diabetes, hypertension, and metabolic syndrome that lead to a heightened risk of cardiovascular disease (CVD). Therefore, regular physical activity plays a central role in reducing the risk of CVD. The Framingham risk score (FRS) is an established assessment of CVD risk that combines six risk factors including age, gender, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), systolic blood pressure, diabetes, and smoking status. The objective of the study was to investigate the effects of a 16-week circuit, interval-based exercise training intervention on FRS and the 10-year FRS-predicted risk of developing CVD among breast, prostate, and colorectal cancer survivors. Methods: This single center, pilot randomized controlled trial consisted of 90 sedentary, overweight or obese (BMI &amp;gt; 25.0 kg/m2) survivors of breast, prostate or colorectal cancers, randomized to exercise (n=60) or usual care (n=30). The 16-week intervention comprised supervised moderate to vigorous intensity aerobic (65-85% of VO2max) and resistance (65-85% of 1-repetition maximum) exercise sessions conducted in a circuit-based interval fashion, occurring three times per week. Blood samples were obtained at baseline and post-intervention time points to measure fasting plasma levels of HDL-C and LDL-C, along with resting systolic blood pressure and diagnosis of diabetes. Paired t-test and repeated measure ANOVA were used to determine between-group differences. Results: Participants (age 63.2 ± 10.8 years) were diagnosed with breast (35%), prostate (30%), and colorectal (35%) cancers and consisted of 55% female participants, participants had a mean BMI of 34.7±5.9, and 85% were obese. Chemotherapy and/or radiation therapy was completed by 75% of participants. Retention and adherence rates to exercise were high (100% and 92%, respectively). Compared to usual care, circuit, interval-based exercise significantly reduced total FRS (between group mean difference, -12.0 points p&amp;lt;0.001) and 10-year CVD risk (-10.0%; p&amp;lt;0.001). Conclusions: This study underscores the critical role of circuit-based, interval exercise interventions in mitigating the elevated cardiovascular risk faced by sedentary, overweight, or obese cancer survivors. The significant reduction in FRS components highlights the potential of structured exercise programs to enhance cardiovascular health, thereby reducing the burden of comorbid conditions and CVD risk in cancer survivors. Citation Format: Amber J. Normann, Rebekah L. Wilson, Cami N. Christopher, Mary K. Norris, Simone Cuomo, Christina M. Dieli-Conwright. Reducing cardiovascular disease risk in cancer survivors: Impact of a 16-week circuit-based interval exercise intervention [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 2238.

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.

Abstract MP61: Independent, Joint-Aerobic, and Dose-Response Associations of Resistance Exercise With Cardiovascular Disease Mortality: A Living Meta-Analysis

Introduction: Cardiovascular diseases (CVDs) account for ~33% of all deaths globally. Aerobic exercise (AE) is a well-established modifiable risk factor for lowering the risk of CVD mortality, but the global prevalence of meeting the World Health Organization’s (WHO’s) recommendation for weekly AE in adults is only ~25%. Given the rapidly growing body of evidence indicating resistance exercise (RE) confers numerous health benefits independent of AE, and may also lower the risk of CVD mortality, we conducted a living meta-analysis (PROSPERO ID: CRD42022356528) to determine: 1) if RE is associated with lower CVD mortality risk independent of, and jointly with, AE; and 2) whether there is a dose-response pattern of CVD mortality by amount of RE. Methods: We searched MEDLINE, Embase, SPORTDiscus, The Cochrane Library, and SCOPUS from inception to October 10, 2023. We included prospective cohort studies in which: 1) AE and RE were the exposures and CVD mortality the outcome; and 2) nonclinical adult populations (aged ≥18 years) were sampled. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD mortality were pooled using random effects meta-analysis models. The independent effect of RE from AE was based on models with AE as a covariate. A random effects dose-response meta-analysis characterized the association between the RE dose (sessions/week) and CVD mortality risk. Results: Ten cohort studies from 5 countries (Mean follow-up time = 10.1 years) were included (9, 8, and 5 examined independent, joint, and dose-response associations, respectively). Relative to no RE, meeting the WHO guideline for RE (1-2 sessions/week), independent of meeting the AE guideline (≥150 minutes/week at moderate to vigorous intensities), was associated with a lower risk of CVD mortality (HR: 0.90, 95% CI: 0.85-0.95). A sensitivity analysis removing a highly weighted study (53%) yielded consistent results. Compared to meeting neither guideline, meeting the joint AE-RE guideline was associated with a larger difference in CVD mortality risk (HR: 0.60, 95% CI: 0.45-0.81). The dose-response meta-analysis showed evidence of a non-linear, U-shaped relationship between the amount of RE (independent of AE) and risk of CVD mortality. In detail, relative to no RE, participating in 1-2 sessions/week of RE was associated with a lower risk of CVD mortality (HR: 0.81; 95% CI: 0.72, 0.91), but there was no difference in CVD mortality risk between those who exceeded the guideline and those who participated in no RE (HR: 1.00, 95% CI: 0.89, 1.12). Conclusion: With the increasing global prevalence of obesity and physical inactivity, RE—a more movement-varied, lower-impact exercise modality—should receive more attention in public health policy to help alleviate the global burden of CVD mortality. Public health surveillance instruments capturing RE volume (sets, repetitions) are needed to improve prescription.

Mustn1 is a smooth muscle cell-secreted microprotein that modulates skeletal muscle extracellular matrix composition

ObjectiveSkeletal muscle plasticity and remodeling are critical for adapting tissue function to use, disuse, and regeneration. The aim of this study was to identify genes and molecular pathways that regulate the transition from atrophy to compensatory hypertrophy or recovery from injury. Here, we have used a mouse model of hindlimb unloading and reloading, which causes skeletal muscle atrophy, and compensatory regeneration and hypertrophy, respectively. MethodsWe analyzed mouse skeletal muscle at the transition from hindlimb unloading to reloading for changes in transcriptome and extracellular fluid proteome. We then used qRT-PCR, immunohistochemistry, and bulk and single-cell RNA sequencing data to determine Mustn1 gene and protein expression, including changes in gene expression in mouse and human skeletal muscle with different challenges such as exercise and muscle injury. We generated Mustn1-deficient genetic mouse models and characterized them in vivo and ex vivo with regard to muscle function and whole-body metabolism. We isolated smooth muscle cells and functionally characterized them, and performed transcriptomics and proteomics analysis of skeletal muscle and aorta of Mustn1-deficient mice. ResultsWe show that Mustn1 (Musculoskeletal embryonic nuclear protein 1, also known as Mustang) is highly expressed in skeletal muscle during the early stages of hindlimb reloading. Mustn1 expression is transiently elevated in mouse and human skeletal muscle in response to intense exercise, resistance exercise, or injury. We find that Mustn1 expression is highest in smooth muscle-rich tissues, followed by skeletal muscle fibers. Muscle from heterozygous Mustn1-deficient mice exhibit differences in gene expression related to extracellular matrix and cell adhesion, compared to wild-type littermates. Mustn1-deficient mice have normal muscle and aorta function and whole-body glucose metabolism. We show that Mustn1 is secreted from smooth muscle cells, and that it is present in arterioles of the muscle microvasculature and in muscle extracellular fluid, particularly during the hindlimb reloading phase. Proteomics analysis of muscle from Mustn1-deficient mice confirms differences in extracellular matrix composition, and female mice display higher collagen content after chemically induced muscle injury compared to wild-type littermates. ConclusionsWe show that, in addition to its previously reported intracellular localization, Mustn1 is a microprotein secreted from smooth muscle cells into the muscle extracellular space. We explore its role in muscle ECM deposition and remodeling in homeostasis and upon muscle injury. The role of Mustn1 in fibrosis and immune infiltration upon muscle injury and dystrophies remains to be investigated, as does its potential for therapeutic interventions.

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.

Independent Exercise During a Videoconference Exercise Program for Cancer Survivors

ABSTRACT Background Independent exercise beyond supervised sessions can help program participants achieve recommended exercise levels and contribute to health benefits. However, independent exercise is rarely reported, making it unclear how much program effects may be attributed to the supervised sessions. The aim of this study was to describe independent exercise during a videoconference-delivered exercise program for cancer survivors. Methods Cancer survivors (N = 46) completed an 8-week program that included videoconference-delivered (i.e., Zoom) exercise sessions once per week and three behavior change discussions. Each week, participants reported frequency, duration, intensity, type, and context (e.g., where, type, with whom) of independent aerobic and resistance exercise. Results Participants (mean ± SD age = 59 ± 10 years; 96% female) had been diagnosed with either ovarian (61%), breast (30%), colorectal (4%), or other (4%) types of cancer. Days per week of independent exercise were 2.7 ± 2.7 for light, 2.8 ± 2.2 for moderate, and 0.67 ± 1.3 for vigorous aerobic exercise. For resistance exercise the days per week performed was 1.3 ± 1.5. Median weekly independent minutes were 60 (range: 0–120) for light aerobic, 120 (range: 36–270) for moderate-to-vigorous aerobic, and 30 (range: 0–60) for resistance exercise. Independent exercise performed was most frequently brisk walking or weightlifting at home or in the neighborhood and with a spouse/partner, other family, or friends. Conclusion Most participants engaged in substantial independent exercise outside of the supervised sessions. These findings provide detailed contextual information regarding independent exercise during an 8-week program and have implications for interpreting program effectiveness.