A Biomechanical Comparison of the Back Squat and Hexagonal Barbell Deadlift.

ABSTRACT: Stahl, CA, Regni, G, Tanguay, J, McElfresh, M, Trihy, E, Diggin, D, and King, DL. A biomechanical comparison of the back squat and hexagonal barbell deadlift. J Strength Cond Res 38(5): 815-824, 2024-Coaches often use different exercises to encourage similar strength adaptations and limit monotony. Anecdotally, the hexagonal barbell deadlift (HBD) exhibits similarities to the back squat (BS). To date, research has not examined the empirical differences between these exercises. This study examined kinematic and kinetic differences between the BS and the HBD across different loads. Sixteen resistance-trained individuals (6 men and 10 women) volunteered to participate. Subjects performed 1-repetition maximum (1RM) testing under BS and HBD conditions. Kinematic and kinetic data were collected during performance of both exercises at submaximal (warm-up sets) and maximal (1RM) loads using a 3D motion capture and force-plate system. Results showed that subjects lifted greater 1RM loads in the HBD relative to the BS (p < 0.05; d = -1.75). Kinematic data indicated that subjects exhibited greater maximum forward lean of the trunk and decreased maximum knee flexion while performing the HBD compared with the BS. The BS resulted in higher maximum extension moments at the hip joint than the HBD. Maximum extension moments at the knee joint showed no difference between the exercises. Data suggest that bar design and position facilitate balanced moment arm length at hip and knee joints during performance of the HBD. By contrast, bar position during performance of the BS increases moment arm length at the hip joint, making it a hip-dominant exercise. The present data have implications for the programming of both exercises. Future research should examine differences in muscle-activation strategies between the 2 exercises.

The Force-Vector Theory Supports Use of the Laterally Resisted Split Squat to Enhance Change of Direction.

ABSTRACT: Cooley, C, Simonson, SR, and Maddy, DA. The force-vector theory supports use of the laterally resisted split squat to enhance change of direction. J Strength Cond Res 38(5): 835-841, 2024-The purpose of this study was to challenge the conventional change of direction (COD) training methods of the modern-day strength and conditioning professional. A new iteration of the modified single-leg squat (MSLS), the laterally resisted split squat (LRSS), is theorized to be the most effective movement for enhancing COD performance. This study lays out a rationale for this hypothesis by biomechanically comparing the LRSS, bilateral back squat (BS), and MSLS with a COD task (90-degree turn). One repetition maximum (1RM) for LRSS, MSLS, and BS was measured for 23 healthy active female subjects. Peak ground reaction forces (GRF) for the dominant leg were recorded when performing COD and the LRSS, MSLS, and BS at 70% 1RM. Peak frontal plane GRF magnitude and angle were calculated for each task and submitted to repeated measures ANOVA. Peak GRF magnitude was significantly larger for COD (2.23 ± 0.62 body weight) than the LRSS, MSLS, and BS (p ≤ 0.001). Peak GRF angle was not significantly different between COD and the LRSS (p = 0.057), whereas the MSLS and BS (p < 0.001) vector angles were significantly greater than COD. In this application of the force-vector theory, the LRSS more closely matches COD than the MSLS or BS. Thus, the LRSS has the greater potential to enhance COD.

Comparison Between Traditional and Alternated Resistance Exercises on Blood Pressure, Acute Neuromuscular Responses, and Rating of Perceived Exertion in Recreationally Resistance-Trained Men.

ABSTRACT: Corrêa Neto, VG, Silva, DdN, Palma, A, de Oliveira, F, Vingren, JL, Marchetti, PH, da Silva Novaes, J, and Monteiro, ER. Comparison between traditional and alternated resistance exercises on blood pressure, acute neuromuscular responses, and rating of perceived exertion in recreationally resistance-trained men. J Strength Cond Res 38(5): e211-e218, 2024-The purpose of this study was to compare the acute effects of traditional and alternated resistance exercises on acute neuromuscular responses (maximum repetition performance, fatigue index, and volume load), rating of perceived exertion (RPE), and blood pressure (BP) in resistance-trained men. Fifteen recreationally resistance-trained men (age: 26.40 ± 4.15 years; height: 173 ± 5 cm, and total body mass: 78.12 ± 13.06 kg) were recruited and performed all 3 experimental conditions in a randomized order: (a) control (CON), (b) traditional (TRT), and (c) alternated (ART). Both conditions (TRT and ART) consisted of 5 sets of bilateral bench press, articulated bench press, back squat, and Smith back squat exercises at 80% 1RM until concentric muscular failure. The total number of repetitions performed across sets in the bench press followed a similar pattern for TRT and ART, with significant reductions between sets 3, 4, and 5 compared with set 1 (p < 0.05). There was a significant difference for set 4 between conditions with a lower number of repetitions performed in the TRT. The volume load was significantly higher for ART when compared with TRT. TRT showed significant reductions in BP after 10-, 40-, and 60-minute postexercise and when compared with CON after 40- and 60-minute postexercise. However, the effect size illustrated large reductions in systolic BP during recovery in both methods. Thus, it is concluded that both methods reduced postexercise BP.

Seasonal Variation and Positional Differences in Anthropometry, Strength, and Power Characteristics in English Premiership Women's Rugby Union Players.

ABSTRACT: Yao, X, Austerberry, A, Bishop, C, Wilson, L, Chiang, C-Y, and Turner, A. Seasonal variation and positional differences in anthropometry, strength, and power characteristics in English premiership women's rugby union players. J Strength Cond Res 38(5): 924-931, 2024-Women's rugby is a collision sport that relies heavily on body composition and physical characteristics of strength and power to achieve competitive success. Furthermore, the seasonal nature presents a variety of physical challenges that can cause fluctuations in a player's physical development. Therefore, the purpose of this study was to determine the differences in anthropometry, strength, and power characteristics between forwards and backs in women's rugby union athletes in England and to identify changes throughout a season. Forty-seven players were recruited from the English premiership women's rugby during the 2020-2021 season. Players were split into forwards and backs and underwent body composition testing by dual-energy X-ray absorptiometry and strength and power tests (countermovement jump, drop jump [DJ], and isometric midthigh pull) on 3 separate occasions (preseason, midseason, postseason). Overall, forwards had significantly ( p < 0.01) higher body mass, fat mass, lean mass [LM], bone mineral content, and take off momentum, and backs had significantly higher ( p < 0.01, d > 0.5) jump height, reactive strength, and shorter DJ contact time. When observing seasonal changes, there were statistically significant differences ( p < 0.01) or moderate-to-large practical differences ( d > 0.5) in LM, reactive strength index modified, time to take-off, and DJ flight time [FT] among forwards when comparing 3 testing time frames. For backs, statistically significant differences ( p < 0.01) or moderate-to-large practical differences ( d > 0.5) were reported in LM and DJ FT throughout the season. In conclusion, the strength and power testing and characteristics shown in this study could support coaches and junior women's rugby athletes to have a basic understanding of English premiership physical standards.

Modern software and physical education: can online training enhance gym training?

BACKGROUND: This study discusses the effectiveness of a 12-week intervention aimed at improving squat jump and sprint performance among second-year sports students. METHODS: The students were randomly divided into experimental (n = 89) and control (n = 92) groups. In addition to gym training, students of the experimental group also underwent online PE training. The students' performance in Squat Jumps, 30 m sprint, and Progressive Aerobic Cardiovascular Endurance Run (PACER), as well as their situational motivation, were assessed before and after the intervention. Furthermore, the students assessed their physical activity weekly using self-reports. RESULTS: The implementation of online training has positively impacted intrinsic and identified motivation, as well as external regulation; however, it was less effective in reducing amotivation compared to traditional gym-based training. CONCLUSIONS: The findings of the study contribute to the data synthesis on the expediency of using modern software in physical education.

Effects of active exergames on physical performance in older people: an overview of systematic reviews and meta-analysis.

This overview assessed the available body of published peer-reviewed systematic reviews and meta-analyses related to the effects of active exergames compared with active/passive control on physical performance outcomes in older people. The methodological quality and certainty of evidence were assessed using PRISMA, AMSTAR 2, and GRADE. The protocol was registered in PROSPERO (code: CRD42023391694). The main outcomes indicate that 4,477 records, five systematic reviews, and 10 meta-analyses were included. The AMSTAR-2 reported six meta-analyses with high methodological quality, four moderate quality, two systematic reviews with low quality, and three very-low quality. Meta-analysis was performed on balance using the Berg Balance Scale (BBS) and Timed Up-and-Go (TUG) tests, on cardiorespiratory fitness using the 6-min walk test, and on upper and lower limbs muscle strength using the handgrip strength, knee extension, and 30-s chair stand tests. Significant differences in favor of the active exergames groups concerning active/passive groups were reported in BBS (SMD = 0.85; 95% CI = 0.12-1.58; I2 = 96%; p = 0.02), TUG (SMD = 1.44; 95% CI = 0.71-2.16; I2 = 97%; p < 0.0001), and 30-s chair stand test (SMD = 0.79; 95% CI = 0.33-1.25; I2 = 88%; p = 0.0008). However, no significant differences were reported in favor of the active exergames groups in 6-min walk (SMD = 0.93; 95% CI = -0.64 to 2.50; I2 = 95%; p = 0.24), handgrip strength (SMD = 0.67; 95% CI = -0.04 to 1.38; I2 = 84%; p = 0.06), and knee extension tests (SMD = 0.20; 95% CI = -0.05 to 0.44; I2 = 95%; p = 0.12) compared to active/passive control. However, it was impossible to perform a meta-analysis for the variables of walking speed as a fall risk due to the diversity of instruments and the small number of systematic reviews with meta-analysis. In conclusion, interventions utilizing active exergames have shown significant improvements in the static and dynamic balance and lower limb muscle strength of apparently healthy older people, compared to control groups of active/inactive participants, as measured by BBS, TUG, and 30-s chair stand tests. However, no significant differences were found in the 6-min walk, HGS, and knee extension tests. Systematic review registration: PROSPERO, CRD42023391694.

Relationship between the strength of the ankle and toe muscles and functional stability in young, healthy adults.

This study investigates the relationship between ankle and toe strength and functional stability in young adults, with a sample comprising sixteen females and fourteen males. The research employed force platform data to determine the center of foot pressure (COP) and calculated the forward functional stability index (FFSI) through foot anthropometric measurements. Strength measurements of toe and ankle muscles, during maximal isometric flexion and extension, were conducted using force transducers. Notable positive correlations were found between toe flexor strength and FFSI (left flexor: r = 0.4, right flexor: r = 0.38, p < 0.05), not influenced by foot anthropometry. Contrarily, no significant correlation was observed between ankle muscle strength and FFSI, despite a positive correlation with the COP range. The moderate correlation coefficients suggest that while toe flexor strength is a contributing factor to functional stability, it does not solely determine functional stability. These findings highlight the critical role of muscle strength in maintaining functional stability, particularly during forward movements and emphasize the utility of FFSI alongside traditional COP measures in balance assessment. It is recommended to employ a multifaceted approach is required in balance training programs.

Modification of velopharyngeal closure pressures during phonation by neuromuscular electrical stimulation in healthy individuals.

Introduction: Rhinophonia aperta may result from velopharyngeal insufficiency. Neuromuscular electrical stimulation (NMES) has been discussed in the context of muscle strengthening. The aim of this study was to evaluate in healthy subjects whether NMES can change the velopharyngeal closure pattern during phonation and increase muscle strength. Method: Eleven healthy adult volunteers (21-57 years) were included. Pressure profiles were measured by high resolution manometry (HRM): isolated sustained articulation of /a/ over 5 s (protocol 1), isolated NMES applied to soft palate above motor threshold (protocol 2) and combined articulation with NMES (protocol 3). Mean activation pressures (MeanAct), maximum pressures (Max), Area under curve (AUC) and type of velum reactions were compared. A statistical comparison of mean values of protocol 1 versus protocol 3 was carried out using the Wilcoxon signed rank test. Ordinally scaled parameters were analyzed by cross table. Results: MeanAct values measured: 17.15±20.69 mmHg (protocol 1), 34.59±25.75 mmHg (protocol 3) on average, Max: 37.86±49.17 mmHg (protocol 1), 87.24±59.53 mmHg (protocol 3) and AUC: 17.06±20.70 mmHg.s (protocol 1), 33.76±23.81 mmHg.s (protocol 3). Protocol 2 produced velum reactions on 32 occasions. These presented with MeanAct values of 13.58±12.40 mmHg, Max values of 56.14±53.14 mmHg and AUC values of 13.84±12.78 mmHg.s on average. Statistical analysis comparing protocol 1 and 3 showed more positive ranks for MeanAct, Max and AUC. This difference reached statistical significance (p=0.026) for maximum pressure values. Conclusions: NMES in combination with articulation results in a change of the velopharyngeal closure pattern with a pressure increase of around 200% in healthy individuals. This might be of therapeutic benefit for patients with velopharyngeal insufficiency.

Influence of lower limb isokinetic muscle strength and power on the occurrence of falls in community-dwelling older adults: A longitudinal study.

INTRODUCTION: Previous studies have highlighted the association between lower limb muscle strength and falls in older adults. However, a comprehensive understanding of the specific influence of each lower limb muscle group on fall occurrences remains lacking. OBJECTIVE: This study aimed to investigate the impact of knee, ankle, and hip muscle strength and power on falls in older adults, with the goal of identifying which muscle groups are more predictive of fall risk in this population. METHODS: This longitudinal observational study enrolled 94 community-dwelling older adults. Muscle strength and power of the ankle's plantiflexors and dorsiflexors, knee flexors and extensors, and hip flexors, extensors, adductors, and abductors were assessed using a Biodex System 4 Pro® isokinetic dynamometer. Fall occurrences were monitored through monthly telephone contact over a year. RESULTS: Participants, with a median age of 69 years (range 64-74), included 67% women, and 63.8% reported a sedentary lifestyle. Among them, 45,7% of older adults were classified as fallers. Comparative analyses revealed that non-fallers displayed significantly superior isokinetic muscle strength in the hip abductors and adductors, along with higher muscle power in the hip abductors, hip flexors, and knee flexors compared to fallers. Multivariate logistic regression analysis indicated that a 1 Nm/Kg increase in hip abductor strength reduced the chance of a fall by 86.3%, and a 1 Watt increase in hip flexor power reduced the chance of a fall by 3.6%. CONCLUSION: The findings indicate that hip abductor strength and hip flexor power can be considered protective factors against falls in independent older adults in the community. These findings may contribute to developing effective fall-prevention strategies for this population.

Effect of adding short foot exercise to hip and knee focused exercises in treatment of patients with patellofemoral pain syndrome: a randomized controlled trial.

BACKGROUND: Patellofemoral pain syndrome is considered a common cause of anterior knee pain that could disturb function and limit daily activities. The purpose of the study was to investigate the effect of adding short foot exercise on pain, function, balance, and hip abductors, and quadriceps muscles strength in the treatment of patients with patellofemoral pain syndrome. METHODS: Twenty-eight male and female patients with patellofemoral pain syndrome with age ranged from 18 to 35 years old participated in this study. They were equally and randomly assigned into two groups; the study group which received short foot exercise in addition to hip and knee exercises (n = 14) and thecontrol group which received hip and knee exercises only (n = 14). Participants received their interventions during 6 consecutive weeks (12 sessions). Pain intensity, function, abductors quadriceps muscle strength, and balance were assessed using the Visual Analog Scale, anterior knee pain scale (AKPS), hand-held dynamometer, and the Biodex Balance System respectively. All measurements were taken before and after 6 weeks of intervention in both groups. Multivariate analysis of variance was performed to compare the within and between groups effects for measured variables. RESULTS: The within-group comparison showed significant improvement in pain severity, function, balance, and hip abductors, and quadriceps muscles strength in both groups post-treatment compared with pre-treatment. Between groups analysis, however, showed no significant statistical difference between both groups in all variables, except in pain, function, and mediolateral stability which showed better improvement compared to the control group. CONCLUSIONS: Adding short foot exercise to hip and knee exercises improved pain, function, and mediolateral stability in patients with patellofemoral pain syndrome. TRIAL REGISTRATION: clinicaltrials.gov. NO: NCT05383781. Date 19/ 5/2022.

A pulmonary rehabilitation program is an effective strategy to improve forced vital capacity, muscle strength, and functional exercise capacity similarly in adults and older people with post-severe COVID-19 who required mechanical ventilation.

BACKGROUND: It is internationally known that our population is aging. At the same time, some patients with COVID-19, due to their symptoms, required mechanical ventilation (MV) and subsequent pulmonary rehabilitation (PR). This study aimed to compare the effects of a multimodal PR program "ADULT" versus "OLDER" people with COVID-19 who were on MV. METHODS: The intervention consisted of an 8-week hybrid PR program (2x week). Forced vital capacity (FVC) was measured at the beginning and end of PR, upper and lower limb strength was obtained through hand grip strength (HGS) and the sit-to-stand test (STST), respectively, and functional exercise capacity was measured with the 6-minute walking test (6MWT). RESULTS: The main results were an increase in the FVC in the ADULT and OLDER groups (time effect, P = 0.000; η2 = 0.27), an increase in HGS in the ADULT and OLDER groups (time effect, P = 0.000; η2 = 0.52), in the same way, the number of repetitions on the STST increased in the ADULT and OLDER groups (time effect, P = 0.000; η2 = 0.55). Finally, the distance covered on the 6MWT increased in the ADULT and OLDER groups (time effect, P = 0.000; η2 = 0.65). CONCLUSIONS: The PR program is an effective strategy to improve FVC, muscle strength, and functional exercise capacity similarly in adults and older people with post severe COVID-19 who required MV.

Effect of whole-body vibration stimulation on plasma soluble TNF receptors in elderly with sarcopenia: a randomized controlled trial.

Sarcopenia is a pathology resulting from a progressive and severe loss of muscle mass, strength, and function in the course of aging, which has deleterious consequences on quality of life. Among the most widespread studies on the issue are those focused on the effect of different types of physical exercise on patients with sarcopenia. This randomized controlled study aimed to compare the effects of a whole-body vibration exercise (WBV) session on the inflammatory parameters of non-sarcopenic (NSG, n=22) and sarcopenic elderly (SG, n=22). NSG and SG participants were randomly divided into two protocols: intervention (squat with WBV) and control (squat without WBV). After a one-week washout period, participants switched protocols, so that everyone performed both protocols. Body composition was assessed by dual-energy radiological absorptiometry (DXA) and function through the six-minute walk test (6MWD) and Short Physical Performance Battery (SPPB). Plasma soluble tumor necrosis factor receptors (sTNFR) were determined by enzyme-linked immunosorbent assay (ELISA) and measured before and immediately after each protocol. After exercise with WBV, there was an increase in sTNFR2 levels in the NSG (P<0.01; d=-0.69 (-1.30; -0.08) and SG (P<0.01, d=-0.95 (-1.57; -0.32) groups. In conclusion, an acute session of WBV influenced sTNFr2 levels, with sarcopenic individuals showing a greater effect. This suggested that WBV had a more pronounced impact on sTNFr2 in those with loss of muscle strength and/or physical performance. Additionally, WBV is gaining recognition as an efficient strategy for those with persistent health issues.

Let's get physical: Aerobic capacity, muscle strength, and muscle endurance after pediatric heart transplantation.

BACKGROUND: Pediatric heart (HTx) and kidney transplant (KTx) recipients may have lower physical fitness than healthy children. This study sought to quantify fitness levels in transplant recipients, investigate associations to clinical factors and quality of life, and identify whether a quick, simple wall-sit test is feasible as a surrogate for overall fitness for longitudinal assessment. METHODS: Aerobic capacity (6-min walk test, 6MWT), normalized muscle strength, muscle endurance, physical activity questionnaire (PAQ), and quality of life (PedsQL™) were prospectively assessed in transplanted children and matched healthy controls. RESULTS: Twenty-two HTx were compared to 20 controls and 6 KTx. 6MWT %predicted was shorter in HTx (87.2 [69.9-118.6] %) than controls (99.9 [80.4-120] %), but similar to KTx (90.3 [78.6-115] %). Muscle strength was lower in HTx deltoids (6.15 [4.35-11.3] kg/m2) and KTx quadriceps (9.27 [8.65-19.1] kg/m2) versus controls. Similarly, muscle endurance was lower in HTx push-ups (28.6 [0-250] %predicted), KTx push-ups (8.35 [0-150] %predicted), HTx curl-ups (115 [0-450] %predicted), and KTx wall-sit time (18.5 [10.0-54.0] s) than controls. In contrast to HTx with only 9%, all KTx were receiving steroid therapy. The wall-sit test significantly correlated with other fitness parameters (normalized quadriceps strength R = .31, #push-ups R = .39, and #curl-ups R = .43) and PedsQL™ (R = .36). CONCLUSIONS: Compared to controls, pediatric HTx and KTx have similarly lower aerobic capacity, but different deficits in muscle strength, likely related to steroid therapy in KTx. The convenient wall-sit test correlates with fitness and reported quality of life, and thus could be a useful easy routine for longitudinal assessment.

The impact of income level on skeletal muscle health in rural Chinese older residents: a study of mediating effects based on dietary knowledge.

China's rural residents have basically solved the problem of subsistence, but due to aging, the prevalence of sarcopenia (abbreviated as sarcopenia) has been increasing year by year, especially the skeletal muscle health of the rural older residents has not been sufficiently paid attention to, so analyses of the impact of income level on the skeletal muscle health of the older people in rural areas of China are of great practical significance. Based on the annual data of the China Health and Nutrition Survey (CHNS) in 2006, 2009, and 2011, we introduced the mediator variable of dietary knowledge and used the Probit model regression, mediation effect model, and instrumental variable regression to assess the skeletal muscle health status of the rural older people in China and explore the mechanism of the influence of the income level on the skeletal muscle health of the rural older residents in China. The primary objectives of this study were to evaluate the impact of income level on the skeletal muscle health status of older adults living in rural areas of China and to investigate the underlying mechanisms. By analyzing the findings of this study, our aim is to establish a correlation between the economic status and skeletal muscle health of older adults in rural communities, as well as elucidate the influence of income level and dietary knowledge on their skeletal muscle health. Through the attainment of these objectives, we hope to provide valuable insights and recommendations for enhancing skeletal muscle health among the rural older population in China. Based on our research findings, it can be inferred that there was a significant association between the financial status of rural older adults and their skeletal muscle health. Additionally, the prevalence of sarcopenia was lower among individuals with higher income levels, and there was a negative correlation between the prevalence of sarcopenia and the level of dietary knowledge among rural older individuals. The knowledge of dietary knowledge level of rural older people plays a mediating role in the income level and the prevalence of sarcopenia. Moreover, with the change in income level and the increase in age, the change in skeletal muscle health status showed obvious heterogeneity, in which the effect on the relatively younger (65-70 years old) samples was greater. Therefore, sustained income growth remains an effective way to improve the skeletal muscle health of older rural residents. At the same time, improving dietary knowledge and dietary quality among the older people is important in preventing a decline in muscle strength and physical function and in preventing the onset of sarcopenia.

Verification of the Effects of a YouTube-Based Home-Based (Self-Managed Intervention) Training System Developed for Frailty Prevention: A Pilot Study.

Resistance training is considered the most effective intervention for increasing older people's muscle mass and strength. Thus, we created the Sukubara®, a self-administered training system (squat + balance training) that incorporates a new low-load exercise. In this study, we hypothesize that introducing Sukubara will positively affect skeletal muscle mass and physical function. A preliminary verification was carried out on healthy, non-elderly participants who were recruited from the hospital staff. Participants were randomly assigned to two groups for a 12-week intervention: the resistance training group (R group) that performed the Sukubara exercise program and the control group (C group) that did not. This study's primary end¬point was a change in skeletal muscle mass, while the secondary endpoints were knee extension strength and one-leg standing time with eyes closed. An analysis of the 18 participants (R group = 8; C group = 10) was performed. Results showed that skeletal muscle mass, knee extension strength, and one-leg standing time were significantly improved or tended to be significantly higher in the R group than in the C group. Our study concluded that, by incorporating low-load exercise, Sukubara resulted in muscle hypertrophy and improved physical function.

Effects of upper limbs' neuromuscular electrical stimulation (NMES) superimposed to voluntary contraction added to a protocol of intradialytic leg cycle ergometer exercise, in muscle strength, functional capacity and quality of life of adult patients with CKD: a randomized clinical trial protocol.

OBJECTIVE: To investigate the effects of unilateral upper limbs' (ULM) neuromuscular electrical stimulation (NMES) superimposed on a voluntary contraction added to a protocol of intradialytic leg cycle ergometer exercise on muscle strength, functional capacity and quality of life of adult patients with chronic kidney disease (CKD). METHODS: This randomized controlled clinical trial will be carried out at a Brazilian University Hospital. The patients will be evaluated and randomly allocated to an intervention group (i.e., unilateral NMES on the upper limb without hemodialysis fistula for 20 min and leg cycle ergometer for 30 min) or a control group (i.e., unilateral NMES-Sham on the upper limb without hemodialysis fistula for 20 min and leg cycle ergometer for 30 min). The patients will be treated for 8 weeks, with three weekly treatment sessions totaling 24 sessions. MEASUREMENTS: ULM muscle strength, functional capacity, quality of life and also the feasibility, safety and patient adherence to the exercise protocol. All physical measurements will be collected by trained researchers before treatment (week 0) and at the end of treatment (week 9), always in the second hemodialysis session of the week. It will be used in an intention-to-treat analysis. RESULTS/CONCLUSIONS: The outcomes of this clinical trial protocol may help to know the possible benefits of unilateral ULM' NMES superimposed on a voluntary contraction added to a protocol of leg cycle ergometer for patients with CKD and to aid clinical decisions about future implementation or not of this technique (NMES) in intradialytic physical training programs.

Effects of a nighttime melatonin ingestion on dynamic postural balance and muscle strength the following morning in people living with multiple sclerosis: A preliminary study.

BACKGROUND: Decreased endogenous melatonin concentrations in people with multiple sclerosis (PwMS) are associated with fatigue and pain that impair postural balance and muscle strength. Melatonin ingestion had analgesic and anti-fatigue effects. However, the acute effect of exogenous melatonin on dynamic postural stability and muscle strength has not been studied yet in PwMS. This study aimed to investigate the safety and the efficacy of a nighttime melatonin intake on dynamic postural balance and lower-extremity muscle strength the following morning in PwMS. METHODS: Fourteen PwMS (28.36 ± 6.81 years) were assessed (8 a.m.) pre- and post-acute intake of melatonin or placebo (6mg, 30 minutes before nocturnal bedtime). Evaluated parameters included dynamic postural balance (force platform), lower-extremity muscle strength [Five-Repetition Sit-To-Stand Test (5-STST)], hand dexterity (Nine-Hole Peg Test), nociceptive pain [Visual Analogue Scale (VAS)], neuropathic pain [Neuropathic Pain 4 Questions (DN4)], sleep quality and fatigue perception [Hooper Index (HI)]. RESULTS: In the frontal plane, melatonin reduced the center of pressure (CoP) path length (CoPL), CoPL in the anteroposterior axis (CoPLY) and CoP sway area (CoPAr) compared with placebo by 7.56% (p=0.02, Cohens'd (d)=1.24), 19.27% (p<0.001, d=2.60) and 13.82% (p<0.001, d=2.02), respectively. Melatonin induced a higher decrease in these posturographic parameters compared with placebo in the sagittal plane [CoPL: 9.10% (p=0.005, d=1.02), CoPLY: 4.29% (p=0.025, d=1.07) and CoPAr: 7.45% (p=0.038, d=0.74)]. Melatonin decreased 5-STST duration as well as VAS, DN4, HI-fatigue and HI-sleep scores compared with placebo by 8.19% (p=0.008, d=1.19), 5.74% (p=0.04, d=0.82), 27.30% (p=0.023, d=0.98), 40.15% (p=0.044, d=0.85) and 30.16% (p=0.012, d=1.10), respectively. CONCLUSION: This preliminary study, among PwMS, showed that acute melatonin ingestion was safe and efficient for improving dynamic postural stability and lower-extremity muscle strength probably through its analgesic and anti-fatigue effects.

Relationship between Eating Alone and Handgrip Strength in Korean Older Adults.

Sarcopenia is defined as an age-related decline in muscle mass, muscle strength, and physical performance. Eating alone has been linked to various health issues in older adults. This study investigated the relationship between eating alone and handgrip strength (HGS) in older adults using data from 7278 individuals (≥65 years) who participated in the 2014-2019 Korea National Health and Nutrition Examination Survey. HGS was measured using a digital grip strength dynamometer, relative HGS was calculated by dividing HGS by body mass index, and dynapenia was defined as an HGS < 28 kg for men and <18 kg for women. Multivariable logistic regression analysis showed that women who ate two meals alone were more likely to exhibit dynapenia than those who never ate alone (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.03-1.77). If the groups that never ate alone or ate one meal alone were combined as the reference group, the probability of dynapenia was higher in the combined groups that ate two or three meals alone (OR, 1.25; 95% CI, 1.04-1.50). No association was observed between eating alone and dynapenia in men. This suggests that eating alone is a modifiable related factor of dynapenia in older women.

Influence of Amputation on Kinetic Chain Musculature Activity During Basic and Modified Core Exercises.

PURPOSE: Core strength is vital for athletic performance, and many more exercises that involve the kinetic chain have been designed for able-bodied athletes. Disabilities that impair the kinetic chain can reduce the effectiveness of strength training. However, the impact of amputation on core strength training of people with disabilities and its underlying mechanism remains unclear. This study aimed to evaluate the muscle activation patterns and levels in athletes with amputation during 4 basic and modified weight-bearing core strength-training exercises. METHODS: Fifteen elite athletes with unilateral amputation (170.6 [7.3] cm; 63.9 [11.9] kg; 25.9 [5.3] y) volunteered for this study. Surface electromyography was used to measure the muscle activity mainly in the lumbopelvic-hip complex-stabilizing muscles during 4 kinetic chain trunk exercises with and without modifications. RESULTS: The significance level was set at α = .05. The results showed a significant difference in muscle activation between different body sides (P < .05). Specifically, amputation on the support position resulted in a diagonal pattern of muscle activation, and amputation on the free distal segments resulted in a unilateral dominant pattern with higher activation in muscles on the nonamputated side (P < .05). Modifications led to significant decreases in muscle activation asymmetry index (P < .05). CONCLUSIONS: Amputation caused muscle activation asymmetry and 2 activation patterns. Modifications by enhancing proximal stability and adjusting distal loading effectively reduced the asymmetry of muscle activation. Coaches and clinicians can use these results to tailor exercises for athletes with disabilities in training and rehabilitation.

Impact of a Multicomponent Exercise Training Program on Muscle Strength After Bariatric Surgery: A Randomized Controlled Trial.

PURPOSE: This study examined the benefits of an 11-months multicomponent exercise program (MEP) on muscular strength (MS) after bariatric surgery. METHODS: Of the 84 randomized patients, 41 participants from the exercise group (EG) and 20 participants from the control group (CG) were included in the analysis. The EG received supervised MEP for 11 months, starting 1-month post-bariatric surgery (BS) in addition to standard medical care, while the CG received medical care recommendations only. Knee and trunk MS was assessed by isokinetic dynamometry pre-surgery, 1-, 6-, and 12-month post-surgery, while body composition was assessed by dual-energy X-ray absorptiometry. RESULTS: The MEP did not significantly impact absolute MS in the dominant knee and trunk regions at 6- and 12-month post-BS. However, relative MS showed significant improvements. At 6-month post-BS, knee flexion at 60°/s relative to body weight (BW) increased significantly (p = 0.047), as did knee extension at 180°/s relative to BW (p = 0.009), and knee extension at 60°/s relative to total lean mass (p=0.040). At 12-month post-BS, knee flexion at 60°/s relative to BW also significantly improved (p=0.038). CONCLUSION: While absolute MS was not significantly improved with MEP, this study found significant enhancements in relative MS, particularly in dominant knee flexion post-MEP participation. Further research should explore different exercise intensities and frequencies to optimize postoperative MS recovery post-BS. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT02843048).