Effects of a Nonlinear Program on Different Health Parameters in the Elderly.

BACKGROUND: The aim of this research was to evaluate the impact of a nonlinear training program on visceral adipose tissue (VAT) and systolic (SBP) and diastolic (DBP) blood pressure, as well as the response of biochemical parameters such as fasting plasma glucose (FPG), total cholesterol (TC), high-density cholesterol (HDL-C), low-density cholesterol (LDL-C), and triglycerides (TG). HYPOTHESIS: The nonlinear periodized program would produce greater improvements in outcomes than the linear periodized training program. STUDY DESIGN: Randomized cross-sectional design. LEVEL OF EVIDENCE: Level 3. METHODS: Older adults with no previous training experience (10 male and 8 female [age, 64 ± 2.1 years; height, 165.12 ± 7.5 cm; body mass, 72.5 ± 11.4 kg; body max index, 26.5 ± 3.2 kg/m2]) were randomized to linear (n = 9, TT) or undulating (n = 9, UT) periodization. After a 3-week familiarization period, all participants performed 3 sessions of resistance training per week; 8 weeks of training were conducted for each group. Dual x-ray absorptiometry was used to measure VAT, and SBP and DBP were measured using an OMRON M3 digital automatic blood pressure monitor. Blood samples were collected between 8:00 a.m. and 9:30 a.m. after 12-hour overnight fasting. RESULTS: Both interventions significantly (P < 0.05) decreased FPG, TC, LDL-C, and TG. A significant decrease in SBP and DBP was observed only in the UT group (P < 0.05). No significant between-group differences in outcomes were observed (P > 0.5). However, the effect size was marginally more pronounced for all outcomes in the UT group. CONCLUSION: An undulating periodization program was effective in improving VAT, TC, LDL-C, FPG, HDL-C, TG, and blood glucose levels in older adults. CLINICAL RELEVANCE: Resistance training can be programmed in an undulating or traditional way in older adults based on improvements in health parameters, considering adherence and individual preferences.

Effects of Whey Protein Supplement on 4-Week Resistance Exercise-Induced Improvements in Muscle Mass and Isokinetic Muscular Function under Dietary Control.

(1) The purpose of this study was to investigate the effect of whey protein supplementation under dietary control on improvements in muscle mass and function following resistance exercise training. (2) Thirty-two men were randomly assigned to a whey protein supplementation group taking whey protein isolate (PSG, n = 17) and a placebo group (CON, n = 15). Participants were provided with three meals per day corresponding to the estimated individual daily energy intake. The supervised resistance exercise program was conducted 60 min per day, six days per week, for four weeks. (3) Post-intervention, there was a significant interaction between groups in terms of muscle mass increase (p = 0.033, η2 = 0.14), with a greater increase in the PSG. There were also significant interactions between the groups and increases in peak torque of the dominant knee flexors (p = 0.048, η2 = 0.12), dominant shoulder extensors, and non-dominant shoulder extensors (p = 0.028, η2 = 0.15; p = 0.015, η2 = 0.18), and the total work of the dominant knee and shoulder extensors (p = 0.012, η2 = 0.19; p = 0.013, η2 = 0.19), with greater increases in the PSG. (4) These results suggest that whey protein supplementation enhances resistance exercise-induced increase in muscle mass and overall muscular strength and endurance, independent of dietary influence.

Effects of resistance training and protein supplementation interventions on muscle volume and muscle function: sex differences in humans.

PURPOSE: This review aimed to identify differences in the effects of co-intervention with resistance training (RT) and protein supplementation according to sex and provide meaningful information for future research on the development of exercise programs to improve muscle volume and muscle function. METHODS: PubMed, Science Direct, and Google Scholar were searched to identify clinical and nonclinical studies that assessed the effects of RT in older adults with sarcopenia; these studies were published between 1990 and 2023. Cross-sectional and double-blind studies (randomized controlled trials, RCTs) were examined in this review. RESULTS: The effects of parallel intervention with RT and protein supplementation on muscle volume and physical function were found to differ according to sex. Both males and females had improvements in muscle strength, muscle mass, and physical function after RT and protein supplementation; however, many studies found a greater increase in muscle volume and function in males than in females. Such difference may be due to differences in physiological characteristics between males and females. CONCLUSION: Based on the findings of this review, the effects of combined intervention with RT and protein supplementation on muscle strength, muscle mass, and physical function to differ according to sex. Owing to these sex differences in the response and physiological characteristics caused by the parallel intervention of RT and protein supplementation, such differences must be considered to maximize the effects of RT and protein supplementation.

Exploring the effects of a combined exercise programme on pain and fatigue outcomes in people with systemic sclerosis: study protocol for a large European multi-centre randomised controlled trial.

BACKGROUND: Pain, related to Raynaud's phenomenon or digital ulceration, has been identified as very prevalent and debilitating symptoms of systemic sclerosis (SSc), both significantly affecting patients' quality of life (QoL). Pharmacological therapeutic strategies were found not to be sufficiently effective in the management of SSc-induced pain and fatigue, and evidence for exercise is scarce. As yet, the effects of a long-term, tailored exercise programme on pain and fatigue in patients with SSc have not been explored. In addition to pain and fatigue, this study aims to evaluate the effects of exercise on QoL, physical fitness, functional capacity, and vascular structure in people with SSc (PwSSc). METHODS: This will be a multicentre (n = 6) randomised controlled clinical trial to assess the effect of a previously established, supervised 12-week combined exercise programme on pain and fatigue as compared to no exercise in PwSSc. The study will recruit 180 patients with SSc that will be allocated randomly to two groups. Group A will perform the exercise programme parallel to standard usual care and group B will receive usual care alone. Patients in the exercise group will undertake two, 45-min sessions each week consisting of 30-min high-intensity interval training (HIIT) (30-s 100% peak power output/30-s passive recovery) on an arm crank ergometer and 15 min of upper body circuit resistance training. Patients will be assessed before as well as at 3 and 6 months following randomisation. Primary outcomes of the study will be pain and fatigue assessed via questionnaires. Secondary outcomes include quality of life, structure of digital microvasculature, body composition, physical fitness, and functional capacity. DISCUSSION: Data from this multi-centre research clinical trial will primarily be used to establish the effectiveness of a combined exercise protocol to improve pain and fatigue in SSc. In parallel, this study will be the first to explore the effects of long-term exercise on potential microvascular alterations assessed via NVC. Overall, this study will provide sufficient data to inform current clinical practice guidelines and may lead to an improvement of QoL for patients with SSc. TRIAL REGISTRATION: ClinicalTrials.gov NCT05234671. Registered on 14 January 2022.

Effects of Neuromuscular Electrical Stimulation and Blood Flow Restriction in Rehabilitation after Anterior Cruciate Ligament Reconstruction.

The present study aimed to examine and compare the effects of a rehabilitation exercise (RE) using neuromuscular electrical stimulation (NMES) and blood flow restriction (BFR) on muscle function and knee functional abilities in patients who underwent anterior cruciate ligament reconstruction (ACLR). A total of 45 patients who underwent ACLR (28.76 ± 0.8 years; 34 males and 11 females) were retrospectively divided into three groups: control (CON, n = 15), NMES (n = 15), and BFR (n = 15). All participants carried out the RE program for 60 min, thrice a week for 12 weeks. The Lysholm score, International Knee Documentation Committee (IKDC) subjective score, thigh circumference at 5 cm from the knee joint, Y-balance posterior medial, and lateral significantly increased in all groups via intervention (p < 0.05). However, NMES showed a higher thigh circumference at 15 cm from the knee joint than CON via intervention (p < 0.05), and the strength and endurance of quadriceps femoris and hamstrings and Y-balance anterior showed a significant increase via intervention in NMES and BFR compared with CON (p < 0.05). In conclusion, we confirmed that RE using NMES and BFR effectively enhances muscle function and balance in ACLR patients.

Effects of hanger reflex on the cervical muscular activation and function: A surface electromyography assessment.

Introduction: Cervical muscular dysfunction is closely associated with disorders and neuromuscular diseases of the cervical spine, and the hanger reflex (HR) has the potential to become a rehabilitation method. The muscular electrophysiology mechanism of HR is unclear. This study aims to identify the impacts of HR on cervical rotators' myoelectrical activity and function. Methods: We designed a self-control clinical trial, and asymptomatic volunteers were continuously included from 1 September 2021 to 30 April 2022 in our department. Rotation tasks were performed on both sides under each of the situations: no HR, unilateral HR, and bilateral HR. Surface electromyography (SEMG) was used to detect the myoelectrical activity of agonistic splenius capitis (SPL), upper trapezius (UTr), and sternocleidomastoid (SCM). The co-contraction ratio (CCR) during rotation tasks was calculated. Correlation analyses and multiple linear regression were performed. Results: Finally, 90 subjects were enrolled (power >90%). The adjusted EMG value (aEMG) of SPL UTr, SCM, and rotating CCR under the unilateral HR and bilateral HR were higher than no HR; the aEMG of SPL and rotating CCR under the bilateral HR were higher than the unilateral HR. Multiple linear regression showed that HR pattern and age were the independent affecting factors for the aEMG of SPL (p < 0.001, p < 0.001), UTr (p < 0.001, p < 0.001), and SCM (p < 0.001, p < 0.001); BMI was an independent affecting factor for the aEMG of SPL (p < 0.001) and SCM (p < 0.001); HR pattern was the only affecting factor for CCR (p < 0.001). Conclusion: HR can increase the cervical rotators' myoelectrical activities and rotating CCR, and the effects of bilateral HR are greater than unilateral HR, suggesting that bilateral HR has a greater clinical potential to become a rehabilitation method for treating cervical neuromuscular disorders.

Neuromuscular Stability of Dental Occlusion in Patients Treated with Aligners and Fixed Orthodontic Appliance: A Preliminary Electromyographical Longitudinal Case-Control Study.

The aim of the present study was to evaluate if, after treatment with aligners (ALIGN) and fixed orthodontic appliance (FOA), alterations of the neuromuscular activity may occur and if differences in these changes can be detected between the two treatments. Sixteen healthy patients (7 FOA, 9 ALIGN) with class I or class II molar relation were recruited. Standardized surface electromyography (ssEMG) was used to evaluate the activity of the masticatory muscles (masseters-MM and temporalis-TM) before the beginning of the orthodontic treatment (T1), at the end (T2), and 3 months (T3) after the end of the treatment. Intragroup (within timepoints) and intergroup differences were statistically analyzed. At T1, the mean values of each ssEMG index were within the normal range in both groups. At T2, the FOA group showed larger differential recruitment of the MM than TA muscles with a value slightly over the normal range. All the indexes were normalized at T3, and no differences emerged between groups. In the FOA group, the index of MM symmetrical contraction increased significantly at T3 compared to T1 and T2. In the ALIGN group, no significant changes were observed between each timepoint. In FOA subjects, a slight alteration of the muscular activity appeared immediately after bracket removal and this alteration normalized after 3 months of rescue. In subjects treated with aligners, no significant alteration of the muscular activity was assessed.

Study of the Kinetics of the Determinants of Performance During a Mountain Ultramarathon: Multidisciplinary Protocol of the First Trail Scientifique de Clécy 2021.

BACKGROUND: The growing interest of the scientific community in trail running has highlighted the acute effects of practice at the time of these races on isolated aspects of physiological and structural systems; biological, physiological, cognitive, and muscular functions; and the psychological state of athletes. However, no integrative study has been conducted under these conditions with so many participants and monitoring of pre-, per-, and postrace variables for up to 10 days over a distance close to 100 miles. OBJECTIVE: The aim of this study was to evaluate the kinetics of the performance parameters during a 156 km trail run and 6000 m of elevation gain in pre-, per-, and postrace conditions. The general hypothesis is based on significant alterations in the psychological, physiological, mechanical, biological, and cognitive parameters. METHODS: The Trail Scientifique de Clécy took place on November 11, 2021. This prospective experimental study provides a comprehensive exploration of the constraints and adaptations of psychophysiological and sociological variables assessed in real race conditions during a trail running of 156 km on hilly ground and 6000 m of elevation gain (D+). The study protocol allowed for repeatability of study measurements under the same experimental conditions during the race, with the race being divided into 6 identical loops of 26 km and 1000 m D+. Measurements were conducted the day before and the morning of the race, at the end of each lap, after a pit stop, and up to 10 days after the race. A total of 55 participants were included, 43 (78%) men and 12 (22%) women, who were experienced in ultra-trail-running events and with no contraindications to the practice of this sport. RESULTS: The launch of the study was authorized on October 26, 2021, under the trial number 21-0166 after a favorable opinion from the Comité de Protection des Personnes Ouest III (21.09.61/SIRIPH 2G 21.01586.000009). Of the 55 runners enrolled, 41 (75%) completed the race and 14 (25%) dropped out for various reasons, including gastric problems, hypothermia, fatigue, and musculoskeletal injuries. All the measurements for each team were completed in full. The race times (ie, excluding the measurements) ranged from 17.8206 hours for the first runner to 35.9225 hours for the last runner. The average time to complete all measurements for each lap was 64 (SD 3) minutes. CONCLUSIONS: The Trail Scientifique de Clécy, by its protocol, allowed for a multidisciplinary approach to the discipline. This approach will allow for the explanation of the studied parameters in relation to each other and observation of the systems of dependence and independence. The initial results are expected in June 2022. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/38027.

Traditional and Undulating Periodization on Body Composition, Strength Levels and Physical Fitness in Older Adults.

INTRODUCTION: Undulating training has been investigated in sedentary and trained adults, but less is known about the influence of undulating training in older adults. PURPOSE: This study aimed to evaluate body composition, strength levels, and physical fitness in response to traditional or undulating training in older adults. METHODS: A controlled, double-arm trial was conducted in eighteen older adults (10 males, 8 females; 64 ± 2.1 years; 165.12 ± 7.5 cm; 72.5 ± 11.4 kg; 26.5 ± 3.2 k·gm-2) who were randomly assigned to traditional (n = 9, TT) or undulating training (n = 9, UT) for eight weeks. Dual X-ray absorptiometry was used to measure fat-free mass (FFM), fat mass (FM), and bone mineral density (BMD). Strength levels were evaluated by the handgrip strength and the one-repetition maximum in vertical chest press, rowing machine, squat, monopodal horizontal leg press, and leg extension. In addition, functional capacity was assessed using the Senior Fitness Test (SFT). Statistical analysis included mean/median comparisons to establish the difference after the intervention (paired Student's t-test or Wilcoxon test), and effect size calculations based on estimates. RESULTS: After correction for fat-free adipose tissue, a significant increase in FFM was observed in both groups, while no significant changes were found in FM and BMD. Upper- and lower-limbs strength showed significant increases in both groups, although clinical significance varied among exercises. Favorable results were seen on the cardiorespiratory fitness and strength components of the SFT in both groups. CONCLUSIONS: The 8-week UT and TT protocols are valid options for improving FFM and increasing strength and functional capacity in women and men over 60 years of age.

Hand grip strength should be normalized by weight not height for eliminating the influence of individual differences: Findings from a cross-sectional study of 1,511 healthy undergraduates.

Background: Hand grip strength (HGS) is a fast, useful, and inexpensive outcome predictor of nutritional status and muscular function assessment. Numerous demographic and anthropometric factors were reported to be associated with HGS, while which one or several factors produce greater variations in HGS has not been discussed in detail. This is important for answering how should HGS be normalized for eliminating the influence of individual differences in clinical practice. Aims: To compare the contribution of age, sex, height, weight, and forearm circumference (FCF) to variations in HGS based on a large-scale sample. Methods: We enrolled 1,511 healthy undergraduate students aged 18-23 years. Age, weight, height, and sex were obtained. HGS was measured using a digital hand dynamometer, and FCF was measured at the point of greatest circumference using a soft ruler in both hands. Pearson's or Spearman's correlation coefficients were calculated with data of women and men separated and mixed for comparison. Partial correlation analysis and multivariate linear regression were used to compare the effect of variables on HGS. Results: Analysis results confirmed the correlates of higher HGS include higher height, heavier weight, being men and dominant hand, and larger FCF. The correlation between HGS and FCF was the highest, and the bivariate correlation coefficient between weight and HGS was largerata of women and men were mixed, than that between height and HGS. When data of women and men were mixed, there were moderate correlations between HGS and height and weight (r = 0.633∼0.682). However, when data were separated, there were weak correlations (r = 0.246∼0.391). Notably, partial correlation analysis revealed no significant correlation between height and HGS after eliminating the weight effect, while the correlation between weight and HGS was still significant after eliminating the height effect. Multivariate linear regression analyses revealed sex was the most significant contributor to the variation in HGS (Beta = -0.541 and -0.527), followed by weight (Beta = 0.243 and 0.261) and height (Beta = 0.102 and 0.103). Conclusion: HGS and FCF reference values of healthy college students were provided. Weight was more correlate with hand grip strength, at least among the healthy undergraduates. Clinical trial registration: http://www.chictr.org.cn/showproj.aspx?proj=165914, identifier ChiCTR2200058586.

Effect of Time-Restricted Feeding on Anthropometric, Metabolic, and Fitness Parameters: A Systematic Review.

Time restricted feeding (TRF) as a form of intermittent fasting (IF) has gained popularity because its ability to reduce body mass (BM) without an emphasis on caloric restriction. However, how this dietary protocol may affect health, fitness, and performance in a relatively healthy cohort remains less clear. The purpose of this article was to systematically review the current literature concerning the effect of TRF on anthropometric, metabolic, and fitness parameters in normal-weight adults and overweight and obese individuals. A systematic search of English literature was conducted through databases including PubMed, CINAHL, and Google Scholar. The search was facilitated by using various combinations of key words related to nutritional interventions, i.e., IF and TRF, and outcomes of interest, i.e., BM, body composition, glucose, insulin, lipid, fitness, and performance. The article selection was made based on the inclusion and exclusion criteria concerning the participants' characteristics, study design, intervention protocols, and targeted dependent variables. Twenty-three full-text longitudinal randomized and nonrandomized controlled studies were selected for this review. Our analysis indicates that TRF can reduce BM and improve nutrient metabolism in both normal- and over-weight individuals. TRF does not appear to alter protein synthesis and fat-free mass nor hamper aerobic fitness and muscular performance among physically active individuals including athletes. In conclusion, TRF as a more easily adaptable form of IF is a promising dietary approach to improving body composition and metabolic health while maintaining fitness and muscular function. However, more research is needed before this dietary protocol can be fully recommended for athletes especially those competing in sports that demand strength and power.Key teaching points and nutritional relevanceTime-restricted feeding (TRF) differs from other fasting protocols due to its emphasis on restricting eating window rather than caloric intake and can be more easily adopted by simply skipping a meal.Its deemphasis on caloric restriction appeals to many young and physically active individuals wanting to optimize body composition but needing sufficient energy to support their physical training and daily activity.Much of what is known regarding the impact of TRF on fitness and athletic performance was derived from studies that use the Ramadan fasting protocol, which differs from TRF in terms of protocol duration and feeding schedule.This review concludes that TRF is a promising dietary approach to improving body composition and metabolic health while maintaining fitness and muscular function in both normal- and over-weight individuals.Due to limited evidence concerning TRF and athletic performance, more research is needed before this dietary protocol can be fully recommended for athletes especially those competing in sports that demand strength and power.

Redistribution of joint moments and dynamic balance control during sit to stand task in persons with Parkinson's disease.

We sought to determine how people with Parkinson disease (PD) perform the sit to stand task (STS). After measuring kinetic and kinematic data our results suggest that people with PD perform the STS task by redistributing their joint torques but is accompanied with postural instability.

Effect of suspension training on neuromuscular function, postural control, and knee kinematics in anterior cruciate ligament reconstruction patients.

BACKGROUND: Suspension training (SET) is a method of neuromuscular training that enables the body to carry out active training under unstable support through a suspension therapy system. However, there have been few reports in the literature on the application of SET to anterior cruciate ligament reconstruction (ACLR) patients. It is not clear what aspects of the patient's function are improved after SET. AIM: To investigate the effect of SET on the neuromuscular function, postural control, and knee kinematics of patients after ACLR surgery. METHODS: Forty participants were randomized to an SET group or a control group. The SET group subjects participated in a SET protocol over 6 wk. The control group subjects participated in a traditional training protocol over 6 wk. Isokinetic muscle strength of the quadriceps and hamstrings, static and dynamic posture stability test, and relative translation of the injured knee were assessed before and after training. RESULTS: The relative peak torque of the quadriceps and hamstrings in both groups increased significantly (P < 0.001), and the SET group increased by a higher percentage than those in the control group (quadriceps: P = 0.004; hamstrings: P = 0.011). After training, both groups showed significant improvements in static and dynamic posture stability (P < 0.01), and the SET group had a greater change than the control group (P < 0.05). No significant improvement on the relative translation of the injured knee was observed after training in either group (P > 0.05). CONCLUSION: Our findings show that SET promotes great responses in quadriceps and hamstring muscle strength and balance function in ACLR patients.

Accelerated decline in quadriceps area and Timed Up and Go test performance are associated with hip fracture risk in older adults with impaired kidney function.

OBJECTIVE: This study aimed to examine whether an accelerated decline in quadriceps cross-sectional area (CSA), attenuation (a surrogate of quality), and strength, as well as lower limb muscular function, are associated with hip fractures in older adults with impaired kidney function. DESIGN: Prospective population-based study. SETTING: Community-dwelling old population in Reykjavik, Iceland. SUBJECTS: A total of 875 older adults (mean baseline age 76 years) from the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study with impaired kidney function. METHODS: Quadriceps CSA and density were determined using computed tomography (CT), knee extension strength was measured with an isometric dynamometer chair, and muscular function was assessed using the Timed Up and Go (TUG) test. All muscle-related measurements were assessed twice over a mean follow-up of 5.2 years. Data on hip fracture incidence was obtained from medical records during a maximum of 8.4 years of follow-up time. RESULTS: Fully adjusted cox-proportional hazard regression models showed that a faster decline in quadriceps CSA and TUG test performance were significantly associated with increased hip fracture risk (HR = 1.55, 95% CI = 1.02-2.36, and HR = 1.80, 95% CI = 1.19-2.72, respectively). A faster decrease in quadriceps density and isometric knee extension strength were not associated with fracture risk. CONCLUSIONS: Accelerated decline in CT-derived quadriceps CSA and muscular function, as measured by the TUG test's performance, are predictive of hip fracture risk in older adults with impaired kidney function. TUG test is a simple measure and easily included in routine medical examinations, compared to CT scans, which seems to be useful for identifying a subgroup of individuals with high risk of fracture.

Resistance Training in Hypoxia as a New Therapeutic Modality for Sarcopenia-A Narrative Review.

Hypoxic training is believed to be generally useful for improving exercise performance in various athletes. Nowadays, exercise intervention in hypoxia is recognized as a new therapeutic modality for health promotion and disease prevention or treatment based on the lower mortality and prevalence of people living in high-altitude environments than those living in low-altitude environments. Recently, resistance training in hypoxia (RTH), a new therapeutic modality combining hypoxia and resistance exercise, has been attempted to improve muscle hypertrophy and muscle function. RTH is known to induce greater muscle size, lean mass, increased muscle strength and endurance, bodily function, and angiogenesis of skeletal muscles than traditional resistance exercise. Therefore, we examined previous studies to understand the clinical and physiological aspects of sarcopenia and RTH for muscular function and hypertrophy. However, few investigations have examined the combined effects of hypoxic stress and resistance exercise, and as such, it is difficult to make recommendations for implementing universal RTH programs for sarcopenia based on current understanding. It should also be acknowledged that a number of mechanisms proposed to facilitate the augmented response to RTH remain poorly understood, particularly the role of metabolic, hormonal, and intracellular signaling pathways. Further RTH intervention studies considering various exercise parameters (e.g., load, recovery time between sets, hypoxic dose, and intervention period) are strongly recommended to reinforce knowledge about the adaptational processes and the effects of this type of resistance training for sarcopenia in older people.

Optimisation of applied loads when using the two-point method for assessing the force-velocity relationship during vertical jumps.

This study aimed to compare the reliability and validity of the force-velocity (F-V) relationship parameters obtained from two-point methods differing in the distance between experimental points, and to evaluate the acute change in unloaded jump height after a vertical jump testing procedure based on multiple loads. Totally, 18 men randomly performed two sessions of the squat jump (SJ) and two sessions of the countermovement jump (CMJ) exercises against five external loads (17, 30, 45, 60 and 75 kg). The unloaded jump height was evaluated before and after each testing procedure. Five two-point methods (0-17, 0-30, 0-45, 0-60 and 0-75 kg) and the multiple-point method (0-17-30-45-60-75 kg) were used to model the F-V relationship. The most distant two-point method (0-75 kg) revealed a comparable reliability (CV< 12.1%; ICC> 0.72) and high concurrent validity (r > 0.91) with respect to the multiple-point method (CV< 10.9%; ICC> 0.72). The reliability and validity of the two-point methods decreased with the proximity of the applied loads. Unloaded jump height was significantly reduced after both testing procedures (p < 0.05). These results support the two-point method based on distant loads as a quick and less prone to fatigue procedure for testing the F-V relationship through vertical jumps.

Fast-Velocity Eccentric Cycling Exercise Causes Greater Muscle Damage Than Slow Eccentric Cycling.

This study aims to investigate muscle damage occurring in the early and recovery phases after fast-velocity and slow-velocity eccentric cycling. Eleven untrained men (age, 20.0 ± 1.7 years; height, 171.3 ± 6.8 cm; weight, 61.8 ± 7.7 kg; and %body fat, 13.2 ± 2.9%) performed slow-velocity maximal isokinetic eccentric cycling (slow-velocity; 30°/s) with one leg and fast-velocity (fast-velocity; 210°/s) isokinetic eccentric cycling with the other leg. Changes in maximal voluntary isokinetic concentric contraction (MVCC) torque at velocities of 30 and 210°/s, range of motion (ROM), and muscle soreness were assessed by pressure using a digital muscle stiffness instrument; thigh circumference, muscle echo intensity, and muscle stiffness were assessed before exercise, and immediately after exercise, 1 day, and 4 days after exercise. Comparing with the results obtained for slow-velocity cycling (post: 215.9 ± 32.3 Nm, day 1: 192.9 ± 47.4 Nm, day 4: 184.3 ± 47.2 Nm) and before exercise, MVCC after fast-velocity cycling significantly decreased at immediately (160.4 ± 43.5 Nm), 1 day (143.6 ± 54.1 Nm), and 4 days (150.1 ± 44.5 Nm) after exercise (p < 0.05). Significant increase in muscle soreness for vastus lateralis was observed after fast-velocity cycling (41.2 ± 16.9 mm) compared with slow-velocity cycling (23.7 ± 12.2 mm) 4 days after exercise (p < 0.05). However, no significant difference in muscle soreness was observed for rectus femoris and vastus medialis at any time points after exercise. In addition, no significant differences were observed in the ROM, thigh circumference, muscle echo intensity, and muscle stiffness. In conclusion, fast-velocity eccentric cycling causes a decrease in muscle strength and an increase in soreness as compared to slow-velocity eccentric cycling.

Reference values for handgrip strength: data from the Tianjin Chronic Low-Grade Systemic Inflammation and Health (TCLSIH) cohort study.

BACKGROUND: although handgrip strength (HGS) is considered an excellent predictor of morbidity and mortality, there are few reference data available, especially across life from young to old populations. OBJECTIVE: to investigate the reference values and determinants for HGS in a large Chinese adult population. DESIGN: this cross-sectional study used data from the Tianjin Chronic Low-Grade Systemic Inflammation and Health Cohort Study ranging from 2013 to 2017. SETTING AND SUBJECTS: in total, 37,707 Chinese adults aged 18-93 years with measures of HGS were included. METHODS: HGS was measured using a handheld digital dynamometer. The percentile distribution of HGS, as well as mean (standard deviation) values of HGS, was calculated according to sex and age categories. The Pearson's or Spearman's correlation coefficient and multiple linear regression were also used. RESULTS: the peak mean value of HGS was 45.2 ± 6.88 kg in men and 26.8 ± 4.65 kg in women. Different reference values for each sex and age category are present. The prevalence of low HGS was 7.69% in men and 6.46% in women. Multiple regression analysis showed that almost 72.5% of HGS variability can be explained by sex, age, height and weight. CONCLUSIONS: the HGS reached peak at 40 years old, maintained or slightly lowered between ages 40 and50 and then start an accelerated decline after 50 years old. Reference values of HGS should be stratified by sex and age group. HGS variability can be largely explained by sex, age, height and weight.

Duration and sequence of muscular activation in dentate individuals and complete denture wearers during simulation of activities of daily living.

Occlusal support may influence muscular function during complex motor tasks. This study evaluated the duration and sequence of muscular activation of masticatory (temporal, masseter), postural head/neck (sternocleidomastoid, trapezius), postural trunk (rectus abdominis, paravertebrals), and low extremity strength (rectus femoris, gastrocnemius) muscles during simulation of activities of daily living (ADL) in edentulous women wearing complete dentures (n = 10) and in dentate women (n = 10). Electromyographic activity was recorded during tests of stand-up/sit down in the Chair, sit up/lie down in the Bed and lift/lower Bags. Occlusal support (dentures) had a significant effect on duration of muscular activation in the Chair Test: the masseter muscle activated longer with dentures during the standing movement. The masseter and sternocleidomastoid muscles showed significant alteration in their order of activation in non-denture-wearing women. For the Bed Test, dentures had significant effect for the gastrocnemius during the sitting-up phase and for the rectus abdominis during the lying-down movement. For the Bag Test, head/neck muscles were activated in a different order as a function of occlusal support. Anticipation of activation of the paravertebral muscles, rectus abdominis, and gastrocnemius was observed in dentate women compared with denture wearers. These findings suggest that occlusal support influences electromyographic activity of some muscles during simulation of ADL.

The Influence of Wheelchair Use of Individuals with Spinal Cord Injury on Upper Extremity Muscular Function and Cross-Sectional Area / 대한스포츠의학회지

PURPOSE: This study was to compare the upper extremity muscular function and cross-sectional area (CSA) between wheelchair users and a pedestrian group and to observe how the changes in the muscle CSA affected upper extremity muscle function. METHODS: The study was conducted on 10 patients with spinal cord injury (SCI) who were divided into two groups based on whether they used wheelchairs (wheelchair using [WU] group and pedestrian [PS] group). The Mann-Whitney U-test was used to analyze the data and determine whether there were significant differences between the groups. RESULTS: Muscle mass in the WU group was significantly lower than in the PS groups (p < 0.01), while body fat percentage in the WU group was significantly higher than in the PS group (p < 0.05). The peak torque of shoulder external and right internal rotation was higher in the WU group than in the PS group (p < 0.05). Wrist muscle function was not significantly different for either group. In addition, the CSA of the right wrist extensor carpi radialis longus and left extensor digitorum communis was higher in the WU group than in the PS group (p < 0.05). CONCLUSION: Using a manual wheelchair may benefit upper extremity function by increasing CSA and muscle function in patients with SCI despite having a negative effect on body composition. However, there is an increased risk of injury with SCI associated with upper extremity overload; thus, an effective exercise protocol is needed to prevent muscle imbalance and injury.