Strength training in relation to injury prevention in professional and semi-professional women's football: A systematic review

The increased practice by the female sector makes knowing the causes that can cause pathologies in the musculoskeletal system more important. Various factors are what can trigger motor limitations and generate pathologies in the musculoskeletal system. The objective of this study is to establish methodological bases in relation to the type of work and the parameters that make up strength training towards injury prevention in professional and semi-professional women's football. To do this, a search was carried out using the Google Scholar and Pubmed platforms, including a time frame from 2000 to December 2019. An analysis of 8 studies was carried out, in which positive relationships were observed in the reduction of injuries in different types of training, thus proposing that strength training shows beneficial effects regarding the prevention of injuries of a different nature. (AU)

The Beneficial Effect of Physical Exercise on Inflammatory Makers in Older Individuals.

Old age is associated with a loss of motor functions and a general progressive decline in cognitive functions. Physical exercise is one of the ways in which inflammatory levels in general can be reduced, and therefore physical exercise can be considered a biological aging decelerator. In this article, we examine the relationships between physical exercise and inflammatory markers reported for the different physical exercise protocols that have been used in studies with older individuals, as well as the effects of these regimens. The different types of exercises programmed, and methods used to implement them were very heterogeneous in the articles we analysed. Both, the aerobic exercise and resistance training protocols produced a decrease in plasma levels of IL-6, CRP and TNF-α, and an increase of IL-10 plasma levels as a chronic effect. However, the acute-response of physical exercise appeared to be an initial increase in IL-6 expression and plasma IL-6 levels. Continuing with these exercise programs usually subsequently achieved a chronic response in which there was a decrease in both the basal levels of IL-6, CRP and TNF-α, and the IL-6 produced as acute responses. Regardless of the type of exercise performed, it seems that the exercise parameters, intensity, duration, subject variables, fitness, and level of inflammation are key factors in achieving the expected balance between proinflammatory and anti-inflammatory cytokines.

Elastic Resistance Training Produces Benefits Similar to Conventional Resistance Training in People With Chronic Obstructive Pulmonary Disease: Systematic Review and Meta-Analysis.

OBJECTIVE: The purpose of this study was to investigate the effectiveness of elastic resistance training on improving muscle strength, functional exercise capacity, health-related quality of life (HRQoL), and dyspnea in people with stable chronic obstructive pulmonary disease (COPD). METHODS: For this systematic review, PubMed, The Cochrane Library, Embase (OVID), PEDro, SciELO, and CINAHL were searched from inception to November 2019. Included studies were randomized clinical trials in which people with stable COPD were allocated to (1) an experimental group that received lower-limb resistance training, upper-limb resistance training, or both using elastic resistance; or (2) a control group that received no or sham resistance training or conventional resistance training using weight machines. Data extraction was performed by 3 review authors. The methodological quality of the studies was assessed using the PEDro scale. Eight studies on 332 participants were included. RESULTS: Knee extensor strength was higher in the experimental group (standardized mean difference = 0.52, 95% CI = 0.09-0.95) compared with the non-exercise control group. Compared with the conventional exercise control, the experimental group presented similar effects for muscle strength, functional exercise capacity, HRQoL, and dyspnea (95% CI overlapped the line of no effect for all). CONCLUSIONS: Elastic resistance training improves muscle strength in people with COPD. The current review suggests elastic resistance as a potential alternative to conventional resistance training using weight machines, as they show similar effects on muscle strength, functional exercise capacity, HRQoL, and dyspnea. IMPACT: Due to its beneficial effects, including reduced risk of exacerbation-related hospitalizations, exercise training is viewed as the cornerstone of pulmonary rehabilitation in people with COPD. This study shows that elastic resistance training can be an effective, portable, practical, and low-cost alternative to conventional weight resistance training. LAY SUMMARY: Training with elastic resistance tubes or bands-which are easy to carry, easy to use, and relatively low cost-can be an effective way to improve strength for people with COPD and promote similar benefits to those achieved with weight machines.

Resistance Training for Children and Adolescents.

Resistance training is becoming more important as an integral part of comprehensive sport training regimens, school physical education classes, and after-school fitness programs. The increasing number of youth who are involved in sport activities, coupled with the health problems of inactivity and being overweight, have resulted in increased interest in resistance training. Secular declines in measures of muscular fitness in modern-day youth highlight the need for participation in youth resistance training for nonathletes as well as athletes. Parents often ask pediatricians to offer advice regarding the safety, benefits, and implementation of an effective resistance-training program. This report is a revision of the 2008 American Academy of Pediatrics policy statement and reviews current information and research on the benefits and risks of resistance training for children and adolescents.

The effect of bed rest on balance control in healthy adults: A systematic scoping review.

The objective of this study was to determine the effect of bed rest on balance control and the mechanisms responsible for these changes. Searches were conducted in six databases. Studies had to be conducted on healthy adults who were subjected to bed rest (≥5 days), with balance control measures obtained before and after bed rest in order to be included. Risk of bias was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. After screening 9,785 articles, 18 were included for qualitative synthesis. Fifteen studies found decrements in at least one balance control measure following bed rest, either compared to baseline or controls, with eight studies observing impairments in >50% of their balance control measures. Of the 14 studies that included an intervention, four (mechanical stimuli, lower-body negative pressure, and training targeting strength, balance and/or aerobic capacity) successfully offset the majority of balance control deficits and targeted the musculoskeletal and cardiovascular systems. The findings of this review support bed rest negatively affecting balance control in healthy individuals. In clinical populations, these deficits may be further accentuated due to various comorbidities that impact balance control systems. PROSPERO Registration: CRD42018098887.

Implications of habitual endurance and resistance exercise for dynamic cerebral autoregulation.

NEW FINDINGS: What is the central question of this study? Does habitual resistance and endurance exercise modify dynamic cerebral autoregulation? What is the main finding and its importance? To the authors' knowledge, this is the first study to directly assess dynamic cerebral autoregulation in resistance-trained individuals, and potential differences between exercise training modalities. Forced oscillations in blood pressure were induced by repeated squat-stands, from which dynamic cerebral autoregulation was assessed using transfer function analysis. These data indicate that dynamic cerebral autoregulatory function is largely unaffected by habitual exercise type, and further document the systemic circulatory effects of regular exercise. ABSTRACT: Regular endurance and resistance exercise produce differential but desirable physiological adaptations in both healthy and clinical populations. The chronic effect of these different exercise modalities on cerebral vessels' ability to respond to rapid changes in blood pressure (BP) had not been examined. We examined dynamic cerebral autoregulation (dCA) in 12 resistance-trained (mean ± SD, 25 ± 6 years), 12 endurance-trained (28 ± 9 years) and 12 sedentary (26 ± 6 years) volunteers. The dCA was assessed using transfer function analysis of forced oscillations in BP vs. middle cerebral artery blood velocity (MCAv), induced via repeated squat-stands at 0.05 and 0.10 Hz. Resting BP and MCAv were similar between groups (interaction: both P ≥ 0.544). The partial pressure of end-tidal carbon dioxide ( PETCO2 ) was unchanged (P = 0.561) across squat-stand manoeuvres (grouped mean for absolute change +0.6 ± 2.3 mmHg). Gain and normalized gain were similar between groups across all frequencies (both P ≥ 0.261). Phase showed a frequency-specific effect between groups (P = 0.043), tending to be lower in resistance-trained (0.63 ± 0.21 radians) than in endurance-trained (0.90 ± 0.41, P = 0.052) and -untrained (0.85 ± 0.38, P = 0.081) groups at slower frequency (0.05 Hz) oscillations. Squat-stands induced mean arterial pressure perturbations differed between groups (interaction: P = 0.031), with greater changes in the resistance (P < 0.001) and endurance (P = 0.001) groups compared with the sedentary group at 0.05 Hz (56 ± 13 and 49 ± 11 vs. 35 ± 11 mmHg, respectively). The differences persisted at 0.1 Hz between resistance and sedentary groups (49 ± 12 vs. 33 ± 7 mmHg, P < 0.001). These results indicate that dCA remains largely unaltered by habitual endurance and resistance exercise with a trend for phase to be lower in the resistance exercise group at lower fequencies.

Impact of inpatient cardiac rehabilitation on Barthel Index score and prognosis in patients with acute decompensated heart failure.

BACKGROUND: Although cardiac rehabilitation (CR) can improve exercise capacity and quality of life in patients with chronic heart failure (HF), the long-term prognostic influence of inpatient CR on patients with acute decompensated HF (ADHF) is not well established. We examined the impact of inpatient CR on disability and prognosis in patients with ADHF. METHODS: A total of 171 patients admitted for ADHF underwent CR that included resistance training and aerobic exercise. Patient disability was evaluated using Barthel Index (BI) scores at pre- (BIpre) and post- (BIpost) rehabilitation. All-cause mortality was retrospectively recorded after discharge. RESULTS: In the study cohort (median age: 76 years), 46 patients experienced all-cause mortality during a median of 478 days of follow-up. Impaired BIpost (i.e., BI < 60) was significantly correlated with older age and lower albumin, hemoglobin, estimated glomerular filtration rate (eGFR), and B-type natriuretic peptide (BNP). In Kaplan-Meier analysis, impaired BIpre and BIpost were significantly associated with all-cause mortality. Better outcomes were observed for improved BI (ΔBI > 15) among patients with impaired baseline BI. BIpost was an independent predictor of all-cause mortality after adjusting for age, sex, eGFR, BNP, hemoglobin, albumin, and left ventricular ejection fraction. CONCLUSIONS: Inpatient CR led to improvements in disabilities among patients with ADHF. Baseline disabilities were associated with a poor prognosis. Greater improvements in BI to inpatient CR were significantly related to better outcomes in patients with impaired baseline BI. CR should be indicated for patients with ADHF.

Effects of ß-hydroxy-ß-methylbutyrate (HMB) supplementation in addition to multicomponent exercise in adults older than 70 years living in nursing homes, a cluster randomized placebo-controlled trial: the HEAL study protocol.

BACKGROUND: Evidence supports the fact that multicomponent exercise and HMB supplementation are, separately, effective in improving older adult's health and palliate functional metabolic diseases in older people. However, the true effect of HMB supplementation combined with a tailored exercise program in frail older adults is still unknown. Thus, the aim of the HEAL (HMB + Exercise = Adults Living longer) study is to assess the effects of the combination of a daily multicomponent exercise and resistance training (VIVIFRAIL program) intervention in addition to HMB supplementation on older adults' health. METHODS/DESIGN: A 24-week cluster randomized, double-blind, placebo-controlled study will be conducted on 104 adults ≥70 years. Nursing homes will be randomized to either of four groups: Ex-HMB (exercise intervention with HMB), Ex-Plac (exercise intervention with placebo), NoEx-HMB (no exercise intervention with HMB), and Controls (No exercise and no HMB). Intervention groups which include exercise will complete the individualized multicomponent (strength, balance and cardiovascular exercises) training program VIVIFRAIL. Intervention groups which include HMB supplementation will receive a 3 g/daily dose of free acid HMB in powder form. The primary outcome measure is the functional capacity. Secondary outcome measures are muscle strength and power, frailty and fall risk, body composition, biochemical analyses and cardiometabolic risk factor, disability and comorbidity, cognitive function and depression. DISCUSSION: The findings of the HEAL study will help professionals from public health systems to identify cost-effective and innovative actions to improve older people's health and quality of life, and endorse exercise practice in older adults and people living in nursing homes. TRIAL REGISTRATION: NCT03827499 ; Date of registration: 01/02/2019.

Effects of resistance training on impulse above end-test torque and muscle fatigue.

NEW FINDINGS: What is the central question of this study? What role do neuromuscular fatigue mechanisms play in resistance training-induced adaptations of the impulse above end-test torque (IET) after the training period? What is the main finding and its importance? IET and global and peripheral fatigue were increased after a short period of resistance training. Thus, resistance training-induced adaptations in neuromuscular fatigue seem to contribute to enhanced IET after the training period. ABSTRACT: Short-term resistance training has a positive influence on the curvature constant of the power-duration relationship (W'). The physiological mechanism of W' enhancement after resistance training is unclear. This study aimed to determine whether one-leg maximal isometric resistance training influences (1) impulse above end-test torque (IET; an analogue of W') during a 5 min all-out isometric test; and (2) exercise tolerance (limit of tolerance, Tlim) and neuromuscular fatigue during severe exercise (i.e. above end-test torque; ET). Sixteen healthy active males participated in a 3-week unilateral knee extensor resistance-training programme, and 10 matched subjects participated as controls. The subjects were instructed to ramp up to 100% of maximal voluntary contraction (MVC) over 1 s, hold it for 3 s, and relax. Each repetition had a 2 s interval (10) and each set, a 2 min interval (3). MVC (18.6%) and muscle thickness (12.8%) were significantly improved after training. Significantly greater global (i.e. reduced MVC, 43.2 ± 13.5% vs. 58.9 ± 6.9%) and peripheral (51.7 ± 13.6% vs. 57.3 ± 15.3%) fatigue, IET (26%) and Tlim (92%) were obtained after resistance training. Moreover, both global (r = 0.57, P < 0.05) and peripheral fatigue (r = 0.55, P < 0.05) accrued during severe exercise were associated with IET. However, echo intensity, which reflects muscle quality, ET and central fatigue remained unchanged throughout the training period. No significant changes in the control group for any variable were observed. Resistance training-induced adaptations in muscle size and neuromuscular fatigue seem to contribute to enhanced IET and Tlim after the training period.

What is known about the effects of exercise or training to reduce skeletal muscle impairments of patients with myotonic dystrophy type 1? A scoping review.

BACKGROUND: Myotonic dystrophy type 1 (DM1) is a neuromuscular disease characterized by multisystemic involvements including a progressive loss of maximal muscle strength and muscle wasting. Poor lower-limb strength is an important factor explaining disrupted social participation of affected individuals. This review aims to map what is known about the effects of exercise and training programs undertaken to counteract skeletal muscle impairments in DM1 patients. METHODS: Medline, CINAHL and EMBASE databases were searched. Regarding study eligibility, title and abstract of 704 studies followed by 45 full articles were reviewed according to the following eligibility criteria. Inclusion: (1) humans with DM1 and (2) experimental protocol relying on exercise or training. Exclusion: (1) studies that do not evaluate skeletal muscle responses or adaptations, (2) reviews covering articles already included and (3) pharmacological intervention at the same time of exercise or training program. RESULTS: Twenty-one papers were selected for in-depth analysis. Different exercise or training protocols were found including: acute exercise, neuromuscular electric stimulation, strength training, aerobic training, balance training and multiple rehabilitation interventions. Seven studies reported clinical measurements only, five physiological parameters only and nine both types. CONCLUSION: This scoping review offers a complete summary of the current scientific literature on the effect of exercise and training in DM1 and a framework for future studies based on the concomitant evaluation of the several outcomes in present literature. Although there were a good number of studies focusing on clinical measurements, heterogeneity between studies does not allow to identify what are the adequate training parameters to obtain exercise or training-induced positive impacts on muscle function. Scientific literature is even more scarce regarding physiological parameters, where much more research is needed to understand the underlying mechanisms of exercise response in DM1.

Does resistance training modulate cardiac autonomic control? A systematic review and meta-analysis.

PURPOSE: To systematically evaluate the literature on the effects of resistance training (RT) on cardiac autonomic control in healthy and diseased individuals. METHODS: Electronic databases Pubmed, PEDro, and Scopus were systematically searched from their inception up to June 2018. Randomized controlled trials, quasi-experimental trials, and cross-over controlled trials investigating the effect of RT (of at least 4 weeks duration) on cardiac autonomic control assessed either by linear or non-linear measures of heart rate variability (HRV), baroreflex sensitivity, or post-exercise heart rate recovery were included. Of the studies retrieved, 28 were included in the systematic review. Meta-analysis was performed on 21 studies of the total 28 studies. RESULTS: Quality and characteristic assessment revealed fair quality evidence. The majority of literature on healthy humans suggested no change in cardiac autonomic control following RT. Standardized mean differences (SMD) showed a significant effect of RT on root mean square of successive differences between adjacent inter-beat (R-R) intervals (RMSSD) [SMD 0.96, 95% confidence interval (CI) 0.20-1.73; p = 0.01], ratio of low- to high-frequency power of HRV (LF/HF ratio; SMD -0.72, 95% CI -1.03 to -0.42; p < 0.00001), standard deviation of the instantaneous beat-to-beat variability (SD1; SMD 1.78, 95% CI 1.07-2.49, p < 0.00001), and sample entropy (SMD 1.17, 95% CI 0.36-1.97, p = 0.005) in diseased individuals. CONCLUSION: This rigorous systematic analysis revealed that RT has no or minimal effects on cardiac autonomic control of healthy individuals, but RT leads to improvement in cardiac autonomic control of diseased individuals.

Effects of Aerobic and Resistance Exercise in Older Adults With Rheumatoid Arthritis: A Randomized Controlled Trial.

OBJECTIVE: To evaluate the effect of a moderate-to-high-intensity, aerobic and resistance exercise with person-centered guidance in older adults with rheumatoid arthritis (RA), through a randomized controlled multicenter trial. METHODS: Older adults (ages 65-75 years) with RA (n = 74) were randomized to either a 20-week exercise intervention at a gym (n = 36) or to home-based exercise of light intensity (n = 38). Assessments were performed at baseline, at 20 weeks, and at 12 months. The primary outcome was the difference in the Health Assessment Questionnaire disability index (HAQ DI) score, and the secondary outcomes were the differences in physical fitness assessed by a cardiopulmonary exercise test, an endurance test, the timed up and go test, the sit to stand test, and an isometric elbow flexion force measurement. RESULTS: No significant differences between the groups were found for the primary outcome, HAQ DI score. Within the intervention group there was a significant improvement in the HAQ DI score when compared to baseline (P = 0.022). Aerobic capacity (P < 0.001) and 3 of 4 additional performance-based tests of endurance and strength significantly improved (P < 0.05) in the intervention group when compared to the control group. In the intervention group, 71% of patients rated their health as much or very much improved compared to 24% of patients in the control group (P < 0.001). At the 12-month follow-up, there were no significant differences in change between the 2 groups on the HAQ DI score. A significant between-group difference was found for change in an endurance test (P = 0.022). CONCLUSION: Aerobic and resistance exercise with person-centered guidance improved physical fitness in terms of aerobic capacity, endurance, and strength in older adults with RA.

Effects of resistance training on arterial compliance and plasma endothelin-1 levels in healthy men.

Arterial compliance (AC) is an index of the elasticity of large arteries. Endothelial dysfunction has been reported to result in reduced arterial compliance, which represents increased arterial stiffness. A reduction in AC is elicited by high-intensity resistance training, however the mechanisms are obscure. Because a single bout of resistance exercise causes a transient increase in circulating plasma endothelin-1 in humans, some vasoconstrictors may play a role in the mechanisms. The present study aimed to investigate whether resistance training-induced decrease in AC is associated with changes in circulating vasoconstrictors levels in young men. Young sedentary men were assigned to control (n=5) or training (n=9) groups. The training group performed four-week high-intensity resistance training (weight training exercise; three sessions/week). We measured AC and plasma levels of endothelin-1, angiotensin II, and norepinephrine before and after intervention. Resistance training significantly decreased AC, whereas the changes in plasma levels of neither endothelin-1, nor angiotensin II, nor norepinephrine were significantly different between the control and the training groups. Moreover, we found no significant correlations between changes in circulating plasma levels (endothelin-1, angiotensin II, and norepinephrine) and in the AC. Despite of no alteration of the resting circulating plasma levels (endothelin-1, etc.), we cannot exclude a possibility that the tissue/local concentrations of vasoconstrictors (endothelin-1, etc.) around the vessels might be increased and also involved in a reduction of AC in the training group. Taken together, the present results suggest that circulating vasoconstrictors (endothelin-1, etc.) in plasma are not involved in a reduction in AC by the resistance training.

Resistance training does not alter same-day sleep architecture in institutionalized older adults.

Sleep disturbance is a common symptom in institutionalized older adults that reduces their quality of life and may contribute to progression of cognitive impairment. While we found that a 7-week combination of resistance training, walking and social activity significantly improved sleep in institutionalized older adults compared with a usual care control group, no one to our knowledge has determined the acute effects of resistance training on same-day sleep in this population. Given the effort required to promote exercise adherence in institutionalized older adults and to obtain a positive training effect, understanding of the acute effects of resistance training on same-day sleep architecture should be elucidated, especially with respect to unintended consequences. This secondary data analysis assessed if resistance training altered the same-day sleep architecture in institutionalized older adults. Forty-three participants (age 81.5 ± 8.1 years, male = 17, female = 26) had two attended overnight polysomnography tests in their rooms for sleep architecture analysis; one polysomnography with same-day resistance training, one without any resistance training. Resistance training consisted of chest and leg press exercises (three sets, eight repetitions, 80% predicted one-repetition maximum). There were no significant changes in sleep architecture between either polysomnography nights; sleep efficiency (P = 0.71), time in non-rapid eye movement stages (P = 0.50), time in rapid eye movement stages (P = 0.14), time awake (P = 0.56), time until sleep onset (P = 0.47), total sleep stage shifts (P = 0.65) or rapid eye movement sleep stage latency (P = 0.57). Our results show no acute same-day effects of resistance training on sleep architecture in institutionalized older adults. Clinical Trial Registration ClinicalTrials.gov Identifier: NCT00888706.

Effects of home-based exercise on pre-dialysis chronic kidney disease patients: a randomized pilot and feasibility trial.

BACKGROUND: Only a few research is available on the effects of home-based exercise training on pre-dialysis chronic kidney disease (CKD) patients. Therefore, we aimed to elucidate the effect of home-based exercise therapy on kidney function and arm and leg muscle strength in pre-dialysis CKD patients. METHODS: Thirty-six male stage 3-4 pre-dialysis CKD patients (age, 68.7 ± 6.8 years; estimated glomerular filtration rate (eGFR), 39.0 ± 11.6 ml/min/1.73 m2) who were being treated as outpatients were included. The subjects were randomly assigned to an exercise intervention group (Ex group: 18) and a control group (C group: 18). The Ex group wore accelerometer pedometers and were instructed to perform home-based aerobic and resistance exercises, such as brisk walking for 30 min per day, for 12 months. The C group subjects wore accelerometer pedometers but received no exercise therapy guidance; the number of steps covered during normal daily activities was recorded for the C group. The outcome measures were changes in kidney function and handgrip and knee extension muscle strength. Values at the baseline (T1) and 12 months later (T2) were compared. RESULTS: There were no significant differences in baseline characteristics between the two groups; however, the C group was more physically active than the Ex group. Eight subjects dropped out, and 28 subjects (14 in each group) were included in the final analysis. Physical activity increased significantly only in the Ex group. Grip strength (F = 7.0, p = 0.01) and knee extension muscle strength (F = 14.3, p < 0.01) were found to improve only in the Ex group. Further, the changes in eGFR were not significantly different between the two groups (F = 0.01, p = 0.93). CONCLUSIONS: Home-based exercise therapy for pre-dialysis CKD patients was feasible and improved arm and leg muscle strength without affecting kidney function. TRIAL REGISTRATION: UMIN Clinical Trials Registry ( UMIN000005091 ). Registered 2/15/2011.

Efectos del entrenamiento de fuerza en la velocidad de golpeo en tenistas jóvenes / Effects of strength training on hitting speed in young tennis players

La velocidad de golpeo es uno de los factores fundamentales para el rendimiento en tenis competitivo. El objetivo del estudio fue determinar el efecto de dos métodos de entrenamiento de fuerza sobre la velocidad de golpeo en tenis. 20 jugadores de nivel regional (promedio ± SD: edad 15.5 ± 0.9 años; peso 61.4 ± 7.6 Kg; talla 170.3 ± 9.4 cm) fueron asignados aleatoriamente en tres grupos. Durante 8 semanas a 3 días por sem-1, un grupo realizó un entrenamiento adicional con sobrecargas (SC), un segundo grupo entrenamiento adicional mediante lanzamientos con balón medicinal y banda elástica (L) y un tercer grupo (C, control) únicamente realizó el entrenamiento técnico-táctico. Todos los grupos mejoraron los niveles de fuerza, excepto el grupo control. El grupo SC obtuvo mayores incrementos en la velocidad de servicio. El grupo L mejoró la velocidad de lanzamiento de balón medicinal aunque no hubo transferencia en la velocidad de golpeo (AU)

Nowadays, hitting speed is an important component of tennis performance. The purpose of this study was to determine the effect of two different strength training methods on hitting speed. 20 tennis players were (mean ± SD: age 15.5 ± 0.9 years; weight 61.4 ± 7.6 kg; height 170.3 ± 9.4 cm) randomly divided into 3 groups. During 8 weeks with a frequency of 3 days per week, the first group (SC) performed one additional training with overloads, the second group (L) completed an additional training with medicine ball and elastic band; and the third group (C, control), only completed the technical-tactical training. Each group increased their strength, except the control group. SC group had the best improvement in serve speed. L group increased the strength levels although there was no transfer from the improved strength to the hitting speed (AU)

Muscle growth: To infinity and beyond?

Strength increases following training are thought to be influenced first by neural adaptions and second by large contributions from muscle growth. This is based largely on the idea that muscle growth is a slow process and that a plateau in muscle growth would substantially hinder long-term increases in strength. This Review examines the literature to determine the time course of skeletal muscle growth in the upper and lower body and to determine whether and when muscle growth plateaus. Studies were included if they had at least 3 muscle size time points, involved participants 18 years or older, and used a resistance training protocol. Muscle growth occurs sooner than had once been hypothesized, and this adaptation is specific to the muscle group. Furthermore, the available studies indicate that the muscle growth response will plateau, and additional growth is not likely to occur appreciably beyond this initial plateau. However, the current study durations are a limitation. Muscle Nerve 56: 1022-1030, 2017.

Lower limb explosive strength capacity in elderly women: effects of resistance training and healthy diet.

The effects of 24 wk of resistance training combined with a healthy diet on lower limb explosive strength capacity were investigated in a population of healthy elderly women. Participants (n = 63; 67.5 ± 0.4 yr) were randomized into three groups; resistance training (RT), resistance training and healthy diet (RT-HD), and control (CON). Progressive resistance training was performed at a load of 75-85% one-repetition maximum. A major adjustment in the healthy dietary approach was an n-6/n-3 polyunsaturated fatty acid (PUFA) ratio below 2. Lower limb maximal strength, explosive force capacity during dynamic and isometric movements, whole body lean mass, and physical function were assessed. Whole body lean mass significantly increased by 1.5 ± 0.5% in RT-HD only. Isometric strength performance during knee extension as well as the performance in the five sit-to-stand and single-leg-stance tests increased similarly in RT and RT-HD. Improvements in dynamic peak power and time to reach peak power (i.e shorter time) during knee extension occurred in both RT (+15.7 ± 2.6 and -11.0 ± 3.8%, respectively) and RT-HD (+24.6 ± 2.6 and -20.3 ± 2.7%, respectively); however, changes were significantly larger in RT-HD. Similarly, changes in peak force and rate of force development during squat jump were higher in RT-HD (+58.5 ± 8.4 and +185.4 ± 32.9%, respectively) compared with RT (+35.7 ± 6.9 and +105.4 ± 22.4%, respectively). In conclusion, a healthy diet rich in n-3 PUFA can optimize the effects of resistance training on dynamic explosive strength capacity during isolated lower limb movements and multijoint exercises in healthy elderly women.NEW & NOTEWORTHY Age-related decline in lower limb explosive strength leads to impaired ability to perform daily living tasks. The present randomized controlled trial demonstrates that a healthy diet rich in n-3 polyunsaturated fatty acid (n-3 PUFA) enhances resistance training-induced gains in dynamic explosive strength capacity during isolated lower limb movements and multijoint exercises in healthy elderly women. This supports the use of strategies combining resistance training and dietary changes to mitigate the decline in explosive strength capacity in older adults.

Eight weeks of local vibration training increases dorsiflexor muscle cortical voluntary activation.

The aim of this study was to evaluate the effects of an 8-wk local vibration training (LVT) program on functional and corticospinal properties of dorsiflexor muscles. Forty-four young subjects were allocated to a training (VIB, n = 22) or control (CON, n = 22) group. The VIB group performed twenty-four 1-h sessions (3 sessions/wk) of 100-Hz vibration applied to the right tibialis anterior. Both legs were tested in each group before training (PRE), after 4 (MID) and 8 (POST) wk of training, and 2 wk after training (POST2W). Maximal voluntary contraction (MVC) torque was assessed, and transcranial magnetic stimulation (TMS) was used to evaluate cortical voluntary activation (VATMS), motor evoked potential (MEP), cortical silent period (CSP), and input-output curve parameters. MVC was significantly increased for VIB at MID for right and left legs [+7.4% (P = 0.001) and +6.2% (P < 0.01), respectively] and remained significantly greater than PRE at POST [+12.0% (P < 0.001) and +10.1% (P < 0.001), respectively]. VATMS was significantly increased for right and left legs at MID [+4.4% (P < 0.01) and +4.7% (P < 0.01), respectively] and at POST [+4.9% (P = 0.001) and +6.2% (P = 0.001), respectively]. These parameters remained enhanced in both legs at POST2W MEP and CSP recorded during MVC and input-output curve parameters did not change at any time point for either leg. Despite no changes in excitability or inhibition being observed, LVT seems to be a promising method to improve strength through an increase of maximal voluntary activation, i.e., neural adaptations. Local vibration may thus be further considered for clinical or aging populations.NEW & NOTEWORTHY The effects of a local vibration training program on cortical voluntary activation measured with transcranial magnetic stimulation were assessed for the first time in dorsiflexors, a functionally important muscle group. We observed that training increased maximal voluntary strength likely because of the strong and repeated activation of Ia spindle afferents during vibration training that led to changes in the cortico-motoneuronal pathway, as demonstrated by the increase in cortical voluntary activation.

Benefits of resistance exercise in lean women with fibromyalgia: involvement of IGF-1 and leptin.

BACKGROUND: Chronic pain and fatigue improves by exercise in fibromyalgia (FM) but underlying mechanisms are not known. Obesity is increased among FM patients and associates with higher levels of pain. Symptom improvement after aerobic exercise is affected by body mass index (BMI) in FM. Metabolic factors such as insulin-like growth factor 1 (IGF-1) and leptin may be involved. In this study, the aim was to evaluate the role of metabolic factors in lean, overweight and obese women during resistance exercise, in relation to symptom severity and muscle strength in women with FM. METHODS: Forty-three women participated in supervised progressive resistance exercise, twice weekly for 15-weeks. Serum free and total IGF-1, IGF-binding protein 3 (IGFBP3), adiponectin, leptin and resistin were determined at baseline and after 15-weeks. Level of current pain was rated on a visual analogue scale (0-100 mm). Level of fatigue was rated by multidimensional fatigue inventory (MFI-20) subscale general fatigue (MFIGF). Knee extension force, elbow flexion force and handgrip force were assessed by dynamometers. RESULTS: Free IGF-1 (p = 0.047), IGFBP3 (p = 0.025) and leptin (p = 0.008) were significantly decreased in lean women (n = 18), but not in the overweight (n = 17) and the obese (n = 8). Lean women with FM benefited from resistance exercise with improvements in current pain (p= 0.039, n = 18), general fatigue (MFIGF, p = 0.022, n = 18) and improved elbow-flexion force (p = 0.017, n = 18). In overweight and obese women with FM there was no significant improvement in pain or fatigue but an improvement in elbow flexion (p = 0.049; p = 0.012) after 15 weeks of resistance exercise. CONCLUSION: The clearest clinical response to resistance exercise was found in lean patients with FM. In these individuals, individualized resistance exercise was followed by changes in IGF-1 and leptin, reduced pain, fatigue and improved muscular strength. In overweight and obese women FM markers of metabolic signaling and clinical symptoms were unchanged, but strength was improved in the upper limb. Resistance exercise combined with dietary interventions might benefit patients with FM and overweight. TRIAL REGISTRATION: The trial was registered 21 of October 2010 with ClinicalTrials.gov identification number: NCT01226784 .