Effects of strength training and vascular occlusion

The purpose of our study was to determine if vascular Occlusion produced an additive effect on muscle hypertrophy and strength performance with high strength training loads. Sixteen physically active men were divided into two groups: high-intensity (HI = 6 RM) and moderate-intensity training (MI = 12 RM). An occlusion cuff was attached to the proximal end of the right thigh, so that blood flow was reduced during the exercise. The left leg served as a control, thus was trained without vascular occlusion. Knee extension 1 RM and quadriceps cross-sectional area (MRI) were evaluated pre- and post-8 weeks of training. We only found a main time effect for both strength gains and quadriceps hypertrophy (p < 0.001). Therefore, we conclude that vascular occlusion in combination with high-intensity strength training does not augment muscle strength or hypertrophy when compared to high-intensity strength training alone.

Time course of strength and power recovery after resistance training with different movement velocities

Ide, BN, Leme, TCF, Lopes, CR, Moreira, A, Dechechi, CJ, Sarraipa, MF, da Mota, GR, Brenzikofer, R, and Macedo, DV. Time course of strength and power recovery after resistance training with different movement velocities. J Strength Cond Res 25(7): 2025-2033, 2011-The purpose of this study was to evaluate the time course of strength and power recovery after a single bout of strength training designed with fast and slow contraction velocities. Nineteen male subjects were randomly divided into 2 groups: the slow-velocity contraction (SV) group and the fast velocity contraction (FV) group. Resistance training protocols consisted of 5 sets of 12 repetition maximum (5 x 12RM) with 50 seconds of rest between sets and 2 minutes between exercises. Contraction velocity was controlled by the execution time for each repetition (SV-6 seconds to complete concentric and eccentric phases and for FV-1.5 seconds). Leg Press 45 degrees 1RM (LP 1RM), horizontal countermovement jump (HCMJ), and right thigh circumference (TC) were accessed in 6 distinct moments: base (1 week before exercise), 0 (immediately after exercises), 24, 48, 72, and 96 hours after exercise protocol. The SV and FV presented significant LP 1RM decrements at 0, and these were still evident 24-48 hours postexercise. The magnitude of decline was significantly (p<0.05) higher for FV. The SV and FV presented significant HCMJ decrements at 0, but only for FV were these still evident 24-72 hours postexercise. The SV and FV presented significant TC increments at 0, and these were still evident 24-48 hours postexercise for SV but for FV it continued up to 96 hours. The magnitude of increase was significantly (p<0.05) higher for FV. In conclusion, the fast contraction velocity protocol resulted in greater decreases in LP 1RM and HCMJ performance, when compared with slow velocity. The results lead us to interpret that this variable may exert direct influence on acute muscle strength and power generation capacity.

Adenotonsillectomy improves the strength of respiratory muscles in children with upper airway obstruction

Objective: The aim of this paper is to study the respiratory muscle strength by evaluating the maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP) and lung volume before and 3 and 6 months after adenotonsillectomy. This is an interventional, before and after trial. It was set at the Department of Otolaryngology. University of Sao Paulo, School of Medicine. We included 29 children (6-13 years old), both genders, consecutively recruited from the waiting list for adenotonsillectomy. Children were submitted to maximal inspiratory pressures (MIP), maximal expiratory pressure (MEP) evaluation using an analog manovacuometer, lung volume, using incentive expirotometer and thoracic and abdominal perimeter using a centimeter tape. Children were evaluated in 3 different moments: 1 week before and 3 and 6 months after surgery. Results: MIP improved significantly 3 months (p < 0.001) after adenotonsillectomy and MEP did not change (p = 1). There were increases in lung volume (p = 000), chest (p = 0.017) and abdominal perimeter (p = 0.05). Six months after surgery, all parameters improved. MIP (p = 0), MEP (p = 0), lung volume (p = 0.02), chest (p = 0.034) and abdominal perimeter (p = 0.23). Conclusion: This study suggests that there was an improvement in respiratory muscular strength, once there was a significant improvement in maximal inspiratory pressure, lung volume and other parameters after adenotonsillectomy. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

Effects of low level laser therapy (808 nm) on physical strength training in humans

Recent studies have investigated whether low level laser therapy (LLLT) can optimize human muscle performance in physical exercise. This study tested the effect of LLLT on muscle performance in physical strength training in humans compared with strength training only. The study involved 36 men (20.8 +/- 2.2 years old), clinically healthy, with a beginner and/or moderate physical activity training pattern. The subjects were randomly distributed into three groups: TLG (training with LLLT), TG (training only) and CG (control). The training for TG and TLG subjects involved the leg-press exercise with a load equal to 80% of one repetition maximum (1RM) in the leg-press test over 12 consecutive weeks. The LLLT was applied to the quadriceps muscle of both lower limbs of the TLG subjects immediately after the end of each training session. Using an infrared laser device (808 nm) with six diodes of 60 mW each a total energy of 50.4 J of LLLT was administered over 140 s. Muscle strength was assessed using the 1RM leg-press test and the isokinetic dynamometer test. The muscle volume of the thigh of the dominant limb was assessed by thigh perimetry. The TLG subjects showed an increase of 55% in the 1RM leg-press test, which was significantly higher than the increases in the TG subjects (26%, P = 0.033) and in the CG subjects (0.27%, P < 0.001). The TLG was the only group to show an increase in muscle performance in the isokinetic dynamometry test compared with baseline. The increases in thigh perimeter in the TLG subjects and TG subjects were not significantly different (4.52% and 2.75%, respectively; P = 0.775). Strength training associated with LLLT can increase muscle performance compared with strength training only.

Preoperative respiratory muscle dysfunction is a predictor of prolonged invasive mechanical ventilation in cardiorespiratory complications after heart valve surgery

Objective: To verify whether preoperative respiratory muscle strength and ventilometric parameters, among other clinically relevant factors, are associated with the need for prolonged invasive mechanical ventilation (PIMV) due to cardiorespiratory complications following heart valve surgery. Methods: Demographics, preoperative ventilometric and manometric data, and the hospital course of 171 patients, who had undergone heart valve surgery at Hospital das Clinicas da Faculdade de Medicina de Ribeirao Preto, were prospectively collected and subjected to univariate analysis for identifying the risk factors for PIMV. Results: The hospital mortality was 7%. About 6% of the patients, who had undergone heart valve surgery required PIMV because of postoperative cardiorespiratory dysfunction. Their hospital mortality was 60% (vs 4%, p < 0.001). Univariate analysis revealed that preoperative respiratory muscle dysfunction, characterized by maximal inspiratory and expiratory pressure below 70% of the predicted values combined with respiratory rate above 15 rpm during ventilometry, was associated with postoperative PIMV (p = 0.030, odds ratio: 50, 95% confidence interval (CI): 1.2-18). Postoperative PIMV was also associated with: (1) body mass index (BMI) < 18.5 (odds ratio: 7.2, 95% CI: 1.5-32), (2) body weight < 50 kg (odds ratio: 6.5, 95% CI: 1.6-25), (3) valve operation due to acute endocarditis (odds ratio: 5.5, 95% CI: 0.98-30), and (4) concomitant operation for mitral and tricuspid valve dysfunction (p = 0.047, odds ratio: 5.0, 95% CI: 1.1-22). Conclusion: Our results have demonstrated that respiratory muscle dysfunction, among other clinical factors, is associated with the need for PIMV due to cardiovascular or pulmonary dysfunction after heart valve surgery. (C) 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B. V. All rights reserved.

Effects of Inspiratory Muscle Training on Muscular and Pulmonary Function After Bariatric Surgery in Obese Patients

This study seeks to assess the effect of inspiratory muscle training (IMT) on pulmonary function, respiratory muscle strength, and endurance in morbidly obese patients submitted to bariatric surgery. Thirty patients were randomly assigned to sham muscular training, or to IMT with a threshold device (40% of maximum inspiratory pressure, MIP), for 30 min/day, from the 2nd until 30th postoperative (PO) day. All of them were submitted to a standard respiratory kinesiotherapy and early deambulation protocol. Data on spirometry, maximum static respiratory pressures, and respiratory muscle endurance were collected on the PO days 2, 7, 14, and 30 in a blinded matter. IMT enabled increases in PO MIP and endurance, and an earlier recovery of the spirometry parameters FEV(1), PEF, and FEF(25-75%). Comparing to preoperative values, MIP was increased by 13% at the 30th PO day in the trained group, whereas control group had a reduction of 8%, with higher values for the IMT group (30th PO, IMT-130.6 +/- 22.9 cmH(2)O; controls-112.9 +/- 25.1 cmH(2)O; p < 0.05). Muscular endurance at the 30th PO day was increased in the trained group comparing to preoperative value (61.5 +/- 39.6 s vs 114.9 +/- 55.2 s; p < 0.05), a finding not observed in the control group (81.7 +/- 44.3 vs 95.2 +/- 42.0 s). IMT improves inspiratory muscle strength and endurance and accounts for an earlier recovery of pulmonary airflows in morbidly obese patients submitted to bariatric surgery.

Maintaining muscle mass during extended disuse: Aestivating frogs as a model species

Prolonged muscle disuse in vertebrates can lead to a pathological change resulting in muscle wasting and a loss of muscle strength. In this paper, we review muscle disuse atrophy in the vertebrates and examine the factors that influence the magnitude of the atrophic response during extended periods of inactivity, both artificially imposed (e.g. limb immobilisation) and naturally occurring, such as the quiescence associated with dormancy (e.g. hibernation and aestivation). The severity of muscle atrophy is positively correlated with mass-specific metabolic rate, and the metabolic depression that occurs during dormancy would appear to have a protective role, reducing or preventing muscle atrophy despite periods of inactivity lasting 6-9 months. In the light of these findings, the role of reactive oxygen species and antioxidants during muscle disuse is emphasised.

Outcomes after trans-tibial amputation: The relationship between quiet stance ability, strength of the hip abductor muscles and gait

Background and Purpose Previous research regarding the symmetry of trans-tibial amputees has examined weight distribution and various gait parameters between prosthetic and sound limbs. However, to date, no known research has determined if asymmetry is present in the strength of the hip abductor muscles or if correlations exist between these categories of symmetry. The purpose of the present study was, therefore, to document asymmetry present in stance, strength and gait measures, and to determine the relationship between these variables. Method Twenty-three elderly, unilateral trans-tibial amputees stood on two adjacent forceplates whilst the weight distribution and standard deviation (SD) of the anterior-posterior and the medio-lateral centre of pressure excursion (COPE) under each limb was recorded during four 40 s trials: quiet stance (QS), with eyes open and eyes closed; and even stance (ES), with eyes open and eyes closed. Gait measures (velocity, cadence, step and stride lengths, stance:swing ratio and period of double support) over 10 m of fast, yet safe walking and measures of the strength of hip abductor muscles were also obtained by use of a stride analyser and a dynamometer, respectively. Results No significant differences were found between QS and ES measures. However, significantly more weight was taken on the sound limb than on the amputated limb. Notably, more anterior-posterior movement occurred under the sound limb than the amputated limb, with this becoming more apparent with the eyes closed. Movement in the medio-lateral direction was found to be the same between sides. No differences in muscle strength or gait measures between limbs were demonstrated. However. strong hip abductor muscles were correlated with increased weight-bearing on the amputated limb, improved gait parameters and reduced medio-lateral COPE under the amputated limb. Conclusions This research confirms the asymmetrical nature of amputee stance and demonstrates symmetry of strength and gait measures between limbs. The correlations between hip abductor muscle strength, weight distribution and gait measures illustrates the importance of pre- and postoperative training of these muscles. Copyright © 2002 Whurr Publishers Ltd.

Handgrip strength

The basic function of the human hand is the manipulation and grasping of various objects in all daily activities, including work activities. This is greatly influenced by strength and manual dexterity. However age, gender and other contexts such as work or leisure activities could influence strength. Handgrip strength, a measure of maximum voluntary force of the hand, has proved to be reliable and valid as an objective parameter to evaluate the functional integrity of the hand as part of the musculoskeletal system. It correlates highly with strength in other muscular groups and is therefore considered as a good indicator of overall muscular strength and functional stress and could be used as a predictor of physical disability. Handgrip strength assessment is simple and reliable and used commonly by several investigators and health professionals, in different contexts (medical, nutritional, rehabilitation, professional settings, engineering, etc.) and with different purposes (research, diagnostic, assessment, etc.). In clinical and rehabilitation settings is of vital importance in the determination of effectiveness of several interventions and for monitoring evolution of diseases. Various ways (methods, techniques and equipments) of collecting information on grip strength have been reported. This chapter will review basic concepts on handgrip function, methodologies of assessment, contexts of application and correlates, such as physical activity, health or nutritional status. Several populations and reference values as also the relationships between handgrip and clinical status, aging, risk of disability and diseases, will be discussed.

From Mind to Body: Is Mental Practice Effective on Strength Gains? A Meta-Analysis

Mental practice is an internal reproduction of a motor act (whose intention is to promote learning and improving motor skills). Some studies have shown that other cognitive strategies also increase the strength and muscular resistance in healthy people by the enhancement of the performance during dynamic tasks. Mental training sessions may be primordial to improving muscle strength in different subjects. The aim of this study was to systematically review and meta-analiyze studies that assessed whether mental practice is effective in improving muscular strength. We conducted an electronic-computed search in Pub-Med/Medline and ISI Web of Knowledge, Scielo and manual searchs, searching papers written in English between 1991 and 2014. There were 44 studies in Pub-Med/Medline, 631 in ISI Web of Knowledge, 11 in Scielo and 3 in manual searchs databases. After exclusion of studies for duplicate, unrelated to the topic by title and summary, different samples and methodologies, a meta-analysis of 4 studies was carried out to identify the dose-response relationship. We did not find evidence that mental practice is effective in increasing strength in healthy individuals. There is no evidence that mental practice alone can be effective to induce strength gains or to optimize the training effects.

Protein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN Expert Group.

The aging process is associated with gradual and progressive loss of muscle mass along with lowered strength and physical endurance. This condition, sarcopenia, has been widely observed with aging in sedentary adults. Regular aerobic and resistance exercise programs have been shown to counteract most aspects of sarcopenia. In addition, good nutrition, especially adequate protein and energy intake, can help limit and treat age-related declines in muscle mass, strength, and functional abilities. Protein nutrition in combination with exercise is considered optimal for maintaining muscle function. With the goal of providing recommendations for health care professionals to help older adults sustain muscle strength and function into older age, the European Society for Clinical Nutrition and Metabolism (ESPEN) hosted a Workshop on Protein Requirements in the Elderly, held in Dubrovnik on November 24 and 25, 2013. Based on the evidence presented and discussed, the following recommendations are made (a) for healthy older people, the diet should provide at least 1.0-1.2 g protein/kg body weight/day, (b) for older people who are malnourished or at risk of malnutrition because they have acute or chronic illness, the diet should provide 1.2-1.5 g protein/kg body weight/day, with even higher intake for individuals with severe illness or injury, and (c) daily physical activity or exercise (resistance training, aerobic exercise) should be undertaken by all older people, for as long as possible.

Shoulder strength imbalances as injury risk in handball.

This study was conducted to analyze whether internal (IR) and external (ER) rotator shoulder muscles weakness and/or imbalance collected through a preseason assessment could be predictors of subsequent shoulder injury during a season in handball players. In preseason, 16 female elite handball players (HPG) and 14 healthy female nonathletes (CG) underwent isokinetic IR and ER strength test with use of a Con-Trex® dynamometer in a seated position with 45° shoulder abduction in scapular plane, at 60, 120 and 240°/s in concentric and at 60°/s in eccentric, for both sides. An imbalanced muscular strength profile was determined using -statistically selected cut-offs from CG values. For HPG, all newly incurred shoulder injuries were reported during the season. There were significant differences between HPG and CG only for dominant eccentric IR strength, ER/IR ratio at 240°/s and for IRecc/ERcon ratio. In HPG, IR and ER strength was higher, and ER/IR ratios lower for dominant than for nondominant side. The relative risk was 2.57 (95%CI: 1.60-3.54; P<0.05) if handball players had an imbalanced muscular strength profile. In youth female handball players IR and ER muscle strength increases on the dominant side without ER/IR imbalances; and higher injury risk was associated with imbalanced muscular strength profile.

Handgrip strength and physical activity in frail elderly

Abstract OBJECTIVE To investigate the association between handgrip strength (HS) and physical activity in physical frailty elderly. METHOD Cross-sectional quantitative study with a sample of 203 elderly calculated based on the population estimated proportion. Tests were applied to detect cognitive impairment and assessment of physical frailty. Descriptive statistics and multivariate analysis by binary logistic regression were used, and also Student's t-test and Fisher's exact test. RESULTS A total of 99 (64.3%) elderly showed decreased handgrip strength and 90 (58.4%) elderly presented decrease in physical activity levels. There was a statistically significant difference between these two components (p=0.019), in which elderly who have decreased HS have lower levels of physical activity. For low levels of physical activity and decreased HS, there was no evidence of significant difference in the probability of the classification as frail elderly (p<0.001). CONCLUSION The components handgrip strength and physical activity are associated with the frail elderly. The joint presence of low levels of physical activity and decreased handgrip strength leads to a significantly higher probability of the elderly to be categorized as frailty.