Resumos selecionados em Ciências do Esporte
Gualano AB, Bozza T, Lopes De Campos P, Roschel H, Dos Santos Costa A, Luiz Marquezi M, Benatti F, Herbert Lancha Junior A. Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion. J Sports Med Phys Fitness. 2011 Mar;51(1):82-8.
AIM: It has been demonstrated that branched-chain amino acids (BCAA) transaminase activation occurs simultaneously with exercise-induced muscle glycogen reduction, suggesting that BCAA supplementation might play an energetic role in this condition. This study aimed to test whether BCAA supplementation enhances exercise capacity and lipid oxidation in glycogen-depleted subjects. METHODS: Using a double-blind cross-over design, volunteers (N.=7) were randomly assigned to either the BCAA (300 mg . kg . day -1) or the placebo (maltodextrine) for 3 days. On the second day, subjects were submitted to an exercise-induced glycogen depletion protocol. They then performed an exhaustive exercise test on the third day, after which time to exhaustion, respiratory exchange ratio (RER), plasma glucose, free fatty acids (FFA), blood ketones and lactate were determined. BCAA supplementation promoted a greater resistance to fatigue when compared to the placebo (+17.2%). Moreover, subjects supplemented with BCAA showed reduced RER and higher plasma glucose levels during the exhaustive exercise test. CONCLUSION: In conclusion, BCAA supplementation increases resistance to fatigue and enhances lipid oxidation during exercise in glycogen-depleted subjects.
Sedano S, Matheu A, Redondo JC, Cuadrado G. Effects of plyometric training on explosive strength, acceleration capacity and kicking speed in young elite soccer players. J Sports Med Phys Fitness. 2011 Mar;51(1):50-8.
AIM: The main aim of this study was to determine the effects of a 10-week plyometric training program on explosive strength, acceleration capacity and
kicking speed in young elite soccer players. METHODS: Twenty-two players participated in the study: control group (CG), (N.=11; 18.2 ± 0.9 years) and treatment group (TG) (N.=11; 18.4 ± 1.1 years). Both groups performed technical and tactical training exercises and matches together. However, the CG players followed the regular physical conditioning program, which was replaced by a plyometric program for TG. Plyometric training took place three days a week and included jumps over hurdles, horizontal jumps and lateral jumps over hurdles. Jumping ability, 10 m sprint and kicking speed were measured on five separate occasions. RESULTS: Two-way analysis of variance (ANOVA) with repeated measures reflected that the TG demonstrated significant increases (P<0.05) in jumping ability and acceleration capacity after six weeks of training and in kicking speed with dominant and non-dominant leg after eight and ten weeks respectively. On the other hand there were no significant changes in CG players throughout the study. CONCLUSION: The main findings revealed that a 10-week plyometric program may be an effective training stimulus to improve explosive strength compared to a more conventional physical training program. The improvements in explosive strength can be transferred to acceleration capacity and kicking speed but players need time to transfer these increases.
Garber CE, Blissmer B, Deschenes MR, Franklin BA, Lamonte MJ, Lee IM, Nieman DC, Swain DP. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc. 2011 Jul;43(7):1334-59.
SUMMARY: The purpose of this Position Stand is to provide guidance to professionals who counsel and prescribe individualized exercise to apparently healthy adults of all ages. These recommendations also may apply to adults with certain chronic diseases or disabilities, when appropriately evaluated and advised by a health professional. This document supersedes the 1998 American College of Sports Medicine (ACSM) Position Stand, “The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults.” The scientific evidence
demonstrating the beneficial effects of exercise is indisputable, and the benefits of exercise far outweigh the risks in most adults. A program of regular exercise that includes cardiorespiratory, resistance, flexibility, and neuromotor exercise training beyond activities of daily living to improve and maintain physical fitness and health is essential for most adults. The ACSM recommends that most adults engage in moderate-intensity cardiorespiratory exercise training for ≥30 min·d on ≥5 d·wk for a total of ≥150 min·wk, vigorous-intensity cardiorespiratory exercise training for ≥20 min·d on ≥3 d·wk (≥75 min·wk), or a combination of moderate- and vigorous-intensity exercise to achieve a total energy expenditure of ≥500-1000 MET·min·wk. On 2-3 d·wk, adults should also perform resistance exercises for each of the major muscle groups, and neuromotor exercise involving balance, agility, and coordination. Crucial to maintaining joint range of movement, completing a series of flexibility exercises for each the major muscle-tendon groups (a total of 60 s per exercise) on ≥2 d·wk is recommended. The exercise program should be modified according to an individual’s habitual physical activity, physical function, health status, exercise responses, and stated goals. Adults who are unable or unwilling to meet the exercise targets outlined here still can benefit from engaging in amounts of exercise less than recommended. In addition to exercising regularly, there are health benefits in concurrently reducing total time engaged in sedentary pursuits and also by interspersing frequent, short bouts of standing and physical activity between periods of sedentary activity, even in physically active adults. Behaviorally based exercise interventions, the use of behavior change strategies, supervision by an experienced fitness instructor, and exercise that is pleasant and enjoyable can improve adoption and adherence to prescribed exercise programs. Educating adults about and screening for signs and symptoms of CHD and gradual progression of exercise intensity and volume may reduce the risks of exercise. Consultations with a medical professional and diagnostic exercise testing for CHD are useful when clinically indicated but are not recommended for universal screening to enhance the safety of exercise.
Libardi CA, de Souza GV, Cavaglieri CR, Madruga VA, Chacon-Mikahil MP. Effect of Resistance, Endurance and Concurrent Training on TNF-α, IL-6 and CRP. Med Sci Sports Exerc. 2011 Jun 21. [Epub ahead of print]
PURPOSE:: The aim of the present study was to evaluate the effects of 16 weeks of resistance, endurance and concurrent training on inflammatory markers, C-reactive protein (CRP) and functional capacity in sedentary middle-aged men. METHODS: Healthy subjects were randomized into resistance training (RT, n = 11), endurance training (ET, n = 12), concurrent training (CT, n = 11) and a control group (CG, n = 13). The subjects performed three weekly sessions lasting about 60 minutes, for 16 weeks. Maximal strength was tested in bench press and leg press. The peak oxygen uptake (VO2peak) was measured in incremental exercise test. Plasma tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and CRP levels were determined by enzyme-linked. RESULTS:: Maximal strength was increased after 16 weeks, with no differences between RT and CT. VO2peak increased in ET and CT comparing pre- and post-training. There were no significant differences in TNF-α, IL-6 and CRP comparing pre- and post-training. CONCLUSION:: 16 weeks of resistance, endurance or concurrent training in middle-aged healthy men have not affected low and moderate IL-6, TNF-α and CRP levels. Concurrent training performed in the same weekly frequency and session duration of endurance and resistance training, was effective in increasing both maximal strength, and peak oxygen uptake, in addition to improvements in lipid profile.
Magrans-Courtney T, Wilborn C, Rasmussen C, Ferreira M, Greenwood L, Campbell B, Kerksick CM, Nassar E, Li R, Iosia M, Cooke M, Dugan K, Willoughby D, Soliah L, Kreider RB. Effects of diet type and supplementation of glucosamine, chondroitin, and MSM on body composition, functional status, and markers of health in women with knee osteoarthritis initiating a resistance-based exercise and weight loss program. J Int Soc Sports Nutr. 2011 Jun 20;8(1):8. [Epub ahead of print]
ABSTRACT: BACKGROUND: The purpose of this study was to determine whether sedentary obese women with knee OA initiating an exercise and weight loss program may experience more beneficial changes in body composition, functional capacity, and/or markers of health following a higher protein diet compared to a higher carbohydrate diet with or without GCM supplementation. METHODS: Thirty sedentary women (54+/-9 yrs, 163+/-6 cm, 88.6+/-13 kg, 46.1+/-3 % fat, 33.3+/-5 kg/m2) with clinically diagnosed knee OA participated in a 14-week exercise and weight loss program. Participants followed an isoenergenic low fat higher carbohydrate (HC) or higher protein (HP) diet while participating in a supervised 30-minute circuit resistance-training program three times per week for 14-weeks. In a randomized and double blind manner, participants ingested supplements containing 1,500 mg/d of glucosamine (as d-glucosamine HCL), 1,200 mg/d of chondroitin sulfate (from chondroitin sulfate sodium), and 900 mg/d of methylsulfonylmethane or a placebo. At 0, 10, and 14-weeks, participants completed a battery of assessments. Data were analyzed by MANOVA with repeated measures. RESULTS: Participants in both
groups experienced significant reductions in body mass (-2.4+/-3%), fat mass (-6.0+/-6%), and body fat (-3.5+/-4%) with no significant changes in fat free mass or resting energy expenditure. Perception of knee pain (-49+/-39%) and knee stiffness (-42+/-37%) was decreased while maximal strength (12%), muscular endurance (20%), balance indices (7% to 20%), lipid levels (-8% to -12%), homeostasis model assessment for estimating insulin resistance (-17%), leptin (-30%), and measures of physical functioning (59%), vitality (120%), and social function (66%) were improved in both groups with no differences among groups.Functional aerobic capacity was increased to a greater degree for those in the HP and GCM groups while there were some trends suggesting that supplementation affected perceptions of knee pain (p < 0.08). CONCLUSIONS: Circuit style resistance-training and weight loss improved functional capacity in women with knee OA. The type of diet and dietary supplementation of GCM provided marginal additive benefits. Trial Registration ClinicalTrials.gov: NCT01271218.
Lobo A, Carvalho J, Santos P. Comparison of functional fitness in elderlies with reference values by Rikli and Jones and after one-year of health intervention programs. J Sports Med Phys Fitness. 2011 Mar;51(1):111-20.
AIM: The purpose of this study was to characterize levels of physical fitness and compare our results with normative standards by Rikli and Jones to determine functional status of institutionalized elders. The effects of different intervention programs on physical fitness were also described. METHODS: A total of 148 institutionalized elders completed one-year health-promotion intervention programs: aerobic training (AT), strength training (ST), health education program and control. Habitual physical activity (MTI Actigraph), physical fitness (Senior Fitness Test), health related quality of life (MOS SF-36), and body composition (BMI) were assessed. RESULTS: Institutionalized elders performance has significantly deteriorated on functional fitness. Nevertheless, higher results than reference values were obtained on both body strength tests and aerobic endurance, specifically in men. Data of one-year intervention demonstrated that ST induced significant changes in body strength and flexibility test and the AT in lower body strength, aerobic endurance and agility/dynamic balance. The final multilevel model shows that AT Program compared with CG, education level, time of institutionalization and HRQoL were predictors for physical fitness score. CONCLUSION: These results suggest that participation in regular exercise programs (both aerobic and strength training) elicits a number of favorable responses that contribute to healthy aging and could play a role in prevention or reducing functional decline in elders. PMID: 21526574 [PubMed – indexed for MEDLINE]
Brentano MA, Martins Kruel LF. A review on strength exercise-induced muscle damage: applications, adaptation mechanisms and limitations. J Sports Med Phys Fitness. 2011 Mar;51(1):1-10.
This study aims to review the main aspects that induce muscle damage, and to discuss the adaptations of this phenomenon, applications and limitations of this study area. Damage induced by strength training has been utilized for two purposes: 1) verification of the recovery period required between training sessions, which has a direct influence on designing exercise programs; and 2) as indication for higher training intensity, mainly in studies on the “repeated bout effect”. here is some speculation about the role of muscle damage in inducing hypertrophy. However, studies demonstrate that exercise- nduced muscle damage may not be a consistent indicator of higher chronic hypertrophic response, because hypertrophy also occurs in training strategies with very low mechanical overloads. In addition, aerobic exercise, also induces muscle damage, exhibits no hypertrophic response after training. The remodeling process induced bay muscle damage promotes alterations to strength x length relationship for stretched positions, indicating an increased number of sarcomeres in series, due to strength exercises. Therefore, the study on strength exercise-induced damage seems to be adequate for implementing adequate rest periods to recovery from different sessions of strength training, and not to suggest chronic hypertrophy.