Leucine Supplementation Does Not Improve Muscle Recovery from Resistance Exercise in Young Adults: A Randomized, Double-Blinded, Crossover Study

International Journal of Exercise Science 14(2): 486-497, 2021. This study aimed to investigate the effects of free leucine supplementation on muscle recovery from resistance exercise (RE) in young adults. Fourteen untrained subjects (23.9 ± 3.6 years old) underwent RE sessions (leg press and hack squat: three sets of 8-12 reps at 70% 1RM) supplemented with leucine (LEU: two daily doses of 3g) or a placebo (PLA), separated by a seven-day washout period. Following each occasion, participants were evaluated in three subsequent days (24h, 48h, and 72h) for muscle recovery via a repetition-to-failure test. The following markers were assessed: repetition performance, perceived exertion, lactate, creatine kinase, muscle soreness (DOMS), testosterone, and cortisol. No significant difference was observed between LEU and PLA conditions (p \u3e 0.05). Number of repetitions performed in the repetition-to-failure tests, perceived exertion, cortisol, and testosterone:cortisol ratio did not change over time (p \u3e 0.05). Creatine kinase increased immediately after exercise, at 24h, and 48h, and was attenuated at 72h post-exercise, while testosterone, lactate, and DOMS increased at 24h post-exercise (p \u3c 0.05) and remained elevated up to 72h. All outcomes were similar between LEU and PLA. Results indicate that a 6g daily dose of free leucine supplementation does not improve muscle recovery following lower-limb RE in untrained young adults

Branched-chain amino acids do not improve muscle recovery from resistance exercise in untrained young adults.

The purpose of this study was to investigate the effects of BCAA supplementation on muscle recovery from resistance exercise (RE) in untrained young adults. Twenty-four young adults (24.0 ± 4.3 years old) were assigned to 1 of 2 groups (n = 12 per group): a placebo-supplement group or a BCAA-supplement group. The groups were supplemented for a period of 5 days. On day 1 and 3, both groups underwent a RE session involving two lower body exercises (hack squat and leg press) and then were evaluated for muscle recovery on the 3 subsequent moments after the RE session [30 min (day 3), 24 h (day 4), and 48 h (day 5)]. The following indicators of muscle recovery were assessed: number of repetitions, rating of perceived exertion in the last RE session, muscle soreness and countermovement jump (CMJ) during recovery period (30 min, 24 h, and 48 h after RE session). Number of repetitions remained unchanged over time (time, P > 0.05), while the rating of perceived exertion increased (time, P  0.05). Muscle soreness increased (time, P  0.05). The results indicate that BCAA supplementation does not improve muscle recovery from RE in untrained young adults

Lumbar stabilisation exercises versus back endurance-resistance exercise training in athletes with chronic low back pain: Protocol of a randomised controlled trial

Background: Chronic low back pain (CLBP) is an important disorder in athletes that may negatively affect their performance in competitions. The literature usually recommends physiotherapy based on exercises for back pain management in athletes. Recent evidence suggests that interventions based on lumbar muscle stabilisation exercises (LMSE) and back endurance-resistance exercises (BERE) may improve back pain and function performance. However, it is still unclear which type of exercise is more effective for the treatment of CLBP in athletes. Objective: To compare the efficacy of LMSE versus BERE in athletes with CLBP. Design: The study is a 2-arm, prospectively registered, randomised controlled trial. Setting: The physical therapy clinical and biomechanics laboratory of the UNOPAR University. Participants: 32 male athletes with CLBP, age between 18 and 40 years old, recruited from the local community. Intervention: An 8-week intervention programme will be carried out with LMSE s versus BERE. Measurements Trunk neuromuscular patterns during balance tasks (unipodal and over a ball) using electromyography and force platform parameters, pain, disability, fear and avoidance will be assessed by a blinded assessor at baseline and at follow-up after 8 weeks of intervention period. Limitations: The absence of blinding intervention and the exclusion of female athletes, seated sports and swimmers will affect the internal and external validity of the study. Conclusions: The results of this study will elucidate which of these two interventions promote better results in trunk neuromuscular pattern, back pain and function in male athletes with CLBP

EFFECTS of CREATINE SUPPLEMENTATION DURING RESISTANCE TRAINING on MYOSIN HEAVY CHAIN (MHC) EXPRESSION IN RAT SKELETAL MUSCLE FIBERS

Aguiar, AF, Aguiar, DH, Felisberto, ADS, Carani, FR, Milanezi, RC, Padovani, CR, and Dal-Pai-Silva, M. Effects of creatine supplementation during resistance training on mysoin heavy chain (MHC) expression in rat skeletal muscle fibers. J Strength Cond Res 24(1): 88-96, 2010-The purpose of this study was to utilize a rodent model to test the hypothesis that creatine (Cr) supplementation during resistance training would influence the pattern of slow-twitch muscle myosin heavy chain (MHC) isoforms expression. Male Wistar rats (2-3 months old, 250300 g) were divided into 4 groups: Nontrained without creatine supplementation (CO), nontrained with creatine supplementation (CR), trained without creatine supplementation (TR), and trained with creatine supplementation (TRCR). TR and TRCR groups were submitted to a resistance training program for 5 weeks (5 days/week) for morphological and biochemical analysis of the soleus muscle. Weightlifting exercise involved jump sessions into water, carrying progressive overload equivalent to percentage of body weight. CR and TRCR groups were given creatine at 0.5 g/kg(-1)/d(-1). Both Cr supplementation and resistance training alone or associated did not result in significant alterations (p > 0.05) in body weight gain, food intake, and muscle weight in the CR, TR and TRCR groups compared to the CO group. Also compared to the CO group, the CR group showed a significant (p 0.05) changes in MHC content of the TRCR group compared to the CO group. The data show that Cr supplementation provides a potential action to abolish the exercise-induced MHC isoform transitions from slow to fast in slow-twitch muscle. Thus, Cr supplementation might be a suitable strategy to maintaining a slow phenotype in slow muscle during resistance training, which may be favorable to maintenance of muscle oxidative capacity of endurance athletes.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Aerobic Exercise Training Prevents Heart Failure-Induced Skeletal Muscle Atrophy by Anti-Catabolic, but Not Anabolic Actions

Background: Heart failure (HF) is associated with cachexia and consequent exercise intolerance. Given the beneficial effects of aerobic exercise training (ET) in HF, the aim of this study was to determine if the ET performed during the transition from cardiac dysfunction to HF would alter the expression of anabolic and catabolic factors, thus preventing skeletal muscle wasting. Methods and Results: We employed ascending aortic stenosis (AS) inducing HF in Wistar male rats. Controls were sham operated animals. At 18 weeks after surgery, rats with cardiac dysfunction were randomized to 10 weeks of aerobic ET (AS-ET) or to an untrained group (AS-UN). At 28 weeks, the AS-UN group presented HF signs in conjunction with high TNF-α serum levels; soleus and plantaris muscle atrophy; and an increase in the expression of TNF-α, NFkB (p65), MAFbx, MuRF1, FoxO1, and myostatin catabolic factors. However, in the AS-ET group, the deterioration of cardiac function was prevented, as well as muscle wasting, and the atrophy promoters were decreased. Interestingly, changes in anabolic factor expression (IGF-I, AKT, and mTOR) were not observed. Nevertheless, in the plantaris muscle, ET maintained high PGC1α levels. Conclusions: Thus, the ET capability to attenuate cardiac function during the transition from cardiac dysfunction to HF was accompanied by a prevention of skeletal muscle atrophy that did not occur via an increase in anabolic factors, but through anti-catabolic activity, presumably caused by PGC1α action. These findings indicate the therapeutic potential of aerobic ET to block HF-induced muscle atrophy by counteracting the increased catabolic state

Resistance training with excessive training load and insufficient recovery alters skeletal muscle mass-related protein expression

The aim of this study was to investigate the effects of a resistance training program with excessive training load and insufficient recovery time between bouts on muscle hypertrophy-and atrophy-related protein expression. Male Wistar rats were randomly assigned to either a trained (TR, N = 9) or a sedentary (SE, N = 9) group. The TR group was subjected to a 12-week resistance training program with excessive training load and insufficient recovery between bouts that was designed to induce plantaris muscle atrophy. After the 12-week experiment, the plantaris muscle was collected to analyze the cross-sectional area (CSA) of the muscle fibers, and MAFbx, MyoD, myogenin, and IGF-I protein expression (Western blot). The CSA was reduced significantly (-17%, p <= 0.05) in the TR group compared with the SE group. Reciprocally, there was a significant (p <= 0.05) 20% increase in MAFbx protein expression, whereas the MyoD (-27%), myogenin (-29%), and IGF-I (-43%) protein levels decreased significantly (p <= 0.05) in the TR group compared with the SE group. In conclusion, our data indicated that muscle atrophy induced by resistance training with excessive training load and insufficient recovery was associated with upregulation of the MAFbx catabolic protein and downregulation of the MyoD, myogenin, and IGF-I anabolic proteins. These findings suggest that quantitative analysis of these proteins can be important and complementary with other biochemical markers to confirm a possible overtraining diagnosis.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Investigaciones sobre el método indagatorio en las técnicas de trabajo de campo aplicado a la didáctica de la Geografía

Objetivo principal: comprobar la eficacia del método indagatorio aplicado a la didáctica de la Geografía. Objetivo específico: elaborar un nuevo sistema de experimentación científica que permita validar empíricamente las teorías existentes a cerca de la aplicación de este método a la enseñanza de esa materia. Dos grupos de 20 y 15 sujetos pertenecientes a tercero y quinto respectivamente, de la asignatura de Geografía de España (licenciatura de Geografía). Se mide la relación entre las siguientes variables: variable independiente, el método indagatorio introducido a través del trabajo de campo realizado por los alumnos en el circo de Peñalara; variable dependiente, aprendizaje de la Geografía física. Como indicadores de esta variable se consideran la comprensión de conceptos, las capacidades intelectuales, la destreza instrumental, los valores estéticos del paisaje y las actitudes hacia la asignatura. Se trata de un diseño cuasi-experimental en el que los dos grupos son sometidos a las pruebas pretest y posttest para evaluar la eficacia del método indagatorio en el aprendizaje de la Geografía. El método indagatorio aplicado a la didáctica de la Geografía actúa en las variables consideradas mejorando las puntuaciones obtenidas en el pretest de la manera siguiente: se produce una mayor comprensión de conceptos, fundamentalmente entre los alumnos menos especializados (tercer curso); en cuanto a las capacidades intelectuales se observa una mejora en el aprendizaje de las fases de las que consta el método científico; las destrezas instrumentales mejoran notablemente, obteniéndose resultados muy positivos en la identificación de formas geográficas y orientación; por último, se observa un cambio en la jerarquía de valores estéticos del paisaje y en las actitudes hacia la asignatura, éstas tanto en un sentido favorable como desfavorable. En general, no se aprecian diferencias significativas entre los dos grupos estudiados tras la prueba posttest.Ministerio Educación CIDEBiblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 Planta; 28014 Madrid; Tel. +34917748000; Fax +34917748026; [email protected]