PROBLEM: Expanding knowledge of how the brain responds to various exercise types may allow for investigation and development of individualized methods of concussion management. PURPOSE: Identify differences in cerebral oxygenation recovery following bouts of maximal anaerobic, resistance and aerobic exercise. METHODS: Twenty-eight active adults were recruited, each partaking in two sessions. At the first, anthropometric measures and leg press 1-RM were determined. During the second session, cerebral oxygenation and ventilatory gas exchange variables were recorded while participants completed maximal anaerobic, resistance, and aerobic tests, and for 15-minutes of recovery. RESULTS: Anaerobic (637.41s ± 330.42s) and aerobic (689.29s ± 311.05s) exercise resulted in longer durations of time to return to baseline compared to resistance (363.07s ± 366.34s). CONCLUSION: Anaerobic and aerobic exercise taking longer than resistance to return to baseline indicates prolonged activity. Expecting equivalent outcomes as concussion management tools from differing exercise methods may be misguided and requires additional research. / February 2017

Carbohydrate plus additional protein supplementation provided immediately after exercise has been found to increase the rate of muscle glycogen restoration compared to carbohydrate alone. To examine whether leucine, and/or β-hydroxy-β-methylbutyrate (HMB) to carbohydrate plus protein supplementation affects short-term recovery (45 min) of muscle glycogen, we compared plasma glucose and insulin, the muscle glycogen concentration, and the cellular signaling proteins controlling muscle glycogen synthesis 45 min after supplementation. Rats (n=35) underwent high-intensity resistance exercise followed by supplementation with carbohydrate (CHO: 1.2g/kg body weight), carbohydrate with whey protein (CP: 1.2g CHO + 375mg whey protein/kg body weight), carbohydrate with whey protein plus HMB (CPH: 1.2g CHO + 375mg whey protein + 400mg HMB/kg body weight), carbohydrate with whey protein, HMB plus leucine (CPHL: 1.2g CHO + 375mg whey protein + 400mg HMB + 444mg leucine/kg body weight) or exercise only (CON). Blood samples were collected immediately after exercise and 45 min after supplementations. Muscle samples of plantaris were excised immediately and 45 min post-exercise. Plasma glucose was increased by CHO and CPH supplementation and reduced by CPHL at 45 min post-exercise. Plasma insulin was elevated by CP and CPHL treatments compare to CHO. Muscle glycogen concentration was unaffected by all treatments and did not differ from CON. Phosphorylation of Akt/PKB, GSK3α/β, and GS at 45 min of recovery for all supplements was not significant difference from CON. Phosphorylation of mTOR was significantly increased by CPHL and CP supplementation compared to CON, CHO, and CPH. Phosphorylation of AS160 was markedly reduced by CPH supplementation compared to CON. These results suggest that supplementing with carbohydrate plus protein with or without leucine and its metabolite, HMB, to enhance muscle glycogen replenishment following exercise may not provide an advantage during the early phase of recovery (45 min). Furthermore, there is some indication that HMB may elicit insulin resistance, and this needs further evaluation. / text

Objectives: Men who receive androgen deprivation therapy (ADT) for prostate cancer (PCa) are at risk of several adverse effects that can be detrimental to both their physical and mental health. Common adverse effects include weight gain, muscle wasting, cardiovascular morbidity, fatigue and impaired quality of life (QOL). This study tested whether a combined aerobic and resistance exercise program can alleviate some of these symptoms in men receiving ADT. Design: Men with PCa, aged 50-80 years, receiving ADT were recruited to participate in this prospective randomized controlled trial. Subjects were assigned to a usual care group (UCG) or an exercise intervention group (EIG). The EIG completed a 16 week combined aerobic and resistance exercise program. Outcomes measures were assessed at baseline, 16 weeks, and 24 weeks and included: cardio-respiratory fitness; muscle strength and endurance; body composition; and reports of QOL, fatigue, mood, partner relations, and exercise behaviour. Results: Fifteen men were recruited to this study, but two participants in the EIG did not finish the study leaving the EIG with an n = 6 and the UCG with an n = 7. The exercise program did not lead to changes in weight, BMI or body fat. There was a small, close to significant, increase in muscle mass in the EIG over the intervention period (p = 0.052). This is encouraging as it demonstrates that exercise can counteract the catabolic effects of ADT. Interestingly, cardio-respiratory fitness improved over the course of the study for both groups. Muscular fitness, however, improved only for the EIG. There was a significant difference in chest press strength (p = 0.041) and leg press strength was bordering significance (p = 0.058). Unexpectedly, QOL declined for both groups during the intervention (p = 0.029). Participants in both groups also reported increased levels of fatigue from baseline to 24 weeks, although these changes were not significant (p = 0.586). Mood worsened over the study period for both groups from baseline to 16 weeks, but this increase in anxiety and depression was reduced at the follow-up period. These changes, too, were not significant (p = 0.364). Reports of partner relationships trended towards lower scores from baseline to 16 weeks. The men’s report in both groups and the women’s report in the EIG improved at the 24 week mark, but women in the UCG experienced further decline. Surprisingly, participants in both groups reported increases in exercise behaviour from baseline to 24 weeks. This could account for the lack of difference found in many of the measures. The power of this study was 0.22. Conclusion: Although this was a small study, it showed that a combined aerobic and resistance exercise program can have some positive benefits for men with PCa who are receiving ADT. Larger trials are needed to further examine the role of exercise in ameliorating the side effects of ADT, particularly in the areas of mood and partner relationships.

Resistance exercise using weights typically offers constant external load during coupled shortening (concentric) and lengthening (eccentric) muscle actions in sets of consecutive repetitions until failure. However, the constant external load and the inherent capability of skeletal muscle to produce greater force in the eccentric compared with the concentric action, would infer that most actions are executed with incomplete motor unit involvement. In contrast, use of the inertia of flywheels to generate resistance allows for maximal voluntary force to be produced throughout the concentric action, and for brief episodes of greater eccentric than concentric loading, i.e. “eccentric overload”. Thus, it was hypothesized that acute flywheel resistance exercise would induce greater motor unit and muscle use, and subsequent fatigue, compared with traditional weight stack/free weight resistance exercise. Furthermore, it was hypothesized that flywheel training would induce more robust neuromuscular adaptations compared with training using weights. A total of 43 trained and untrained men were investigated in these studies. Knee extensor muscle activation, fatigue response and muscle use were assessed during exercises by recording electromyographic signals and by means of functional magnetic resonance imaging, respectively. Flywheel resistance exercise provoked maximal or near maximal muscle activation from the first repetition, induced robust fatigue, and prompted more substantial motor unit and muscle use than weight stack/free weight resistance exercise in both novice and resistance trained men. Both prior to and following five weeks of unilateral knee extension training, the eccentric muscle activation was greater with flywheel than weight stack training. Furthermore, weight stack training generated greater increases of dynamic strength and neural adaptations, while flywheel training generated more prominent hypertrophy of individual quadriceps muscles and greater improvement of maximal isometric strength. Hence, due to the preferential metabolic cost of the concentric rather than eccentric actions, the maximal activation through the entire range of the concentric action within each repetition of a set during flywheel resistance exercise probably evoked the marked fatigue, and prompted more substantial muscle use than resistance exercise using weights. Furthermore, while any cause‐effect relationship remains to be determined, results of the pesent study suggest that brief episodes of “eccentric overload” amplify muscular adaptations following concentriceccentric resistance training.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

<p>Sarcopenia is the age-associated loss of muscle mass and strength. Studies have shown that combining resistance training with high protein intake increases muscle mass and strength in older adults. Women are at higher risk than men of sarcopenia. Thus, it is essential to find interventions to lessen women’s risk of losing muscle mass with aging. However, limited studies combine a specific higher-protein diet and a resistance training program in older women to determine skeletal muscle responses. This study aimed to assess the impact of a 12-week resistance training program with a high protein lean beef diet on skeletal muscle mass, strength, and quality in older women compared to a normal protein diet or a high protein diet composed of a lesser amount of beef. </p> <p>The study included three diets; a USDA recommended protein diet (0.8 g/kg/day), a high protein lean beef diet (1.4 g/kg/day), and a high protein diet composed of lesser beef (1.4 g/kg/day). Sixteen subjects were included in the study. The resistance training program consisted of leg extension, leg press, leg curl, chest press, and seated row. Muscle strength was determined by one-repetition maximum assessment at weeks one, six, and twelve. In addition, subjects underwent an MRI pre- and post-intervention to assess quadriceps volume and intermuscular adipose tissue (IMAT). Muscle quality was defined as the leg extension one-repetition maximum over the quadriceps volume. </p> <p>Muscle strength, muscle quality, and quadriceps volume increased with training in all three diet groups (P<0.05, main effect of time). No difference in muscle strength, quality, or quadriceps volume was found between the diet groups. IMAT decreased in all diet groups (P<0.05, main effect of time), but no differences were seen between the diet groups. These findings suggest that the 12-weeks of resistance training increased skeletal muscle strength, quality, and mass, independent of the normal protein or high protein diet and the source of protein in the diet.</p>

No description available.

The effects of low carbohydrate (CHO), high fat (LCHF) diets on adaptations to high-intensity exercise have recently gained interest. Consuming a LCHF may potentially decrease the ability to use CHO during exercise and impair high-intensity exercise adaptations. Therefore, the purpose of this investigation was to examine the importance of CHO timing while consuming a LCHF diet and completing a high-intensity exercise program. Eighteen resistance trained males were randomized into two treatment groups. Both groups completed 6 weeks of a high-intensity exercise training program with the first 2 weeks serving as familiarization to resistance training (RT) 3 days per week and completing one high-intensity interval training (HIIT) session. During the final 4 weeks, participants trained 5 days per weeks, three days of RT and two days of HIIT (repeated 30 s all out sprints). All participants consumed a LCHF diet (~25%, ~25%, and ~50% of daily kilocalorie intake coming from CHO, protein, and fat). The supplemented (SUPP) group (n=9) consumed 30 g of CHO during exercise and 40 g of CHO immediately after each exercise session. The remainder of the SUPP groups daily CHO intake came outside of training. The non-supplemented (NONSUPP) group (n=9) consumed an artificially flavored placebo during exercise. The NONSUPP group had the same daily CHO intake as the SUPP group, with the only difference being CHO timing. Dependent variables measured pre-and post-training included back squat and bench press one-repetition maximums, peak oxygen consumption (V̇O2 peak), power output (Wingate test), body composition, fasted glucose, insulin, and testosterone, and gastrointestinal distress (GID) during exercise. Both groups significantly improved back squat and bench press strength, biceps thickness, absolute and relative V̇O2 peak, and power output. Respiratory exchange ratio was significantly lower and time to exhaustion significantly increased during the post V̇O2 peak test. However, there were no changes in resting glucose, insulin, and testosterone or body fat. RT and HIIT caused significant increases in GID, independent of beverage content, with no differences between training. Our results suggest that CHO timing has no impact on adaptations to exercise training, but favorable training adaptations can be made while consuming a LCHF diet.

No description available.

This study determined the effect of milk or carbohydrate-electrolyte supplementation immediately after resistance exercise on muscle protein breakdown before and after a 10-week resistance training program. Nineteen untrained males, 18-25 years of age, consumed either a carbohydrate-electrolyte (CHO) or milk (MILK) beverage immediately after a strenuous leg resistance exercise bout, both before and after training. Muscle protein breakdown, as estimated by 3-methylhistidine-to-creatinine ratio, was significantly reduced after resistance exercise for both groups, as the ratio was decreased by 19.9% from baseline on the day of resistance exercise. A trend was present for a training effect for 3-methylhistidine-to-creatinine ratio (p<0.07), as the reduction from before to after resistance exercise was greater after training. There was no difference in muscle protein breakdown between the groups. One hour after exercise, serum concentrations of amino acids were significantly elevated for MILK and significantly reduced for CHO. Serum glucose was significantly higher for both groups 30 minutes post-exercise than baseline, and serum insulin was greater than baseline 30 minutes and 1 hour after exercise. Serum insulin was significantly greater for CHO than MILK 1 hour after resistance exercise. No effect of training was observed for the response of serum amino acids, glucose, or insulin to resistance exercise with beverage ingestion. In conclusion, although the type of beverage ingested post-exercise affected serum insulin and amino acid concentrations, it did not influence the reduction in muscle protein breakdown observed after resistance exercise. A trend was present for a greater reduction in protein breakdown after training. / Master of Science