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A 1-week diet break improves muscle endurance during an intermittent dieting regime in adult athletes: A pre-specified secondary analysis of the ICECAP trial.
Peos, JJ, Helms, ER, Fournier, PA, Krieger, J, Sainsbury, A
PloS one. 2021;(2):e0247292
Abstract
Athletes undergoing energy restriction for weight/fat reduction sometimes apply 'diet breaks' involving increased energy intake, but there is little empirical evidence of effects on outcomes. Twenty-six resistance-trained athletes (11/26 or 42% female) who had completed 12 weeks of intermittent energy restriction participated in this study. Participants had a mean (SD) age of 29.3 (6.4) years, a weight of 72.7 (15.9) kg, and a body fat percentage of 21.3 (7.5) %. During the 1-week diet break, energy intake was increased (by means of increased carbohydrate intake) to predicted weight maintenance requirements. While the 1-week diet break had no significant effect on fat mass, it led to small but significant increases in mean body weight (0.6 kg, P<0.001), fat-free mass (0.7 kg, P<0.001) and in resting energy expenditure, from a mean (and 95% confidence interval) of 7000 (6420 to 7580) kJ/day to 7200 (6620 to 7780) kJ/day (P = 0.026). Overall, muscle endurance in the legs (but not arms) improved after the diet break, including significant increases in the work completed by the quadriceps and hamstrings in a maximum-effort 25-repetition set, with values increasing from 2530 (2170 to 2890) J to 2660 (2310 to 3010) J (P = 0.018) and from 1280 (1130 to 1430) J to 1380 (1220 to 1540) J (P = 0.018) following the diet break, respectively. However, muscle strength did not change. Participants reported significantly lower sensations of hunger (P = 0.017), prospective consumption (P = 0.020) and irritability (P = 0.041) after the diet break, and significantly higher sensations of fullness (P = 0.002), satisfaction (P = 0.002), and alertness (P = 0.003). In summary, a 1-week diet break improved muscle endurance in the legs and increased mental alertness, and reduced appetite and irritability. With this considered, it may be wise for athletes to coordinate diet breaks with training sessions that require muscle endurance of the legs and/or mental focus, as well as in the latter parts of a weight loss phase when increases in appetite might threaten dietary adherence. Trial registration: Australian New Zealand Clinical Trials Registry Reference Number: ACTRN12618000638235 anzctr.org.au.
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Acute L-Citrulline Supplementation Increases Nitric Oxide Bioavailability but Not Inspiratory Muscle Oxygenation and Respiratory Performance.
Theodorou, AA, Zinelis, PT, Malliou, VJ, Chatzinikolaou, PN, Margaritelis, NV, Mandalidis, D, Geladas, ND, Paschalis, V
Nutrients. 2021;(10)
Abstract
The present study aimed to investigate whether acute L-citrulline supplementation would affect inspiratory muscle oxygenation and respiratory performance. Twelve healthy males received 6 g of L-citrulline or placebo in a double-blind crossover design. Pulmonary function (i.e., forced expired volume in 1 s, forced vital capacity and their ratio), maximal inspiratory pressure (MIP), fractional exhaled nitric oxide (NO•), and sternocleidomastoid muscle oxygenation were measured at baseline, one hour post supplementation, and after an incremental resistive breathing protocol to task failure of the respiratory muscles. The resistive breathing task consisted of 30 inspirations at 70% and 80% of MIP followed by continuous inspirations at 90% of MIP until task failure. Sternocleidomastoid muscle oxygenation was assessed using near-infrared spectroscopy. One-hour post-L-citrulline supplementation, exhaled NO• was significantly increased (19.2%; p < 0.05), and this increase was preserved until the end of the resistive breathing (16.4%; p < 0.05). In contrast, no difference was observed in the placebo condition. Pulmonary function and MIP were not affected by the L-citrulline supplementation. During resistive breathing, sternocleidomastoid muscle oxygenation was significantly reduced, with no difference noted between the two supplementation conditions. In conclusion, a single ingestion of 6 g L-citrulline increased NO• bioavailability but not the respiratory performance and inspiratory muscle oxygenation.
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Effect of modified fasting therapy on body weight, fat and muscle mass, and blood chemistry in patients with obesity.
Kim, KW, Song, MY, Chung, SH, Chung, WS
Journal of traditional Chinese medicine = Chung i tsa chih ying wen pan. 2016;(1):57-62
Abstract
OBJECTIVE The aim of this study was to investigate the effects and safety of modified fasting therapy using fermented medicinal herbs and exercise on body weight, fat and muscle mass, and blood chemistry in obese subjects. METHODS Twenty-six patients participated in a 14-day fast, during which they ingested a supplement made from fermented medicinal herbs and carbohydrates (intake: 400-600 kcal/d). The schedule included 7 prefasting relief days and 14 days of stepwise reintroduction of food. The patients also took part in an exercise program that incorporated Qigong, weight training, and walking exercises. The efficacy of treatments was observed by assessing body fat mass and muscle mass, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), cholesterol, and triglycerides in each study period. Specific symptoms or side effects were reported. RESULTS Body weight and body fat mass both decreased significantly by (5.16 ± 0.95) and (3.89 ± 0.79) kg (both P < 0.05), while muscle mass decreased by an average of (0.26 ± 0.22) kg, without statistical significance. ALT levels were significantly decreased (P < 0.05), while AST levels decreased without statistical significance (P = 0.052). The levels of total cholesterol and triglycerides were also significantly decreased (both P < 0.05). There were few adverse events except for mild dizziness, which did not affect everyday living. CONCLUSION These results suggest that modified fasting therapy using fermented medicinal herbs and exercise could be effective and safe on obese patients.
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Greater association of peak neuromuscular performance with cortical bone geometry, bone mass and bone strength than bone density: A study in 417 older women.
Belavý, DL, Armbrecht, G, Blenk, T, Bock, O, Börst, H, Kocakaya, E, Luhn, F, Rantalainen, T, Rawer, R, Tomasius, F, et al
Bone. 2016;:119-126
Abstract
BACKGROUND We evaluated which aspects of neuromuscular performance are associated with bone mass, density, strength and geometry. METHODS 417 women aged 60-94years were examined. Countermovement jump, sit-to-stand test, grip strength, forearm and calf muscle cross-sectional area, areal bone mineral content and density (aBMC and aBMD) at the hip and lumbar spine via dual X-ray absorptiometry, and measures of volumetric vBMC and vBMD, bone geometry and section modulus at 4% and 66% of radius length and 4%, 38% and 66% of tibia length via peripheral quantitative computed tomography were performed. The first principal component of the neuromuscular variables was calculated to generate a summary neuromuscular variable. Percentage of total variance in bone parameters explained by the neuromuscular parameters was calculated. Step-wise regression was also performed. RESULTS At all pQCT bone sites (radius, ulna, tibia, fibula), a greater percentage of total variance in measures of bone mass, cortical geometry and/or bone strength was explained by peak neuromuscular performance than for vBMD. Sit-to-stand performance did not relate strongly to bone parameters. No obvious differential in the explanatory power of neuromuscular performance was seen for DXA aBMC versus aBMD. In step-wise regression, bone mass, cortical morphology, and/or strength remained significant in relation to the first principal component of the neuromuscular variables. In no case was vBMD positively related to neuromuscular performance in the final step-wise regression models. CONCLUSION Peak neuromuscular performance has a stronger relationship with leg and forearm bone mass and cortical geometry as well as proximal forearm section modulus than with vBMD.
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Comparison of markers for muscle damage, inflammation, and pain using minimally invasive direct anterior versus direct lateral approach in total hip arthroplasty: A prospective, randomized, controlled trial.
Mjaaland, KE, Kivle, K, Svenningsen, S, Pripp, AH, Nordsletten, L
Journal of orthopaedic research : official publication of the Orthopaedic Research Society. 2015;(9):1305-10
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Abstract
It is proposed that the use of biochemical markers for muscle damage and inflammation provides an objective measure on invasiveness in total hip arthroplasty. We analyzed levels of creatine kinase and C-reactive protein (CRP) after total hip arthroplasty in patients randomized to minimally invasive direct anterior approach or direct lateral approach, also recording consumption of pain medication and levels of pain postoperatively. Eighty-three patients were operated by the use of anterior approach and eighty using lateral. Creatine kinase and CRP levels were measured preoperatively, creatine kinase directly after surgery, and both creatine kinase and CRP on postoperative day 1 through 4. The use of pain medication and levels of pain were recorded. Creatine kinase were higher in the anterior group compared to the lateral group, reaching statistical significance directly postoperative and on day 4. Levels of CRP did not differ, reaching a maximum of mean 52 mg/L on day 3. The use of pain medication was higher in the lateral group on the day of surgery (p = 0.011), and pain levels were higher on all days in the lateral group (p < 0.007). In conclusion, the use of minimally invasive anterior approach caused less pain, but higher postoperative levels of CK, than the use of direct lateral approach.
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Consumption of Milk Protein or Whey Protein Results in a Similar Increase in Muscle Protein Synthesis in Middle Aged Men.
Mitchell, CJ, McGregor, RA, D'Souza, RF, Thorstensen, EB, Markworth, JF, Fanning, AC, Poppitt, SD, Cameron-Smith, D
Nutrients. 2015;(10):8685-99
Abstract
The differential ability of various milk protein fractions to stimulate muscle protein synthesis (MPS) has been previously described, with whey protein generally considered to be superior to other fractions. However, the relative ability of a whole milk protein to stimulate MPS has not been compared to whey. Sixteen healthy middle-aged males ingested either 20 g of milk protein (n = 8) or whey protein (n = 8) while undergoing a primed constant infusion of ring (13)C₆ phenylalanine. Muscle biopsies were obtained 120 min prior to consumption of the protein and 90 and 210 min afterwards. Resting myofibrillar fractional synthetic rates (FSR) were 0.019% ± 0.009% and 0.021% ± 0.018% h(-1) in the milk and whey groups respectively. For the first 90 min after protein ingestion the FSR increased (p < 0.001) to 0.057% ± 0.018% and 0.052% ± 0.024% h(-1) in the milk and whey groups respectively with no difference between groups (p = 0.810). FSR returned to baseline in both groups between 90 and 210 min after protein ingestion. Despite evidence of increased rate of digestion and leucine availability following the ingestion of whey protein, there was similar activation of MPS in middle-aged men with either 20 g of milk protein or whey protein.
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Lanreotide Reduces Liver Volume, But Might Not Improve Muscle Wasting or Weight Loss, in Patients With Symptomatic Polycystic Liver Disease.
Temmerman, F, Ho, TA, Vanslembrouck, R, Coudyzer, W, Billen, J, Dobbels, F, van Pelt, J, Bammens, B, Pirson, Y, Nevens, F
Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association. 2015;(13):2353-9.e1
Abstract
BACKGROUND & AIMS Polycystic liver disease (PCLD) can induce malnutrition owing to extensive hepatomegaly and patients might require liver transplantation. Six months of treatment with the somatostatin analogue lanreotide (120 mg) reduces liver volume. We investigated the efficacy of a lower dose of lanreotide and its effects on nutritional status. METHODS We performed an 18-month prospective study at 2 tertiary medical centers in Belgium from January 2011 through August 2012. Fifty-nine patients with symptomatic PCLD were given lanreotide (90 mg, every 4 weeks) for 6 months. Patients with reductions in liver volume of more than 100 mL (responders, primary end point) continued to receive lanreotide (90 mg) for an additional year (18 months total). Nonresponders were offered increased doses, up to 120 mg lanreotide, until 18 months. Liver volume and body composition were measured by computed tomography at baseline and at months 6 and 18. Patients also were assessed by the PCLD-specific complaint assessment at these time points. RESULTS Fifty-three patients completed the study; 21 patients (40%) were responders. Nineteen of the responders (90%) continued as responders until 18 months. At this time point, they had a mean reduction in absolute liver volume of 430 ± 92 mL. In nonresponders (n = 32), liver volume increased by a mean volume of 120 ± 42 mL at 6 months. However, no further increase was observed after dose escalation in the 24 patients who continued to the 18-month end point. All subjects had decreased scores on all subscales of the PCLD-specific complaint assessment, including better food intake (P = .04). Subjects did not have a mean change in subcutaneous or visceral fat mass, but did have decreases in mean body weight (2 kg) and total muscle mass (1.06 cm(2)/h(2)). Subjects also had a significant mean reduction in their level of insulin-like growth factor 1, from 19% below the age-adjusted normal range level at baseline to 50% at 18 months (P = .002). CONCLUSIONS In a prospective study, we observed that low doses of lanreotide (90 mg every 4 weeks) reduced liver volumes and symptoms in patients with PCLD. However, patients continued to lose weight and muscle mass. The effects of somatostatin analogues on sarcopenia require investigation. Clinicaltrials.gov: NCT01315795.
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The effect of endurance training on resting oxygen stores in muscle evaluated by near infrared continuous wave spectroscopy.
Sako, T
Advances in experimental medicine and biology. 2010;:341-6
Abstract
The purpose of this study was to examine the effects of endurance training (ET) on resting oxygen store (r-O(2)mus) using near infrared continuous wave spectroscopy (NIR(CWS)), and the validity of using this method for the evaluation of resting muscle oxygen consumption (r-VO(2)mus) in a training study. Ten female subjects were tested in the following study. All subjects were physically active, but did not participate in any regular training besides this study. The subjects were fully informed of the risks and gave their consent before the start of the experiments. For ET subjects cycled for 40 min at 60-70% VO(2)peak, three times a week, for 4 weeks. Before and after the period of ET, VO(2)peak and r-O(2)mus for the vastus lateralis muscle were measured. r-O(2)mus was defined as the amount of O(2) consumed by the muscle, which was determined from r-VO(2)mus measured by NIR(CWS) (HEO200, Omron) during arterial occlusion induced by a pneumatic tourniquet. In order to verify the measurements using NIR(CWS), oxygen consumption for both the whole body (40%-VO(2)) and vastus lateralis muscle (40%-VO(2)mus) were measured at pre and post ET. 40%-VO(2)mus was calculated from the ratio of the declining rates of Hb/MbO(2) immediately post-exercise and during rest (r-VO(2)mus). As a result, VO(2)peak significantly increased after ET. r-O(2)mus also significantly increased (p < 0.05). Neither 40%-VO(2) nor 40%-VO(2)mus changed following ET. Therefore these findings suggest the increase in r-O(2)mus calculated from r-VO(2)mus reflects an increase in resting oxygen stores in the trained muscle. Under the condition when resting muscle oxygen consumption is unchanged, NIR(CWS) can be a useful non-invasive tool for measuring muscle oxygen stores.
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Individual prognosis regarding effectiveness of a therapeutic intervention using pre-therapeutic "kinesiology muscle test".
Waxenegger, I, Endler, PC, Wulkersdorfer, B, Spranger, H
TheScientificWorldJournal. 2007;:1703-7
Abstract
Since a therapy's full positive effect and possible adverse effects are individual and not predictable for every single patient, scientists have been searching for methods to predict optimal effects of a therapy. This pilot study investigated the applicability of the "kinesiology muscle test" as a prognostic tool regarding effectiveness in a defined therapeutic procedure. Each of 11 test persons with elevated total cholesterol values received a naturopathic drug supposed to lower cholesterol level on a daily basis for eight consecutive weeks. Prior to treatment the "kinesiology muscle test" was performed, where the patients' ability to maintain a flexed position in a selected joint was evaluated. The resistance created by the patient against the tester's pressure was monitored. Being in touch with healthful or unhealthful chemical substances may, according to the kinesiology literature, increase or decrease this resistance. For testing purposes, the drug was placed onto the patients' skin. The ability of the brachioradial muscle to resist the tester's pressure was determined on a subjective scale (0-100%). The Pearson product-moment correlation coefficient between four variables (total cholesterol value before therapy, total cholesterol value after therapy, difference of total cholesterol values before and after therapy, prior to treatment kinesiology testing) was chosen. A significant correlation between the difference of total cholesterol values before-after and the prior to treatment test was found, as well as a significant correlation between the total cholesterol values after therapy and the prior to treatment kinesiology test.
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Effects of hypoxia on the onset of muscle deoxygenation and the lactate threshold.
Lorenz, KA, Hom, C, Lopez, J, Pozos, RS, Buono, MJ, Kolkhorst, FW
The journal of physiological sciences : JPS. 2006;(4):321-3
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Abstract
Six subjects performed two trials of incremental cycling to exhaustion under normoxic and hypoxic conditions. The lactate threshold and onset of muscle deoxygenation were highly correlated under both conditions, and during the hypoxic condition both variables shifted leftward.