Nitric oxide enhancement supplement containing beet nitrite and nitrate benefits high intensity cycle interval training.

This study investigated the effects of a beet nitric oxide enhancing (NOE) supplement comprised of nitrite and nitrate on cycling performance indices in trained cyclists. METHODS: Subjects completed a lactate threshold test and a high-intensity interval (HIIT) protocol at 50% above functional threshold power with or without oral NOE supplement. RESULTS: NOE supplementation enhanced lactate threshold by 7.2% (Placebo = 191.6 ± 37.3 W, NOE = 205.3 ± 39.9; p = 0.01; Effect Size (ES) = 0.40). During the HIIT protocol, NOE supplementation improved time to exhaustion 18% (Placebo = 1251 ± 562s, NOE = 1474 ± 504s; p = 0.02; ES = 0.42) and total energy expended 22.3% (Placebo = 251 ± 48.6 kJ, NOE = 306.6 ± 55.2 kJ; p = 0.01; ES = 1.079). NOE supplementation increased the intervals completed (Placebo = 7.00 ± 2.5, NOE = 8.14 ± 2.4; p = 0.03; ES = 0.42) and distance cycled (Placebo = 10.9 ± 4.0 km, NOE = 13.5 ± 3.9 km; p = 0.01; ES = 0.65). Also, target power was achieved at a higher cadence during the HIIT work and rest periods (p = 0.02), which enhanced muscle oxygen saturation (SmO2) recovery. Time-to-fatigue was negatively correlated with the degree of SmO2, desaturation during the HIIT work interval segment (r = -0.67; p 0.008), while both SmO2 desaturation and the SmO2 starting work segment saturation level correlated with a cyclist's kJ expended (SmO2 desaturation: r = -0.51, p = 0.06; SmO2 starting saturation: r = 0.59, p = 0.03). CONCLUSION: NOE supplementation containing beet nitrite and nitrate enhanced submaximal (lactate threshold) and HIIT maximal effort work. The NOE supplementation resulted in a cyclist riding at higher cadence rates with lower absolute torque values at the same power during both the work and rest periods, which in-turn delayed over-all fatigue and improved total work output.

Validity of the InBody 520™ to predict metabolic rate in apparently healthy adults.

BACKGROUND: The present study seeks to assess the validity of the InBody 520™ device to predict RMR in apparently healthy adults relative to a metabolic cart (the standard, yet time-intensive, method for determining resting metabolic rate). METHODS: Twenty-six apparently healthy adults participated in the study. Predicted RMR (pRMR) was calculated by the InBody 520™ and measured RMR (mRMR) was determined by 30-minute gas analysis and ventilated hood system. Of the 78 measurement trials conducted, 64 yielded acceptable measurement trials. RESULTS: A Pearson product-moment correlation was used to determine the relationship between pRMR and mRMR (r=0.87, P<0.001). No significant difference existed between the pRMR (1650.89±295.96 kcal) and mRMR (1675.36±278.69 kcal) values (P=0.19). CONCLUSIONS: Study findings suggest that the InBody520™ provides valid measurements of RMR in apparently healthy adults and can be an effective and efficient method for collecting data in a clinical setting.

The Acute Effects of Nonstimulant Over-the-Counter Dietary Herbal Supplements on Resting Metabolic Rate.

BACKGROUND: Weight loss supplements are widely advertised and highly sought out products. Many supplements claim to increase body fat utilization, increase resting metabolic rate (RMR), and to improve body composition by decreasing total body fat composition. Therefore, the purpose of this study was to determine the acute effect of nonstimulant herbal supplements on RMR and substrate utilization. METHODS: Ten female and 16 male participants (mean age 23.7 ± 3.9 years; mean weight 79.2 ± 18.2 kg) completed a random-repeated measures crossover study. Participants completed a total of three RMRs by either ingesting a placebo (P) or one of two supplements [raspberry ketones (R) or metabolic activator blend (MAB)] 2 hours prior to testing. RESULTS: No significant difference was found for RMR for P vs. MAB (p = .130), vs. R (p = .588), and MAB vs. R (p = .636). No significant difference was found for respiratory quotient for P vs. MAB (p = .056), vs. R (p = .149), and MAB vs. R (p = .764). No significant difference was found for substrate utilization: percent carbohydrate utilization, P vs. MAB (p = .052), P vs. R (p = .124), and MAB vs. R (p = .680); and percent fat utilization, P vs. MAB (p = .052), P vs. R (p = .120), and MAB vs. R (p = .749). CONCLUSIONS: Therefore, nonstimulant weight loss supplements may not be beneficial for weight loss, or an increase of fat utilization.

Validity and Reliability of a Glucometer Against Industry Reference Standards.

As an appealing alternative to reference glucose analyzers, portable glucometers are recommended for self-monitoring at home, in the field, and in research settings. The purpose was to characterize the accuracy and precision, and bias of glucometers in biomedical research. Fifteen young (20-36 years; mean = 24.5), moderately to highly active men (n = 10) and women (n = 5), defined by exercising 2 to 3 times a week for the past 6 months, were given an oral glucose tolerance test (OGTT) after an overnight fast. Participants ingested 50, 75, or 150 grams of glucose over a 5-minute period. The glucometer was compared to a reference instrument. The glucometer had 39% of values within 15% of measurements made using the reference instrument ranging from 45.05 to 169.37 mg/dl. There was both a proportional (-0.45 to -0.39) and small fixed (5.06 and 0.90 mg/dl) bias. Results of the present study suggest that the glucometer provided poor validity and reliability results compared to the results provided by the reference laboratory analyzer. The portable glucometers should be used for patient management, but not for diagnosis, treatment, or research purposes.

A comparison of COSMED metabolic systems for the determination of resting metabolic rate.

This study determined the reliability of measuring resting metabolic rate (RMR) with COSMED's FitMate™ metabolic system using a canopy dilution set-up compared with a previously validated COSMED QUARK CPET research-based system in 30 healthy adults (age: 28.4 ± 7.0 yrs, weight: 79.9 ± 20.2 kg, percent body fat: 22.5 ± 8.6%). The FitMate was developed as an inexpensive metabolic system for RMR and fitness testing. Subjects were randomly assigned to start testing on either the FitMate or Quark CPET for four 10-minute measurements. Test-retest intraclass correlations were 0.95-0.99, p ≤ 0.0001 for all parameters tested. Ve, RMR, VO2, and heart rate were not significantly different between the two systems. These results suggest that the FitMate is a reliable canopy dilution system for RMR measurements in healthy adults.

A method-comparison study regarding the validity and reliability of the Lactate Plus analyzer.

OBJECTIVES: The aims of this study were to: (1) determine the validity and reliability of the Nova Biomedical Lactate Plus portable analyzer, and quantify any fixed or proportional bias; (2) determine the effect of any bias on the determination of the lactate threshold and (3) determine the effect that blood sampling methods have on validity and reliability. DESIGN: In this method comparison study we compared blood lactate concentration measured using the Lactate Plus portable analyzer to lactate concentration measured by a reference analyzer, the YSI 2300. SETTING: University campus in the USA. PARTICIPANTS: Fifteen active men and women performed a discontinuous graded exercise test to volitional exhaustion on a motorised treadmill. Blood samples were taken via finger prick and collected in microcapillary tubes for analysis by the reference instrument at the end of each stage. Duplicate samples for the portable analyzer were either taken directly from the finger or from the micro capillary tubes. PRIMARY OUTCOME MEASUREMENTS: Ordinary least products regressions were used to assess validity, reliability and bias in the portable analyzer. Lactate threshold was determined by visual inspection. RESULTS: Though measurements from both instruments were correlated (r=0.91), the differences between instruments had large variability (SD=1.45 mM/l) when blood was sampled directly from finger. This variability was reduced by ∼95% when both instruments measured blood collected in the capillary tubes. As the proportional and fixed bias between instruments was small, there was no difference in estimates of the lactate threshold between instruments. Reliability for the portable instrument was strong (r=0.99, p<0.05) with no proportional bias (slope=1.02) and small fixed bias (-0.19 mM/l). CONCLUSIONS: The Lactate Plus analyzer provides accurate and reproducible measurements of blood lactate concentration that can be used to estimate workloads corresponding to blood lactate transitions or any absolute lactate concentrations.

The acute effects of flotation restricted environmental stimulation technique on recovery from maximal eccentric exercise.

Flotation restricted environmental stimulation technique (REST) involves compromising senses of sound, sight, and touch by creating a quiet dark environment. The individual lies supine in a tank of Epsom salt and water heated to roughly skin temperature (34-35° C). This study was performed to determine if a 1-hour flotation REST session would aid in the recovery process after maximal eccentric knee extensions and flexions. Twenty-four untrained male students (23.29 ± 2.1 years, 184.17 ± 6.85 cm, 85.16 ± 11.54 kg) participated in a randomized, repeated measures crossover study. The participants completed 2 exercise and recovery protocols: a 1-hour flotation REST session and a 1-hour seated control (passive recovery). After isometric muscle strength testing, participants were fatigued with eccentric isokinetic muscle contractions (50 repetitions at 60°·s) of the nondominant knee extensors and flexors. Blood lactate, blood glucose, heart rate, OMNI-rating of perceived exertion for resistance exercise (OMNI-RPE), perceived pain, muscle soreness, and isometric strength were collected before exercise, after treatment, and 24 and 48 hours later. A multivariate analysis of covariance found that treatment had a significant main effect on blood lactate, whereas subsequent univariate analyses of variance found statistical significance with the immediate posttreatment blood lactate measures. The results indicate that flotation REST appears to have a significant impact on blood lactate and perceived pain compared with a 1-hour passive recovery session in untrained healthy men. No difference was found between conditions for muscle strength, blood glucose, muscle soreness, heart rate, or OMNI-RPE. Flotation REST may be used for recreational and professional athletes to help reduce blood lactate levels after eccentric exercise.

Competitive athletic participation, thigh muscle strength, and bone density in elite senior athletes and controls.

The relationship between participation in highly competitive exercise, thigh muscle strength, and regional and total body bone mineral density (BMD) in elite senior athletes and healthy elderly controls was investigated. One hundred and four elite senior athletes (age: 72.6 ± 6.4 years, height: 168.7 ± 8.6 cm, mass: 72.6 ± 13.5 kg, 57 male:47 female) and 79 healthy controls (age: 75.4 ± 5.6 years, height: 170.8 ± 25.5 cm, mass: 79.5 ± 11.7 kg, 46 male:33 female) participated in this cross-sectional study. Vitamin D and calcium intake were assessed via a recall survey. Isometric knee extension and flexion peak torque were measured via a custom strength measurement device. Total body and regional BMD of the hip, radius, and spine were assessed with a dual-energy x-ray absorptiometer. For each BMD site assessed, multivariate linear regression analysis was performed in 4 steps (α = 0.10) to examine the contribution of (a) age, sex, bodyweight, and calcium and vitamin D intake; (b) group (elite senior athlete, control); (c) knee extension peak torque; and (d) knee flexion peak torque on BMD. Sex, age, bodyweight, and calcium and vitamin D intake explained a significant amount of variance in BMD in each site. Group was not significant. Knee extension peak torque explained an additional 3.8% of the variance in hip BMD (p = 0.06). Knee flexion peak torque was not correlated to BMD at any of the sites assessed. In conclusion, participation in highly competitive athletics was not related to total body or regional BMD. Age, sex, bodyweight, and vitamin D and calcium intake were significantly related to BMD at all the sites assessed. Quadriceps strength contributed slightly to hip BMD. Our results imply that participation in highly competitive senior athletics does not have a protective effect on BMD, perhaps because of a lower bodyweight or other confounding factors.

Decreased neuromuscular function in Crohn's disease patients is not associated with low serum vitamin D levels.

BACKGROUND: Neuromuscular fatigue is a common complaint in Crohn's disease (CD) patients. A correlation between serum vitamin D concentrations and neuromuscular function has been found in the elderly or non-ambulant populations. AIMS: The aim of this study was to determine whether CD patients exhibit impaired neuromuscular function and if so, is there a link between vitamin D and neuromuscular function. METHODS: Crohn's disease patients (n = 19) with at least one prior small bowel resection and matched controls (n = 19) underwent muscle strength and endurance testing, vitamin D, and nerve function analysis. RESULTS: Knee extension and flexion peak torque (Nm/kg) were greater in the control group than in the CD patients (P = 0.04 and 0.014, respectively. A significant difference was found between fatigue rates of the rectus femoris (P = 0.015) between CD patients and controls, but no difference was found in serum vitamin D levels between groups (P = 0.317). Knee extension and flexion torque measurements, with age as a covariate, were compared with high and low vitamin D levels. Those subjects with high serum vitamin D levels had a significantly greater extension peak torque (P = 0.045) and extension average torque (Nm/kg) (P = 0.014) than those with low levels. CONCLUSION: Crohn's disease patients with sufficient vitamin D levels experienced a 43 % greater extension peak torque. Although vitamin D deficiency has been associated with neuromuscular dysfunction, there were no differences in serum vitamin D levels between the CD and healthy controls to explain the decreased muscle strength.

Protein timing and its effects on muscular hypertrophy and strength in individuals engaged in weight-training.

The purpose of this review was to determine whether past research provides conclusive evidence about the effects of type and timing of ingestion of specific sources of protein by those engaged in resistance weight training. Two essential, nutrition-related, tenets need to be followed by weightlifters to maximize muscle hypertrophy: the consumption of 1.2-2.0 g protein.kg -1 of body weight, and ≥44-50 kcal.kg-1 of body weight. Researchers have tested the effects of timing of protein supplement ingestion on various physical changes in weightlifters. In general, protein supplementation pre- and post-workout increases physical performance, training session recovery, lean body mass, muscle hypertrophy, and strength. Specific gains, differ however based on protein type and amounts. Studies on timing of consumption of milk have indicated that fat-free milk post-workout was effective in promoting increases in lean body mass, strength, muscle hypertrophy and decreases in body fat. The leucine content of a protein source has an impact on protein synthesis, and affects muscle hypertrophy. Consumption of 3-4 g of leucine is needed to promote maximum protein synthesis. An ideal supplement following resistance exercise should contain whey protein that provides at least 3 g of leucine per serving. A combination of a fast-acting carbohydrate source such as maltodextrin or glucose should be consumed with the protein source, as leucine cannot modulate protein synthesis as effectively without the presence of insulin. Such a supplement post-workout would be most effective in increasing muscle protein synthesis, resulting in greater muscle hypertrophy and strength. In contrast, the consumption of essential amino acids and dextrose appears to be most effective at evoking protein synthesis prior to rather than following resistance exercise. To further enhance muscle hypertrophy and strength, a resistance weight- training program of at least 10-12 weeks with compound movements for both upper and lower body exercises should be followed.

The effects of group cycling on gait and pain-related disability in individuals with mild-to-moderate knee osteoarthritis: a randomized controlled trial.

STUDY DESIGN: Randomized controlled trial. OBJECTIVE: To determine the effectiveness of a community-based program of stationary group cycling on gait, pain, and physical function in individuals with mild-to-moderate knee osteoarthritis (OA). BACKGROUND: Knee pain and disability are common symptoms in individuals with knee OA. Though exercise for knee OA has acknowledged benefits, it has the potential to aggravate symptoms in some instances. METHODS: Thirty-seven subjects (27 women, 10 men) with a mean ± SD age of 57.7 ± 9.8 years were randomly assigned to a cycling (n = 19) or control (n = 18) group for a 12-week intervention study. Outcome variables, measured at baseline and 12 weeks, included preferred and maximal gait velocity, a visual analog pain scale at rest and following a 6-minute walk test, muscle strength, and functional-outcome questionnaires. Data were analyzed using mixed-model analyses of variance for group and time differences. RESULTS: After 12 weeks, the individuals receiving the cycling intervention showed significantly greater improvements (P<.05) for preferred gait velocity (mean difference between groups, 8.7 cm/s; 95% confidence interval [CI]: 2.2, 15.1), visual analog pain scale on the 6-minute walk test (mean difference, 16.5 mm; 95% CI: 2.1, 31.0), the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale (mean difference, 14.9 points; 95% CI: 2.6, 27.0) and stiffness subscale (mean difference, 10.8 points; 95% CI: 0.7, 21.3), the Knee injury and Osteoarthritis Outcome Score pain subscale (mean difference, 13.3 points; 95% CI: 3.4, 23.3), and the Knee Outcome Survey activities of daily living subscale (mean difference, 13.9 points; 95% CI: 2.0, 25.9) compared to controls. CONCLUSION: Stationary group cycling may be an effective exercise option for individuals with mild-to-moderate knee OA and may reduce pain with walking. US trial registration NCT00917618. LEVEL OF EVIDENCE: Therapy, level 1b-.

Thigh muscle strength in senior athletes and healthy controls.

Exercise is commonly recommended to counteract aging-related muscle weakness. While numerous exercise intervention studies on the elderly have been performed, few have included elite senior athletes, such as those who participate in the National Senior Games. The extent to which participation in highly competitive exercise affects muscle strength is unknown, as well as the extent to which such participation mitigates any aging-related strength losses. The purpose of this study was to examine isometric thigh muscle strength in selected athletes of the National Senior Games and healthy noncompetitive controls of similar age, as well as to investigate strength changes with aging in both groups. In all, 95 athletes of the Games and 72 healthy controls participated. Of the senior athletes, 43 were runners, 12 cyclists, and 40 swimmers. Three trials of isometric knee flexion and extension strength were collected using a load cell affixed to a custom-designed chair. Strength data were normalized to dual-energy x-ray absorptiometry-obtained lean mass of the leg. A 3-factor multivariate analysis of variance (group x gender x age group) was performed, which included both the extension and flexion variables (alpha = 0.05). Athletes exhibited 38% more extension strength and 66% more flexion strength than the controls (p < 0.001). Strength did not decrease with advancing age in either the athletes or the controls (p = 0.345). In conclusion, senior athletes who participate in highly competitive exercise have greater strength than healthy aged-matched individuals who do not. Neither group displayed the expected strength losses with aging. Our subject cohorts, however, were not typical of those over age 65 years because individuals with existing health conditions were excluded from the study.