High-intensity interval training: Modulating interval duration in overweight/obese men

High-intensity interval training (HIIT) is a time-efficient strategy shown to induce various cardiovascular and metabolic adaptations. Little is known about the optimal tolerable combination of intensity and volume necessary for adaptations, especially in clinical populations

The effects of pomegranate extract on blood flow, vessel diameter, and exercise tolerance

During exercise, the demand for oxygen and energy substrates is elevated in active skeletal muscle. Supplements with high nitrate and polyphenol content have been shown to increase nitric oxide production and enhance exercise efficiency. The current randomized, double-blind, placebo-controlled, crossover study aimed to investigate the acute effects of pomegranate extract on blood flow, vessel diameter, and exercise performance in active individuals

The acute effect of exercise and nutrition on respiratory exchange ratio in women

Few studies exist evaluating metabolic responses to exercise and nutrition in women. Understanding sex-specific fuel differences may improve exercise prescription. PURPOSE: To examine the effect of exercise modality and pre-exercise carbohydrate (CHO) or protein (PRO) ingestion on respiratory exchange ratio (RER) in women

Effects of dietary macronutrient distribution on resting and post-exercise metabolism

Previous research has demonstrated that habitual dietary macronutrient distribution affects energy substrate utilization at rest and during exercise. The primary purpose of the current study was to examine the relationships between habitual baseline macronutrient intakes, expressed relative to bodyweight and percentage of total energy intake, and metabolism at rest and after exercise in women

Effects of pomegranate extract on blood flow and running time to exhaustion

Recent research has shown dietary nitrate to impart favorable effects on blood flow and exercise. The purpose of this randomized, double-blind, placebo-controlled, crossover study was to investigate the acute effects of pomegranate extract on blood flow, vessel diameter, and exercise performance in active individuals. Nineteen men and women (Mean ± SD; Age: 22.2 ± 2.2 yrs; Height: 174.8 ± 10.7 cm; Body mass: 71.9±13.5 kg) were randomly assigned to a placebo (PL) or pomegranate extract (PE) group. Participants performed a maximal oxygen consumption treadmill test to determine peak velocity (PV). Participants returned after 24–48 hours, and ingested either PL or PE. Brachial artery blood flow was assessed using ultrasound at baseline and 30 minutes post-ingestion (30minPI). Three treadmill runs to exhaustion (TTE) were performed at 90%, 100%, and 110%PV. Blood flow was assessed immediately after each exercise bout and 30 minutes post-exercise (30minPEx). After a 7–10 day washout, participants repeated the same procedures, ingesting the opposite supplement. Separate repeated measures ANOVAs were performed for blood flow, vessel diameter, and TTE. Blood flow was significantly augmented (p=0.033) 30minPI with PE in comparison to PL. Vessel diameter was significantly larger (p=0.036) 30minPEx with PE. Ingestion of the PE was found to significantly augment TTE at 90% (p=0.009) and 100% PV (p=0.027). Acute ingestion of PE 30 min prior to exercise may enhance vessel diameter, blood flow, and delay fatigue during exercise. Results of the current study indicate that PE is ergogenic for intermittent running, eliciting beneficial effects on blood flow

Evaluation of Muscle Quality Reliability and Racial Differences in Body Composition of Overweight Individuals

The purpose of this study was to evaluate the reliability of ultrasound measures of muscle cross-sectional area (mCSA) and echo intensity (EI) in overweight subjects. A secondary purpose was to evaluate racial differences in EI, mCSA and body composition. In 33 overweight subjects, mCSA and EI were determined from a panoramic ultrasound scan of the vastus lateralis. Body composition was determined using dual-energy X-ray absorptiometry (DXA). Reliability of mCSA and EI was calculated from the intra-class correlation coefficient (ICC), standard error of the measurement (SEM) and minimal difference (MD). The ICC, SEM and MD for mCSA and EI were 0.87, 2.12, 5.89 and 0.74, 4.58, 12.69, respectively. There were no significant racial differences in body composition (p > 0.05); however, EI was significantly lower for black subjects (p = 0.018). These results suggest ultrasound measures of mCSA and EI are reliable in overweight subjects, and EI may provide additional muscle composition evaluations, beyond DXA measures

Muscle Size, Quality, and Body Composition: Characteristics of Division I Cross-Country Runners

The primary purpose was to identify the relationship between muscle cross sectional area (mCSA), echo intensity (EI), and body composition of Division I cross-country runners. The secondary purpose was to examine differences in these variables in athletes stratified based on stress fracture (SFx) history. Thirty-six athletes were stratified based on sex and previous SFx history. A panoramic scan vastus lateralis (VL) was performed using a GE logiq-e B-mode ultrasound (US). Echo intensity and mCSA were determined from the scan by using a grayscale imaging software (Image-J). Body composition measures were determined using dual-energy xray absorptiometry (DEXA). For females, mCSA was significantly correlated with left leg lean mass (LM; R=0.54) and EI (R= −0.57). Lean mass was significantly correlated with bone mineral density (BMD; R=0.58) and content (BMC; R=0.56), while BMC was also correlated with leg LM (R=0.72). For males, mCSA was significantly correlated with leg LM (R=0.66), BMD (R=0.50), and BMC (R=0.54). Leg LM was significantly correlated with BMD (R=0.53) and BMC (R=0.77). Personal best times for males were significantly correlated with FM (R=0.489) and %fat (R=0.556) for the 10 kilometer and 5 kilometer races, respectively. Female and male athletes with previous history of SFx were not significantly different across any variables when compared to athletes with no previous history. These correlations suggest more muscle mass may associate with higher BMD and BMC for stronger bone structure. Modifications in training strategies to include heavy resistance training and plyometrics may be advantageous for preventing risk factors associated with stress fracture reoccurrence