Michelle Gray

Breakfasts Higher in Protein Increase Postprandial Energy Expenditure, Increase Fat Oxidation, and Reduce Hunger in Overweight Children from 8 to 12 Years of Age

BACKGROUND Currently 1 in every 3 children aged 2-19 y is overweight or obese. Breakfast is a key component of a healthy diet and has the potential to affect childrens health. OBJECTIVE The objective of this study was to determine whether consumption of a protein-based breakfast (PRO) increases postprandial energy metabolism and substrate oxidation, reduces hunger, and reduces food intake at lunch compared with a carbohydrate-based breakfast (CHO) in normal weight (NW) vs. overweight/obese (OW) children. METHODS A randomized, crossover-design study was conducted in NW (n = 16; 33 ± 1 kg) and OW (n = 13; 46 ± 2 kg) children (10 ± 1 y). Participants were served either a PRO [344 kcal, 21% protein (18 g), 52% carbohydrate, and 27% fat] or CHO [327 kcal, 4% protein (3 g), 67% carbohydrate, and 29% fat]. Energy expenditure (EE), substrate oxidation, appetite, and blood glucose were measured over a 4 h period. Four hour postprandial participants were provided with access to a lunch buffet and food intake was recorded. RESULTS After breakfast, OW children in the PRO group had higher (P < 0.0001) EEs and fat oxidation over the 4 h period than did the NW children in the CHO and PRO groups. There was no difference in postprandial EE or carbohydrate oxidation between the CHO and PRO groups over the 4 h period; however, fat oxidation was 16% higher (P < 0.05) after the PRO than the CHO and postprandial carbohydrate oxidation at 4 h was 32% higher after the PRO than the CHO (P < 0.01), independent of weight group. All participants had decreased feelings of hunger (-14%; P < 0.01) and increased fullness (+32%; P < 0.05) after the PRO than the CHO. Finally, there was no difference in food intake within the NW and OW groups. CONCLUSION This study indicates that breakfast macronutrient composition affects postprandial responses in both NW and OW children. A PRO increases postprandial EE and fat oxidation, reduces hunger, and increases satiety when compared with a carbohydrate-based breakfast.

The effects of loaded and unloaded high-velocity resistance training on functional fitness among community-dwelling older adults

BACKGROUND Physical function declines up to 4% per year after the age of 65. High-velocity training is important for maintaining muscular power and ultimately, physical function; however, whether performing high-velocity training without external resistance increases functional fitness among older adults remains unclear. OBJECTIVE The purpose of this investigation was to evaluate loaded and unloaded high-velocity training on lower body muscular power and functional fitness in older adults. SUBJECTS Fifty-seven community-dwelling older adults (n = 16 males, n = 41 females) participated in this study. Inclusion criteria comprised ≥65 years of age, ≥24 on the Mini-mental state examination and no falls within past year. METHODS Two groups completed a 20-week high-velocity training intervention. The non-weighted group (UNLOAD, n = 27) performed the protocol without external load while the intervention group (LOAD, n = 30) used external loads via exercise machines. Functional fitness was assessed using the Short Physical Performance Battery (SPPB), Senior Fitness Test (SFT), hand-grip and lower body power measures. RESULTS Multivariate ANOVA revealed that both groups had significant improvements for average (17.21%) and peak (9.26%) lower body power, along with the SFT arm curl (16.94%), chair stand (20.10%) and 8 ft. up-and-go (15.67%). Improvements were also noticed for SPPB 8 ft. walk (25.21%). However, improvements for all functional fitness measures were independent of training group. CONCLUSIONS Unloaded high-velocity training increased functional fitness and power the same as loaded training. The ability of high-velocity movements to elicit gains in functional fitness without external loads may help health professionals develop fitness programs when time/space is limiting factor.

Thermic effect of food, exercise, and total energy expenditure in active females

OBJECTIVES Exercise and the thermic effect of food contribute to total energy expenditure and overall maintenance of health. The aim of this study was to determine the interaction between TEF and exercise on TEE based on meal protein content. DESIGN A randomized, repeated measures study. METHODS Ten active females, of normal body weight, participated. Preliminary maximal aerobic capacity (VO₂max) was determined. Three additional testing sessions consisted of performing a 30-min bout of exercise at 60% VO₂max after consumption of a high (45% total kcal) or low (15% total kcal) protein meal, or fasted. RESULTS Repeated measures ANOVA indicated a significant main effect for the feeding protocols (α=.05). The high protein meal elicited a 30.39% and 98.15% greater increase in TEF compared to the low protein meal (p=.006) and fasted state (p<.001), respectively. The low protein meal resulted in 94.34% greater TEF compared to fasted (p<.001). Combined with exercise, high protein meal TEF was significantly greater compared to fasted (p=.010) but was not significantly greater than the low protein meal (p=.122). Significant differences were not found between the low protein meals with exercise compared to fasted conditions (p=.094). CONCLUSIONS Findings of this study provide insight on increased TEE under acute high protein feeding conditions as compared to a low protein meal and fasted state. Combined with exercise, potential for further increases in TEE exists as a result of TEF.

Hydration status affects mood state and pain sensation during ultra-endurance cycling.

Abstract Laboratory-based studies indicate mild dehydration adversely affects mood. Although ultra-endurance events often result in mild to moderate dehydration, little research has evaluated whether the relationship between hydration status and mood state also exists in these arduous events. Therefore, the purpose of this study was to evaluate how hydration status affected mood state and perceptual measures during a 161 km ultra-endurance cycling event. One hundred and nineteen cyclists (103 males, 16 females; age = 46 ± 9 years; height = 175.4 ± 17.9 cm; mass = 82.8 ± 16.3 kg) from the 2011 and 2013 Hotter’N Hell events participated. Perceived exertion, Thermal, Thirst, and Pain sensations, Brunel Profile of Mood States, and urine specific gravity (USG) were measured pre- (~1 h before), mid- (~97 km), and post-ride. Participants were classified at each time point as dehydrated (USG ≥ 1.022) or euhydrated (USG ≤ 1.018). Independent of time point, dehydrated participants (USG = 1.027 ± 0.004) had decreased Vigour and increased Fatigue, Pain, Thirst, and Thermal sensations compared to euhydrated participants (USG = 1.012 ± 0.004; all P < 0.01). USG significantly correlated with Fatigue (r = 0.36), Vigour (r = −0.27), Thirst (r = 0.15), and Pain (r = 0.22; all P < 0.05). In conclusion, dehydrated participants had greater Fatigue and Pain than euhydrated participants. These findings indicate dehydration may adversely affect mood state and perceptual ratings during ultra-endurance cycling.

Parameters of gait among community-dwelling older adults.

Background:Functional fitness is the ability of an older adult to perform activities of daily living. Stair-climb power is a well-documented marker of functional fitness among older adults. Gait velocity and parameters of gait are related to functional fitness but have been understudied to date. Purpose:The purpose of this observational study was to determine differences in parameters of gait between high- and low-functioning older adults. Methods:Twenty high-functioning older adults, mean age (SD) = 71.6 (5.6), volunteered for the cross-sectional observational study. Functional fitness was determined by a stair-climb performance test. Parameters of gait included velocity, step length, swing and stance phase, double support time, ground reaction forces, impulse, and propulsion during habitual walking. Analysis of variance was performed to determine differences in the dependent variables between groups. Results:Individuals with high levels of functional fitness walked 13.1% faster than the lower-functioning group (P = .01). No significant differences (P > .05) were detected for any other measure; however, all gait parameters were more favorable in the higher-functioning group. Conclusion:Functional fitness is imperative for older adults as declines could hinder mobility. Thus, earlier detection of declines in gait parameters may reduce the risk of falling. The results suggest that gait velocity was slower among older adults with lower levels of functional fitness.

Acute citrulline-malate supplementation improves maximal strength and anaerobic power in female, masters athletes tennis players

Abstract Citrulline-malate (CM) is a precursor to nitric-oxide (NO) in the NO synthase (NOS) pathway and is suggested to increase exercise performance in younger individuals. With age, NO production decreases and augmented NO production may provide beneficial effects on sports performance among masters athletes (MAs). Purpose: To examine the effects of acute CM supplementation on grip strength, vertical power, and anaerobic cycling performance in female, MA tennis players. Methods: Seventeen female MA (51 ± 9 years) completed two double-blind, randomized trials consuming CM (12 g dextrose + 8 g CM) and placebo (PLA) (12 g dextrose). One hour after consumption, subjects completed grip strength, vertical power, and Wingate anaerobic cycling assessments in respective order. Maximal and average grip strength, peak and average vertical power, anaerobic capacity, peak power, explosive power, and ability to sustain anaerobic power were calculated from the tests. Results: When consuming CM, participants exhibited greater maximal (p = .042) and average (p = .045) grip strength compared to PLA. No differences existed between trials for peak (p = .51) or average (p = .51) vertical power. For the Wingate, peak power (p < .001) and explosive power (p < .001) were significantly greater when consuming CM compared to PLA. For the ability to sustain power, a significant effect (p < .001) was observed for time within trials, but no significant differences were observed between trials regarding supplement consumed. Conclusions: These data suggest that consuming CM before competition has the potential to improve tennis match-play performance in masters tennis athletes. However, this study utilized a controlled laboratory environment and research evaluating direct application to on-court performance is warranted.

Relationship of Sit-to-Stand Lower-Body Power With Functional Fitness Measures Among Older Adults With and Without Sarcopenia.

Background and Purpose: When evaluating health in older adults, batteries of tests are typically utilized to assess functional fitness. Unfortunately, physicians visits are time-sensitive, and it may be important to develop faster methods to assess functional fitness that can be utilized in professional or clinical settings. Therefore, the purpose of this investigation was to examine the relationship of sit-to-stand (STS) power generated through the STS task with previously established measures of functional fitness, specifically strength, endurance, speed, agility, and flexibility in older adults with and without sarcopenia. Methods: This study consisted of 57 community-dwelling older adults (n = 16 males; n = 41 females). Functional fitness was assessed using the Short Physical Performance Battery (SPPB), Senior Fitness Test, handgrip, gait speed (habitual and maximal), balance, and STS power generated via the Tendo Weightlifting Analyzer. On the basis of data distribution, second-degree polynomial (quadratic) curvilinear models (lines of best fit) were applied for the relationships of 5-time STS time with average and peak power. Zero-order correlations were evaluated between STS power and all other functional fitness measures. Older adults with sarcopenia were also identified (n = 15), and relationships were reevaluated within this subset. Results: STS power (average and peak) was significantly (P ⩽ .01) correlated with physical performance measured via previously established assessments. For average power, this was observed during the senior fitness test (6-minute walk [r = 0.39], 8-ft up-and-go [r = −0.46], arm curl [r = 0.46], and chair stand [r = 0.55]), SPPB (5-time STS time [r = −0.63] and 8-ft walk [r = −0.32]), and other independent functional fitness measures (grip strength [r = 0.65] and maximal gait speed [r = −0.31]). Similar results were observed for peak power during the senior fitness test (6-minute walk [r = 0.39], 8-ft up-and-go [r = −0.46], arm curl [r = 0.45], chair stand [r = 0.52], and sit-and-reach [r = −0.27]), SPPB (5-time STS time [r = −0.60] and 8-ft walk [r = −0.33]), and other independent functional fitness measures (grip strength [r = 0.70] and maximal gait speed [r = −0.32]). Within the sarcopenic subset, for average and peak power, respectively, significant relationships were still retained for handgrip strength (r = 0.57 and r = 0.57), 6-minute walk (r = 0.55 and r = 0.61), chair stand (r = 0.76 and r = 0.81), and 5-time STS time (r = −0.76 and r = −0.80) tests. Discussion/Conclusions: STS power generated via the STS task significantly relates to commonly administered functional fitness measures. These relationships also appear to exist when evaluating these relationships in older adults with sarcopenia. STS power may be utilized as an independent measure of functional fitness that is feasible to incorporate in clinical settings where time and space are often limiting factors.

Effects of Acute Beta-Alanine Supplementation on Anaerobic Performance in Trained Female Cyclists.

Longitudinal beta-alanine (BA) supplementation can improve exercise performance in males through increases in carnosine; however, females experience greater relative increases in carnosine compared to males. This potentially allows females to benefit from acute BA doses; however, effects of an acute BA dose on performance in females remain unknown. The purpose of this investigation was to evaluate how an acute dose of 1.6 g BA affects anaerobic performance in female cyclists. Twelve females (age=26.6±1.3 y) volunteered to participate in this randomized, double-blind study. All participants completed two supplement trials: 1) Placebo=34 g dextrose and 2) BA=1.6 g BA + 34 g dextrose. Thirty-minutes after supplementation, participants performed three repeated Wingate cycling tests with 2 min of active rest after each. Fatigue index, mean power, and peak power were measured during each Wingate. Lactate, heart rate, and rating of perceived exertion (RPE) were measured at rest, immediately after each Wingate, and after each active rest period. RPE significantly decreased (p<0.001) immediately following Wingates 1 and 2 and after each 2-min rest period for the BA trials; however, no differences were observed immediately after Wingate 3 (p>0.05). No significant supplementation effect was observed for any performance or physiological variable (p>0.05 for all variables). Findings suggest that an acute dose of BA (1.6 g) decreases RPE during anaerobic power activities in trained female cyclists.

Habitual and Maximal Dual-Task Gait Speeds Among Sedentary, Recreationally Active, and Masters Athlete Late Middle-Aged Adults

UNLABELLED Gait speed predicts survival in older adults; however, gait has not been evaluated in late middle-aged (LMA) populations. PURPOSE Evaluate single- and dual-task gait speeds among sedentary (SED), recreationally active (RA), and masters athlete (MA) LMA adults. METHODS Participants were SED (n = 20, age = 61.0 ± 5.8), RA (n = 57, age = 63.5 ± 8.4), and MA (n = 25, age = 57.5 ± 7.9). Two trials of each task (10 m) were completed: habitual speed (HS), maximal speed (MS), dual-task (counting backward from a number by 3) habitual speed (DTHS), and dual-task maximal speed (DT-MS). RESULTS MA (2.08 ± 0.63 m/s) had significantly (p < .05) greater MS compared with SED (1.94 ± 0.30 m/s) and RA (1.99 ± 0.53 m/s). Similar differences existed for DT-MS (SED = 1.77 ± 0.32 m/s, RA = 1.80 ± 0.51 m/s, MA = 1.89 ± 0.63 m/s). MA had smaller MS and DT-MS changes (difference between MS and DT-MS speeds) compared with RA (12%) and SED (13%). CONCLUSION Maintaining a competitively active lifestyle increases MS in LMA adults and may support healthy aging.

An Evaluation of Functional Sit-to-Stand Power in Cohorts of Healthy Adults Aged 18–97 Years

This investigation examined differences in functional sit-to-stand power/velocity between cohorts of adults aged 18-97 years. This study included 264 healthy adults classified into four cohorts (18-40, C1; 60-69, C2; 70-79, C2; ≥ 80, C4). Participants completed the sit-to-stand task five times. Power and velocity were measured via the TENDO power analyzer. Absolute average power was maintained from C1-C3, but decreased (p < .01) in C4. Absolute peak power decreased between C1-C2 (p < .01), was similar between C2-C3, and decreased in C4 (p < .01). Relative (to body weight) average and peak power decreased between C1-C2 (p < .01), was similar between C2-C3, and decreased in C4 (p < .01). Average velocity was similar between C1 and C2, but decreased in C3 (p < .01) and C4 (p < .01), respectively. Peak velocity was significantly different between all cohorts (p < .01). Declines in functional power may plateau during the seventh and eighth decades, accelerating after 80 years.