M. Kent Todd

Effects of a Carbohydrate-Protein Beverage on Cycling Endurance and Muscle Damage

INTRODUCTION The purpose of this study was to determine whether endurance cycling performance and postexercise muscle damage were altered when consuming a carbohydrate and protein beverage (CHO+P; 7.3% and 1.8% concentrations) versus a carbohydrate-only (CHO; 7.3%) beverage. METHODS Fifteen male cyclists (mean (.-)VO(2peak) = 52.6 +/- 10.3 mL x kg x min) rode a cycle ergometer at 75% (.-)VO(2peak) to volitional exhaustion, followed 12 - 15 h later by a second ride to exhaustion at 85% (.-)VO(2peak). Subjects consumed 1.8 mL x kg BW of randomly assigned CHO or CHO+P beverage every 15 min of exercise, and 10 mL x kg BW immediately after exercise. Beverages were matched for carbohydrate content, resulting in 20% lower total caloric content per administration of CHO beverage. Subjects were blinded to treatment beverage and repeated the same protocol seven to 14 d later with the other beverage. RESULTS In the first ride (75% (.-)VO(2peak)), subjects rode 29% longer (P < 0.05) when consuming the CHO+P beverage (106.3 +/- 45.2 min) than the CHO beverage (82.3 +/- 32.6 min). In the second ride (85% (.-)VO(2peak)), subjects performed 40% longer when consuming the CHO+P beverage (43.6 +/- 12.5 min) than when consuming the CHO beverage (31.2 +/- 8.7 min). Peak postexercise plasma CPK levels, indicative of muscle damage, were 83% lower after the CHO+P trial (216.3 +/- 122.0 U x L) than the CHO trial (1318.1 +/- 1935.6 U x L). There were no significant differences in exercising levels of (.-)VO(2), ventilation, heart rate, RPE, blood glucose, or blood lactate between treatments in either trial. CONCLUSION A carbohydrate beverage with additional protein calories produced significant improvements in time to fatigue and reductions in muscle damage in endurance athletes. Further research is necessary to determine whether these effects were the result of higher total caloric content of the CHO+P beverage or due to specific protein-mediated mechanisms.

Effect of a family-based intervention on electronic media use and body composition among boys aged 8—11 years: a pilot study:

This study measured the effect of a 20-week, family-centered electronic media intervention on electronic media use, body composition (dual-energy X-ray absorptiometry; DXA), physical activity and dietary behaviors in boys. Twenty-two boys were assigned and 21 were analyzed in an experimental or control group. Boys in the experimental group set electronic media use goals and used TV Allowance™ device and ENUFF® software to reduce electronic media use. Data were collected at baseline, 10 weeks and 20 weeks. Interactions were found in daily electronic media use and DXA. At 10 weeks, step counts increased by 543 steps per day in the experimental group and decreased by 340 steps per day in the controls. Steps in both groups were higher at 20 weeks. Meals or snacks eaten while using electronic media decreased in the experimental group only. In conclusion, a family-centered electronic media intervention may reduce electronic media use and contribute to desirable changes in body composition.

Comparison of Health and Academic Indices between Campus Recreation Facility Users and Nonusers

Body mass index (BMI), electronic media (EM) use, International Physical Activity Questionnaire (IPAQ) scores, selected nutrient intake, smoking, and grade point averages (GPA) were compared between campus recreation (CR) facility users and nonusers at a public, four-year institution in the mid-Atlantic region. Participants (n = 1034) were categorized by CR visits: nonusers, low users (>0 to <1 visit/wk), moderate users (≥1 to <3 visits/wk), or high users (≥3 visits/wk). Significant (p < .05) main effects between user groups were found for BMI, EM use, IPAQ scores, fat intake, smoking, and GPA. High users had better GPA (3.35 vs. ≤3.15 for others), IPAQ scores (8135 MET-min/wk vs. <6800 MET-min/wk for others), and lower fat intake (<30% of total calories vs. >30.9% of total calories for others) than all other groups. High users also had lower BMI (22.8 kg/m2) than moderate users and nonusers (>23.9 kg/m2) and lower EM use (5.56 hr/d) than nonusers (6.55 hr/d). These results indicate that CR visitations are favorably associated with academic achievement and good health.

Comparison of Responses to Exercise When Consuming Carbohydrate and Carbohydrate/Protein Beverages: 1996

RESULTS: Oxygen uptake did not differ among CHO+P, CHO1 and CHO2 trials, respectively (41.0±8.1, 42.0±7.7, 42.3±6.8 mL-kgmm). Blood lactate was significantly lower (p<.05) in the CHO+P trial (2.9±1.1 mmol L) versus CHO1 (3.6±1.2) and CHO2 (3.6±1.4). Heart rate was also lower in the CHO+P trial (153.3±9.3 bpm) compared to CHO1 (159.0±8.5) and CHO2 (158.1±12.4). RPE in the CHO+P trial (12.9± 1.1) was significantly lower than CHO1 (13.7±1.1), but did not significantly differ from CHO2 (13.2±2.0). Plasma glucose concentrations did not differ between trials (67.7±20.1, 72.5±22.3, 74.2±11.7 mg-dL)

Inter-Study Examination of Physiological Variables Associated with Improved Endurance Performance with Carbohydrate/Protein Administration: 1067

PURPOSE: Previous studies from our laboratory reported improvements in endurance performance when athletes consumed carbohydrate/protein (CHO+P) beverages or gels compared to carbohydrate-only (CHO) treatments. However, relatively small sample sizes in these studies precluded the ability to examine correlations between physiological variables that may have been associated with performance benefits. Therefore, the purpose of this study was to examine data across multiple studies to determine if improvements in performance were related to alterations in physiological measures during exercise.

The Effects of Obstructive Sleep Apnea on Autonomic Function during Steady-State Exercise: 2363 Board #110 May 29, 11

Purpose The aim of this study is to assess autonomic function by analyzing heart rate variability (HRV) at rest and during submaximal exercise in OSA patients and a nonOSA control group. Methods Subjects were classified as OSA (n=10) or non-OSA (n=16) based on results from an at-home sleep assessment. Height, weight, waist and neck circumferences, and body composition were collected during the first visit for each subject. Physical activity during the day and nocturnal movement were assessed over a period of 4 days, including 3 weekdays and 1 weekend day, using accelerometers. HRV and blood pressure were recorded at rest (visit 2) and during a submaximal graded exercise test (visit 3). HRV variables that were not normally distributed were log transformed before statistical analysis. Independent samples t-tests were used to establish differences between groups. Pearson correlations were calculated to determine relationships between OSA and HRV in terms of age and BMI. If there was a significant correlation between variables and age and/or BMI, then a repeated measures ANCOVA was used with age or BMI as the covariate. If there was not a significant correlation, a repeated measures ANOVA was utilized. Results At rest, the OSA group had lower SDNN, RMSSD, and Total Power (p<0.05). A higher LF-HF ratio was found in the control group than the OSA group during exercise (p<0.05). LFnu and HFnu were trending towards significance, both higher in the OSA