Supplemental Facts
FAQ
R4 System
STUDIES
1. EFFECTS OF RECOVERY BEVERAGES ON GLYCOGEN RESTORATION AND ENDURANCE EXERCISE PERFORMANCE
J Strength Cond Res, 2003 Feb;17(1):12-19
Michael B. Williams, Peter B. Raven, Donovan L. Fogt and John L. Ivy. Cardiovascular Research Institute, University of North Texas, Health Science Center at Fort Worth, TX 76107, and Exercise Physiology and Metabolism Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, TX 78712
The restorative capacities of a high carbohydrate-protein (CHO-PRO) beverage containing electrolytes and a traditional 6% carbohydrate-electrolyte sports beverage were assessed following glycogen-depleting exercise. Post-exercise ingestion of CHO-PRO beverage, in comparison to the sports beverage, resulted in a 55% greater time to exhaustion during a subsequent exercise bout at 85% VO2max. It was hypothesized that the greater recovery following the CHO-PRO beverage was due to a greater rate of muscle glycogen storage. Therefore, a second study was designed to investigate the effects of post exercise CHO-PRO and sports beverage supplements on muscle glycogen restoration.
Methods: Eight endurance-trained cyclists (VO2max = 62.1 ± 2.2 ml ? kg-1 body wt ? min-1) performed two trials consisting of a 2 h glycogen depletion ride at 65 to 75% VO2max. CHO-PRO (355 ml; ~0.8 g carbohydrate ? kg-1 body wt and ~0.2 g protein ? kg-1 body wt) or sports beverage (355 ml; ~0.3 g carbohydrate ? kg-1 body wt) was provided immediately and 2 h post exercise. Trials were randomized and separated by 7 to 15 days.
Results: Ingestion of the CHO-PRO beverage resulted in a 17% greater plasma glucose response, a 92% greater insulin response and a 128% greater storage of muscle glycogen (159 ± 18 and 69 ± 32 µmol ? g-1 dry weight for CHO-PRO and sports beverages, respectively) compared to the sports beverage (p < 0.05).
Conclusions: These findings indicate that the rate of recovery is coupled with the rate of muscle glycogen replenishment, and suggest recovery supplements should be consumed to optimize muscle glycogen synthesis as well as fluid replacement.
2. Effects Of Recovery Drinks After Prolonged Glycogen-Depletion Exercise
Medicine & Science in Sports and Exercise. 31(5)S124, 1999.
Williams, M., J. Ivy, And P. Raven. Cardiovascular Research Institute University of North Texas Health Science Center at Fort Worth, TX 76107 and Department of Kinesiology University of Texas, Austin, TX 78712 *
Purpose: Eight high-fit (bicycle VO2max = 62.4 (1.10 ml (kg -1(min-1) male cyclists, aged 28.4 (1.65 yrs. performed a two hour endurance bicycle exercise to achieve depletion of skeletal muscle and liver glycogen. During recovery, R4 Recovery Drink, or Gatorade, was ingested to investigate their relative restorative capacities to enable further exercise.
Methods: Each subject performed two days of resting: one for each drink presented in random order. On each testing day, the twelve-hour fasted subject performed a two-hour cycling exercise bout at 75% VO2max followed by one to three 5-minute sprints at 85% VO2max. At the end of this exercise blood glucose concentrations were 3.98 (0.138 mmol/L. A four-hour recovery period ensued in which the subject was given 24 ounces of the recovery drink. A performance test at 85% VO2max to exhaustion was then conducted. Ventilatory responses were collected breath-to-breath, while venous blood samples were measured for oxidation products, glucose and insulin concentrations.
Results: The recovery phase showed significant increases in both plasma glucose and insulin following R4 Recovery Drink ingestion as compared to Gatorade. There was a significant increase in time to exhaustion (+66%) following R4 Recovery Drink during the performance ride compared to Gatorade. Final oxidation products following R4 Recovery Drink ingestion were significantly decreased as compared to Gatorade ingestion, as well as Thiobarbituric Acid Reactive Substrates (T-BARS).
Conclusions: These data indicate that recovery from glycogen-depleting exercise was significantly enhanced by R4 Recovery Drink when compared to Gatorade. In addition, R4 Recovery Drink decreased the formation of final oxidation products, when compared to Gatorade.
3. The Effect of Two Sports Drink Formulations on Muscle Stress and Performance
Medicine & Science in Sports and Exercise. 31(5)S119, 1999.
S.L. Ready, J.G. Seifert. & E. Burke. Human Performance Lab, SCSU, St. Cloud, MN 56303. Dept. of Biology, UCCS, Colorado Springs, CO.
Creatine kinase (CK) levels are frequently used as an indicator of muscle stress and damage. It is thought that CK leakage from cells occurs because of a disruption in the cell membrane. The purpose of this study was to compare two formulations on post-exercise muscle stress and performance time in a moderate-intensity duathlon. Ten college age males and females ingested a 15% CHO/protein/electrolyte beverage (CP) in a formulation containing CHO: protein in a 4:1 ratio or a 6% CHO/electrolyte (CE) beverage in a double blind, counterbalanced design. Subjects completed a 45-min run, rested in a 10-min transition, cycled for 90 min, and then performed a 90kJ time trial (TT). Each sport drink was ingested during the transition (360 ml) and 30 min into the bike segment (180 ml). Blood samples were collected and analyzed for CK, lactic acid (LA) and glucose (GL). Heart rate (HR), VO2, and RPE were measured.
Results: The 90kJ TT was enhanced by an average of 27 sec for 7 of the 10 subjects in the CP group. However, an ANOVA revealed no statistical difference for the time trial between the two groups (CP=395 +90 sec; CE=409 +78 sec). GL was statistically increased in the CP group. No differences were observed for LA, HR, VO2, or RPE. In the CP group there was a significant reduction of 36% for the 24-hour post exercise CK level.
Conclusions: These results suggest that CP, by providing additional CHO and amino acids, may reduce post-exercise muscle stress, as evidenced by a 36% decrease in 24- hour CK levels. A possible mechanism for this reduced stress could be through the maintenance of cell membrane integrity.
4. Effects 0f Post Exercise Carbohydrate-Protein Supplement On Skeletal Muscle Glycogen Storage
Medicine & Science in Sports and Exercise. 32(5)S60, 2000.
D.L. Fogt, J.L. Ivy Department of Kinesiology University of Texas, Austin, TX 78712 *
Previously it was shown that ingestion of a high carbohydrate-protein (CHO-PRO) supplement after glycogen-depleting exercise enabled a 55% greater time to exhaustion in a subsequent exercise bout when compared with a typical 6% carbohydrate (CHO) sports drink (Williams, M.B. et al., MSSE 31:(Suppl.) S124, 1999). It was hypothesized that the greater recovery following the CHO-PRO supplement was due to a greater rate of muscle glycogen storage. The present study was designed to investigate the effects of post exercise CHO-PRO and CHO supplements on muscle glycogen restoration. Eight endurance-trained (cycle VO2max = 62.1 ± 2.2 ml ? kg body wt-1 ? min-1) cyclists performed two trials consisting of a 2 h glycogen depletion ride followed by ingestion of 12 oz of CHO-PRO or CHO supplement immediately and 2 h post exercise. Trials were randomized and separated by 7 days. The manufacturer-suggested serving (12 oz) of the CHO-PRO contained 53 g CHO and 14 g PRO, providing 0.8 g CHO ? kg body wt-1 and 0.2 g PRO ? kg body wt-1, whereas the equivalent serving (12 oz) of the CHO supplement provided 20 g CHO (0.3 g CHO ? kg body wt-1) and contained no PRO. Blood samples were collected prior to exercise and throughout the 4 h post exercise recovery period. Muscle biopsies were taken immediately after and 4 h post exercise for determination of muscle glycogen content.
Results: Blood lactate concentrations were similar following both treatments. However, ingestion of the CHO-PRO supplement resulted in a 17% greater plasma glucose response [incremental area under the curve (AUC)], a 92% greater insulin response (AUC) and a 128% greater storage of muscle glycogen (33.66 ± 4.5 and 17.42 ± 5.2 µmol ? g dry weight-1 ? h-1 for CHO-PRO and CHO, respectively) compared to the CHO supplement (p<0.05).
Conclusions: Thus, the greater rate of recovery following glycogen-depleting exercise during the CHO-PRO treatment shown previously was likely due to a greater glycogen restoration although other possibilities exist.
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