Postexercise carbohydrate-protein supplementation improves subsequent exercise performance and intracellular signaling for protein synthesis

Postexercise carbohydrate-protein (CHO + PRO) supplementation has been proposed to improve recovery and subsequent endurance performance compared to CHO supplementation. This study compared the effects of a CHO + PRO supplement in the form of chocolate milk (CM), isocaloric CHO, and placebo (PLA) on recovery and subsequent exercise performance. Ten cyclists performed 3 trials, cycling 1.5 hours at 70% VO?max plus 10 minutes of intervals. They ingested supplements immediately postexercise and 2 hours into a 4-hour recovery. Biopsies were performed at recovery minutes 0, 45, and 240 (R0, R45, REnd). Postrecovery, subjects performed a 40-km time trial (TT). The TT time was faster in CM than in CHO and in PLA (79.43 ± 2.11 vs. 85.74 ± 3.44 and 86.92 ± 3.28 minutes, p ≤ 0.05). Muscle glycogen resynthesis was higher in CM and in CHO than in PLA (23.58 and 30.58 vs. 7.05 μmol·g?1 wet weight, p ≤ 0.05). The mammalian target of rapamycin phosphorylation was greater at R45 in CM than in CHO or in PLA (174.4 ± 36.3 vs. 131.3 ± 28.1 and 73.7 ± 7.8% standard, p ≤ 0.05) and at REnd in CM than in PLA (94.5 ± 9.9 vs. 69.1 ± 3.8%, p ≤ 0.05). rpS6 phosphorylation was greater in CM than in PLA at R45 (41.0 ± 8.3 vs. 15.3 ± 2.9%, p ≤ 0.05) and REnd (16.8 ± 2.8 vs. 8.4 ± 1.9%, p ≤ 0.05). FOXO3A phosphorylation was greater at R45 in CM and in CHO than in PLA (84.7 ± 6.7 and 85.4 ± 4.7 vs. 69.2 ± 5.5%, p ≤ 0.05). These results indicate that postexercise CM supplementation can improve subsequent exercise performance and provide a greater intracellular signaling stimulus for PRO synthesis compared to CHO and placebo.     

Iron supplementation improves endurance after training in iron-depleted, nonanemic women.

Our objective was to investigate the effects of iron depletion on adaptation to aerobic exercise, assessed by time to complete a 15-km cycle ergometer test. Forty-two iron-depleted (serum ferritin <16 microg/l), nonanemic (Hb >12 g/dl) women (18-33 yr old) received 100 mg of ferrous sulfate (S) or placebo (P) per day for 6 wk in a randomized, double-blind trial. Subjects trained for 30 min/day, 5 days/wk at 75-85% of maximum heart rate for the final 4 wk of the study. There were no group differences in baseline iron status or in 15-km time. Iron supplementation increased serum ferritin and decreased transferrin receptors in the S compared with the P group. The S and P groups decreased 15-km time and respiratory exchange ratio and increased work rate during the 15-km time trial after training. The decrease in 15-km time was greater in the S than in the P group (P = 0.04) and could be partially attributed to increases in serum ferritin and Hb. These results indicate that iron deficiency without anemia impairs favorable adaptation to aerobic exercise.     

Cardiometabolic risk in US Army recruits and the effects of basic combat training

Background

Cardiometabolic disease risk in US military recruits and the effects of military training have not been determined. This study examined lifestyle factors and biomarkers associated with cardiometabolic risk in US Army recruits (209; 118 male, 91 female, 23±5 yr) before, during, and after basic combat training (BCT).

Methodology/Principal Findings

Anthropometrics; fasting total (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol; triglycerides (TG); glucose; and insulin were measured at baseline and every 3 wks during the 10 wk BCT course. At baseline, 14% of recruits were obese (BMI>30 kg/m²), 27% were cigarette smokers, 37% were sedentary, and 34% reported a family history of cardiometabolic disease. TC was above recommended levels in 8%, LDL in 39%, TG in 5%, and glucose in 8% of recruits, and HDL was below recommended levels in 33% of recruits at baseline. By week 9, TC decreased 8%, LDL 10%, TG 13%, glucose 6% and homeostasis model assessment of insulin resistance (HOMA-IR) 40% in men (P<0.05). In women, TC, LDL, glucose and HOMA-IR were decreased from baseline at weeks 3 and 6 (P<0.05), but were not different from baseline levels at week 9. During BCT, body weight declined in men but not women, while body fat percentage declined in both men and women (P<0.05).

Conclusions/Significance

At the start of military service, the prevalence of cardiometabolic risk in US military recruits is comparable to that reported in similar, college-aged populations. Military training appears to be an effective strategy that may mitigate risk in young people through improvements in lipid profiles and glycemic control.     

Postexercise muscle glycogen resynthesis in obese insulin-resistant Zucker rats.

We determined the effect of an acute bout of swimming (8 x 30 min) followed by either carbohydrate administration (0.5 mg/g glucose ip and ad libitum access to chow; CHO) or fasting (Fast) on postexercise glycogen resynthesis in soleus muscle and liver from female lean (ZL) and obese insulin-resistant (ZO) Zucker rats. Resting soleus muscle glycogen concentration ([glycogen]) was similar between genotypes and was reduced by 73 (ZL) and 63% (ZO) after exercise (P < 0.05). Liver [glycogen] at rest was greater in ZO than ZL (334 +/- 31 vs. 247 +/- 16 micromol/g wet wt; P < 0.01) and fell by 44 and 94% after exercise (P < 0.05). The fractional activity of glycogen synthase (active/total) increased immediately after exercise (from 0.22 +/- 0.05 and 0.32 +/- 0.04 to 0.63 +/- 0.08 vs. 0.57 +/- 0.05; P < 0.01 for ZL and ZO rats, respectively) and remained elevated above resting values after 30 min of recovery. During this time, muscle [glycogen] in ZO increased 68% with CHO (P < 0.05) but did not change in Fast. Muscle [glycogen] was unchanged in ZL from postexercise values after both treatments. After 6 h recovery, GLUT-4 protein concentration was increased above resting levels by a similar extent for both genotypes in both fasted (approximately 45%) and CHO-supplemented (approximately 115%) rats. Accordingly, during this time CHO refeeding resulted in supercompensation in both genotypes (68% vs. 44% for ZL and ZO). With CHO, liver [glycogen] was restored to resting levels in ZL but remained at postexercise values for ZO after both treatments. We conclude that the increased glucose availability with carbohydrate refeeding after glycogen-depleting exercise resulted in glycogen supercompensation, even in the face of muscle insulin-resistance.     

Diarrhea outbreak during U.S. military training in El Salvador

Infectious diarrhea remains a major risk to deployed military units worldwide in addition to their impact on travelers and populations living in the developing world. This report describes an outbreak of diarrheal illness in the U.S. military’s 130^th Maneuver Enhancement Brigade deployed in San Vicente, El Salvador during a training and humanitarian assistance mission. An outbreak investigation team from U.S. Naval Medical Research Unit – Six conducted an epidemiologic survey and environmental assessment, patient interviews, and collected stool samples for analysis in an at risk population of 287 personnel from May 31^st to June 3^rd, 2011. Personnel (n = 241) completed an epidemiological survey (87% response rate) and 67 (27%) reported diarrhea and/or vomiting during the past two weeks. The median duration of illness was reported to be 3 days (IQR 2–4 days) and abdominal pain was reported among 30 (49%) individuals. Presentation to the medical aid station was sought by (62%) individuals and 9 (15%) had to stop or significantly reduce work for at least one day. Microscopy and PCR analysis of 14 stool samples collected from previously symptomatic patients, Shigella (7), Cryptosporidium (5), and Cyclospora (4) were the most prevalent pathogens detected. Consumption of food from on-base local vendors (RR = 4.01, 95% CI = 1.53–10.5, p-value <0.001) and arriving on base within the past two weeks (RR = 2.79, 95% confidence [CI] = 1.35–5.76, p-value = 0.001) were associated with increased risk of developing diarrheal disease. The risk of infectious diarrhea is great among reserve military personnel during two week training exercises. The consumption of local food, prepared without proper monitoring, is a risk factor for deployed personnel developing diarrheal illness. Additional information is needed to better understand disease risks to personnel conducting humanitarian assistance activities in the Latin America Region.     

Combined creatine and protein supplementation in conjunction with resistance training promotes muscle GLUT-4 content and glucose tolerance in humans.

The present study was undertaken to explore the effects of creatine and creatine plus protein supplementation on GLUT-4 and glycogen content of human skeletal muscle. This was investigated in muscles undergoing a decrease (immobilization) and subsequent increase (resistance training) in activity level, compared with muscles with unaltered activity pattern. A double-blind, placebo-controlled trial was performed by 33 young healthy subjects. The subjects' right legs were immobilized with a cast for 2 wk, followed by a 6-wk resistance training program for the right knee extensor muscles. The participants were supplemented throughout the study with either placebo (Pl group) or creatine (Cr group) or with creatine during immobilization and creatine plus protein during retraining (Cr+P group). Needle biopsies were bilaterally taken from the vastus lateralis. GLUT-4 protein expression was reduced by the immobilization in all groups (P < 0.05). During retraining, GLUT-4 content increased (P < 0.05) in both Cr (+24%) and Cr+P (+33%), which resulted in higher posttraining GLUT-4 expression compared with Pl (P < 0.05). Compared with Pl, muscle glycogen content was higher (P < 0.05) in the trained leg in both Cr and Cr+P. Supplements had no effect on GLUT-4 expression or glycogen content in contralateral control legs. Area under the glucose curve during the oral glucose tolerance test was decreased from 232 +/- 23 mmol. l(-1). min(-1) at baseline to 170 +/- 23 mmol. l(-1). min(-1) at the end of the retraining period in Cr+P (P < 0.05), but it did not change in Cr or Pl. We conclude that creatine intake stimulates GLUT-4 and glycogen content in human muscle only when combined with changes in habitual activity level. Furthermore, combined protein and creatine supplementation improved oral glucose tolerance, which is supposedly unrelated to the changes in muscle GLUT-4 expression.     

The effect of creatine supplementation upon inflammatory and muscle soreness markers after a 30km race

We have evaluated the effect of a creatine supplementation protocol upon inflammatory and muscle soreness markers: creatine kinase (CK), lactate dehydrogenase (LDH), prostaglandin E2) (PGE2) and tumor necrosis factor-alpha (TNF-alpha) after running 30km. Runners with previously experience in running marathons, with their personal best between 2.5-3h were supplemented for 5 days prior to the 30km race with 4 doses of 5g of creatine and 15g of maltodextrine per day while the control group received the same amount of maltodextrine. Pre-race blood samples were collected immediately before running the 30km, and 24h after the end of the test (the post-race samples). After the test, athletes from the control group presented an increase in plasma CK (4.4-fold), LDH (43%), PGE2 6.6-fold) and TNF-alpha (2.34-fold) concentrations, indicating a high level of cell injury and inflammation. Creatine supplementation attenuated the changes observed for CK (by 19%), PGE2 and TNF-alpha (by 60.9% and 33.7%, respectively, p<0.05) and abolished the increase in LDH plasma concentration observed after running 30km, The athletes did not present any side effects such as cramping, dehydration or diarrhea, neither during the period of supplementation, nor during the 30km race. All the athletes finished the race in a time equivalent to their personal best +/- 5.8%. These results indicate that creatine supplementation reduced cell damage and inflammation after an exhaustive intense race.     

Postexercise recovery of skeletal muscle malonyl-CoA, acetyl-CoA carboxylase, and AMP-activated protein kinase

Previous studies have demonstrated that oxygenconsumption and fat oxidation remain elevated in the postexerciseperiod. The purpose of this study was to determine whether malonyl-CoA,an inhibitor of fatty acid oxidation, remains depressed in muscle afterexercise. Rats were sprinted for 5 min (40 m/min, 5% grade) or run for30 min (21 m/min, 15% grade). Red quadriceps malonyl-CoA returned toresting values by 90 min postexercise in the sprinting rats andremained significantly lower at least 90 min postexercise in the 30-minexercise group. AMP-activated protein kinase activity remainedsignificantly elevated (P < 0.05)for 10 min after exercise in both groups. The most rapid rate ofglycogen repletion was in the first 30 min postexercise. Therespiratory exchange ratio decreased from a nonexercise value of 0.87 ± 0.01 to an average 0.82 ± 0.01 during the 90-min period after30 min of exercise. Thus muscle malonyl-CoA remains depressed and fatoxidation is elevated for relatively prolonged periods after a singlebout of exercise. This may allow fat oxidation to contribute more to muscle energy requirements, thus leaving more glucose for replenishment of muscle glycogen.

     

Resting energy expenditure and delayed-onset muscle soreness after full-body resistance training with an eccentric concentration

The purpose of this investigation was to determine the effect of an acute bout of high-volume, full-body resistance training with an eccentric concentration on resting energy expenditure (REE) and indicators of delayed-onset muscle soreness (DOMS). Eight resistance trained (RT) and eight untrained (UT) participants (mean: age = 23.5 years; height = 180.76 cm; weight = 87.58 kg; body fat = 19.34%; lean mass = 68.71 kg) were measured on four consecutive mornings for REE and indicators of DOMS: creatine kinase (CK) and rating of perceived muscle soreness (RPMS). Delayed-onset muscle soreness was induced by performing eight exercises, eight sets, and six repetitions using a 1-second concentric and 3-second eccentric muscle action duration. A two-factor repeated-measures analysis of variance revealed that REE was significantly (p < 0.05) elevated at 24, 48, and 72 hours post compared with baseline measures for both UT and RT groups. Ratings of perceived muscle soreness were significantly elevated within groups for UT and RT at 24 and 48 hours post and for UT only at 72 hours post compared with baseline (p < 0.05). Nonparametric analyses revealed that CK was significantly increased at 24 hours post for both UT and RT and at 48 and 72 hours post for UT only compared with baseline (p < 0.05). Resting energy expenditure and indicators of DOMS were higher in UT compared with RT on all measures, but no significant differences were determined. The main finding of this investigation is that full-body resistance training with an eccentric concentration significantly increased REE up to 72 hours postexercise in UT and RT participants.     

Effects of leucine and whey protein supplementation during eight weeks of unilateral resistance training

The purpose of this study was to determine the effects of resistance training in combination with a leucine and whey protein supplement or a carbohydrate placebo on strength and muscle cross-sectional area (CSA). Thirty-three men (mean age +/- SD = 22.4 +/- 2.4 years) were assigned to 1 of 3 groups: (1) supplementation group (SUPP), (2) placebo group (PL), or (3) control group (CON). The SUPP and PL performed unilateral training of the leg extensor muscles with the nondominant limb for 8 weeks. The strength of each limb, muscle CSA of the quadriceps femoris (QF), and body composition were assessed pretraining and posttraining. The results indicated significant increases in strength for both limbs in the SUPP but only the trained limb in the PL. The increase in strength for the trained limb of the SUPP was greater than that for the trained limb of the PL. There was no significant increase in strength for either limb in the CON. There were significant increases in the CSA of all muscles of the QF of the trained limb for the SUPP and PL, and of the vastus lateralis of the untrained limb for the SUPP. The increases in QF CSA did not differ between the SUPP and PL. No significant CSA changes were found for either limb in the CON. There were no significant changes in body composition for the SUPP, PL, or CON. The current findings suggest that leucine and whey protein supplementation may provide an ergogenic effect which enhances the acquisition of strength beyond that achieved with resistance training and a carbohydrate placebo.     

The effects of protein and amino acid supplementation on performance and training adaptations during ten weeks of resistance training

The purpose of this study was to examine the effects of whey protein supplementation on body composition, muscular strength, muscular endurance, and anaerobic capacity during 10 weeks of resistance training. Thirty-six resistance-trained males (31.0 +/- 8.0 years, 179.1 +/- 8.0 cm, 84.0 +/- 12.9 kg, 17.8 +/- 6.6%) followed a 4 days-per-week split body part resistance training program for 10 weeks. Three groups of supplements were randomly assigned, prior to the beginning of the exercise program, in a double-blind manner to all subjects: 48 g per day (g.d(-1)) carbohydrate placebo (P), 40 g.d(-1) of whey protein + 8 g.d(-1) of casein (WC), or 40 g.d(-1) of whey protein + 3 g.d(-1) branched-chain amino acids + 5 g.d(-1) L-glutamine (WBG). At 0, 5, and 10 weeks, subjects were tested for fasting blood samples, body mass, body composition using dual-energy x-ray absorptiometry (DEXA), 1 repetition maximum (1RM) bench and leg press, 80% 1RM maximal repetitions to fatigue for bench press and leg press, and 30-second Wingate anaerobic capacity tests. No changes (p > 0.05) were noted in all groups for energy intake, training volume, blood parameters, and anaerobic capacity. WC experienced the greatest increases in DEXA lean mass (P = 0.0 +/- 0.9; WC = 1.9 +/- 0.6; WBG = -0.1 +/- 0.3 kg, p < 0.05) and DEXA fat-free mass (P = 0.1 +/- 1.0; WC = 1.8 +/- 0.6; WBG = -0.1 +/- 0.2 kg, p < 0.05). Significant increases in 1RM bench press and leg press were observed in all groups after 10 weeks. In this study, the combination of whey and casein protein promoted the greatest increases in fat-free mass after 10 weeks of heavy resistance training. Athletes, coaches, and nutritionists can use these findings to increase fat-free mass and to improve body composition during resistance training.     

Effects of resistance training and protein plus amino acid supplementation on muscle anabolism,mass, and strength

Summary. This study examined 10 wks of resistance training and the ingestion of supplemental protein and amino acids on muscle performance and markers of muscle anabolism. Nineteen untrained males were randomly assigned to supplement groups containing either 20 g protein (14 g whey and casein protein, 6 g free amino acids) or 20 g dextrose placebo ingested 1 h before and after exercise for a total of 40 g/d. Participants exercised 4 times/wk using 3 sets of 6–8 repetitions at 85–90% of the one repetition maximum. Data were analyzed with two-way ANOVA (p < 0.05). The protein supplement resulted in greater increases in total body mass, fat-free mass, thigh mass, muscle strength, serum IGF-1, IGF-1 mRNA, MHC I and IIa expression, and myofibrillar protein. Ten-wks of resistance training with 20 g protein and amino acids ingested 1 h before and after exercise is more effective than carbohydrate placebo in up-regulating markers of muscle protein synthesis and anabolism along with subsequent improvements in muscle performance.     

Postexercise muscle and liver glycogen metabolism in male and female rats

Male and female Wistar rats were run for 5 min at 1.7 mph at a 17% grade to determine whether a sex difference exists in the rate of glycogen resynthesis during recovery in fast-twitch red muscle, fast-twitch white muscle, and liver. Rats were killed at one of three time points: immediately after the exercise bout, and at 1 or 4 h later. Males had significantly higher resting muscle glycogen levels (P less than 0.05). Exercise resulted in significant glycogen depletion in both sexes (P less than 0.01). Males utilized approximately 50% more glycogen during the exercise bout than females (P less than 0.05). During the food-restricted 4-h recovery period, muscle glycogen was repleted significantly during the 1st h (P less than 0.05). Liver glycogen was not depleted as a result of the exercise bout, but fell during the first h of recovery (P less than 0.05) and remained low during the subsequent 3 h. The greater glycogen utilization in red and white fast-twitch muscle during exercise by males could represent a true sex difference but could also be attributable in part to the males having performed more work as a result of 20% greater body mass. We conclude that no sex difference was observed in the rates of muscle glycogen repletion after exercise or in liver glycogen metabolism during and after exercise, and rapid postexercise muscle glycogen repletion occurred at a time of accelerated liver glycogen depletion.     

Angiotensin-converting enzyme genotype and physical performance during US Army basic training.

Prior studies have suggested that angiotensin I-converting enzyme (ACE) genotype correlates with superior physical performance in highly selected populations. This study assessed whether such an association exists in a heterogeneous population. Using polymerase chain reaction techniques, we determined the ACE genotypes (insertion/insertion, deletion/insertion, or deletion/deletion) of 62 male and 85 female US Army recruits. Before and after 8 wk of basic training, we determined peak oxygen uptake and performance on the Army Physical Fitness Test (APFT), which includes standardized measures of muscular endurance (sit-ups, push-ups) and a 2-mile run. Subjects of different ACE genotypes had similar peak oxygen uptakes and APFT scores, both before and after training. Subjects with genotype II had higher APFT scores than others, but the differences were not statistically significant. Furthermore, no ACE genotype group had a performance advantage in analyses that adjusted for baseline fitness. We conclude that ACE genotype does not have a strong effect on aerobic power or muscular endurance in healthy, young American adults drawn from an ethnically and geographically diverse population.     

Gender effects on trapezius surface EMG during delayed onset muscle soreness due to eccentric shoulder exercise.

The purpose of this study was to investigate gender-specific motor control strategies during eccentric exercise and delayed onset muscle soreness (DOMS) in the shoulder region. Twelve healthy males and females participated in the study. Eccentric shoulder exercises were conducted on the dominant shoulder while the other side served as control. The exerted force, range of shoulder elevation, rating of perceived exertion, pain intensity, and surface electromyography (EMG) from the trapezius muscles were recorded and analyzed. A significant decrease in exerted force during exercise was only found in males despite similar rating of perceived exertion among genders. During eccentric exercise: males showed increasing root mean square (RMS) of the EMG while a decrease occurred for females, no difference between genders in mean power frequency of the EMG were seen. During static and dynamic contractions: no differences between genders in pain intensity or RMS were observed; RMS of the exercised side were lower than that of the control side (P<0.05) at 24 h after exercise. The results indicated a more prominent muscle fatigue resistance in females compared with males and mobilization of different muscle activation strategies during eccentric exercise. A protective adaptation to DOMS, i.e. decrease in RMS values was found with no gender differences.     

Postexercise responses of muscle sympathetic nerve activity and blood flow to hyperinsulinemia in humans.

Although insulin and exercise cause dramatic changes in physiological parameters, the impact of exercise on neural and hemodynamic responses to insulin administration has not been described. In a study of the effects of a single bout of exercise on blood pressure (BP), muscle sympathetic nerve activity (MSNA), and forearm blood flow (FBF) responses to insulin infusion during the postexercise period, 11 healthy men underwent, in a random order, two hyperinsulinemic euglycemic clamps performed after 45 min of 1) bicycle exercise (50% peak O(2) uptake, Exercise session) and 2) seated rest (Control session). Data were analyzed during baseline and steady-state periods. Although insulin levels and insulin sensitivity were similar, baseline plasma glucose levels were significantly lower in the Exercise than in the Control session. Mean BP was significantly lower (3%) and FBF was higher (27%) in the Exercise session. Exercise increased insulin-induced MSNA enhancement (84%) without changing FBF and BP responses to hyperinsulinemia. In conclusion, a single bout of exercise that does not alter insulin sensitivity exacerbates insulin-induced increase in MSNA without changing FBF and BP responses to hyperinsulinemia.     

Explosive-strength training improves 5-km running time by improving running economy and muscle power.

To investigate the effects of simultaneous explosive-strength and endurance training on physical performance characteristics, 10 experimental (E) and 8 control (C) endurance athletes trained for 9 wk. The total training volume was kept the same in both groups, but 32% of training in E and 3% in C was replaced by explosive-type strength training. A 5-km time trial (5K), running economy (RE), maximal 20-m speed (V20 m), and 5-jump (5J) tests were measured on a track. Maximal anaerobic (MART) and aerobic treadmill running tests were used to determine maximal velocity in the MART (VMART) and maximal oxygen uptake (VO2 max). The 5K time, RE, and VMART improved (P < 0.05) in E, but no changes were observed in C. V20 m and 5J increased in E (P < 0.01) and decreased in C (P < 0.05). VO2 max increased in C (P < 0.05), but no changes were observed in E. In the pooled data, the changes in the 5K velocity during 9 wk of training correlated (P < 0.05) with the changes in RE [O2 uptake (r = -0.54)] and VMART (r = 0.55). In conclusion, the present simultaneous explosive-strength and endurance training improved the 5K time in well-trained endurance athletes without changes in their VO2 max. This improvement was due to improved neuromuscular characteristics that were transferred into improved VMART and running economy.     

Postexercise protein-carbohydrate and carbohydrate supplements increase muscle glycogen in men and women

Tarnopolsky, M. A., M. Bosman, J. R. MacDonald, D. Vandeputte, J. Martin, and B. D. Roy. Postexerciseprotein-carbohydrate and carbohydrate supplements increase muscleglycogen in men and women. J. Appl.Physiol. 83(6): 1877-1883, 1997.We havepreviously demonstrated that women did not increase intramuscularglycogen in response to an increased percent of dietary carbohydrate(CHO) (from 60 to 75% of energy intake) (M. A. Tarnopolsky, S. A. Atkinson, S. M. Phillips, and J. D. MacDougall.J. Appl. Physiol. 78: 1360-1368, 1995). CHO and CHO-protein (Pro) supplementation postexercise canpotentiate glycogen resynthesis compared with placebo (K. M. Zawadzki,B. B. Yaspelkis, and J. L. Ivy. J. Appl.Physiol. 72: 1854-1859, 1992). We studied theeffect of isoenergetic CHO and CHO-Pro-Fat supplements on muscleglycogen resynthesis in the first 4 h after endurance exercise (90 minat 65% peak O₂ consumption) intrained endurance athletes (men, n = 8; women, tested in midfollicular phase,n = 8). Each subject completed threesequential trials separated by 3 wk; a supplement was provided immediately and 1-h postexercise: 1)CHO (0.75 g/kg) + Pro (0.1 g/kg) + Fat (0.02 g/kg),2) CHO (1 g/kg), and3) placebo (Pl; artificialsweetener). Subjects were given prepackaged, isoenergetic, isonitrogenous diets, individualized to their habitual diet, for theday before and during the exercise trial. During exercise, womenoxidized more lipid than did men (P < 0.05). Both of the supplement trials resulted in greaterpostexercise glucose and insulin compared with Pl(P < 0.01), with no genderdifferences. Similarly, both of these trials resulted in increasedglycogen resynthesis (37.2 vs. 24.6 mmol · kg drymuscle¹ · h¹,CHO vs. CHO-Pro-Fat, respectively) compared with Pl (7.5 mmol · kg drymuscle¹ · h¹;P < 0.001) with no genderdifferences. We conclude that postexercise CHO and CHO-Pro-Fatnutritional supplements can increase glycogen resynthesis to a greaterextent than Pl for both men and women.