I Shiung Cheng

The consumption of dietary supplements to enhance endurance performance and fitness is gaining popularity among professional athletes and nonathletes. Astaxanthin (AST), a natural ketocarotenoid, has been tested for its ergogenic, antioxidant, and tissue protective properties in young male adults. Ten physically active male adults (22.5 ± 0.9 years) were randomized into placebo or AST trials (according to CONSORT), and consumed placebo or AST (28 mg/d) supplements orally for 4 days. On day-4, participants performed an exhaustive cycling challenge at 75% maximum rate of O2 uptake (V̇O2max), and the time to exhaustion (TTE) was recorded. Blood and gaseous samples were collected before, during, and immediately after cycling to determine changes in muscle damage, inflammation, oxidative stress, and substrate utilization. Short-term AST supplementation significantly enhanced exercise performance, as we found longer TTE in the AST trial (85.41 ± 4.42 min) than in the placebo trial (72.11 ± 2.24 min). Statistical analysis revealed a significant larger effect (P < 0.001; partial eta squared (η²p) = 0.71) on enhanced TTE with AST. Exhaustive exercise-induced muscle damage, indicated by increased creatine kinase (CK) and lactate dehydrogenase release, was significantly (P < 0.05) decreased by AST. A significant time and treatment interaction effect for CK (P = 0.039, η²p = 0.217) indicating potential attenuation of muscle damage by AST. In addition, lipid peroxidation, as evidenced by increased malondialdehyde levels during and immediately after exercise, was substantially inhibited by AST (P < 0.05). However, inflammatory markers (tumor necrosis factor-alpha and C-reactive protein) did not respond to either AST supplementation or exercise challenge. Substrate utilization during and after exercise appeared to be similar in both trials. Importantly, AST supplementation had no adverse effects on the ‘profile of mood states’ among participants. Short-term AST supplementation could be a nutritional ergogenic aid to enhance endurance performance and attenuate exhaustive exercise-induced muscle damage or oxidative stress in young adults. The study was approved by the Human Research Ethics Committee of China Medical University Hospital (CMUH111-REC3-081) and registered at clinicaltrials.gov under registration number NCT06593535 (dated 05-09-2024).

Prolonged exercise usually leads to exercise fatigue, which has a negative short-term impact on exercise performance and metabolic rate; thus, fatigue needs to be resolved. Okara is a protein-rich residue of soy processing. Enzyme hydrolysis is known to increase the content of branched-chain amino acids (BCAAs), which have been reported to confer benefits for exercise. The purpose of this study was to investigate the antifatigue effect of okara protein hydrolysate (OPH) on cycling exercise. A total of 16 male participants who habitually exercised (2 times or more per week and without participation in athletic contests) were instructed to receive 11.74 g of OPH once a day. They then completed two intense cycling exercise challenges before and after four weeks of supplementation. Exercise time and blood markers related to fatigue and energy metabolism were measured. The results showed that the time to exhaustion significantly increased after the treatment. The levels of lactate during exercise and at the end of exercise were significantly lower after treatment than before. Additionally, postexercise insulin sensitivity was increased after treatment. This study showed that OPH supplementation can promote endurance in exercise by decreasing the accumulation of fatigue-related metabolites during exercise and can promote energy recovery by increasing insulin function. These findings suggest that OPH has an antifatigue property.

Background/Objectives: While previous evidence has shown that using free weights for resistance training is a more practical approach to enhancing strength, there is a relatively low prevalence of free-weight resistance training among adolescent kayak/canoe athletes. Therefore, this study aims to assess the impact of free-weight resistance training on body composition and various performance factors among adolescent canoe/kayak athletes. Methods: Twenty-seven young sprint kayakers and canoeists (14 ± 1 years; 164 ± 7 cm; 56 ± 8 kg) completed this study. Following baseline assessments, athletes were randomly divided into two training groups: the free-weight resistance training group (FW) or the control group (C). The FW group underwent free-weight resistance training sessions twice weekly for 24 weeks. The C group maintained their regular bodyweight training sessions during the same timeframe. All participants performed both the pre- and post-training assessments for the following dependent variables: body composition, upper-body power, upper-body isometric muscle strength, isometric mid-thigh pull, core strength, countermovement jump, balance, anaerobic ability, and aerobic performance. Results: After 24 weeks of training, the free-weight resistance training group exhibited a significant increase in body weight (from 56 ± 5 kg to 58 ± 4 kg, p < 0.05) and improvements in the number of straight leg raise repetitions (from 23 ± 6 to 26 ± 4, p < 0.05) compared to the control group. However, the two groups observed no significant differences between upper-body isometric muscle strength, power, balance, and anaerobic/aerobic performance. Conclusions: A 24-week training duration might be insufficient for novice participants in resistance training. Future research should consider incorporating an adaptation period or a learning phase for movements before training, thereby enhancing the efficacy of free-weight resistance training in increasing strength.

Garlic extract (GA) is purported to enhance antioxidant and anti-inflammatory activity and glucose regulation in humans. The present study investigated the effects of post-exercise GA supplementation on GLUT4 expression, glycogen replenishment, and the transcript factors involved with mitochondrial biosynthesis in exercised human skeletal muscle. The single-blinded crossover counterbalanced study was completed by 12 participants. Participants were randomly divided into either GA (2000 mg of GA) or placebo trials immediately after completing a single bout of cycling exercise at 75% Maximal oxygen uptake (VO_2max) for 60 minutes. Participants consumed either GA (2000 mg) or placebo capsules with a high glycemic index carbohydrate meal (2 g carb/body weight) immediately after exercise. Muscle samples were collected at 0-h and 3-h post-exercise. Muscle samples were used to measure glycogen levels, GLUT4 protein expression, as well as transcription factors for glucose uptake, and mitochondria biogenesis. Plasma glucose, insulin, glycerol, non-esterified fatty acid (NEFA) concentrations, and respiratory exchange ratio (RER) were also analyzed during the post-exercise recovery periods. Skeletal muscle glycogen replenishment was significantly elevated during the 3-h recovery period for GA concurrent with no difference in GLUT4 protein expression between the garlic and placebo trials. PGC1-α gene expression was up-regulated for both GA and placebo after exercise (p < 0.05). Transcript factors corresponding to muscle mitochondrial biosynthesis were significantly enhanced under acute garlic supplementation as demonstrated by TFAM and FIS1. However, the gene expression of SIRT1, ERRα, NFR1, NFR2, MFN1, MFN2, OPA1, Beclin-1, DRP1 were not enhanced, nor were there any improvements in GLUT4 expression, following post-exercise garlic supplementation. Acute post-exercise garlic supplementation may improve the replenishment of muscle glycogen, but this appears to be unrelated to the gene expression for glucose uptake and mitochondrial biosynthesis in exercised human skeletal muscle.

Garlic extract has been shown to enhance antioxidant and anti-inflammation activities in humans. The present study investigated the effects of garlic supplementation on 40-km cycling time trial per...

Aim: Quercetin has been reported to have antioxidant and anti-inflammatory properties on health promotion in human studies. The main purpose of this study was to investigate the effect of short-term oral quercetin supplementation on post-exercise whole-body energy metabolism. This study also aimed to determine the effects of supplementation on oxygen stress, inflammation, muscle damage, and high-intensity cycling exercise performance.Method: Twelve healthy participants, physically active students, were recruited to perform a randomized, single-blind crossover study. All subjects completed 7-days of quercetin (quercetin:1,000 mg per day for 7-days) and placebo supplementation in a randomized order. Supplement/placebo was combined with exercise consisting of 70% V̇O_2max cycling for 60-min, followed by 3-h of recovery, then a subsequent single bout of cycling exercise with 75% V̇O_2max to exhaustion. Time to exhaustion, indicators of muscle damage, as well as blood and gaseous parameters relating to energy metabolism, oxidative stress, inflammatory response, respectively, were determined.Results: The results showed that 7-day quercetin supplementation significantly attenuated the post-exercise glucose-induced insulin response, increased total antioxidant capacity (TAC) and superoxidase dismutase (SOD) activities, and mitigated malondialdehyde (MDA) levels during the recovery period (p < 0.05). While subsequent 75% V̇O_2max cycling performance was significantly improved after quercetin treatment and accompanied by lower responses of interleukin 6 and creatine kinase at 24-h. However, it’s noted that there were no significant responses in glucose, respiratory exchange rate, tumor necrosis factor-α (TNF-α), myoglobin, and high sensitivity C-reactive protein between quercetin and placebo trials.Conclusion: Our findings concluded that 7-day oral quercetin supplementation enhances high-intensity cycling time to exhaustion, which may be due in part to the increase in whole-body insulin-stimulated glucose uptake and attenuation of exercise-induced oxygen stress and pro-inflammation. Therefore, quercetin may be considered an effective ergogenic aid for enhancing high-intensity cycling performance among young adults.

Background: Capsinoids (CSN), the novel non-pungent capsaicin analogs have been reported to promote metabolic health and exercise tolerance. However, the effect of CSN on fat oxidation and changes in skeletal muscle glycogen levels during post-exercise recovery has not been investigated in humans. Purpose: We examined the effect of CSN supplementation on energy reliance, glycogen resynthesis and molecular proteins in the skeletal muscle of young adults during post-exercise recovery. Methods: In this crossover-designed study, nine healthy adult male volunteers (aged 21.4±0.2 years, BMI 21.9±1.3 kg/m2) completed a 60-min cycling exercise at 70% VO2max. Participants consumed either CSN (12 mg, single dosage) or placebo capsules with a high-carbohydrate meal (2 g carb/kg bodyweight) immediately after exercise. Biopsied muscle samples (vastus lateralis), blood, and gaseous samples were obtained during 3h postexercise recovery period. Results: We found that oral CSN supplementation right after exercise significantly altered the energy reliance on fat oxidation during recovery. This was evidenced by lower respiratory exchange ratio (RER) and higher fat oxidation rate in CSN trial. Despite this, acute CSN dosage does not contribute in enhancing the glycogen replenishment in skeletal muscle during 3h recovery. We identified no significant differences in postprandial glucose and insulin area under the curve in both trials. Western blot data showed an increased muscle GLUT4 expression, but no significant response of p-Akt/Akt ratio with CSN during post-exercise recovery. Conclusion: Our findings conclude that acute CSN intake could change energy reliance on fat oxidation but is unable to enhance muscle glycogen resynthesis during post-exercise recovery. Thus, ergogenic properties of CSN in relevance to muscle glycogen restoration following exercise needs to be further investigated in young adults.

Previous studies demonstrated that resveratrol (RES) is able to enhance antioxidant, anti-inflammatory and insulin actions in humans. It is unclear whether RES can be used as ergogenic aids to enhance high-intensity cycling exercise performance and attenuate the high-intensity exercise-induced oxidative stress and inflammation. This study investigated the effect of RES supplementation on oxidative stress, inflammation, exercise-induced fatigue, and endurance performance. Eight male athletes participated in this single-blind crossover designed study and randomly instructed to receive four days of either oral RES (480 mg per day, totally 1920mg) or placebo supplementation. The cycling exercise challenge at 80% maximal oxygen consumption with 60 rpm was performed following 4 days of either RES or placebo supplementation. The total cycling performance time was recorded. In addition, blood samples were obtained to analyze the changes in blood glucose, plasma non-esterified fatty acid, serum lactate dehydrogenase, creatine kinase, uric acid, total antioxidant capacity, malondialdehyde, tumor necrosis factor-α, and interleukin-6. The exhausting time of cycling exercise challenge was not significantly increased in RES compared to that in placebo. However, IL-6 response was significantly decreased during exercise challenge in RES trial, and there were no differences in blood biomarkers, fatigue factors, and antioxidative response. Oral RES supplementation can attenuate exercise-induced IL-6 response but not fatigue and oxidative stress, inflammation response. However, we infer that 4-day oral RES supplementation has no ergogenic property on enhancing the high-intensity cycling exercise performance.

The present study aimed to investigate the effect of oral resveratrol supplementation on the key molecular gene expressions involved in mitochondria biogenesis and glycogen resynthesis in human skeletal muscle. Nine young male athletes participated in the single-blind and crossover designed study. All subjects completed a 4-day resveratrol and placebo supplement in a randomized order while performing a single bout of cycling exercise. Immediately after the exercise challenge, the subjects consumed a carbohydrate (CHO) meal (2 g CHO/Kg body mass) with either resveratrol or placebo capsules. Biopsied muscle samples, blood samples and expired gas samples were obtained at 0 h and 3 h after exercise. The muscle samples were measured for gene transcription factor expression by real-time PCR for glucose uptake and mitochondria biogenesis. Plasma glucose, insulin, glycerol, non-esterified fatty acid concentrations and respiratory exchange ratio were analyzed during post-exercise recovery periods. The results showed that the muscle glycogen concentrations were higher at 3 h than at 0 h; however, there were no difference between resveratrol trial and placebo trial. There were no significantly different concentrations in plasma parameters between the two trials. Similarly, no measured gene expressions were significant between the two trials. The evidence concluded that the 4-day oral resveratrol supplementation did not improve post-exercise muscle glycogen resynthesis and related glucose uptake and mitochondrial biosynthesis gene expression in men.

This randomized, double-blind, clinical trial was designed to compare the endurance capacity (ergogenic property) in healthy athletes after consumption of apple cider vinegar (ACV) and a commercial sports drink (CSD) before and during endurance exercise. Fourteen healthy participants were enrolled in this trial and were divided into two groups as ACV and CSD with seven participants in each. Participants were requested to consume 500 mL of either commercial ACV or CSD 1 h before endurance exercise (bicycle ergometer). Blood samples were collected at baseline, 0, 20, 40, 60 min until exhaustion to assess glucose, lactate, ammonia and non-esterified fatty acids (NEFA). Respiratory exchange rate (RER) score was measured every 15 min and the heart rate (HR) was measured every 5 min. The outcome of the present trial clearly showed that no significant differences were observed between ACV and CSD except in the blood level of ammonia (only at exhaustion time). Thus, these results show that ACV and the CSD both possessing the ergogenic property, enhanced blood glucose, NEFA, and suppress the production of lactate as well as maintains normal RER score, and HR throughout the endurance exercise. Overall this trial showcases that ACV did not significantly improve the ergogenic activity over the CSD.