Periodized carbohydrate availability can enhance exercise capacity, but the effects of short-term fat adaptation carbohydrate restoration (FACR) diets on metabolic responses and exercise performance in endurance athletes have not been conclusively determined. This study aimed to investigate the effect of a FACR diet on measures of resting metabolism, exercise metabolism, and exercise performance. Well-trained male runners (n = 8) completed a FACR dietary intervention (five days’ carbohydrate < 20% and fat > 60% energy, plus one-day carbohydrate ≥ 70% energy), and a control high-carbohydrate (HCHO) diet for six days (carbohydrate > 60% energy; fat < 20% energy) in a randomized crossover design. Pre- and post-intervention metabolic measures included resting metabolic rate (RMR), respiratory quotient (RQ), maximum fat oxidation rate during exercise (MFO), and maximum fat oxidation intensity (FATmax). Measures of exercise performance included maximal oxygen uptake (VO2max), running economy (RE), and 5 km running time trial (5 km-TT). In FACR compared with HCHO, there were significant improvements in FATmax (p = 0.006) and RE (p = 0.048). There were no significant differences (p > 0.05) between FACR and HCHO in RMR, RQ, VO2max, or 5 km-TT. Findings suggest that a short-term (six days) FACR diet may facilitate increased fat oxidation and submaximal exercise economy but does not improve 5 km-TT performance.

Background: Sodium pyruvate (PYR) has been reported to improve aerobic metabolism and attenuate metabolic acidosis. Aerobic capacity and the ability to remove hydrogen ions affect the recovery from repeated high intensity activities. However, the effects of PYR supplementation on repeated sprint exercise (RSE) performance have not been elucidated. This study explored the effects of PYR ingestion on RSE ability and recovery.Methods: A total of 14 male soccer athletes (aged 20±2 years) participated in this double-blinded crossover study. The subjects completed two experimental sessions after randomized ingestion of either PYR or the maltodextrin placebo (PLA) for 1 week. At each session, participants completed high-intensity interval exercise (HIIE) and RSE 60 minutes after supplementation. Additionally, acid-base parameters in venous blood, energy system contributions, and power output were assessed.Results: Compared to PLA, PYR supplementation significantly increased the relative peak power output (PPO) of the first (P=0.034) and fifth (P=0.043) sprints, and the relative mean power output (MPO) of the fifth sprint (P=0.026). In addition, the mean PPO (P=0.031) and MPO (P=0.033) of sprints 1-6 were significantly elevated after PYR supplementation. After PYR administration, the phosphagen energy system [adenosine triphosphate (ATP)-phosphocreatine (PCr)] resynthesis of the fourth (P=0.034) and the overall recovery periods during HIIE (P=0.029) were higher than PLA administration. Additionally, the ATP-PCr resynthesis of the first (P=0.033) and fifth (P=0.019) recovery periods, and the mean of the six recovery periods during RSE (P=0.041) were increased in the PYR group compared to the PLA group. Furthermore, participants on the PYR regimen had higher blood pH, HCO 3 − , and base excess at pre-HIIE, post-HIIE, and pre-RSE (all P<0.05) compared to participants receiving PLA.Conclusions: PYR supplementation enhanced RSE performance, and the improvement may be attributed to accelerated restoration of the acid-base balance and ATP-PCr regeneration.

With the continuous development of physical education reform, the defects and deficiencies of physical education teaching in colleges and universities are increasingly exposed. The reform of the original physical education teaching thought, education system, teaching mode, and method has achieved little. At present, the research on the prediction of physical education teaching achievements is mainly aimed at the prediction of athletes and physical education teaching achievements or the prediction of the past data of college students. This paper studies the physical education under the decision tree under the background of big data and constructs the physical education management system. When the number of tests reaches 40, the qualified rate of long-distance running is 65.2%, that of basketball is 68.1%, and that of volleyball is 68.2%. The quality of physical education teaching determines the lifeline of the development of school physical education teaching. In the process of collecting and selecting teaching materials, this paper enriches teaching materials and teaching reflection, cultivates one’s own understanding, and improves the artistic appeal and creativity of teaching.

Purpose: To evaluate the effectiveness of heart-rate variability (HRV) biofeedback in improving autonomic function, mood, and sleep in elite bobsleigh athletes. Methods: Eight Chinese Winter Olympic bobsleigh athletes (age: 24 [2] y, body mass: 89 [15] kg, and height: 184 [5] cm) completed a randomized crossover study with and without HRV biofeedback before a single night’s sleep. HRV biofeedback was provided 35 minutes prior to bedtime in the experimental condition. The assessment of HRV took place 45 and 10 minutes before bedtime. The Profile of Mood States questionnaire was completed 50 and 15 minutes prior to bedtime. Sleep duration and quality were measured through an air-mattress sleep-monitoring system. Results: Sleep efficiency (P = .020; F = 7.831; CI, 0.008 to 0.072) and the percentage of deep sleep duration increased (P = .013; F = 10.875; CI, 0.006 to 0.035), while the percentage of light sleep decreased (P = .034; F = 6.893; CI, −0.038 to −0.002). Presleep HRV biofeedback increased parasympathetic and decreased sympathetic activity. Mood states of anger (P = .006, F = 7.573), panic (P = .031, F = 4.288), tension (P = .011, F = 6.284), depression (P = .010, F = 6.016), fatigue (P = .000, F = 16.901), and total mood disturbance (P = .001, F = 11.225) were reduced before sleep. Conclusion: Presleep HRV biofeedback improved some measures of autonomic function, mood, and sleep quality in Chinese Olympic bobsleigh athletes. Presleep HRV biofeedback provides a practical strategy that may help reduce sleep disturbances during periods of training and competition.

IntroductionThere is no denying the clinical benefits of exogenous pyruvate in the treatment of pathological metabolic acidosis. However, whether it can prevent exercise physiological metabolic acidosis, delay the occurrence of exercise fatigue, and improve the beneficial effects of exercise and its internal mechanism remain unclear.MethodsWe randomly divided 24 male SD rats into 3 groups: one group was a control without exercise (CC, n = 8), and the other two groups were supplemented with 616 mg/kg/day pyruvate (EP, n = 8) or distilled water of equal volume (EC, n = 8). These groups completed acute high-intensity interval exercise (HIIE) after 7 days of supplementation. The acid metabolism variables were measured immediately after exercise including blood pH (pHe), base excess (BE), HCO3−, blood lactic acid and skeletal muscle pH (pHi). The redox state was determined by measuring the oxidized coenzyme I/reduced coenzyme I (nicotinamide adenine dinucleotide [NAD+]/reduced NAD+ [NADH]) ratio and lactate/pyruvate (L/P) ratio. In addition, the activities of lactate dehydrogenase A (LDHA), hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK) were determined by ELISA.ResultsPyruvate supplementation significantly reversed the decrease of pHe, BE, HCO3− and pHi values after HIIE (p &lt; 0.001), while significantly increased the activities of LDHA (p = 0.048), HK (p = 0.006), and PFK (p = 0.047). Compared with the CC, the NAD+/NADH (p = 0.008) ratio and the activities of LDHA (p = 0.002), HK (p &lt; 0.001), PFK (p &lt; 0.001), and PK (p = 0.006) were significantly improved in EP group.DiscussionThis study provides compelling evidence that oral pyruvate attenuates HIIE-induced intracellular and extracellular acidification, possibly due to increased activity of LDHA, which promotes the absorption of H+ in the LDH reaction. The beneficial effects of improving the redox state and glycolysis rate were also shown. Our results suggest that pyruvate can be used as an oral nutritional supplement to buffer HIIE induced metabolic acidosis.