Anaerobic exercise may result in repetitive eccentric contractions [1] and tissue vibrations [2], potentially causing muscle damage and delayed-onset muscle soreness (DOMS). Alterations in blood creatine kinase (CK) and C-reactive protein (CRP) levels, which are typically observed post-exercise and are linked to DOMS onset, can serve as indicators of skeletal muscle recovery. Intense anaerobic exercises, whether performed for prolonged or brief durations, have also been shown to elevate the cellular production of reactive oxygen species (ROS) [3,4], potentially resulting in oxidative stress and cellular damage. Under typical exercise conditions, oxidative equilibrium is maintained within physiological thresholds, thereby mitigating the risk of oxidative injury [5]. This equilibrium is maintained through a multifaceted antioxidant defense system comprising antioxidant enzymes, such as superoxide dismutase (SOD), catalase, glutathione peroxidase (Gpx), peroxiredoxin, and thioredoxin, which neutralize ROS. Additionally, endogenous antioxidant substrates, such as glutathione, actively scavenge both ROS and RNS [6].

Nutrition is important for the prevention and recovery of antioxidant levels and muscle damage. Various supplements can be used to achieve this; however, nutrition through the diet is more important7. Even small performance improvements in sports can lead to substantial differences in results. Nutrition is an important factor determining athlete performance and physical health [7,8]. Additionally, proper nutritional knowledge can lead to positive changes for athletes, whereas incorrect nutritional knowledge can have unexpected effects. As such, an analysis of athlete knowledge and eating habits is necessary to identify their motor functional effects, as eating habits vary according to individual taste and nutritional knowledge.

The nutritional knowledge of weight-class athletes affects their body weight reduction strategies [9], and the function of athletes differs according to their level of nutritional knowledge [10]. However, studies analyzing athlete diet and nutritional knowledge together are lacking, and researchers have not analyzed differences in athlete levels, diet, and nutritional knowledge with respect to hematological variables.

Therefore, the aim in this study was to investigate and understand the differences in the diet, nutritional knowledge, motor function, muscle damage indicators, and antioxidant enzyme levels of elite Korean wrestlers, according to athlete level. In addition, we prepared a plan to use educational materials to improve athletes’ nutritional knowledge, based on study results and prior overseas education data.

In this study, we investigated the diet and nutritional knowledge of elite Korean wrestlers and verified the differences in exercise performance, muscle damage indicators, and antioxidant enzyme levels according to athlete expertise. The results indicated differences between the groups, particularly in terms of nutritional knowledge and dietary intake.

In the pro group, carbohydrate intake accounted for 60% of total energy intake, reflecting traditional Korean dietary patterns characterized by a reliance on rice. Conversely, the dietary habits of the nat group, with carbohydrate consumption below 60%, displayed a westernized trend. The Korean diet is currently undergoing rapid westernization, evident in both the general population and athletes consuming increased quantities of protein and fat. Protein stands as a crucial nutrient for athletes, particularly those engaged in continuous training. Elevated protein intake is associated with augmented muscle size, increased cross-sectional area of muscle fibers [12], and enhanced strength and exercise performance. As suggested by Thomas et al. [13] and Beiset et al. [14], strength and power athletes are typically advised to consume protein levels near the upper end of the recommended range, with temporary increases in consumption during intense training phases, potentially offering additional benefits. In this study, the nat group exhibited a higher daily protein intake (measured in grams and kilocalories) and greater anaerobic power output.

High-intensity training methods are important for minimizing muscle fatigue and preventing muscle injury during high-intensity exercise; additional, nutrition is crucial [15]. When muscles are damaged through high-intensity exercise, the CK levels inside the muscles substantially increase. CK is an enzyme that is abundant in skeletal muscles and is widely used as an indicator of muscle injury during exercise [16]. Blood CK concentrations are significantly higher compared with baseline levels for 24 to 48 h after downhill running [17] and high-intensity uphill running [18], which are considered renal exercises [4]. Brown et al. [19] reported an increase in blood CK concentration 72 h after lower-extremity renal exercises in young men and women. In addition, muscle damage likely leads to inflammatory reactions, and muscle damage and inflammation are related [20]. Lee et al. [21] reported that carbohydrate-based diets are more effective than fat-based diets in preventing or alleviating muscle injuries during high-intensity exercise. In this study, the blood CK and CRP levels of the pro group, who consumed a large amount of carbohydrates, were lower than those of the nat group, in alignment with the results of previous studies.

Intense physical activity can cause muscle injury and persistent fatigue, which are often attributable to the detrimental effects of free radicals [22]. We observed discrepancies in SOD activity between groups after the Wingate test. These results signify the onset of oxidative stress induced by exercise, consistent with prior research illustrating heightened oxidative stress parameters across various running exercise modalities (aerobic, anaerobic, intermittent, and continuous exercises) [23,24]. In addition, Lee [25] analyzed the free radical production via a one-time measurement using a bicycle ergometer during anaerobic exercise in 10 adult men and reported a statistically significant increase in free radical levels 120 min after exercise. However, in our study, no changes in free radical levels were identified, which was the result of a shorter time period than that considered in previous studies and focusing on elite athletes who train every day. High-intensity training induces the production of peroxide radicals (O₂−). SOD activity, the first line of antioxidant defense, increases to protect against the harmful effects of O₂ radicals [26]. Most of the generated O₂ radicals are continuously neutralized by conventional antioxidant defenses, which may explain the lack of changes in SOD activity [27]. In addition, changes in SOD activity may differ from between ordinary adults and elite athletes who train every day.

The maximum blood lactic acid concentration varies depending on the subject, exercise method, and exercise intensity, increasing up to 25 mmol/L [28]. Simon et al. [29] found that the higher the exercise ability, the higher the lactic acid diffusion rate, and the faster the increase in blood lactic acid concentration after exercise, the higher the exchange area as the density of capillaries through training increases [30]. As noted by Lecoultre et al. [31], increased carbohydrate intake among athletes may elevate lactate levels, consistent with the results of our study. However, it is crucial to acknowledge several limitations in our assessment of lactate recovery, which primarily focused on dietary factors. Further investigations are warranted to explore the variation in lactate recovery among wrestlers based on their dietary intake.

The nutritional knowledge scores of national and professional adult athletes were analyzed. Nutrition management is necessary to improve performance, and nutrition education is crucial for the practice of personal nutrition management [32]. The results of this study confirmed that the nutritional knowledge scores of national team players were higher than those of professional adult athletes, and the knowledge of those who were younger was also related to eating habits and exercise function. Additionally, more than half of the participants had high compliance scores, similar to those reported in previous studies comparing the GNKQ of athletes [28]. Additionally, in the field, coaches, and athletes can use our findings to educate athletes on nutrition, manage eating habits, and set up training programs. This study provides data on maintaining the eating habits and performance of athletes who lose weight in sports. Finally, our study will positively influence on individual athletes’ management and quality of life.

Nutrition is an essential component of success in sports activities. The nutritional management of athletes affects not only daily training but also competition. In this study, we examined wrestlers’ understanding of nutrition and their eating habits. This provided an opportunity to verify the disparity in exercise performance and post-exercise recovery at the athlete level. However, the number of subjects was too low, and the use of surveys, such as the SGNKQ, TFEQ, and GNKQ, was insufficient. Therefore, a comprehensive study on the nutrition knowledge and training of athletes is required with a wider scope and an analysis of additional ; this future study could be used to build educational materials for active nutrition education and the management of sports leaders and athletes.