Dietary supplements are commonly employed to provide additional nutritional support for athletes. In taekwondo, there is a need for evidence-based analyses to evaluate the effects of dietary supplements on training outcomes, competitive performance, and injury recovery. Taekwondo primarily relies on oxidative metabolism, yet decisive lower-limb attacks depend on non-oxidative pathways. A comprehensive literature search was conducted in PubMed, Scopus, and Web of Science databases in November 2024, utilizing keywords including ‘Dietary Supplements’, ‘Supplements’, ‘Food Supplementations’, and ‘Taekwondo’. Of the 203 articles identified, 26 met the inclusion criteria, collectively assessing the impact of 14 different dietary supplements. Among these studies, eight provided strong evidence that acute ingestion of 3–5 mg/kg of caffeine significantly enhanced athletes’ physical performance and psychological well-being. However, the ergogenic effects of the compound Fufang Ejiaojiang, creatine, sodium bicarbonate, beetroot, vitamins, and long beans require further investigation to validate their efficacy. Additionally, dietary supplements, such as amino acids, turmeric powder, ginger, spirulina, octacosanol, nucleotides, and yogurt, can reduce fatigue, supporting injury recovery, and boosting immune function, although current evidence remains insufficient. Future research should pay closer attention to reporting adverse reactions linked to dietary supplements. Doing so would provide coaches and athletes with more reliable safety information, supporting safer choices and reducing potential health risks.

Soccer, as a high-intensity sport, places significant physical demands on athletes and is associated with a high risk of injury. Electrical muscle stimulation (EMS), a training and rehabilitation technology, has gained attention for its potential benefits in sports settings. This systematic review, conducted under the PRISMA guidelines, rigorously assessed the effectiveness of EMS in improving muscle strength, promoting post-exercise recovery, and facilitating injury rehabilitation among soccer players. A comprehensive search of the PubMed, Scopus, and Web of Science databases identified 10 studies meeting the inclusion criteria. Among these, six studies demonstrated a significant improvement in athletic performance following local or whole-body EMS application. Four studies provided evidence supporting EMS’s efficacy in enhancing post-exercise recovery and reducing recovery time after injuries, with observed reductions in recovery time. However, the majority of the included studies were not double-blind, which limits the strength of the evidence. None of the included studies reported EMS-related adverse effects. Overall, the current results suggest that EMS may be a useful adjunct to improve athletic performance and facilitate recovery in soccer players. This review offers actionable insights for coaches and athletes regarding the safe and effective application of EMS in soccer training and rehabilitation programs.

Background/Objectives: Body mass index (BMI) does not distinguish fat mass from lean mass. Gallagher et al. proposed percentage body fat (%BF) ranges at NIH/WHO BMI cutoffs, but no study has derived %BF ranges for the full set of Asian-specific BMI cutoffs adopted in Korea. This study aimed to develop and externally validate prediction equations for %BF from BMI in Korean adults and to derive %BF ranges corresponding to Korean Society for the Study of Obesity (KSSO) BMI cutoffs. Methods: Sex-specific equations were developed using survey-weighted linear regression with the 1/BMI transformation in adults aged ≥ 19 years from KNHANES 2022 (n = 4466) using InBody 970 BIA, and externally validated in KNHANES 2023 (n = 4778). Predicted %BF values were calculated at each KSSO BMI cutoff (18.5, 23.0, 25.0, 30.0, and 35.0 kg/m²) across age-group midpoints. Results: Final equations were: Men, %BF = 51.98 − 733.89 × (1/BMI) + 0.058 × age (R² = 0.544; SEE = 3.95%); Women, %BF = 64.92 − 731.24 × (1/BMI) (R² = 0.638; SEE = 3.66%). Age was not significant in women (p = 0.82). External validation showed mean bias of −0.10% and calibration slope of 1.02. The predicted %BF at the pre-obese cutoff (BMI 23.0) was 21.5–24.4% in men and 33.1% in women; at class I obesity (BMI 25.0), 24.1–27.0% and 35.7%, respectively. Conclusions: This study provides the first nationally representative %BF ranges for all five KSSO BMI cutoffs. The predicted %BF at BMI 25.0 corresponds to %BF-defined obesity in both sexes, and is consistent with the clinical relevance of the lower obesity cutoff adopted for Asian populations.