Caffeine is commonly used to combat fatigue and enhance both cognitive and physical performance. However, its effects on neurophysiological responses and sport-specific performance following fatigue induction remain unclear, particularly in combat sports such as Taekwondo. This study investigated the effects of a 200 mg caffeine dose on physiological markers, electroencephalographic (EEG) brainwave activity, auditory P300 event-related potentials (ERPs), and Taekwondo-specific performance following combined mental and physical fatigue. Thirteen male Taekwondo athletes participated in a randomized, double-blind, crossover study with caffeine (CAF) and placebo (PLA) conditions. Measurements were taken at baseline (pre-supplementation), 30 minutes post-supplementation (post-Sup), and after fatigue induction (post-I). Physiological parameters (heart rate, blood glucose, blood lactate, and ratings of perceived exertion), EEG brainwave activity during resting eyes-open conditions, auditory P300 ERPs, and Taekwondo-specific agility (TSAT) were assessed at all time points. Caffeine significantly reduced delta wave power at frontal and parieto-occipital sites at post-Sup (p < 0.05), indicating decreased cortical drowsiness; however, this effect was not sustained at post-I (p > 0.05). P300 amplitude significantly increased in the CAF condition compared to PLA from post-Sup to post-I at the central and parietal electrode sites (p < 0.05), while P300 latency remained unchanged (p > 0.05). No significant differences were observed in reaction time, accuracy, or error rate in the auditory oddball task or TSAT performance across conditions (p > 0.05). Similarly, physiological parameters remained unchanged between groups (p > 0.05). A single 200 mg dose of caffeine reduced central fatigue and enhanced cognitive processing, as reflected by suppressed delta wave activity at post-Sup and increased P300 amplitude at post-I. However, caffeine did not influence physiological responses or Taekwondo-specific performance. These findings suggest that low-dose caffeine primarily benefits cognitive function rather than physical performance in combat sports. Future studies should explore dose-response relationships and individual variability in caffeine metabolism to optimize its application in competitive settings.

Delayed-onset muscle soreness (DOMS) is associated with increases in acute inflammatory and biochemical markers, muscle swelling, pain, and reduced functional performance. This study aimed to investigate the preventative effects of crocodile blood supplementation on DOMS induced by eccentric exercise. Sixteen healthy males were randomly allocated to either a crocodile blood (CB, n = 8) or a placebo (PL, n = 8) treatment. Participants receiving the CB treatment consumed four capsules of freeze–dried CB powder (1 g day⁻¹) over 18 days. Participants receiving the other treatment were administered a placebo over the same period. An eccentric exercise protocol was performed, and functional performance, visual analogue scale (VAS)-measured pain, knee range of movement (ROM), thigh circumference (swelling), and cytokines, enzymes, and biochemical parameters were assessed immediately after exercise as well as after 24 h, 48 h, and 72 h. CB supplementation could significantly maintain maximum voluntary isometric contraction (MVIC) at 24 h (p = 0.001) and 48 h after exercise (p = 0.001) when comparing values at different times for the CB group. In the CB group, thigh circumference decreased only immediately after eccentric exercise (p = 0.031) in comparison with pre-eccentric exercise values. An 18-day supplementation (1 g day⁻¹) of crocodile blood does aid in the maintenance of functional performance and muscle swelling after eccentric exercise. Our data indicate that 1 g day⁻¹ of crocodile blood supplementation should be safe for human consumption.

Introduction: Anthocyanin-rich blackcurrant extract altered exercise-induced metabolic responses (e.g., enhanced fat oxidation) in case studies with Caucasian non-heat acclimatized male endurance athletes. We examined 2–3 weeks before marathon competition the effects of 7-day intake of the extract (i.e., 420 mg of anthocyanins per day) during supine rest and 1 h of moderate-intensity running in an elite national level female Southeast Asian endurance athlete (age: 48 years, BMI: 19.3 kg·m ⁻² , body fat: 21.8%, V ˙ O 2 max : 44.4 mL·kg ⁻¹ ·min ⁻¹ , 28 marathons since 2017) living and training outdoors in Thailand. Methods: Non-invasive beat-to-beat hemodynamic monitoring (PhysioFlow®) and breath-by-breath gas technology (Cortex Metalyzer 3B) techniques were used during supine rest and a 1-hour indoor (∼24.5 °C, relative humidity: ∼42%) treadmill run at 50% V ˙ O 2 max (7.5 km·h ⁻¹ ) with blood lactate (XPER L1) taken 3 min on completion. Study was single-blind and placebo-controlled with final intake of the extract 2 h before starting the treadmill run. Results: During rest, the blackcurrant extract condition was associated with higher heart rate (+6 bpm), cardiac output (+10%), carbohydrate oxidation (+31%), and respiratory exchange ratio (+0.02 units), with lower systemic vascular resistance (−18%) compared with placebo. Stroke volume, oxygen uptake, and fat oxidation values appeared similar between conditions. During the 1-h treadmill run at 50% V ˙ O 2 max , the blackcurrant extract condition was associated with higher stroke volume (+9%), cardiac output (+10%), oxygen uptake (+6%), carbohydrate oxidation (+43%), and respiratory exchange ratio (+0.03 units), with lower systemic vascular resistance (−24%) and fat oxidation (−7%) compared with placebo. Heart rate and rating of perceived exertion values appeared similar between conditions. Post-run lactate concentration was 59% lower in the blackcurrant extract condition (placebo: 1.7 ± 0.1 mMol·L ⁻¹ ; extract: 0.7 ± 0 mMol·L ⁻¹ ). Discussion: This case study provided preliminary observations that a highly endurance-trained elite National Southeast Asian female athlete responded physiologically to the intake of blackcurrant extract. Seven-day intake with 420 mg per day of blackcurrant anthocyanins was associated with alterations in cardiovascular, metabolic, and respiratory responses during rest and moderate-intensity running, including lower post-run lactate concentrations. However, the mechanisms underlying this observation remain unclear and should be interpreted cautiously given the exploratory single-participant design.

Beneficial metabolic and cardiovascular effects of anthocyanin-rich New Zealand blackcurrant (NZBC) were primarily observed in studies with female and male Caucasian participants. We examined the effects of 14-day intake of NZBC extract (daily 210 mg of anthocyanins) during supine rest and moderate-intensity treadmill walking in Southeast Asian women ( n = 16, age: 23 ± 5 years, BMI: 22.9 ± 3.8 kg·m ^− 2 , body fat (BF): 35 ± 5%). A randomized, double-blind, placebo-controlled, cross-over design was used. Beat-by-beat (PhysioFlow ^® Endure™) and breath-by-breath (Cortex Metalyzer 3B) measurements were recorded during 10-min of supine rest and 30-min of moderate-intensity treadmill walking (speed: 4.84 ± 1.00 km·h ^− 1 ). At rest, NZBC extract had no effect on the cardiovascular, physiological and metabolic responses. During moderate-intensity exercise, only lower systemic vascular resistance (15%) was observed in 50% of the participants based on the smallest worthwhile change analysis ( P = 0.08 for the cohort with moderate effect size, d = 0.62). There was a significant correlation between fat oxidation during rest and moderate-intensity walking in the placebo and NZBC extract condition. There was a trend ( P = 0.08) for the linear relationship between the walking-induced placebo respiratory exchange ratio and change in fat oxidation by intake of NZBC extract. In Southeast Asian women, 14-day anthocyanin-rich NZBC extract did not elicit consistent cardiorespiratory and metabolic effects, although some participants showed reduced systemic vascular resistance. It is possible that there was not the bioavailability of plasma anthocyanin-induced metabolites that could alter cell function for metabolic responses. Further research should optimize dosing strategies and examine the roles of ethnicity, sex, and anthocyanin-induced metabolite bioavailability in shaping responsiveness to the intake of anthocyanins.