Background: Mental fatigue (MF) is a psychobiological state that could negatively impact physical and cognitive performance, although the extent of this impact remains controversial. While laboratory studies have provided valuable insights into the acute effects of MF, their ecological validity in real-world sport settings remains limited. Recent research indicates that MF can naturally arise during sport activities, leading to chronic effects on endurance and perceptual-cognitive skills. These effects may persist beyond individual sessions, potentially increasing the risk of injury due to their cumulative nature. Purpose: This commentary aims to guide future research by emphasizing the need to investigate the natural occurrence and chronic effects of MF in applied sport settings. Conclusions: Understanding how MF develops and manifests in real-world settings, particularly individual differences in perception and response, is crucial for creating more effective management strategies. Addressing these factors will enable better support for athletes who may experience prolonged periods of MF that could affect their training and competitive performance. Future research should prioritize studying MF in natural sport settings to enhance the ecological validity of findings. By focusing on the chronic and cumulative nature of MF, as well as individual variability, researchers can develop more tailored and effective strategies for managing MF. This research will not only bridge the gap between laboratory studies and real-world applications but also contribute to more precise monitoring and intervention techniques. Ultimately, these advancements will improve athletes’ ability to maintain peak performance and reduce the risk of injury, thereby enhancing overall athletic well-being.

Mental fatigue (MF) has been shown to acutely impair the psychological responses and endurance running performance of orienteers. This study aimed to explore MF levels experienced by orienteers during a 4‐day competition preparation camp that consisted of simulated sprint, middle‐distance, long‐distance, relay and night races. Eleven national junior orienteers participated in the study (age: 15–17 years, height: 1.69 ± 0.07 m and body mass: 59.9 ± 5.22 kg). Subjective ratings of MF, motivation, stress, physical fatigue (PF) and tiredness were measured using a 100‐mm visual analogue scale. The Brunel Mood Scale (BRUMS) was utilized to assess the mood state of the orienteers. The self‐report measures were taken within 30 min of waking, immediately after the post‐training session, and after 24 and 48 h following the final training session. The pre–post orienteering training combined analysis showed that there was a moderate increase in perceived MF (ES = 1.06 [0.66, 1.45]), PF (ES = 1.07 [0.69, 1.45]) and BRUMS fatigue (ES = 0.74 [0.4, 1.1]) after orienteering training. At 48 h post the final training session, MF remained moderately elevated (ES = 0.86 [−0.07, 1.75]), while PF also remained elevated to a small extent (ES = 0.46 [−0.46, 1.39]) compared to the pre‐training values. A moderate impairment was still observed in BRUMS vigor (ES = −1.02 [−1.65, −0.36]), but BRUMS confusion scores were moderately lower (ES = −0.85 [−1.71, 0.04]) than pre‐training values. This study found that orienteering training induced acute MF, persisting for at least 48 h after the final session.

The purpose of this study was to examine the effectiveness of a 6-week core stabilization training program (CSTP) in improving dynamic balance and back-extensor endurance of horse riders; and develop a measurement tool in assessing the dynamic postural stabilization endurance for horse riders. Twelve male horse riders (age: 23.58 ± 1.93 years; height: 165.09 ± 4.60 cm; weight: 56.53 ± 4.75 kg; experience in horse racing: 1.75 ± 0.34 years) completed 12 training sessions in 6 weeks. Subjects performed the CSTP with two progressions. CSTP started with the basic consciousness activation exercises, and then eliminated visual feedback in dynamic balance task on unstable surfaces and finished with switching the center of gravity. Moderate-to-large difference was demonstrated in the Y-Balance test scores for right leg (102.81 ± 8.32 vs 106.471 ± 4.35 cm, d = 0.55, 95% CL 0.00 to 1.08) and left leg (102.04 ± 3.20 vs 106.29 ± 3.62 cm, d = 1.25, 95% CL 0.41 to 2.05) following 6 weeks CSTP. However, trivial to small differences was reported between left and right leg in pre (d = 0.12, 95% CL − 0.49 to 0.73) and post 6-week CSTP (d = 0.04, 95% CL − 0.69 to 0.78). Biering–Sørensen test (BST) shows largely greater performance after 6-week CSTP (98.3 ± 30.1 vs 131.8 ± 19.0 s, d = 1.33, 95% CL 0.54–2.09). A novel measurement, Swiss ball four-point kneeling test was shown to be correlated with the change in BST (r = 0.633).

Background: This study investigated the impact of competitive fatigue on physiological (blood lactate and heart rate [HR]), neuromuscular (countermovement jump [CMJ]), and psychological (rate of perceived exertion [RPE]) variables in youth swimmers. Methods: Forty-two swimmers (mean ± SD, 14 ± 0.5 years; height for boys: 1.73 ± 0.03 m, girls: 1.69 ± 0.02 m; body mass: 67 ± 2.8 kg for boys and 62 ± 2.8 kg for girls) participated during a four-day championship, with data collected before and after their competition heats. Results: Significant post-race increases in lactate levels (p < 0.05) and RPE (p < 0.05) were observed across all distances, particularly after the 100 m and 200+ m events. Heart rate showed a decrease after the 50 m event and an increase after longer distances, reflecting different recovery demands. Although CMJ performance decreased after the races, these changes were not statistically significant (p = 0.810). The findings underscore the importance of race distance in modulating fatigue responses and suggest that RPE and lactate are the most sensitive indicators of competition-induced stress in these youth swimmers. Conclusions: Lactate accumulation and perceived exertion were the most sensitive indicators of fatigue (both p < 0.01), while HR and CMJ responses exhibited variability depending on race distance. These findings highlight the practical use of lactate and RPE monitoring related to fatigue and recovery strategies during competitions in youth swimmers.