Purpose: Two new designs of track spikes have recently emerged: spikes with a compliant and resilient midsole foam (eg, polyether block amide [PEBA]) and spikes that combine such modern foam with a carbon fiber plate. We evaluated the effect of these different spikes on running performance measures for middle- and long-distance track events in trained runners. Methods: Fourteen females on a single visit performed six 200-m trials at a self-perceived 800-m race pace in 3 different spike conditions (Control, PEBA, and PEBA + Plate), twice in a mirrored order. Sixteen males completed 4 visits. During each of the first 3 visits, they performed six 200-m trials at a self-perceived 800-m race pace, twice in each condition, followed by a 3000-m time trial in 1 of the 3 spike conditions. During visit 4, participants completed six 4-minute running-economy trials at 5 m/s, twice in each condition. Results: At the 800-m race pace, females ran faster in PEBA (2.1%) and PEBA + Plate (2.0%) compared with Control. Males ran faster in PEBA (1.4%) and PEBA + Plate (2.4%) compared with Control and in PEBA + Plate compared with PEBA (1.1%). Similarly, males ran the 3000-m time trial faster in PEBA (1.0%) and PEBA + Plate (2.4%) than in Control. Running economy was better in PEBA (5.1%) and PEBA + Plate (4.0%) than in Control. Conclusions: Compared with traditional spiked shoes, shoes with PEBA foam (both with and without a plate) enhanced distance-running performance measures by 1% to 2% in females and males, with greater benefits in the PEBA + Plate condition in males.

Objective: This study aims to evaluate the effects of a 20-week endurance and strength training program on running economy and physiological, spatiotemporal, and neuromuscular variables in trained runners. Methods: A total of 18 runners (13 males and 5 females) completed a running economy test (2 bouts of 5 min at 3.06 m·s⁻¹ for females and at 3.61 m·s⁻¹ for males) and a graded exercise test (5 min at 2.78 m⋅s⁻¹, with speed increasing by 0.28 m⋅s−1 every 1 min until volitional exhaustion). During the training program, the participants completed different low-intensity continuous running sessions, high-intensity interval running sessions, and auxiliary strength training sessions. Results: Running economy, measured as oxygen cost and energy cost, increased by 4% (p = 0.011) and 3.4% (p = 0.011), respectively. Relative maximal oxygen uptake (VO_2max) increased by 4.6%. There was an improvement in the speed associated with the first (VT₁) and the second ventilatory threshold and with the maximal aerobic speed by 9.4, 3.7, and 2.8% (p = 0.000, p = 0.004, and p = 0.004, respectively). The %VO_2max value of VT₁ increased by 4.8% (p = 0.014). Conclusions: These findings suggest that a 20-week endurance and strength training program significantly improves performance and physiological factors without changing the runner’s biomechanics.

Background: This study aimed to examine the effects of two complex training sequences on acute post-activation potentiation enhancement in countermovement jump (CMJ) performance. Methods: Twenty-two recreationally active males performed CMJ before and 1, 4, and 8 min after two sequences of complex training conducted in reverse order, consisting of a heavy load comprising three sets of squats with a 15% velocity-loss and three sets of maximal CMJ with a 10% height-loss for the low load. Results: No significant differences (p > 0.05) were observed in the interaction time × condition in CMJ variables. At the individual level, 23, 9, and 32% of participants improved CMJ performance in the high loads–low loads sequence at 1, 4, and 8 min compared to the baseline, respectively. In comparison, 14%, 23%, and 27% of participants improved CMJ performance in the light loads–high loads sequence. Eight participants in each sequence did not improve CMJ performance at any time, although these participants were not the same in both sequences. Conclusions: Stronger athletes (1.65 ± 0.28 relative force) seemed to benefit more from the high loads-low loads sequence. In conclusion, there were no non-responders, as all the participants improved at some time point. The strength levels may be one of the moderating variables.

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.

Purpose : This study systematically reviewed the fatigue mechanisms that constrain trail running performance and examined the influence of sex and event distance on these responses. PRISMA guidelines were followed. PubMed, Web of Science, and Dimensions AI databases were searched up to August 10, 2025 for studies involving adult-trained or experienced trail runners that compared prerace and postrace fatigue markers after a standard trail race or laboratory race simulation. Risk of bias was assessed using the ROBINS-I. Twenty-four studies met the inclusion criteria (n = 674 subjects; 506 men and 168 women). Most studies (n = 21) examined only or predominantly male runners, and only four studies specifically assessed sex differences. Participants were trained adults (mean age = 39.4 [8.5] y), with sample sizes ranging from 6 to 72 individuals. Regarding race distance, 4 studies investigated short races (≤60 km), 4 medium races (60–100 km), 8 long races (≥100 km), and 8 compared multiple distances within the same study. Fatigue assessment primarily relied on knee extensor and plantar flexor torque testing to evaluate central and peripheral fatigue, complemented by alternative methods such as tensiomyography, soft tissue vibration, strength, and jump tests. Ten of the studies analyzed blood biomarkers related to muscle damage, inflammation, and renal function. Conclusions : Neuromuscular fatigue in trail running arises from both central and peripheral mechanisms, depending on race duration and testing methods. While central fatigue predominates in shorter races, peripheral fatigue and muscle damage become more evident in longer events (≥100 km). Moreover, sex differences are minimal, although methodological heterogeneity limits the strength and comparability of the findings.