Víctor Cuadrado-Peñafiel

The aims of the present study were to (a) analyze the relationship between acceleration capacity at low and high initial running speeds and the player’s ability to cover high-intensity running distances and perform high-intensity accelerations during competition and (b) examine whether these differences also occur across playing positions in professional soccer players. A total of 222 professional male soccer players from LALIGA participated in the study during the 2021–2022 and 2022–2023 seasons. Players were classified in six positions: central defender (CD), full back (FB), central midfielder (CM), offensive midfielder (OM), winger (W) and forward (F). K-means clustering was applied to classify players based on the maximal theoretical acceleration (A_0Int) capacity and the maximal theoretical initial running speed (S_0Int). Mixed models were used to examine the accelerations performed above 75% of the acceleration–speed profile (Mean₇₅AS₀) according to IntS; distance covered at high speeds (21–24 km·h⁻¹, >24 km·h⁻¹, >28 km·h⁻¹); and maximum speed across playing positions, cluster groups and contextual variables. C1 (high A_0Int and S_0Int) showed a significantly greater distance covered during high-intensity running and accelerations than C2 (low A_0Int and S_0Int) across all IntS thresholds. C3 (high A_0Int and low S_0Int) achieved higher accelerations at a low IntS. In conclusion, offensive positions displayed greater distance covered during high-intensity running and acceleration across all IntS categories, while CD produced lower values. In conclusion, this study highlights how the accelerations quantified in relation to the IntS vary according to the relationship between A_0Int and S_0Int during competition and the positional role of the player.

This systematic review examined the influence of menstrual cycle phases on lower-limb muscle activation patterns in eumenorrheic women. Following the PRISMA guidelines, a comprehensive search was conducted in PubMed, Web of Science, and SPORTDiscus using the keywords: (menstrual cycle OR menstrual phase* OR menstruation) AND (neuromuscular activation OR muscle activation OR muscle activity OR neuromuscular control patterns) AND (electromyography OR EMG). Inclusion criteria required participants to be eumenorrheic women with regular menstrual cycles, verified through blood analysis and other physiological confirmation methods, and without menstrual disorders or hormonal contraceptive use. Additionally, eligible studies had to assess lower-limb muscle activation using electromyography. Seven studies met the criteria, comprising a total of 116 eumenorrheic women. Most studies reported no statistically significant differences in muscle activation patterns across menstrual cycle phases. Overall, hormonal fluctuations may influence muscle activation depending on the nature of the task performed (dynamic vs. static; fatiguing vs. non-fatiguing). Future research should incorporate larger sample sizes, longer monitoring periods, and more standardized methodological approaches.

Background: Caffeine has become the psychostimulant with the highest use worldwide by different segments of the population. This is mainly due to the wide variety of benefits it offers in different contexts of use. It is available in various forms, with caffeine chewing gum recently generating great interest due to its characteristics and absorption time. Methods: A placebo-controlled study was conducted in which 20 healthy university students were exposed to three different conditions (single dose, partial dose, and placebo). The intervention consisted of a dual task in which heart rate, perceived exertion, and reaction time were monitored using the Stroop test and choice reaction time test while participants performed two blocks of cycloergometer exercise. Results: A t-test comparison between blocks showed differences in the Stroop test under all conditions, with the single dose having the best performance (Gr.A p < 0.001; Gr.B p < 0.029; Gr.C p < 0.009). The single dose group also showed favorable results for the HR/RPE ratio (p < 0.044) and an increase in the rate of perceived exertion (p < 0.006). No changes in reaction time were observed under any condition of the choice reaction time test. Conclusions: These results suggest that caffeine supplementation has positive effects on variables related to psychophysiological performance during a dual task. A single dose showed the best results in this study; however, longer intervention designs could be considered in the future to see the effect of partial doses of caffeine over time.

Acceleration and Acceleration-Initial Speed Running are important factors in soccer performance. The aims of the study were (a) analyze by playing position the acceleration-initial speed (AS₀) profile and (b) analyze the relevance of the number of accelerations > 3 m·s⁻² according to final league position. The subjects (n = 309) from the Spanish First Division during the 2021–2022 and 2022–2023 seasons were classified in six positions: Central Defenders (CD), Full Backs (FB), Central Midfielders (CM), Offensive Midfielders (OF), Wingers (W), and Forwards (F). A total of 6180 match observations were recorded using the Mediacoach System. The parameters analyzed were accelerations > 3 m·s⁻² and AS₀ profile variables, maximal theoretical acceleration (A_0Int), and maximal theoretical initial running speed (S_0Int). The AS₀ profile was calculated using a linear regression model. Welch’s analysis of variance (ANOVA) revealed a consistent relationship between the A_0Int variable of the AS₀ profile and team success in CM, FB, and W positions. Moreover, the successful teams for CD, CM, FB, OM, and W positions showed a statistically higher number of accelerations > 3 m·s⁻² than unsuccessful teams. In conclusion, these findings suggest the importance of enhancing acceleration abilities, particularly for lower-performing teams, to achieve the physical standards of successful teams.

Beach handball (BH) is characterized by high-intensity actions, such as accelerations and short rest times, in combination with long periods of low-intensity activity during a match. The purpose of this study was to establish a comparative analysis between the effect of a hard surface vs. sandy surface on the properties of the sprint Force–Velocity–Power Profile (FVP) of female beach handball top-level players. Fourteen female BH players participated in this research. A cross-sectional investigation was performed in order to evaluate the determining variables of the FVP profile for different surfaces. After a specific warm-up, two maximal 20–30 m sprints (4 min resting between trials) were performed in two conditions (hard surface and sand) within 10 min. The female BH players showed higher mean values for all the FVP profile variables (p < 0.001) on the hard surface compared to sand, in addition to lower values for the 5 m (ES = 2.29 to 3.89) and 20 m sprinting times (ES = 2.39 to 3.99) (p < 0.001). However, the decrease in the ratio of force over acceleration was not discriminant between the surfaces. Positive correlations were found for the speed variables (0.691–0.807, p < 0.01), as well as the Pmax (0.520, p = 0.035), between the surfaces. A prior knowledge of the FVP profile for hard–sandy surfaces could offer an important reference value about the sprint properties of this population, and be useful for evaluating the efficiency, as well as the effect on the sprint and gaming performance, of specifically oriented training programs based on those reference values.

Training systems based on high-intensity interval training (HIIT) have experienced great influence in recent years within the context of exercise and sport. This study aims to provide insight on whether the immediate outcomes (e.g., central and peripheral acute responses) may be intensified or attenuated when a HIIT protocol is performed using a FFP2/N95 face mask in active healthy adult women. In other words, it strives to provide new findings relative to the use of face masks as a potential performance enhancing tool. In the current study, the same training session was carried out on two occasions under different conditions (i.e., with FFP2/N95 and without FFP2/N95) in a cross-over experimental design. The following study variables were assessed before and after the HIIT in both sessions: Lactate, cortisol, alpha-amylase, selective attention, countermovement jump (CMJ), and power output. Additionally, central and peripheral Rates of Perceived Exertion (RPE) were assessed before and during the HIIT. This study makes novel contributions to prior research, showing that the use of FFP2/N95 face mask (vs. no mask) yielded higher alpha-amylase, selective attention, and peripheral RPE scores. No significant differences were found for lactate, cortisol, CMJ, and power output. Interestingly, central RPE scores were significantly lower under FFP2/N95 face mask (vs. no mask) condition. The main suggestion in light of these results is that researchers and practitioners should consider potential peripheral and central responses to training stimuli when using FFP2/N95 face masks.

Introduction: The implementation of optimal sprint training volume is a relevant component of team sport performance. This study aimed to compare the efficiency and effectiveness of two different configurations of within-season training load distribution on sprint performance over 6 weeks. Methods: Twenty male professional FH players participated in the study. Players were conveniently assigned to two groups: the experimental group (MG; n = 11; applying the microdosing training methodology) and the control group (TG; n = 9; traditional training, with players being selected by the national team). Sprint performance was evaluated through 20 m sprint time (T20) m and horizontal force–velocity profile (HFVP) tests before (Pre) and after (Post) intervention. Both measurements were separated by a period of 6 weeks. The specific sprint training program was performed for each group (for vs. two weekly sessions for MG and TG, respectively) attempting to influence the full spectrum of the F-V relationship. Results: Conditional demands analysis (matches and training sessions) showed no significant differences between the groups during the intervention period (p > 0.05). No significant between-group differences were found at Pre or Post for any sprint-related performance (p > 0.05). Nevertheless, intra-group analysis revealed significant differences in F0, Pmax, RFmean at 10 m and every achieved time for distances ranging from 5 to 25 m for MG (p < 0.05). Such changes in mechanical capabilities and sprint performance were characterized by an increase in stride length and a decrease in stride frequency during the maximal velocity phase (p < 0.05). Conclusion: Implementing strategies such as microdosed training load distribution appears to be an effective and efficient alternative for sprint training in team sports such as hockey.

Considering the existing controversy over the possible role of acute antioxidant vitamins in reducing exercise-induced muscle damage (EIMD), this doubled-blind, randomized and controlled trial aimed to determine whether supplementation with vitamins C and E could mitigate the EIMD in endurance-trained runners (n = 18). The exercise protocol involved a warm-up followed by 6 to 8 bouts of 1 km running at 75% maximum heart rate (HRmax). Two hours before the exercise protocol, participants took the supplementation with vitamins or placebo, and immediately afterwards, blood lactate, rate of perceived exertion and performance were assessed. At 24 h post-exercise, CK, delayed onset muscle soreness and performance were determined (countermovement jump, squat jump and stiffness test). The elastic index and vertical stiffness were calculated using a stiffness test. Immediately after the exercise protocol, all participants showed improved maximum countermovement jump, which only persisted after 24 h in the vitamin group (p < 0.05). In both groups, squat jump height was significantly greater (p < 0.05) immediately after exercise and returned to baseline values after 24 h. The elastic index increased in the vitamin group (p < 0.05), but not in the placebo group. In both groups, lactate levels increased from pre- to immediately post-exercise (p < 0.05), and CK increased from pre- to 24 h post-exercise (p < 0.05). No significant differences between groups were observed in any of the variables (p > 0.05). Vitamin C and E supplementation does not seem to help with EIMD in endurance-trained individuals.

Spatial navigation is a key aspect of human behavior and it is still not completely understood. A number of experimental approaches exist, although most of the published data in the last decades have relied on virtual maze on-screen simulation or not-completely freely moving 3D devices. Some interesting recent developments, such as circular mazes, have contributed to analyze critical aspects of freely moving human spatial navigation in real space, although dedicated protocols only allow for simple approaches. Here, we have developed both specifically designed and home-assembled hardware equipment, and a customized protocol for spatial navigation evaluation in freely moving humans in a real space circular arena. The spatial navigation protocol poses an imitation of a real-space multiple-choice path maze with cul-de-sac and instances of non-linear movement. We have compared the results of this system to those of a number of validated, both virtual and real, spatial navigation tests in a group of participants. The system composed by hardware, the test protocol, and dedicated measure analysis designed in our laboratory allows us to evaluate human spatial navigation in a complex maze with a small and portable structure, yielding a highly flexible, adaptable, and versatile access to information about the subjects’ spatial navigation abilities.

The aim of the present study was to determine the influence of maturation status on the components of the sprint force-velocity (F-V) profile in young soccer players. Sixty-two young male soccer players from the same professional soccer academy took part in the present study. A cross-sectional design was implemented to compare the main components of the sprint F-V profile (i.e., maximal theoretical force (F₀), velocity (V₀), power (P_max), and ratio of horizontal-to-resultant force (RF_peak), and decrease in the ratio of horizontal-to-resultant force (DRF)) and sprint performance (5, 20, and 30 m sprint time) among participants’ maturation stages (i.e., pre-, mid- and post-peak height velocity (PHV) groups). The results show that the ES of differences in 5 min sprint performance, F₀, and RF_peak (i.e., strength- and acceleration-related components of the sprint F-V profile) were greater between pre- and mid-PHV groups than those between mid- and post-PHV groups (i.e., large and very large effects (1.24 ≤ ES ≤ 2.42) vs. moderate, small, and zero effects (0 ≤ ES ≤ 0.69), respectively). However, the ES of differences in V₀ and DRF (i.e., peak speed-related components of the sprint F-V profile) were greater between mid- and post-PHV groups than those between pre- and mid-PHV groups (i.e., large effects (1.54 ≤ ES ≤ 1.92) vs. moderate effects (−0.59 ≤ ES ≤ 1), respectively). Once the strength development is achieved to a great extent from the pre- to mid-PHV groups, specific strength training methods may be used for young soccer players to improve their sprint performance.