Scientific Journal of Sport and Performance

Characteristics of body movements and ground reaction forces during the follow-through phase in baseball

Kanzi Ohyama, Akira Maeda — Tue, 18 Nov 2025 00:00:00 +0100

In baseball, batters run to first base after hitting the ball, meaning the batting motion following impact may transition into running motion. This study aimed to clarify the characteristics of ground reaction forces (GRF) and body movements related to base running by comparing batting and running conditions (BRC) with batting-only conditions (BC) during the follow-through phase (FT phase). Thirteen right-handed male university baseball players participated. Using motion capture and force plates, the players batted at inside, middle, and outside pitch locations under both conditions. During the FT phase, BRC showed a decrease in GRF on the stride side and an increase in GRF on the axis side compared to BC. Shoulder and hip rotation angles and angular velocities were significantly lower in BRC. Furthermore, whole-body centre of gravity displacement was significantly higher in BRC for pitches on the middle and outside corners. These results suggest that the FT phase contributes not only to the completion of the swing but also to the initiation of base running.

Effects of high intensity interval training combined with plyometrics on vertical jump and repeated sprint ability in young soccer players

Amar Mouissa, Lilia Kebaili, Oussama Kessouri — Tue, 18 Nov 2025 00:00:00 +0100

The aim of this study was to examine the effects of High Intensity Interval Training (HIIT) combined with plyometric exercises on vertical jump (VJ) and repeated sprint ability (RSA) in young soccer players. Eighteen U19 players were participated in this study, and were divided into two groups, experimental group (EG) and control group (CG). Players performed the 30-15 Intermittent Fitness Test (IFT), Repeated Sprint ability (RSA) test, Sargent Jump Test (SJT), and the Rating of Perceived Exertion (RPE) for data collection. A significant improvement was observed in VJ height and peak power within the EG (p = .044, moderate effect) compared to CG (p = .661, trivial effect). Time × group interaction for these variables was not significant (p = .275, moderate effect). RSA_mean significantly improved in EG (p = .005, large effect), while a significant decline was observed in CG (p = .006, large effect). RSA_best significantly declined in CG (p = .042, small effect). In contrast, no significant differences were found in RSA_best in EG. Both groups showed no significant improvement in RSA_dec (p > .05). Only RSA_mean showed a significant interaction effect (p = .000, large effect), indicating a greater improvement in the EG than the CG. The study shows that HIIT combined with plyometric exercises for 8 weeks improved both VJ and RSA_mean. The authors suggest integrating HIIT with plyometric exercises to improve VJ and RSA_mean for soccer players.

Comparison of different pose estimation models for lower-body kinematics

Takashi Fukushima, Patrick Blauberger, Tiago Guedes Russomanno, Martin Lames — Tue, 09 Dec 2025 00:00:00 +0100

As pose estimation has garnered considerable attention for kinematic analysis, numerous pose estimation models have been developed in recent times. A pose estimation model is a trained neural network that predicts human body landmarks from an image. Each model contains different strong and weak points, which make it difficult for users to decide which model to use for kinematic analysis. The accuracy of the model can be one big factor for model selection, but there are not many studies investigating this critical point. Therefore, this study aims to investigate the accuracy of different models and variants by comparing the measurements from the models and variants against reference measurements. Five male participants were invited to this study. Each participant was asked to perform five exercises: squat, squat jump, counter movement jump, walk, and jog while being recorded by twelve normal RGB cameras (Contemplas) and ten marker-based tracking cameras (VICON). The video recordings from the Contemplas were processed by six different pose estimation models and variants: Mediapipe, MeTRAbs Small, MeTRAbs X Large, YOLO, MoveNet Lightning, and MoveNet Thunder to detect joint positions. From the detected joint positions, four joint angles, left hip, right hip, left knee, and right knee, were calculated. Three-way repeated measures ANOVA and Tukey HSD post-hoc analysis were applied to compare the pose estimation models with VICON measurements. The ANOVA result showed that exercise and model factors had a significant impact on the measurement errors although angle factor did not. In the post-hoc analysis, knee joint angle errors from YOLO, MoveNet Lightning, and MoveNet Thunder in jog and walk were significantly higher than those from Mediapipe, MeTRAbs Small, and MeTRAbs X Large. In conclusion, differentiated recommendations can be given for optimum model and variant choice in different conditions in kinematic analyses.

Relationship between curvilinear sprint performance, hip strength, jump performance and reactive strength in elite youth soccer players

Ažbe Ribič, Matic Sašek — Tue, 09 Dec 2025 00:00:00 +0100

The aim of this study was to investigate the relationships between hip strength, vertical jump performance, reactive strength index, and curvilinear sprint (CS) performance and to compare these variables between different playing positions in youth soccer players. Thirty-four players completed two test sessions. Hip adduction and abduction strength was measured using a hand-held dynamometer. A force plate was used to measure the height of the countermovement jump and the drop jump as well as the contact time, from which the modified reactive strength index and the reactive strength index (RSI) were calculated. The CS was tested on the penalty arch of a soccer pitch. One way ANOVA was used to test the effects of playing position whereas the Pearson's r was used to test the relationship between variables. There were no significant differences in the measured variables between defenders, midfielders and attackers (p ≥ .140). Along with RSI, which showed significant moderate to large correlations (r = -0.39 to -0.59), hip abduction strength was also significantly associated with CS split times (r = -0.36 to -0.38). Results emphasize the relevance of ankle reactive strength and hip strength for CS performance and supports the inclusion of ankle and hip-specific strength exercises in the training of youth soccer players.

Habits of Spanish and European athletes on altitude training

Carlos Campo Beamud, Francisco Javier Sancho Bielsa, Victor Rodrigo-Carranza — Sat, 21 Feb 2026 00:00:00 +0100

Objective: The training context of athletes from different locations can affect their altitude training camps. The aim of this study was to compare the habits of Spanish and European athletes during high altitude training camps. Methods: Descriptive analysis using questionnaires was conducted to investigate the altitude training practices of elite European athletes (n = 28) compared with Spanish athletes (n = 35). Moreover, all variables were assessed with an analysis of variance (ANOVA). Results: The most commonly method used by athletes was Live High - Train High (LHTH) . Most Spanish athletes train at altitudes above 2000m, while European athletes train at 1800m. The European athletes group usually compete 2-3 days after the camp, while the most Spanish athletes compete 3 weeks after the camp. In both groups, the feeling of improved performance after the camp was similar. Spanish athletes had higher feeling of fatigue and more sleep problems than European athletes during the training camp (p < .005) while the Europeans have a better feeling at the end of the camp. Conclusion: Spanish athletes had similar habits to those of athletes from the rest of Europe. The main differences between groups were that the feeling of fatigue at the end of the altitude periods and the sleep problems during the camp. These subjective feelings during the training camp may affect the fact that Spanish athletes preferred to compete up to three weeks after the camp while European athletes preferred to compete in the first 2-3 days after the camp.

Quantifying the Impact of basketball performance metrics on winning in professional and collegiate basketball

Alp Aslan Uysal, Kevin Carroll, Alan Huebner, Anna Krush, Michael Henry Stone — Sat, 21 Feb 2026 00:00:00 +0100

The aim of the investigators was to statistically analyze the relationships between basketball performance metrics and winning percentage (WIN%) in professional and collegiate basketball. Game data from 10 seasons between 2014 and 2024 were analyzed from the NBA, WNBA, NCAA, and NCAAW leagues. Basketball performance metrics included the number of possessions, points scored (PTS), three-point percentage (3P%), two-point percentage (2P%), number of free throw attempts (FTA), free throw percentage (FT%), offensive rebound percentage (OREB%), defensive rebound percentage (DREB%), turnover ratio (TOV%), assists (AST), steals (STL), blocks (BLK), personal fouls (PF), relative offensive (ORtg±) and defensive (DRtg±) ratings. Among the statistically significant relationships between WIN% and basketball performance metrics, 3P% had the strongest relationship with WIN% in NBA, whereas BLK had the strongest relationship with WIN% in WNBA and NCAA. AST had the strongest relationship with WIN% in NCAAW and was not statistically related to WIN% in NBA. The only league in which DRtg± was not statistically related to WIN% was the NBA. NBA is an offense-oriented league where creating individual scoring opportunities had a stronger impact on winning. In contrast, offensive and defensive performance showed a closer balance in their contributions to team success in the other leagues analyzed.

Comparative performance analysis of rating systems in junior and collegiate tennis

Seth Richey, Nathan David Pifer, James Du, Ryan Rodenberg — Sat, 21 Feb 2026 00:00:00 +0100

This paper analyzes the performance of two tennis rating systems—Universal Tennis Rating (UTR) and World Tennis Number (WTN)—in forecasting match outcomes in junior and collegiate tennis tournaments occurring after the September 2024 update to WTN. Results indicate no statistically significant difference in performance accuracy between UTR and WTN in junior tennis. However, in men’s collegiate tennis, UTR demonstrates an advantage over WTN in predictive performance. In addition, interaction terms in select models show that the positive effects of a rating advantage on a player’s probability of winning are mitigated in matches featuring higher-rated competitors. These findings highlight the importance of using evaluation metrics that are most relevant to a specific context and underscore the role of sports analytics in promoting fairness in competitive tennis.

Effect of light stimuli on squat jump performance

Yoshiki Fujisawa, Kanta Inada, Ryohei Hayashi — Sat, 21 Feb 2026 00:00:00 +0100

We aimed to compare the effects of intentional jump conditions (IJC) and reactive jump conditions (RJC) using light stimuli on SJ performance, focusing on differences between track and field sports and football. Twenty-five university track and field athletes (TF group) and 25 male football players (F group) performed four SJs, receiving intentional or reactive jump verbal instructions. Reaction time (RT), jump height (JH), peak force (PF), peak rate of force development (PRFD), and average rate of force development (ARFD) during the SJ were recorded. Unpaired t-tests were used to evaluate differences in each variable between IJC and RJC, while two-way analysis of variance was used to assess differences between conditions and between sports. For all participants, JH and PF were significantly higher during IJC, whereas PRFD and ARFD were higher during RJC (p < .05). The TF group showed significantly higher JH and PF and significantly lower RT than the F group. In the F group, PRFD and ARFD increased significantly under RJC (p < .05), while PF did not decrease across conditions. These findings suggest that light stimulation affects SJ performance differently by sport. Notably, football players may enhance force development velocity under reactive conditions while maintaining force output.

The effect of self-regulated neck-cooling on physical and cognitive performance during heat stress

Aine Bagnall, Enrico Giuliani, Christopher Tyler, Henning Myrene — Sat, 21 Feb 2026 00:00:00 +0100

This study investigated the physiological, perceptual, cognitive, and performance effects of self-regulated neck-cooling during heat stress. Nine, healthy, non-heat acclimated, participants undertook two experimental trials in the heat (35°C; 50% rh) during which they completed bouts of supine rest (30min), submaximal cycling exercise (20min at ~140bpm), and supine recovery (15min). Participants wore a novel electronic cooling collar in one trial (COOL) and were able to personalise the frequency and intensity of the cooling to maintain thermal comfort using a tablet-based application. Participants reduced the collar temperature over time which reduced their mean neck temperature throughout (-2.2 ± 0.6°C) and local neck thermal sensation during the rest and exercise bouts. The collar had no effect on physiological (rectal temperature [Δ 0.0 ± 0.1°C], aural temperature [Δ 0.0 ± 0.2°C], skin temperature [Δ 0.1 ± 0.3°C], or heart rate [Δ -4 ± 7 bpm]) or perceptual strain (whole-body thermal sensation and comfort) during rest or exercise bouts nor did it improve cognitive performance (reaction time, movement time, and spatial working memory), mood, or overhead press performance. The demands of the protocol investigated may have been insufficient to alter physiological strain or mood sufficiently to necessitate neck cooling despite improved localized thermal sensation.

Temporal characteristics of 100-m hurdles performance based on race analysis–ranging 12–18 s

Sat, 21 Feb 2026 00:00:00 +0100

The aim of this study was to clarify the characteristics of 100-m hurdles performance in female athletes, spanning from the world-record time to the 18-s range. Video data were randomly selected from internet broadcasts, covering race times from 12.12 s to 18.98 s, from international and national competitions held between 1987 and 2024. Time for each hurdle section from start to finish was measured, along with the total number of steps. Maximal running velocity occurred in the 4th and 5th hurdles (H4–5) for athletes at the world-class and national championship levels, similar to the finding for a 100-m sprint race around the 50-m mark. Conversely, athletes at the regional competition level tended to show maximal running velocities in the early sections of the race (H1–2 or H2–3), followed by a decrease in velocity. Across all groups, the ratio of running to hurdling time in the shortest interval section was consistently approximately 60%–40%. In the final section (H9–10), running time increased in the 17-s and 18-s groups. Sprinting ability and step count are crucial factors in determining race patterns. Athletes with more than 35 steps in total were limited to performances in the high 15-s range.

Combined aerobic and brain exercise can improve executive function among adolescent girls

Maraym Momeni, Rasool Abedanzadeh, Saeed Ahmadi Barati — Tue, 18 Nov 2025 00:00:00 +0100

Objectives: The aim of this study was to investigate the effectiveness of a training program consisting of aerobic exercise, video games, brain exercises, and combination of all of it on the executive functions among adolescent girls. Methods: The research utilized a semi-experimental design with a mixed design approach, where the training groups were treated as between-group factors and the assessed tests (pre-test and post-test) as within-group factors. A total of 48 female students aged 11 to 17 from Deir city (Ahvaz, Iran) were randomly assigned to four equal groups: video game, brain exercise, aerobic exercise, and combined. Prior to the training sessions, all participants completed tests assessing inhibitory, working memory, and cognitive flexibility in a pre-test. These exercises were conducted three times a week for 20 minutes per session, totaling 12 sessions. Following the intervention, a post-test was administered under the same conditions as the pre-test. Results: The results of the covariance analysis revealed that video games had a significant effect on working memory and inhibitory, brain exercises had an impact on working memory, cognitive flexibility, and inhibitory, and aerobic exercise influenced working memory and inhibitory. However, there was no significant difference between aerobic exercise and video games in terms of cognitive flexibility. Conclusion: In conclusion, conducting an intervention course incorporating video games, brain exercises, and aerobic exercise can improve executive functions such as working memory, selective attention, and cognitive flexibility. Therefore, it is recommended that teachers and sports coaches consider implementing combined training approach to enhance executive functions in teenagers.

How can we assess neuromuscular performance in female football players?

Claudia Moreno-Ortega, Jaime Gonzalez-Garcia, Blanca Romero-Moraleda — Fri, 24 Oct 2025 00:00:00 +0200

Women's football has experienced exponential growth in popularity, leading to a notable improvement in player performance and an increased interest in optimizing player development. This systematic review aimed to identify the most frequently used tests for evaluating neuromuscular performance in female football players. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a systematic search of the literature using keywords related to football, neuromuscular training, and measurement methods. The literature search yielded 109 articles (PubMed = 27; WoS = 31; Scopus = 32; SportDiscus = 19). After screening, 19 articles met the inclusion criteria and were thoroughly reviewed. The most commonly assessed variables in neuromuscular testing included jump ability, agility, sprinting, fitness, strength, and balance. The wide variety of tests used for each skill, coupled with a lack of standardized methodologies, hinders the establishment of robust recommendations. Consequently, further research is necessary to evaluate the validity of these tests and to develop an appropriate battery of neuromuscular assessments.

Debunking the plant protein paradox

Aniket V. Inamdar, Yashendra Sethi, Umesh Sharma — Fri, 24 Oct 2025 00:00:00 +0200

The increasing adoption of plant-based diets (PBDs) has raised questions regarding their adequacy in supporting muscular strength and performance, particularly given concerns around the amino acid profile and bioavailability of plant proteins. This review synthesises current meta-analytical and clinical trial evidence to address the "plant protein paradox," which posits that plant proteins are inferior for maintaining muscle mass and strength. Recent high-quality data reveal no significant differences in muscular strength or athletic performance outcomes between plant-based and omnivorous diets when total protein intake and quality are optimised. Mechanistic studies demonstrate comparable muscle protein synthesis rates across protein sources, with soy and certain mixed plant proteins showing anabolic potential equivalent to animal proteins. Clinical recommendations emphasise attention to protein quantity, quality, leucine content, and micronutrient sufficiency to maximise muscle health on PBDs. Specific populations—including older adults and athletes—can safely adopt plant-based nutrition without compromising strength or functional performance. This evidence supports a shift beyond traditional, protein hierarchy models, positioning plant-based diets as a viable strategy for musculoskeletal health alongside their cardiovascular and environmental benefits.

Optimizing weight cutting practices in MMA

Lucas Barbosa, Ana Carolina Staub, Maria Luiza Caetano Dias — Fri, 24 Oct 2025 00:00:00 +0200

As in other combat sports, mixed martial arts (MMA) is contested within standardized weight classes; athletes routinely manipulate body mass in the pre competition period (“weight making”) to satisfy divisional limits at the official weigh-in. This systematic review evaluated the safest weight making strategies in MMA athletes from psychological, physiological, and nutritional perspectives. The protocol was submitted to PROSPERO (CRD420251083111) and the review adhered to PRISMA guidelines. PubMed, Embase, and Web of Science were searched from inception to June 8, 2025. Eligible studies were English language, peer reviewed original research involving MMA athletes preparing for competition. Fifteen studies met inclusion criteria. Across studies, a progressive multi week gradual weight loss (GWL) phase, typically achieved through dietary energy restriction and increased training load, was favored over aggressive rapid weight loss (RWL). Although both GWL and short term RWL can achieve target weigh in mass, RWL was associated with acute hypohydration at competition time, elevations in muscle damage/catabolic biomarkers, increased renal strain (with isolated reports of acute kidney injury), and adverse psychological effects (e.g., mood disturbance, cognitive impairment risk) in limited evidence. These findings support prioritizing structured GWL across the preparation period and minimizing the magnitude and duration of RWL when required.

Injury incidence among soccer referees

Antonio Brusini, Simone Tersigni, Benedetta Papotti — Tue, 18 Nov 2025 00:00:00 +0100

Background: The scientific interest in the match performances of soccer referees has grown substantially over the past two decades. Referees need to maintain good physical performance to reduce injuries. So, this study aims to identify the injury rates in soccer referees. Methods: A search was conducted on the main international databases (PubMed, Scopus, Web of Science). Amateur and professional levels are both considered. Reviews, no English language studies, and studies that did not investigate only referees are not considered. Results: The search produced 380 results, 167 after removing duplicate results. In the end, 11 studies are selected. The match injury incidence ranges from 0.7 to 19.6 per 1000 hours; the training injury incidence ranges from 0.3 to 4.6 per 1000 hours. Conclusions: Monitoring injury incidence in referees is crucial, particularly in short-time competitions, which exhibit a notably high incidence.