Search Results (366)

Background: Concentric knee and trunk strength may contribute differently to maximal force and stretch-shortening cycle performance in youth sailors. This study evaluated the predictive value of concentric knee and trunk isokinetic strength for these outcomes in highly trained youth Optimist sailors. Methods: Forty highly trained Optimist sailors (20 boys and 20 girls; age, 13.03 ± 1.40 years) completed knee and trunk isokinetic testing at 60°·s⁻¹ and 180°·s⁻¹, isometric mid-thigh pull, squat jump, and countermovement jump tests. Velocity-specific multiple linear regression models included a composite of dominant and nondominant knee extensor and flexor strength, trunk extensor strength, trunk flexor strength, and sex. Results: The models explained 60.7% and 49.4% of the variance in isometric mid-thigh pull peak force at 60°·s⁻¹ and 180°·s⁻¹, respectively. The knee strength composite was independently associated with peak force at both velocities (β = 0.51, p = 0.003; β = 0.56, p = 0.006). The models explained 1.3–3.5% of dynamic strength index variance and 17.8% and 4.5% of eccentric utilization ratio and elastic index variance at 60°·s⁻¹ and 180°·s⁻¹, respectively. Trunk flexor strength was associated with eccentric utilization ratio and elastic index at 60°·s⁻¹ (β = 0.52, p = 0.029), although these outcomes are mathematically dependent. Sex was not associated with any outcome. Conclusions: Concentric isokinetic strength showed greater predictive value for maximal force than for stretch-shortening cycle performance. Combined knee extensor and flexor strength was consistently associated with maximal force, whereas limited variance was explained in stretch-shortening cycle outcomes. Full article

Background: Paired-set (PS) resistance exercise is widely used to increase training density; however, evidence-based guidance remains limited due to heterogeneous exercise sequences and rest configurations. This systematic review aimed to synthesize acute mechanical, training-efficiency, and perceptual responses across distinct PS configurations compared with traditional sets (TSs) in young resistance-trained adults. Methods: Eight databases were searched through 5 August 2026, for acute randomized crossover/parallel trials. PS protocols were categorized into PS-A (alternating exercises with preserved TS rest after each exercise), PS-B (interleaved exercises during recovery), and PS-C (modified post-pair rest). Study-level means and unstandardized percentage differences for volume load (VL), completed repetitions, training efficiency (VL accumulated per unit of time), and rating of perceived exertion (RPE) were synthesized descriptively. Results: Fifteen reports representing 14 studies (223 participants) were included, and all exhibited “some concerns” according to RoB 2. PS-A consistently elicited higher work-output point estimates (VL: 7.9–27.2%; repetitions: 6.3–26.7% vs. TS) with negligible changes in session duration. PS-B consistently reduced session duration by 44.8–50.0%, though repetitions and VL were often compromised depending on the exercise. PS-C responses were configuration-dependent; matched post-pair rest (PS-C_MPR) decreased duration (39.7–46.9%) with variable VL (−8.2% to +30.1%) and higher RPE, whereas extended rest (PS-C_EPR) showed distinct protocol-specific trade-offs between volume retention and training efficiency. Conclusions: Based on acute trials in young trained populations, PS configurations should be selected by session priority (PS-A for work capacity, PS-B for time constraints, PS-C for versatility). Given the consistent “some concerns” regarding risk of bias, these practical recommendations warrant caution. Full article

Background and Objectives: Low-volume plyometric conditioning may elicit post-activation performance enhancement (PAPE), but the early response to pogo-jump exercise in adolescent basketball players remains uncertain. This randomized crossover pilot study estimated the effect of adding 24 bilateral pogo jumps to a standardized warm-up on countermovement-jump (CMJ) and drop-jump (DJ) height, compared with time-matched low-intensity walking. Methods: Twenty-seven male basketball players were recruited, and 21 (age, 16.55 ± 0.88 years) completed both conditions. In randomized order, separated by a 7-day washout, participants performed 3 sets of 8 bilateral pogo jumps with 1 min between sets or approximately 3 min of low-intensity walking. Post-condition jump assessments began after a 1 min recovery and comprised three consecutive CMJs, a 30 s transition, and three consecutive DJs, with all measurements completed within approximately 2 min after each condition. The highest valid trial was retained for each jump type. Period-adjusted treatment effects were estimated using separate linear mixed-effects models, with repeated-measures ANOVA and Wilcoxon analyses retained as sensitivity analyses. Results: The period-adjusted between-condition difference in change was −0.89 cm for CMJ (95% CI, −2.92 to 1.14; p = 0.389) and 0.34 cm for DJ (95% CI, −1.77 to 2.45; p = 0.753). Sensitivity analyses yielded the same overall interpretation. All completers performed the protocol, and perceived exertion was 11.4 ± 1.2. The pogo-jump protocol showed favorable immediate tolerability, with all completers reporting 0/10 anterior-knee pain immediately after the condition. Conclusions: The pilot estimates did not indicate a detectable group-level improvement in CMJ or DJ height during the early post-conditioning assessment. However, the confidence intervals were compatible with potentially meaningful effects in either direction. The small sample, single dose, single early assessment window, and variable DJ reliability limit the precision and generalizability of the findings. Full article

Background and Aim: The identification of factors that optimize competitive performance is a primary focus for athletes and coaches in any sport, particularly variables that are modifiable through tailored nutritional and training strategies. Since data regarding volleyball remain scarce, this investigation aimed to explore the association between the baseline preseason anthropometry, body composition, and dietary habits of elite adult male volleyball players and the key performance indicators (KPIs) retrieved as match-by-match data during an official tournament. Methods: Nineteen elite male volleyball players (mean age: 23.79 ± 5.72 years; BMI: 23.88 ± 1.97 kg/m²) underwent comprehensive assessments. Anthropometric data and muscle strength (MS) were evaluated via body circumferences and handgrip dynamometry, respectively. Body composition was analyzed using bioelectrical impedance vector analysis (BIVA), while Mediterranean diet adherence was assessed with the validated Mediterranean diet adherence score (MEDAS) questionnaire, all measured cross-sectionally at one time point, identified as the baseline preseason phase of the competitive season. The tournament KPIs included serving, attack, and reception efficiencies, and block points per set were retrieved longitudinally during each match of the competitive season. Data were analyzed utilizing correlation and linear mixed-model regressions. Results: Right-hand MS correlated positively with higher MEDAS scores (ρ = 0.488, p < 0.05). Furthermore, both right-hand MS (β = 1.005, 95% CI [0.178, 1.831], p = 0.026) and thigh circumference (β = 3.030, 95% CI [0.083, 5.977], p = 0.046) were found to be positively associated with higher serving efficiency (adjusted R²_m ≈ 0.12). Conclusions: Monitoring muscle strength and thigh circumference alongside targeted nutritional and training strategies may be considered in elite male volleyball, as these factors were associated with serving efficiency. However, due to the observational nature of the research, our findings require replication in larger, multicenter intervention studies. Full article

Background: Achilles tendon viscoelasticity and ankle neuromuscular co-contraction are functionally linked, yet how they jointly adapt during brief high-speed repetitive loading remains unclear. We simultaneously quantified Achilles tendon viscoelasticity (MyotonPRO) and ankle agonist–antagonist co-contraction (surface electromyography, sEMG) under two stance conditions and three repetition counts. Methods: Twenty-seven active male collegiate American football players (23.19 ± 2.63 years) performed rapid heel-raise/landing cycles in a bilateral ground stance (BGS) and a unilateral box stance (UBS) at 1, 5, and 10 repetitions. Tendon decrement (D), stiffness (S), and tone (F), the co-activation index (CoAct), and the co-contraction index (CCI) were analyzed using two-way (2 × 3) repeated-measures ANOVA. Results: D decreased significantly as repetitions increased (pooled across stance conditions: 1 rep 0.973 → 10 reps 0.937; F (2, 52) = 4.68, p = 0.014, ηp² = 0.153), indicating improved elastic-recovery efficiency, whereas S and F remained stable. CoAct was maintained constantly at ≈72% regardless of stance or repetition (all p > 0.05), and the medial gastrocnemius was consistently activated first (agonist-led feedforward priming). Tissue-level elastic adaptation thus occurred without a concurrent change in neuromuscular co-contraction—a tissue–neural dissociation confirmed in both change scores and correlation structure. Conclusions: Acute enhancement of Achilles tendon elasticity during high-speed repetition appears to be a peripheral, tissue-level mechanical phenomenon expressed independently of neuromuscular co-contraction. Combined myotonometric–sEMG assessment reveals functional information not captured by imaging alone. Full article

Background and Objectives: Upper-extremity strength is considered an important contributor to badminton stroke performance; however, the independent contributions of specific muscle groups to shuttlecock velocity in young players remain unclear. This study investigated the associations between segmental upper-extremity isometric strength and shuttlecock velocity in young badminton players. Methods: Twenty-four competitive U11 badminton players (12 males and 12 females; mean age, 10 years) participated in this cross-sectional study. Handgrip and segmental upper-extremity isometric strength (elbow, shoulder, and wrist muscle groups) were assessed using dynamometry. Shuttlecock velocity during a badminton smash was measured using a radar gun. Results: Shuttlecock velocity was positively correlated with all measured upper-extremity strength variables (r = 0.408–0.704, all p < 0.05). After adjustment for sex and upper-limb length, only shoulder extension (r = 0.529, p = 0.011), shoulder flexion (r = 0.557, p = 0.007), shoulder external rotation (r = 0.430, p = 0.046), and shoulder internal rotation strength (r = 0.495, p = 0.019) remained significantly associated with shuttlecock velocity. Multiple regression analyses confirmed these shoulder-specific strength measures as independent predictors of shuttlecock velocity (β = 0.343–0.468, all p < 0.05), explaining 57.2–63.8% of the adjusted variance. Conclusions: Although shuttlecock velocity was initially associated with all upper-extremity strength measures, only shoulder-specific strength remained associated with performance after adjustment for sex and upper-limb length. These exploratory findings suggest that shoulder strength may represent a relevant physical correlate of badminton smash performance in young athletes; however, confirmation in larger, adequately powered studies is required. Full article

Background: Small-sided games (SSGs) are widely used in soccer training to develop physical, physiological, and technical–tactical capacities under game-representative conditions. Although task constraints have been investigated individually, evidence integrating their effects across major categories remains limited. This systematic review synthesized the effects of six task-constraint domains on SSG demands in association football. Methods: Following PRISMA 2020 guidelines, systematic searches were conducted in PubMed, SPORTDiscus, Web of Science, and Scopus. Forty studies published between 2015 and 2025 met the eligibility criteria and were categorized into six task-constraint domains: pitch size or area per player (n = 13), player number (n = 8), goalkeeper inclusion (n = 6), goal type (n = 5), numerical imbalance and floater players (n = 8), and transition games (n = 6). The review protocol was prospectively registered in PROSPERO. Results: Larger pitch areas consistently increased high-speed running but were insufficient to reproduce match-level sprint demands. Goalkeeper exclusion increased physiological intensity, particularly in smaller formats, whereas mini-goals reduced external locomotor load while maintaining comparable internal responses. Numerical disadvantage increased sprinting and high-intensity running demands for outnumbered players, while floaters experienced substantially lower physical loads than regular players. Transition games elicited the greatest locomotor demands, exceeding match values for high-speed running and sprinting across several playing positions. Conclusions: No single SSG format adequately addresses all match-relevant physical demands. Accordingly, practitioners should systematically manipulate and combine task constraints in accordance with specific training objectives. These findings provide evidence-informed guidance for optimizing SSG design to elicit targeted physical, physiological, and technical–tactical adaptations. Full article

Background: The aim was to investigate the stride-by-stride development of spatiotemporal parameters, joint kinematics, kinetics, and electromyographic (EMG) activity during a 50 m sprint, providing a comprehensive analysis of the biomechanical and neuromuscular changes throughout the entire sprint. Methods: Fifteen male sprinters (age 20.5 ± 1.3 years, body mass 66.8 ± 4.5 kg, body height 1.74 ± 0.06 m, 100 m personal best: 11.24 ± 0.34 s) performed a 50 m sprint, while the spatiotemporal parameters, joint kinematics, kinetics, and EMG activity of nine muscles were measured. Results: The main findings were that the 50 m sprint could be divided into three phases: initial acceleration, transition and maximal velocity and involve tightly coordinated changes across multiple biomechanical domains. The initial acceleration (the first 3–5 strides) was dominated by rapid increases in stride frequency, rapid changes in joint angles, and rising EMG activity in key muscles. In the transition phase (up to ~30–35 m), continued increases in stride length, decreasing contact time, and stabilization of kinematics and EMG activity were the main characteristics. In the maximal-velocity phase, a plateau in velocity, increased flight time, greater reliance on vertical force (an increase in vertical force relative to the horizontal forces), and stabilized neuromuscular patterns were observed. Conclusion: The phased progression supports contemporary biomechanical models of sprinting and emphasizes the importance of both mechanical and neuromuscular efficiency in achieving optimal sprint performance. Full article

Background and Objectives: Running-related musculoskeletal injuries remain highly prevalent among recreational runners, and the absence of population-specific biomechanical reference values limits clinical and sports interpretation in Latin American populations. This study aimed to establish reference values for spatiotemporal and selected running kinematic/mechanical values (initial contact angle, vertical leg stiffness, and vertical oscillation) in healthy adult recreational runners from Barranquilla (Colombia) using three-dimensional motion capture. Methods: A cross-sectional observational study was conducted in 25 healthy adults (13 men, 12 women; mean age 32.7 ± 7.4 years, range 20–47 years). Running biomechanics were assessed using a BTS SMART-DX three-dimensional motion capture system and a Modified Helen Hayes marker model with 30 reflective markers. Participants completed treadmill running trials at 7, 9, 11, and 13 km/h. Key spatiotemporal parameters and global kinematic/mechanical metrics were processed using BTS Smart Clinic software. Reference values were defined using the 10th and 90th percentiles, stratified by sex and running speed, and accompanied by bootstrap 95% confidence intervals. Effects of sex and speed were tested by two-way ANOVA with partial eta squared and Holm-adjusted p values, with a linear mixed-effects model as a robustness check. Results: Motorized treadmill-specific biomechanical reference values (10th and 90th percentiles) were established and stratified strictly by running speed (7, 9, 11, and 13 km/h) and sex. Under the primary linear mixed-effects model, running speed significantly affected all ten evaluated biomechanical variables (all adjusted p < 0.001), including initial contact angle and vertical oscillation, confirming that speed-disaggregated estimates are mandatory for clinical interpretation. Conversely, sex effects were robust to multiplicity adjustment only for flight time and vertical leg stiffness. Compared with a European reference cohort, and after adjustment for sex, age, stature, body mass and speed through the published reference equations, this cohort showed a 6.6% shorter flight time, a 19.0% lower vertical oscillation, a 3.8% shorter stride length, and a 3.1% higher cadence. Conclusions: This study provides the preliminary regional reference database for running spatiotemporal and selected kinematic parameters in a cohort of healthy adult recreational runners from Barranquilla (Colombia). These preliminary values provide a baseline restricted to motorized treadmill running at fixed speeds; while they support standardized treadmill screening and rehabilitation tracking, their direct applicability to overground or self-paced running remains limited and warrants caution. Full article

Background: Subjective autoregulation methods are gaining interest among resistance-trained athletes. In particular, velocity perception (PV) and velocity loss perception (PVL) have shown promising practical applicability. This study aimed to investigate the temporal stability of PV and PVL across an eight-week period. Methods: Fifteen participants, after sessions of familiarization with PV and PVL, completed three test sessions: the first 48 h after the familiarization, and the others 4 and 8 weeks later. Each test session included five sets of back squats with light (55%–60%–65% 1RM) and heavy (75%–85% 1RM) loads. Light loads were executed with a 10–20–30%VL, while heavy loads with a 10–20%VL. PV accuracy was assessed using the |DeltaScore|, defined as the absolute difference between perceived velocity (Vp) and the velocity provided by the encoder (Vr): |DeltaScore| = |Vp − Vr|. PVL was measured by the |Vscore|, defined as the absolute difference between the number of repetitions perceived as correct relative to the target %VL (Np) and the repetitions that actually met it (Nr): |Vscore| = |Np − Nr|. Results: The results demonstrated that both PV and PVL are stable after 4 weeks at all loads and %VL (p > 0.05). In contrast, after 8 weeks, PV accuracy significantly decreased at all loads (p < 0.05; η²p = 0.04), whereas PVL accuracy decreased only at light loads (p < 0.05; η²p = 0.18). Moreover, PV error values remained below the previously suggested acceptability threshold of 0.09 m·s⁻¹ for up to 4 weeks. This error threshold corresponds to a load variation of ~10% 1RM in the back squat. Conclusions: The present results support the applicability of PV and PVL in real training contexts for a maximum of 4 weeks when monitoring devices are unavailable. Full article

Objectives: The main purpose of this exploratory study was to examine differences between high-performing (HP) and low-performing (LP) female taekwondo athletes in body composition, lower extremities power, and knee extension/flexion isokinetic torque. A secondary aim was to explore how body composition, torque, and power relate to performance in the multiple frequency speed of kick test (FSKT_MULT). Methods: Twenty-six female taekwondo athletes (age: 18.0 ± 2.8 years; body mass: 58.1 ± 9.9 kg; height: 166.0 ± 0.05 cm) participated in the study. Athletes were classified as high performers (HP) or low performers (LP) based on their total score in the FSKT_MULT. Measurements included body composition assessed with dual-energy X-ray absorptiometry, countermovement jump (CMJ), standing long jump (LJ), and isokinetic knee extension and flexion at 60°/s and 240°/s. Results: High performers completed significantly more kicks during the first FSKT_MULT set than low performers (19.8 ± 1.1 vs. 18.0 ± 0.9 kicks; p = 0.001). They also showed higher trunk lean mass (p = 0.038), greater total lean mass (p = 0.036), and better standing long jump performance (p = 0.016). Mean and peak knee-flexion torque at 60°/s were higher in HP compared to LP. When all athletes were analyzed as one group, moderate-to-large correlations were observed between FSKT_MULT performance and body composition, as well as knee extension and flexion torque at both 60°/s and 240°/s. Conclusions: These findings indicate that high-performing female taekwondo athletes are stronger and generate greater power than low performers. Lean mass and knee extension and flexion torque showed moderate associations with FSKT_MULT performance. Full article

Background: While the biomechanical, physiological, and nutritional determinants of table tennis (TT) performance have already been summarized, a dedicated synthesis of players’ anthropometric and motor characteristics is still lacking. This review aimed to synthesize current evidence across different ages, genders, and competitive levels. Methods: BASE, PubMed, ScienceDirect, Scopus, Semantic Scholar, and Web of Science databases were searched for study selection. Cross-sectional studies investigating the anthropometric and motor characteristics of healthy TT players aged 7–40 years were considered eligible. Results: Thirty-one studies were included. Eighteen studies focused on motor characteristics, seven on anthropometric traits, and six examined both. Conclusions: Adult male TT players predominantly exhibit an endomorph–ectomorph profile with greater lean mass, whereas females show an endomorph–ectomorph somatotype. Moreover, higher-ranked athletes generally display greater lean mass. Compared to specific strength-based sports athletes, TT players tend to have lower limb circumferences and lower lean and muscle mass, while showing higher body fat than specific speed- and agility-based sports. Higher-level players tend to demonstrate faster reaction and movement times, as well as superior change-of-direction abilities. Compared to other racket sports, they tend to exhibit superior coincidence-anticipation timing under high stimulus velocities and distinctive motor coordination. In terms of strength, TT players show proficiency in horizontal jumps and dynamic back strength, despite lower vertical explosive power. The identified characteristics provide a descriptive profile of table tennis players and may inform future longitudinal research investigating their potential relevance for talent identification and development. Full article

Background and Objectives: Sports performance is influenced by a variety of perceptual, cognitive, and motor factors. A better understanding of these factors can help coaches optimize training and improve athletic performance. The present study examined the acute effects of internal, external, and holistic attentional focus instructions on javelin-throwing performance under different visual conditions in novice performers. Methods: Twenty-four university students (12 females and 12 males; mean age: 21.50 ± 1.47 years) with no prior javelin-throwing experience completed 30 throws under six experimental conditions (5 throws per condition) based on three attentional focus instructions (internal, external, and holistic) and two visual conditions (vision-present and vision-absent) using a within-subject repeated-measures design. Throwing distance was measured as the primary performance outcome. Results: The results revealed significant main effects of both vision (F_{(1, 23)} = 14.49, p = 0.001, ηp² = 0.38) and attentional focus (F_{(2, 46)} = 5.73, p = 0.006, ηp² = 0.20). Overall throwing performance was superior when visual information was available compared to when vision was occluded (p = 0.001). In addition, both external and holistic focus conditions produced significantly greater throwing distances than the internal focus condition (p = 0.03; p = 0.04, respectively), with no significant differences observed between external and holistic focus (p > 0.05). No significant interaction was found between attentional focus and vision (F(_{2, 46}) = 0.74, p = 0.48, ηp² = 0.03), indicating that the effect of attentional focus did not significantly differ between the visual conditions. Conclusions: The present findings extend the attentional focus literature to a complex, whole-body ballistic skill, demonstrating that the adoption of external and holistic attentional focus instructions resulted in greater throwing distances than the internal focus condition in novice javelin throwers. Full article

Background and Objectives: The aim was to investigate the external load of different types of floaters and regular players in small-sided games (SSG) with different relative pitch sizes to inform the return-to-play process. Methods: Twenty-four professional soccer players from a Greek top-tier soccer club played SSG as regular players, internal floaters, and external floaters. Global-positioning units were utilized to investigate total distance (TD), as well as high-intensity running distances (HID), which was further divided into HID1 (15.0–19.9 km/h and HID2 (20.0–24.9 km/h). High-intensity running (HIR) was analyzed by distance and number of efforts (HIRnb) greater than 19.8 km/h. Velocity zones were categorized into zones such as 10.8–14.4 km/h (Zone3), 14.5–19.8 km/h (Zone4), 19.9–24.9 km/h (Zone5), >25 km/h (Zone6). Sprint metrics included number of sprints (Sprint/Nm) and sprint distance (Sprint/Dist). Acceleration bands were defined as high >4 m/s² (ACC4), moderate 3–3.9 m/s² (ACC3), and low 0–2.9 m/s² (ACC2); and decelerations were defined as high <−4 m/s² (DEC4), moderate −3.9–3 m/s² (DEC3), and low −2.9–0 (DEC2 m/s²). All data were reported as relative value (standardized over a 1 min playing period). Results: Regular players showed the highest value, followed by internal floaters and external floaters for all variables, except for Zone5 distance. The majority of variables differed significantly between the regular players and the internal floaters except for TD, distance in Zone3 and Zone6, and number of ACC3, ACC4, and DEC4. ACC4 was the only variable found to be not significantly different between the regular players and the external floaters. In games with both floater types, internal floaters showed significantly higher values in all variables except for HIR, Zone6 distance, Sprint/Dist, Sprint/Nm, ACC3, ACC4, and DEC4. The comparison of external load variables between internal and external floaters when each player type was playing against regular players only revealed significantly higher values for all variables except for Sprint/Dist, Sprint/Nm, Zone6 distance, ACC3, and ACC4 for the internal floaters. Regression analyses were provided for all player types in the appropriated game format (RP with IF, RP with EF, RP with IF and EF). Conclusions: The on-field return-to-play process for individual players in the final stages incorporating SSG with different relative pitch sizes benefits from the utilization of different types of floaters. Increasing external load is ensured through starting with external floaters followed by internal floaters easing into the final role, the regular player role. Full article

Background: Primitive reflex (PR) assessments based on the Institute for Neuro-Physiological Psychology (INPP) framework are increasingly used in developmental and athletic populations. However, the reproducibility of these observer-based assessments remains insufficiently documented. This study investigated the intra- and inter-rater reliability of subjective PR assessments and examined the potential influence of evaluator expertise in elite youth football athletes. Methods: Sixty-nine male youth football players from an elite academy (age: 18 ± 2 years) participated in this study. PR assessments included the Moro reflex, asymmetrical tonic neck reflex, symmetrical tonic neck reflex, and tonic labyrinthine reflex, evaluated using standardized INPP procedures (0–4 ordinal scoring scale). Intra-rater reliability was assessed by an experienced examiner across three testing sessions performed over six months. Inter-rater reliability was evaluated using standardized video recordings independently scored by two novice raters. Relative reliability was assessed using intraclass correlation coefficients (ICCs) with corresponding 95% confidence intervals (95% CIs), while absolute reliability was quantified using the standard error of measurement (SEM) and the minimal detectable change at the 95% confidence level (MDC95). Results: Good to excellent intra-rater relative reliability (ICC = 0.86–0.98; 95% CI = [0.81–0.99]) was observed, with SEM values of 0.1–0.6 and MDC95 values of 0.3–1.7 points. Moderate to excellent video-based inter-rater reliability was found (ICC = 0.69–0.99; 95% CI [0.56–0.99]), with SEM values of 0.1–0.7 and MDC95 values of 0.3–2.0 points. Pairwise comparisons among raters showed moderate to excellent relative reliability (ICC = 0.57–0.99; 95% CI [0.35–0.99]), with SEM values of 0.1–0.5 and MDC95 values of 0.2–1.3 points. Conclusions: Subjective PR assessments performed using the INPP framework demonstrated good to excellent intra-rater relative reliability and moderate to excellent video-based inter-rater relative reliability, together with generally low absolute measurement error in elite youth football athletes. These findings provide preliminary psychometric support for the use of standardized PR assessments in research and applied sport settings. Full article