The present study aimed to quantify changes in spinal kinematics during Nordic walking compared to regular walking for 60 seconds on a training path among physically fit young males (n = 20, aged 19–22 years). Two walking speeds were analyzed: 3 km/h and 5 km/h. The experimental setup was designed to assess spinal angular rotations using five kinematic parameters: upper spine, lower spine, thoracic region, lumbar region, and pelvis. The data is acquired from 9 compact inertial sensors and the following motion analysis is carried out using 3D MioMotion IMU sensor’s analysis system. The differences in the obtained cyclic biomechanical parameters are detetcted using functional ANOVA (fANOVA) statistical tests. The key finding of the study is that Nordic walking significantly alters the angular kinematic pattern of spinal movement by revealed significant differences in all five measured parameters when compared to normal walking. Notably, the most pronounced changes were observed in the upper spine and pelvis motion. Additionally, the influence of Nordic walking on the two phases of the gait cycle, the stance and swing phases, was evaluated: i) significantly increased the duration of the stance phase in all three planes of motion; ii) significantly increased the velocity during the stance phase across all three planes. These reported findings highlight the biomechanical, preventive, therapeutic, and rehabilitative potential of Nordic walking.

This study examined which technical-tactical indicators are associated with match outcomes in the Bulgarian First Professional Football League. Match-level Wyscout data were analysed for 829 fixtures across three seasons (2022/23–2024/25), with each fixture contributing a single record and indicators expressed as home-minus-away differences per 90 minutes. An ordinal proportional-odds logistic regression predicted the ordered match outcome (loss < draw < win), controlling for opponent strength, corroborated by a Random Forest classifier with permutation importance and SHAP attribution and by a structural equation model with a latent progression construct. A process-only regression was significant (McFadden pseudo-R² = 0.264): penalty-area entries via runs (OR = 1.75), counterattacks (OR = 1.63), interceptions (OR = 1.35), and deep completed passes (OR = 1.30) were positively associated with favourable outcomes, whereas penalty-area entries via crosses (OR = 0.50) and, after adjustment, ball possession (OR = 0.70) were negatively associated; all three corroborating methods converged on this pattern. Adding outcome-proximal indicators (expected goals, shots on target) improved fit (pseudo-R² = 0.354) but reflected outcome proximity rather than antecedent prediction. Match outcomes here are associated with how teams enter the penalty area—carried entries and transitions rather than crosses—rather than with possession dominance, extending the possession paradox in a less-resourced national competition and offering a transferable analytical template for under-studied leagues.

Background: The lower-limb neuromuscular profile of football match officials remains poorly characterised, and inter-limb asymmetry and the eccentric utilisation ratio (EUR) have not been examined in this population. The objective was to characterise jump-derived neuromuscular performance in male professional referees and to test the hypotheses that referees outperform assistant referees and that asymmetry prevalence is independent of competitive level. Methods: In this retrospective cross-sectional study, 125 male Bulgarian First and Second League officials (33.4 ± 6.1 years) completed squat jump (SJ), countermovement jump (CMJ), and unilateral CMJ testing with an optical system. Two-way analyses of covariance (Type III) were adjusted for age and body mass, with Hedges’ g effect sizes. Results: Trial-to-trial reliability was excellent after exclusion of five technically failed trials (ICC = 0.92–0.95). Referees outperformed assistant referees in SJ (g = 0.68), CMJ (g = 0.70), and estimated relative peak power (g = 0.70; all Holm-adjusted p = 0.001). First League officials were older (36.5 vs. 30.5 years), and no league effect remained after adjustment (p ≥ 0.50). Median asymmetry was 8.5%; 46.8% of officials exceeded 10%, independent of league and role. Mean EUR was 1.01 ± 0.06. Conclusions: Officiating role, rather than competitive level, was associated with lower-limb explosive performance. Asymmetry and EUR values warrant longitudinal investigation.

Muscle strength and bilateral asymmetry of the lower limbs are relevant to injury risk and performance in football, yet their age-related development in adolescent players outside elite Western European cohorts is insufficiently described. This study determined age-related differences in lower-limb strength and muscular balance in Bulgarian male football players. A total of 122 players aged 13 to over 19 years from three clubs were assessed at the end of the competitive season. Maximal concentric knee extension and flexion peak force of both legs was measured at 60°/s using a system with electronically controlled resistance (Kineo); relative strength (force per body mass) was used for the main between-age comparisons to control for growth. Age differences were analysed with ANOVA and Tukey tests (extension) and Kruskal–Wallis with DSCF comparisons (flexion) across seven age groups. Relative strength differed significantly with age (extension η²_p = 0.28–0.36; flexion ε² = 0.43–0.49), rising most up to 16 years and then plateauing. The concentric H/Q balance index ranged from 0.48 to 0.62. The findings provide a descriptive developmental profile relevant to individualised strength programming in youth football.

Muscle strength and bilateral asymmetry of the lower limbs are central determinants of injury risk and performance in football, yet their age-related development in adolescent players outside elite Western European cohorts remains insufficiently described. This study determined age-related differences in lower-limb muscle strength and muscular balance in Bulgarian male football players. A total of 122 players aged 13 to over 19 years from three clubs were assessed at the end of the competitive season. Maximal concentric knee extension and flexion strength of both legs were measured at 60°/s using a system with electronically controlled resistance (Kineo). Relative strength, bilateral asymmetry, hamstring-to-quadriceps (H/Q) ratios and a knee muscle balance index were calculated. Age differences were analysed using one-way ANOVA with Tukey post-hoc tests (extension) and the Kruskal–Wallis test with DSCF comparisons (flexion). Strength increased by 132–149% in extension and 186–191% in flexion, with the largest gains at 13–14 years and a second peak around 16 years; the effect of age was large (η²p = 0.59–0.61; ε² = 0.58). The balance index ranged from 0.48 to 0.62. These findings have direct implications for individualised strength and injury-prevention programming in youth football.

The 400 m hurdle race is a challenging event that combines speed, endurance, and technique. To clear the 10 hurdles, athletes must have high speed, a stable rhythm, effective technique, and endurance. Success requires striking a balance between speed and energy control. The race distance has four parts: the first 100 m is a fast start; the second 100 m focuses on high speed and smooth hurdling while conserving energy; the third 100 m brings fatigue, but runners must maintain rhythm (top hurdlers excel here); and the final 100 m, or “home stretch,” is when athletes push through fatigue, adjusting strides to maximise effort and reach the finish line despite lactic acid buildup. Based on the above specifics, we aim to analyse running patterns in the 400 m hurdles for elite male athletes. We studied 80 athletes from 24 nations, all of whom are participants in the Olympic Games in Paris 2024. For the study, we analysed the lap and split times for clearing each hurdle and different parts of the race using the official time data provided by the Olympic Committee. Various statistical methods were employed for data processing, including descriptive statistics and correlation analysis. The outcomes present different race models applicable to elite hurdlers. The respondents' sports performance results range from 46,46 seconds to 51.02 seconds, with an average of 48,87 seconds. The fastest hurdle splits are generally found between the second and fifth hurdles. Based on lap times, fatigue influences the sports results after the seventh or eighth hurdle. This conclusion applies solely to elite hurdlers. Different parts of the race correlate variably with sports results, revealing different race models. We also found that, based on the sports results, there are different race models.