ECSS Paris 2023: OP-AP29
INTRODUCTION: The force–velocity (F-v) relationship provides a theoretical and practical model to describe the interaction between muscle force and contraction velocity, offering key insights into maximal strength (F₀), maximal velocity (V₀), and maximal power (Pmax). While this concept has been extensively validated in field tests such as jumps and sprints, its application to isokinetic dynamometry remains limited. Establishing valid and reliable F-v profiles from isokinetic testing could enhance the interpretation of neuromuscular function and support individualized rehabilitation and performance strategies. This study aimed to evaluate the validity and intra-session reliability of F-v profiles derived from isokinetic dynamometry METHODS: A prospective, cross-sectional, single-center study was conducted at the Orthosport Center (France) between June and August 2025. Twelve healthy, physically active male athletes (mean ± SD: 26.5 ± 3.8 years; 1.81 ± 0.06 m; 76.3 ± 5.9 kg) volunteered to participate. Inclusion criteria comprised a Tegner activity score ≥ 7, Marx Activity Rating Scale ≥ 12, and no history of lower-limb injury or surgery within six months. After a standardized warm-up (10 min cycling at 1.5 W/kg + 3 sets of bodyweight squats), participants underwent concentric isokinetic knee extension and flexion testing on a Humac Norm dynamometer (Athlex, France). Each leg was tested separately at five preset angular velocities (30°, 60°, 180°, 240°, 300°/s). For each velocity, three maximal trials were performed following a submaximal familiarization repetition. Participants were stabilized with straps at the trunk, pelvis, and thigh, ensuring alignment of the knee joint with the dynamometer axis. Torque–velocity data from the five test conditions were extracted and averaged per limb and muscle group. Individual linear regressions were computed (torque = f(velocity)) in Microsoft Excel to derive F₀ (y-intercept), V₀ (x-intercept = −slope/F₀), and Pmax = (F₀ × V₀)/4. The coefficient of determination (R²) was calculated to quantify model linearity. All analyses were performed separately for quadriceps and hamstrings. RESULTS: High linearity of the F-v relationship was observed (mean R² = 0.98 ± 0.02 for dominant quadriceps and 0.97 ± 0.01 for dominant hamstrings). Mean F₀, V₀, and Pmax for the quadriceps were 234.8 ± 31.8 N, 598.7 ± 102.9°/s, and 2418.7 ± 345.8 W, respectively. For the hamstrings, mean F₀ = 178.8 ± 37.9 N, V₀ = 861.7 ± 698.0°/s, and Pmax = 2351.7 ± 972.0 W. ICC values ranged from 0.79 to 0.98 for quadriceps and 0.74 to 0.98 for hamstrings. SEM% values were generally below 10%, and CV values remained acceptable (< 20%) across velocities. CONCLUSION: Isokinetic F-v profiling is a valid and reliable method for characterizing neuromuscular performance in healthy athletes. This approach bridges laboratory-based and field-based assessments by integrating mechanical variables into a single framework.
Read CV Ayrton MOIROUX--SAHRAOUIECSS Paris 2023: OP-AP29
INTRODUCTION: Despite the well-established importance of physical and dual-task neurocognitive demands in athletic performance, neurocognitive assessments for upper extremity performance remain limited. We aimed to develop tests that combine motor and cognitive tasks simultaneously to assess functional upper quadrant stability (UQS) in athletes and to determine their test–retest reliability. Furthermore, the effect of neurocognitive load on Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) performance and the association between the Neurocognitive Upper Quadrant Y Balance Test (NC-UQYBT) and the traditional Upper Quadrant Y Balance Test (UQYBT) were investigated. METHODS: Nineteen healthy male athletes (age: 19.8±0.4 years; body mass index: 24.9±0.6 kg/m²; dominant shoulder: right 100%; Kerlan–Jobe Shoulder and Elbow Score: 74.1±7.2; Tegner Activity Level: 8.8±0.1) participated in the study. Neurocognitive test protocols were developed based on the UQYBT and CKCUEST and integrated with standardized cognitive tasks targeting attention, reaction, and decision-making. The NC-UQYBT assessed bilateral reaction time (ms), while the Neurocognitive Closed Kinetic Chain Stability Test (NC-CKCUEST) measured reaction time (ms) and total touches. Test performance was evaluated under single-task and dual-task conditions. For reliability analysis, all participants completed the tests twice within a one-week interval. Neurocognitive load was calculated as the percentage change in performance between the single-task and dual-task performance. Pearson and Spearman correlation analysis was performed to examine the relationship between the NC-UQYBT and the UQYBT. RESULTS: For the NC-UQYBT, test–retest reliability was excellent for the dominant [(ICC = 0.91 (95% CI: 0.80–0.96; SEM: 30.46; MDC: 84.43)], and non-dominant sides [ICC = 0.96 (95% CI: 0.88–0.98; SEM: 24.41; MDC: 67.66)]. For the NC-CKCUEST, test–retest reliability was good for reaction time [ICC = 0.88 (95% CI: 0.71–0.95; SEM: 39.12; MDC: 108.43)], and touches [ICC = 0.75 (95% CI: 0.47–0.89; SEM: 0.93; MDC: 2.57)]. Neurocognitive load resulted in a 54.92 ± 1.75% reduction in CKCUEST performance. No significant correlations were found between the NC-UQYBT and UQYBT for either the dominant (r=-0.22, p=0.36) or non-dominant side (r=-0.26, p=0.27). CONCLUSION: The neurocognitive UQS Tests demonstrated good to excellent test–retest reliability in athletes, indicating that they are reliable tools for assessing upper extremity performance under combined motor and cognitive demands. The substantial reduction in performance under neurocognitive load highlights the importance of incorporating cognitive challenges into UQS assessments. However, the lack of correlation between the neurocognitive and traditional Y Balance Tests suggests that these assessments may capture distinct aspects of upper quadrant function. Therefore, the proposed neurocognitive test battery may be useful in clinical and sports settings for performance assessments.
Read CV CANSU AKKUŞECSS Paris 2023: OP-AP29
INTRODUCTION: Police activity demands complex and varied intellectual and strategic capabilities, beyond an equally crucial physical dimension, as officers perform a wide diversity of physically demanding actions, such as running, climbing up and down stairs, pulling, pushing, overcoming obstacles, and arresting suspects (1, 2, 3). Several authors argue(4) that the physical dimension gains even greater relevance regarding special police units. For this reason, it is fundamental to have suitable instruments that allow for a rigorous assessment of these professionals' operational competencies. To evaluate the reliability and validity of the Elite Police Occupational Circuit (EPOC), developed to simulate and assess the occupational physical fitness (PF) of the Intervention Corps (IC) officers of the Public Security Police (PSP). METHODS: Thirty-one (31) Elite Police Officers participated (34.48 ± 7.87 years old, Height = 1.76 ± 0.05 m, Weight = 80.55 ± 6.42 kg, BMI = 25.89 ± 1.35 kg/m², %BF = 13.59 ± 2.68). Participants performed the EPOC on two occasions, separated by a one-week interval, wearing full personal protective equipment (V-TOP). Heart rate, blood lactate, and rating of perceived exertion data were collected. Additionally, general PF tests (aerobic capacity, strength, power, agility, flexibility, muscular endurance) were performed to analyze the association with circuit performance. Test-retest reliability (ICC), correlations with biomotor abilities, and performance predictors via multiple linear regression were evaluated. RESULTS: The EPOC showed good reliability for the total execution time (ICC = 0.821) (5), although with variability in some specific tasks. Strong and significant correlations were found between total EPOC time and variables such as V̇O2max (r = -0.73, p < 0.01), T-Teste (r = 0.70; p <0.01), pull-ups (r = -0.68; p < 0.01), standing broad jump (r = -0.63; p < 0.01), handgrip strength (r = -0.63; p < 0.01), and standing medicine ball throw (r = -0.58; p < 0.01). The variables: standing and seated medicine ball throw, V̇O2max, handgrip strength, maximum bench press velocity, and sit-ups were identified as significant predictors of EPOC performance, explaining 82.2% of the variance in overall performance (R2a = 0.822; p <0.001). CONCLUSION: It is concluded that the EPOC is a reliable, valid, and functionally representative test of the demands of CI police activity, being useful in contexts of assessment, monitoring, and training prescription for officers of this subunit.
Read CV LUÍS MONTEIROECSS Paris 2023: OP-AP29