Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026Neuromuscular and Kinetic Adaptations to Symmetric and Asymmetric Load Carriage During Walking in Individuals with Chronic Low Back Pain
Tajik, Raheleh; Dhahbi, Wissem; Mimar, Raghad; Khaleghi Tazji, Mehdi; Ceylan, Halil İbrahim; Bayrakdaroğlu, Serdar; Stefanica, Valentina; Hammami, Nadhir
Aim: This study examined how load size and symmetry affect trunk muscle activation patterns, vertical ground reaction forces, and estimated lumbar spine compression during overground walking in individuals with chronic low back pain (CLBP) and those without symptoms. Methods: Thirty male participants (15 with CLBP, 15 controls; ages 23–28 years) performed walking tests under four load conditions: symmetric and asymmetric carriage at 10% and 20% of body weight. Bilateral surface electromyography measured activation from seven trunk muscles (rectus abdominis, external oblique, internal oblique, latissimus dorsi, lumbar erector spinae, multifidus) and the thoracolumbar fascia region, normalized to maximum voluntary isometric contractions (%MVIC). Force plates recorded vertical ground reaction forces synchronized with heel-strike events. A repeated-measures ANOVA with Bonferroni corrections was used to analyze the effects of load configuration and magnitude. Results: Asymmetric loading at 20% body weight caused significantly higher peak vertical ground reaction forces compared to symmetric loading (mean difference = 47.3 N, p < 0.001), with a significant interaction between load magnitude and configuration (p = 0.004, ηp2 = 0.26). Participants with CLBP showed consistently higher trunk muscle activation throughout the gait cycle (peak: 37% MVIC vs. 30% MVIC in controls; p < 0.001, d = 1.68), with maximum recruitment at shorter muscle lengths and 24% less activation at optimal length (95% CI: 18.2–29.8%). The lumbar erector spinae and multifidus muscles exhibited the highest activation during asymmetric 20% loading in CLBP participants (0.282 and 0.263%MVIC, respectively), indicating compensatory neuromuscular strategies. Conclusion: Asymmetric load carriage creates disproportionately high mechanical and neuromuscular demands, effects that are greatly amplified in individuals with CLBP. These findings support rehabilitation strategies that improve load distribution and restore motor control, thereby reducing compensatory strain and enhancing trunk stability.
- MakaleAçık Erişim2025Concurrent Validity of the Optojump Infrared Photocell System in Lower Limb Peak Power Assessment: Comparative Analysis with the Wingate Anaerobic Test and Sprint Performance
Khemiri, Aymen; Negra, Yassine; Ceylan, Halil İbrahim; Hajri, Manel; Njah, Abdelmonom; Hachana, Younes; Yıldız, Mevlüt; Bayrakdaroğlu, Serdar; Muntean, Raul Ioan; Attia, Ahmed
Aim: This study analyzed the concurrent validity of the Optojump infrared photocell system for estimating lower limb peak power by comparing it with the 15 s Wingate anaerobic test (WAnT) and examining relationships with sprint performance indicators. Methods: Twelve physically active university students (ten males, two females; age: 23.39 ± 1.47 years; body mass: 73.08 ± 9.19 kg; height: 173.67 ± 6.97 cm; BMI: 24.17 ± 1.48 kg·m−2) completed a cross-sectional validation protocol. Participants performed WAnT on a calibrated Monark ergometer (7.5% body weight for males, 5.5% for females), 30 s continuous jump tests using the Optojump system (Microgate, Italy), and 30 m sprint assessments with 10 m and 20 m split times. Peak power was expressed in absolute (W), relative (W·kg−1), and allometric (W·kg−0.67) terms. Results: Thirty-second continuous jump testing produced systematically higher peak power values across all metrics (p < 0.001). Mean differences indicated large effect sizes: relative power (Cohen’s d = 0.99; 18.263 ± 4.243 vs. 10.99 ± 1.58 W·kg−1), absolute power (d = 0.86; 1381.71 ± 393.44 vs. 807.28 ± 175.45 W), and allometric power (d = 0.79). Strong correlations emerged between protocols, with absolute power showing the strongest association (r = 0.842, p < 0.001). Linear regression analysis revealed that 30 s continuous jump-derived measurements explained 71% of the variance in Wingate outcomes (R2 = 0.710, p < 0.001). Sprint performance showed equivalent predictive capacity for both tests (Wingate: R2 = 0.66; 30 s continuous jump: R2 = 0.67). Conclusions: The Optojump infrared photocell system provides a valid and practical alternative to laboratory-based ergometry for assessing lower limb anaerobic power. While it systematically overestimates absolute values compared with the Wingate anaerobic test, its strong concurrent validity (r > 0.80), large effect sizes, and equivalent predictive ability for sprint performance (R2 = 0.66–0.71) confirm its reliability as a field-based assessment tool. These findings underscore the importance of sport-specific, weight-bearing assessment technologies in modern sports biomechanics, providing coaches, practitioners, and clinicians with a feasible method for monitoring performance, talent identification, and training optimization. The results further suggest that Optojump-based protocols can bridge the gap between laboratory precision and ecological validity, supporting both athletic performance enhancement and injury prevention strategies.
- MakaleAçık Erişim2025Casein Supplementation Timing and Exercise Performance in Soccer Players: Pre-Sleep vs. Post-Exercise Intake—A Randomized Controlled Trial
Bayrakdaroğlu, Serdar; Ateş, Zeynep Hazal; Ceylan, Halil İbrahim; Kul, Murat; Muntean, Raul Ioan; Dhahbi, Wissem
Background: Nutrient timing strategies may influence recovery and performance in athletes; however, the effects of ingesting casein protein before sleep versus immediately after exercise remain unclear. This study compared the acute effects of pre-sleep and post-exercise ingestion of casein on high-intensity anaerobic performance in highly trained soccer players. Methods: Twenty-four highly trained male soccer players (mean age: 20.6 ± 1.8 years) were randomly assigned to three groups: post-exercise casein ingestion group (PECIG; n = 8), pre-sleep casein ingestion group (PSCIG; n = 8), and control group (CG; n = 8). Following a standardized high-intensity resistance training protocol, participants consumed 30 g of micellar casein dissolved in 300 mL of water either immediately after exercise or 30–60 min before bedtime. Performance was assessed using the Countermovement Jump (CMJ), the Illinois Agility Test (IAT), and the Running-based Anaerobic Sprint Test (RAST), which were conducted both before and 24 h after the training session. Results: Repeated-measures ANOVA revealed significant group-by-time effects for CMJ (F = 8.21, p = 0.002, η2p = 0.36) and RAST performance variables, including peak power (F = 6.94, p = 0.003, η2p = 0.32), mean power (F = 7.42, p = 0.002, η2p = 0.34), and fatigue index (F = 5.87, p = 0.008, η2p = 0.28). Post hoc analyses showed that PSCIG significantly improved CMJ (Δ = +1.45 cm; p < 0.001, d = 2.04) and RAST mean power (Δ = +125.14 W; p = 0.002, d = 1.55) compared with the control condition. PECIG significantly enhanced RAST peak power (Δ = +205.79 W; p = 0.001, d = 1.64), mean power (Δ = +128.43 W; p = 0.013, d = 1.24), and fatigue index (Δ = +4.12 W/s; p = 0.010, d = 1.29) relative to CG. No performance differences were observed between PSCIG and PECIG timing conditions (all p > 0.05). Conclusions: Both pre-sleep and post-exercise casein ingestion enhanced anaerobic performance in highly trained soccer players, with each timing method favoring different performance outcomes. However, neither strategy demonstrated superiority over the other, suggesting that casein timing may be flexibly applied according to athletes’ preferences and training contexts.
- MakaleAçık Erişim2024Exploring the associations between ankle dorsal and plantar flexion strength, reactive strength index, and balance in elite youth soccer players
Kayhan, Recep Fatih; Terzi, Esranur; Bayrakdaroğlu, Serdar; Ceylan, Halil İbrahim; Morgans, Ryland; Nikolaidis, Pantelis T.
Background: Enhanced muscular strength has been widely acknowledged as a fundamental determinant of improved performance in the lower extremities. However, the specific impact of ankle strength on explosive strength and balance remains inadequately elucidated. Consequently, this study aims to (a) evaluate balance, reactive power, and flexor–extensor muscle balances in soccer players, and (b) evaluate ankle dorsal and plantar flexion muscle strength as predictive factors for reactive strength index and balance performance. Methodology: A cohort comprising 38 actively engaged Turkish National League soccer players participated in the study. The assessment encompassed explosive power through a drop jump, dynamic balance utilizing a moving disc, and ankle strength measured with a handheld dynamometer. Results: The findings revealed that dominant lower limb dorsal flexion strength emerged as a significant predictor of both reactive strength (R2 = 0.106, p < 0.05) and balance (R2 = 0.121, p < 0.05). Similarly, non-dominant lower limb dorsal flexion strength was identified as a significant predictor of reactive strength (R2 = 0.362, p < 0.05). Furthermore, the study established that dominant lower limb plantar flexion strength significantly predicted balance (R2 = 0.121, p < 0.05), while non-dominant lower limb plantar flexion strength served as a significant predictor of both reactive strength (R2 = 0.148, p < 0.05) and balance (R2 = 0.179, p < 0.05). Conclusions: Consequently, these findings emphasize the significance of incorporating targeted exercises designed to enhance intrinsic foot musculature, thereby augmenting both explosive strength and balance in athletes. While acknowledging the persistent importance of strength assessment in evaluating lower extremity performance, our results underscore the critical role played by ankle muscle strength in the execution of explosive strength and balance.