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Copyright of Revista Andaluza de Medicina del Deporte is the property of Centro Andaluza de Medicina del Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and Objective: Due to the disruption of the body's natural posture because of the loss of interior arch of the foot in people with foot pronation, which may change amount and direction of forces and muscles electrical activity exerted on the foot during running movement, the purpose of this study was to compare ground reaction forces and muscles electrical activity of the ankle during running movement in young men with normal and pronation feet. Materials and Methods: In this descriptive study, from male students of Physical Education and Sport Science in Khwarizmi University (2016), 15 people with pronated foot deformity and 15 healthy people were selected as subject. Force plate was used to measure ground reaction force. Surface electromyography signals were recorded during the running test by using an Electromyography that was simultaneous with force plate. To analyze data, MATLAB was used, and to describe data, mean and standard deviation were measured. Independent t-test was used to compare the two groups. Results: The findings indicated there was a statistically significant difference in the medial-lateral direction between normal and pronated foot groups during the running movement in the variable of peak ground reaction force (p=.018). In the variable of muscles electrical activity during running, a significant difference was observed in the tibialis anterior (p=.02) and peroneus longus (p=.01) muscles between the two groups. Conclusion: According to the results, it seems that foot pronation can be regarded as a factor affecting the biomechanics of side cut with a change in the medial-lateral ground reaction forces and muscles electrical activity during running movement. [ABSTRACT FROM AUTHOR]

Understanding the intricacies of human movement coordination and variability during running is crucial to unraveling the dynamics of locomotion, identifying potential injury mechanisms and understanding skill development. Identification of minimum number of cycles for calculation of reliable coordination and its variability could help with better test organization and efficient assessment time. By adopting a cross-sectional study design, this study investigated the minimum required cycles for calculating hip-knee, hip-ankle and knee-ankle coordination and their variability using a continuous relative phase (CRP) method. Twenty-nine healthy adults ran on a treadmill at speeds of 9, 12.5, and 16 km.h -1 while 3D kinematic data of their lower limbs were recorded using 6 optoelectronic cameras. Using Intraclass Correlation Coefficient (ICC) analysis, reliability between CRP and its variability (CRPv) in different gait cycles (3, 5, 10, 20, 30) was assessed for each speed. A minimum of 10 cycles was required for CRP calculation across all speeds, whereas CRPv necessitated a minimum of 30 cycles for moderate to good reliability. While increasing the number of cycles improved ICC values for inter-joint CRP, the same trend was not consistently observed for CRPv, emphasizing the importance of separately assessing CRP and its variability metrics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objective: The objective of this study was to examine the effects of fatigue on the coordination variability between the trunk, pelvis, and hips during treadmill running., Methods: The kinematics data were recorded during ten successive treadmill steps running at the preferred speed and at 80% and 120% of the preferred speed. The angle segment data obtained during the running cycles were normalized to 100 data points, and they were split into ten periods. The coordination variability was calculated using the continuous relative phase (CRP) and variability (VCRP) methods for the trunk, pelvic and hip segments before and after the fatigue protocol., Results: The repeated measures analysis of variance showed significant differences in the trunk-pelvic and trunk-hip CRPs and in the CRP variability during the last 30% of the treadmill running cycles after fatigue (p≤0.05). In addition, significant differences were observed in the pelvic-hip CRP and the CRP variability in 40% of the initial treadmill running cycles after fatigue (p≤0.05)., Conclusion: According to the results of this study, fatigue reduces coordination and increases variability. The central nervous system probably exerts more control on the distal segments for maintaining moving patterns in fatigue conditions., Competing Interests: The authors have no conflict of interest.

Anterior Cruciate Ligament (ACL) injuries commonly occur when attention is simultaneously on the environment (other players, objects) and maintaining neuromuscular control. Therefore, our purpose was to investigate lower-extremity coordination following ACLR during a run-to-cut with ecological validity to sport competition. Sixteen male basketball players with ACLR (20.8 ± 3.42 years, time since surgery: 9.5 ± 2.4 months) were contrasted with 16 healthy male control basketball players (21.3 ± 3.17 years) during a run-to-cut maneuver under two conditions: 1) standard, run and initiate a ∼40° side-cut and 2) simulated sport, run-to-cut with the presence of a defender and engaged in a dual-task to intercept a ball. Lower limb kinematics were used to calculate continuous relative phase metrics for evaluation of coordination pattern and variability. Independent t-test and effect size were used to evaluate the difference between the two groups and across condition via change score. The simulated sports cutting maneuver coordination patterns were significantly different between groups for hip-ankle, hip-knee, knee-knee, and knee-ankle coupling (p < .05). Only hip-knee coupling had a significant condition change score (p = .01) with ACLR increasing (51.8 ± 79.1%) and healthy controls (-16.04 ± 64.1%) decreasing hip flexion-extension and keen abduction-adduction coupling. There was no significant difference in normal cut coordination between groups. The addition of simulated sport visual attention and dual task motor planning during the run-to-cut might elicit different lower limb movement patterns in ACLR athletes compared to the healthy counterparts, potentially contributing to the elevated reinjury risk in those with ACLR history when returning to sport., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Vertical stiffness has been highlighted as a potential determinant of performance and may be estimated across a range of different performance tasks. The aim of the current study was to investigate the relationship between vertical stiffness determined during 9 different hopping tests and performance of vertical jumps. Twenty healthy, active males performed vertical hopping tests with three different strategies (self-selected, maximal, and controlled) and three different limb configurations (bilateral, unilateral preferred, and unilateral non-preferred), resulting in nine different variations, during which vertical stiffness was determined. In addition, participants performed squat jump (SQJ) and countermovement jump (CMJ) during which jump height, CMJ stiffness, and eccentric utilization ratio (EUR) were determined. Vertical stiffness in bilateral and unilateral preferred tasks performed with a self-selected and maximal, but not controlled, strategy was associated with stiffness in the CMJ ( r  = 0.61-0.64; p  < 0.05). However, stiffness obtained during unilateral preferred and non-preferred hopping with self-selected strategy was negatively associated with performance in SQJ and CMJ tasks ( r  = -0.50 to -0.57; p  < 0.05). These findings suggest that high levels of vertical stiffness may be disadvantageous to static vertical jumping performance. In addition, unilateral hopping with a self-selected strategy may be the most appropriate task variation if seeking to determine relationships with vertical jumping performance. Highlights Stiffness obtained during unilateral hopping with a preferred strategy was negatively associated with vertical jumping performancesStiffness obtained during hopping with preferred and maximal strategies was associated with stiffness obtained during a countermovement jumpIn this population, hopping stiffness may therefore be reflective of an individual's countermovement jump strategyHigh levels of stiffness may be disadvantageous to static-start vertical jumping.

The aerobic endurance is considered an important physiological capacity of soccer players which is examined by Incremental Exercise Test (IET). However, it is not clear how general fatigue induced by IET influences physiological and biomechanical gait features in soccer players and how players recover optimally at post-IET. Here, the effect of general fatigue induced by IET on energy cost, gait variability and stability in soccer players was investigated. To identify an optimal recovery mode, the effect of walking at Preferred Walking Speed (PWS), running at Individual Ventilation Threshold (IVT) (two active recovery modes), and Rest (a passive recovery mode) on aforementioned features were studied. Nine male players walked 4-min at PWS on a treadmill prior IET (PreT), which was followed by four 4-min walking trials (PosT-0, 1, 2, and 3) with three 4-min recovery intervals (PWS, IVT, or Rest) between them, in three sessions (one for each recovery mode) in a random order. Energy cost, gait variability and stability were examined at PreT (baseline), and at PosT-0, 1, 2, and 3 (intervals of respectively 0-4, 8-12, 16-20, 24-28 min at post-IET). Gait variability was assessed by the standard deviation of trunk angle and gait stability was assessed by the local dynamic stability of trunk angular velocity. Gait stability was not affected by IET, despite increases in gait variability and energy cost. Different from IVT, PWS and Rest recovery modes reduced energy cost at post-IET. Gait variability and energy cost recovered at PosT-1 and PosT-2, suggesting that 8-12 and 16-20 min recovery intervals, respectively, were required for returning to their baselines. No preference for active over passive recovery was found in terms of gait variability and energy cost., Competing Interests: Conflict of interest statement None of the authors of this paper have any financial and personal relationships with other people or organizations that could inappropriately influence the presented work., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Long-standing groin pain (LSGP) is a chronic painful condition resulting in both impaired performance and time loss from participation in multidirectional field sport., Research Question: What are the differences in intersegmental coordination strategy and variability of trunk-pelvic and thigh coupling during change of direction in subjects with athletic LSGP and asymptomatic control subjects?, Methods: A motion analysis system was used to collect 3-D kinematic data of the continuous relative phase and the variability of the right and left leg hip. Thoracic-thigh segment data were also collected during multiple ipsilateral turns at a self-selected pace from 16 males with LSGP and 16 asymptomatic controls. It is worth mentioning that, for a more detailed analysis, we divided each cycle diagram into four phases. Independent T-tests were used to compare the two groups., Results: Subjects with LSGP demonstrate except in phase 2 of the left foot, more out-of-phase movement with both increased variabilities in right/ left thigh - pelvic coupling, right/ left thigh-thoracic, and pelvic- thoracic in every 4 phases and in the decoupling of segmental coordination., Significance: Decrease in coordination with higher variability is apparent in subjects with LSGP and this aberrant coordination may lead to unexpected compensatory strategies and control impairments., Competing Interests: Declaration of Competing Interest We confirm that there are no known conflicts of interest associated with this publication and there has been no financial support for this work that could have influenced its outcome. The researchers independently collected, analyzed, and interpreted the results and have no financial interests in the results of this study. Furthermore, dissemination of the results of this study does not constitute endorsement by the researchers or their institutional affiliations., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Context: Female volleyball players are more predisposed to anterior cruciate ligament injury in comparison with their male counterparts. Recent research on anterior cruciate ligament injury prevention strategies has shown the positive results of adopting the external focus (EF) of attention in sports., Objective: To determine the effect of 6-week EF instruction exercises on performance and kinetic factors associated with lower-extremity injury in landing after the volleyball blocks of female athletes., Design: Pretest and posttest control study., Setting: University research laboratory., Participants: Thirty-two female volleyball players (18-24 y old) from the same team randomly divided into experimental (n = 16) and control (n = 16) groups., Intervention: The experimental group performed a 6-week exercise program with EF instructions. The control group continued its regular volleyball team schedule., Main Outcome Measures: To assess function, single-leg triple hop test for distance was used. A force plate was used to evaluate kinetic variables including vertical ground reaction forces, the rate of loading, and dynamic postural stability index. All data were assessed at baseline and after the intervention., Results: There was a significant increase in single-leg triple hop test (P < .05) and in the first and second peak ground reaction force, rate of loadings, dynamic postural stability index (P < .05)., Conclusion: According to the results of this study, anterior cruciate ligament injury prevention programs should incorporate EF instruction exercises to enhance the kinetics and to increase athletes' functional performance.

Background: Groin pain is one of the common problems in multidirectional sports. It seems that abnormal muscular activity and improper movement strategy led to prolongation and high rate of this injury. Therefore, the aim of this study was to Comparing the Average amplitude of Electromyography (AEMG), co-contraction ratio (CCR) of selected thigh and thoracic muscle during turning in individuals with chronic groin pain and healthy individuals., Methods: Surface electromyography was collected from the internal oblique/transversus abdominis (IO/TrA), multifidus (MF), adductor Longus (AL) and gluteus Medius (GM) for AEMG and CCR analyzed in 16-males with LSGP and 16-controls in four motion phases during 11 cycles of gait coupled with turning., Results: Results revealed that in the AEMG apart from the third phase in the muscle of the IO/ Tr. A muscle and in the second phase in the MF muscle in the trunk and in the third phase in the muscle of the AL and the fourth phase in the GM foot Left There was a significant difference in other phases. There was a significant difference in the CCR, except in the second phase of the trunk and the fourth phase of the left foot in the rest of the phases., Conclusions: It seems that in athletes with LSGP, have selective muscular activation and CCR have during turning, that may be resulting in compensatory strategies and movement control defects, which may be a useful tool to predict LSGP occurrence in players with a history of groin pain., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Signs and symptoms of impaired function of the musculoskeletal system may be targeted by treating dysfunction located elsewhere., Hypothesis: Abdominal control feedback and scapular stabilization exercise interventions would result in positive changes in pain intensity, strength, electromyography, and flexion-relaxation phenomena in women with forward head and round shoulder postures and neck movement impairment., Study Design: Pretest-posttest intervention., Level of Evidence: Level 1., Methods: A total of 135 women (aged 27.23 ± 1.9 years) with forward head and round shoulder postures were randomized to 3 groups. Group 1 received 6-week scapular stabilization exercises with abdominal control feedback (n = 45), group 2 received 6-week scapular stabilization exercises without abdominal control feedback (n = 45), and group 3 received active self-exercise as a control group (n = 45). Posture, pain, proprioception, strength, and electromyography were assessed before and after the interventions., Results: There were significant between-group differences in pain, proprioception, strength, and electromyography favoring group 1. There were significant within-group changes in posture, pain, proprioception, strength, and electromyography in both groups 1 and 2. No significant change was observed for muscle strength., Conclusion: The addition of abdominal control feedback to the scapular stabilization exercises was shown to be superior to the scapular stabilization exercises alone for decreasing neck pain and restoring proper proprioception, strength, and electromyography in females with forward head and round shoulder postures and neck movement impairment., Clinical Relevance: The addition of abdominal control feedback to scapular stabilization exercises is superior to scapular stabilization exercises alone on the neck for improving electromyography, strength, and function in females with forward head and round shoulder postures and neck movement impairment.

Background: Patellofemoral pain syndrome (PFPS) is sometimes related to excessive hip adduction and internal rotation, as well as knee valgus during weightbearing activities in females. Research on injury prevention and rehabilitation strategies has shown the positive effects of valgus control instruction (VCI) exercise programs in training., Hypothesis: A VCI program would result in a positive change in pain, eccentric hip muscle torque, and performance in females with PFPS., Study Design: Controlled laboratory study., Level of Evidence: Level 1., Methods: Sixty-four amateur female volleyball players from our university (age, 18-25 years) with PFPS and equal years of exercise experience were randomly divided into VCI (n = 32; age, 22.1 ± 5.88 years) and control (n = 32; age, 23.1 ± 6.49 years) groups. Function (single, triple, and crossover hops), strength (hip abductor and external rotators), pain (visual analog scale), and knee valgus angle (single-leg squat) were assessed at baseline and after intervention., Results: There was a significant difference before and after implementation of the VCI program with regard to pain (49.18% ↓, P = 0.000), single-leg hop test (24.62% ↑, P = 0.000), triple-hop test (23.75% ↑, P = 0.000), crossover hop test (12.88% ↑, P = 0.000), single-leg 6-m timed hop test (7.43% ↓, P = 0.000), knee dynamic valgus angle (59.48% ↓, P = 0.000), peak abductor to adductor eccentric torque ratio (14.60% ↑, P = 0.000), peak external (59.73% ↑, P = 0.023) and internal rotator (15.45% ↑, P = 0.028) eccentric torques, and the ratio of peak external to internal rotator eccentric torque (40.90% ↑, P = 0.000) ( P < 0.05)., Conclusion: PFPS rehabilitation and prevention programs should consider VCI exercises to decrease pain, improve strength, and increase athletes' functional performance., Clinical Relevance: This study investigated the effect of VCI exercises on knee valgus angle, pain, and functionality of individuals with PFPS. The VCI program improves performance, knee dynamic valgus angle, and strength in participants with PFPS. A controlled and optimal knee valgus angle during a functional task is the most important factor for injury prevention specialists. VCI training can be used as a supplemental method to prevent and treat lower extremity injury in patients with PFPS.