Segmental Coordination Research Articles

THE STUDY OF THE SPATIO-TEMPORAL ORIENTATION ABILITY OF STUDENTS PRACTICING SPORTS DANCE AT THE UNIVERSITY OF BUCHAREST

Background. Sports dance is characterized by a complex coordination, its most important components being, in our opinion: the segmental, general and multisegmental coordination; the capacity of kinesthetic differentiation; the static and dynamic coordination, the ability of spatio-temporal orientation; the ability to perceive and reproduce musical rhythm and tempo. Sports dance lessons are held in the University of Bucharest with students who opt for this discipline without having a prior selection. In sports dance, all the motor capacities are involved in different weights, but we proposed for this study to analyze from the perspective of the coordinative capacities, the spatio-temporal orientation. Objectives. The subjects in this study are students in the 1st and 2nd years, belonging to different faculties of the university and they were divided into the control and the experimental groups. Both groups worked to test a salsa choreography during the lessons. In the experimental group, the choreography was practiced facing points 1,3,5,7, and in the control group, the choreography was practiced facing point 1. The test was realized with reference to point 5. Methods. The working methods used are observation, testing method, statistical-mathematical and graphical interpretation method. Results. The results were significantly better in the experimental group compared to the control group. The subjects in the experimental group were able to orient themselves better in space and time in a percentage of 85% and in the control group the percentage was about 30% Conclusion. We believe that the orientation in space and time can be improved by simple means, prepared by the teacher in the sports discipline, the methodological work being implemented according to the groups.

Enhancing the performance of recyclable polyurea through coordination of rigid chain segments and graphene platelets

In response to the global focus on environmental preservation and sustainable practices, developing nanocomposites featuring recyclable and healing properties is indispensable for high-performance and long-life structures. This study presents a facile approach to develop a recyclable and thermally-induced healing polyurea (PU)/graphene platelet (GNP) nanocomposites with high mechanical properties. A straightforward synthesis method was employed using isophorone diamine (IPDA) as chain extender with rigid cyclic structure. GNPs were modified with IPDA before adding into PU, showing remarkable enhancements in mechanical performance. At 0.10 wt.% GNPs, PU nanocomposites exhibited the maximum mechanical properties, with modified GNPs (M-GNPs) significantly outperforming pristine GNPs. Specifically, the tensile strength of PU increased by 41.3 % with M-GNPs, compared to only 12 % with pristine GNPs, underscoring the critical role of modifying the reinforcing phase. Furthermore, the nanocomposites demonstrated outstanding healing capabilities, achieving 89 % healing efficiency after 24 h at 120 °C. In addition, PU/M-GNP nanocomposites showed exceptional resistance to acidic and alkaline environments in comparison to neat PU. The study not only exemplifies developing high-strength and environmentally friendly materials but also holds promise for diverse applications, including aerospace, vibration damping, and protective coatings.

Using Reinforcement Learning to Develop a Novel Gait for a Bio-Robotic California Sea Lion.

While researchers have made notable progress in bio-inspired swimming robot development, a persistent challenge lies in creating propulsive gaits tailored to these robotic systems. The California sea lion achieves its robust swimming abilities through a careful coordination of foreflippers and body segments. In this paper, reinforcement learning (RL) was used to develop a novel sea lion foreflipper gait for a bio-robotic swimmer using a numerically modelled computational representation of the robot. This model integration enabled reinforcement learning to develop desired swimming gaits in the challenging underwater domain. The novel RL gait outperformed the characteristic sea lion foreflipper gait in the simulated underwater domain. When applied to the real-world robot, the RL constructed novel gait performed as well as or better than the characteristic sea lion gait in many factors. This work shows the potential for using complimentary bio-robotic and numerical models with reinforcement learning to enable the development of effective gaits and maneuvers for underwater swimming vehicles.

Lower-limb coordination changes following a 6-week training intervention that elicited enhancements to maximum velocity sprint performance.

Alterations to intra- and inter-limb coordination with improved maximal velocity performance remain largely unexplored. This study quantified within-day variability in lower-limb segmental coordination profiles during maximal velocity sprinting and investigated the modifications to coordination strategies in 15 recreationally active males following a 6-week period comprised of a multimodal training programme [intervention group (INT); n=7] or continued participation in sports (control group; n=8). The INT demonstrated a large decrease (effect size=-1.54) in within-day coordination profile variability, suggesting potential skill development. Thigh-thigh coordination modifications for the INT were characterised by an earlier onset of trail thigh reversal in early swing (26 versus 28% stride) and lead thigh reversal in late swing (76 versus 79% stride), rather than increases in overall time spent in anti-phase. Moreover, an increase in backward rotation of thigh relative to shank (effect size, 95% CIs: 0.75, 0.17 to 1.33) and shank relative to foot (0.76, -0.17 to 1.68) during late swing likely facilitated more aggressive acceleration of the limb, contributing to reduced touchdown distance and more favourable lower-limb configuration at initial ground contact. These novel findings provide empirical support for the role of longitudinal coordination modifications in improving maximal velocity performance.

The Effect of Neuromuscular Fatigue on the Spatiotemporal Coordination of Rowing

Within rowing, lower back disorders (LBDs) are common, but the mechanisms underpinning LBDs are poorly understood. Considering this, it is essential to understand how coordination and motor control change under different constraints such as ergometer rowing and fatigue. This can help better inform movement features linked to LBDs. Measurement of the continuous relative phase (CRP) is a method used to quantify body segment and joint coordination, as CRP measures the spatiotemporal control of multi-joint movement. The purpose of this study was twofold: to examine the general spatiotemporal coordination aspects of ergometer rowing in an unfatigued state, and to quantify how the spatiotemporal coordination of a rowing movement changes in response to a fatigue-inducing rowing trial. Wearable IMUs monitored 20 participants’ movement during a 2000 m ergometer row. The Borg-10 Rating of Perceived Exertion (RPE) scale was used to quantify perceived fatigue. Despite significant RPE increases across all athletes, the spatiotemporal coordination of rowing revealed prevailing strategies for the lumbar spine and lower extremity but no significant effects (α = 0.05) of fatigue on CRP outcomes (MARP, DP), cross-correlation lag (RXY), or range of motion. These findings provide further insight into rowing movements and support the idea that heterogeneous responses to fatigue may exist, requiring further study.

Regulation effects on naphthalimide self-assembly system by terminal pyridine isomers and the coordination of metal ions

Three novel naphthalimide-based gelators (NAPP, NAMP and NAOP) linked three different amines: 4-(aminomethyl)pyridine, 3-(aminomethyl)pyridine, or 2-(aminomethyl)pyridine were designed and synthesized. NAPP, NAMP and NAOP could self-assemble into fluorescent gels in some solvents and formed a variety of morphologies. The self-assembly behaviors of three gelators in DMSO/H2O (10/1, v/v) were characterized by UV–vis absorption, fluorescence, Fourier transform infrared (FTIR), X-ray diffractions (XRD) and water contact angle experiment, and the effect of different N sites in pyridine in this self-assembly system was investigated. On the base of coordination ability of pyridine groups to metal ions, the self-assembly process could be regulated by the addition of metal ions. NAPP, NAMP and NAOP solutions had highly selective and ultrafast fluorescence detection capabilities for Fe3+ with a low limit of detection. The self-assembly structure and surface wettability of the gel self-assembly system could be adjusted by adding metal ions. The hydrophobic surface of xerogels NAPP and NAMP is transformed into a hydrophilic surface at the present of Fe3+. And the hydrophilic and hydrophobic surfaces of NAPP and NAMP could realize the transformation of hydrophilic and hydrophobic surfaces by the coordination of metal ions. This study provided a way for regulating the self-assembly process by the distance between the N site on pyridine and the amide segment and metal coordination.

Influence of dancesport on segmental coordination development in 6-8-year-old children

Background and Study Aim. Dancesport significantly contributes to segmental coordination development in 6-8-year-old children through rhythmic movements and interaction with dance partner. The study aimed to investigate the impact of dancesport on segmental coordination development in children aged 6 to 8. Material and Methods. The study involved a group of 14 children aged 6 to 8 from the National Children's Palace in Bucharest. Research was conducted from February to June 2023. Segmental coordination assessment for upper limbs was done using Witty SEM, with 16 impulses of the smart semaphores (Lap L1-16) at 4 difficulty levels. Parameters measured: visual reaction time for each Lap (seconds), Lap mean (seconds), and total time (seconds). During the study period, a program with dancesport elements (Standard and Latino styles) was implemented for 36 hours, 2 hours per week. Comparative analysis between difficulty levels was done using ANOVA test, Single Factor Analysis of Variance, and Paired Comparison for Means. Statistical significance was set at p<0.05. Results. Comparative analysis between difficulty levels in the initial and final tests reveals an increase in Lap mean from L1-2 (24.5%) in the final test to L2-3 (53.8%) and L3-4 (24.6%) in the initial test. Comparing the average results of difficulty levels between tests, a decrease in visual reaction time by 0.04 seconds at L1, an increase by 0.03 seconds at L2, a decrease by 0.08 seconds at L3, and a decrease by 0.19 seconds at L4 were observed. Comparative analysis results of segmental coordination between tests at each difficulty level show significant differences of 5.6% (p<0.05) and 22.2% (p<0.01). Negative differences, indicating better performance between tests, are also observed at L1 by 33.3%, at L2 by 55.5%, at L3 by 38.9%, and at L4 by 27.8%. Conclusions. The study results reveal a significant increase in difficulty level among 6-8-year-old children, emphasizing the positive influence of dancesport elements on segmental coordination development. Comparative analysis of visual segmental reaction across different difficulty levels highlighted significant differences. Superior performances observed at lower difficulty levels comparing initial with final tests indicate an improvement in segmental coordination abilities.

Energy Efficiency in Petroleum Supply Chain Optimization: Push Segment Coordination

Today, the world is transitioning from traditional energy to clean, renewable sources. The petroleum sector is to play a role in this transition by supporting material and energy needs related to developing new energy systems. It is, therefore, vital that in upcoming years, the petroleum sector runs in a smart and efficient way, which can be achieved by coordination and the meaningful integration of decision-making issues in petroleum supply chains (PSCs). The existing literature on PSC optimization reveals a research gap; specifically, there is an insufficient level of technological detail considered while planning capacities of new infrastructures and its impact on the efficiency of further operations, specifically in the push segment of the PSC. This paper proposes a mixed-integer nonlinear programming model for planning capacities and coordinating activities within the mentioned PSC segment. The infrastructure capacity planning model covers technological details such as hydraulics and pump systems’ operational efficiency. The results reveal that the proposed model and its technological decision-making criterion of minimizing energy consumption drive infrastructural choices and operational modes to achieve machinery performance close to the best efficiency point. Also, the computational results demonstrate how traditional (minimum-cost) approaches lead to inefficient energy use while producing and transporting hydrocarbons. The proposed framework aims to facilitate the preliminary design stage of projects undertaken by engineering contractors in the energy sector.

Kinematic synergy of speed reduction during stair descent

Purpose This study aimed to quantify multi-segmental coordination using Uncontrolled Manifold (UCM) analysis to examine the effect of speed reduction on the control of stair descent. Methods Twenty healthy participants performed stair descent at a self-comfortable pace for normal speed conditions, and at a slow speed set to a metronome rhythm of 60 beats/min. UCM analysis was separately conducted for the COM and swing foot, with anteroposterior and vertical movements designated as task variables, and segment angles defined as elemental variables. ΔV, the normalized difference between the variance in segment angle that does not affect task performance (VUCM) and the variance that does affect task performance (VORT) was calculated separately for the COM and swing foot and compared between normal and slow speeds. Results The VORT for the COM and the swing foot in the anteroposterior direction were significantly lower at slow speeds than at normal speeds. The VORT of task-relevant segment angles affecting COM control in the vertical direction was significantly higher at slow speed compared to normal speed. Additionally, the ΔV in segment angle variance impacting swing foot control in the anteroposterior direction was significantly greater at slow speed than at normal speed. Conclusions The findings suggest that descending stairs at reduced speed promotes enhanced coordination of lower limb segments for controlling the swing foot in the anteroposterior direction, while concurrently increasing segmental variability that destabilizes the vertical COM.

Development study determining motor qualities in rhythmic gymnastics. Mobility and coordination in gymnasts 10-12 years old

Rhythmic gymnastics is one of the sports that educates one of the basic components of physical beauty, also falling into the category of technical-combination sports. Achieving a high performance in rhythmic gymnastics is a complex process, which requires a comprehensive approach to the development of motor qualities and specific skills. In particular, two fundamental motor qualities, addressed in the paper, are essential for achieving success in this discipline: joint mobility and muscle elasticity, as well as coordination of body segments. Thus, through the appropriate introduction and implementation of specific exercises in the rhythmic gymnastics training of performance athletes, we highlighted the importance, the beneficial and essential effect in improving sports performance. The purpose of the research is to evaluate and analyze the impact of the means used in training on the development of mobility and coordination of gymnasts. The obtained results underline the positive influence of exercises on sportswomen's performances and through the planning and proper implementation of exercises in training, a holistic and sustainable development of athletes in their sports activities can be ensured.

Role of kinetic chain in sports performance and injury risk: a narrative review.

The kinetic chain refers to the body's intricate coordination of various segments to perform a specific activity involving precise positioning, timing, and speed. This process is based on task-oriented and activity-specific pre-programmed muscle activation patterns enhanced by repeated practice. It demands muscular eccentric strength, joint flexibility, and musculotendinous elastic energy storage. The body core (lumbopelvic-hip complex) forms the kinetic chains' central point of activities in most sports because it facilitates load transfers to and from the limbs. The kinetic chain relationship with fascia, peripheral nerves, and tensegrity is fundamental to holistic human body movements. The kinetic chain function demands neuromuscular, sensorimotor, and neurocognitive control. Any blockage or defect in the kinetic chain can develop compensatory patterns, high demands on distal parts, and overuse and overload injuries. Taking a holistic approach and evaluating the integrity of the kinetic chain in athletes can significantly enhance efforts to improve sports performance and mitigate injury risk.

Kinematics and mechanical changes with step frequency at different running speeds.

Running at a given speed can be achieved by taking large steps at a low frequency or on the contrary by taking small steps at a high frequency. The consequences of a change in step frequency, at a fixed speed, affects the stiffness of the lower limb differently. In this study, we compared the running mechanics and kinematics at different imposed step frequencies (from 2 step s-1 to 3.6 step s-1) to understand the relationship between kinematic and kinetic parameters. Eight recreational male runners ran on a treadmill at 5 different speeds and 5 different step frequencies. The lower-limb segment motion and the ground reaction forces were recorded. Mechanical powers, general gait parameters, lower-limb movements and coordination were investigated. At low step frequencies, in order to limit the magnitude of the ground reaction force, the vertical stiffness is reduced and thus runners deviate from an elastic rebound. At high step frequencies, the stiffness is increased and the elastic rebound is optimised in its ability to absorb and restore energy during the contact phase. We studied the consequences of a change in step frequency on the bouncing mechanics of running. We showed that the lower limb stiffness and the intersegmental coordination of the lower-limb segments are affected by running step frequency rather than speed. The runner rather adapts their lower limb stiffness to match a step frequency for a given speed than the opposite.

Gait asymmetry in children with Duchenne muscular dystrophy: evaluated through kinematic synergies and muscle synergies of lower limbs

BackgroundGait is a complex, whole-body movement that requires the coordinated action of multiple joints and muscles of our musculoskeletal system. In the context of Duchenne muscular dystrophy (DMD), a disease characterized by progressive muscle weakness and joint contractures, previous studies have generally assumed symmetrical behavior of the lower limbs during gait. However, such a symmetric gait pattern of DMD was controversial. One aspect of this is criticized, because most of these studies have primarily focused on univariate variables, rather than on the coordination of multiple body segments and even less investigate gait symmetry under a motor synergy of view.MethodsWe investigated the gait pattern of 20 patients with DMD, compared to 18 typical developing children (TD) through 3D Gait Analysis. Kinematic and muscle synergies were extracted with principal component analysis (PCA) and non-negative matrix factorization (NNMF), respectively. The synergies extracted from the left and right sides were compared with each other to obtain a symmetry value. In addition, bilateral spatiotemporal variables of gait, such as stride length, percentage of stance and swing phase, step length, and percentage of double support phase, were used for calculating the symmetry index (SI) to evaluate gait symmetry as well.ResultsCompared with the TD group, the DMD group walked with decreased gait velocity (both p < 0.01), stride length (both p < 0.01), and step length (both p < 0.001). No significant difference was found between groups in SI of all spatiotemporal parameters extracted between the left and right lower limbs. In addition, the DMD group exhibited lower kinematic synergy symmetry values compared to the TD group (p < 0.001), while no such significant group difference was observed in symmetry values of muscle synergy.ConclusionsThe findings of this study suggest that DMD influences, to some extent, the symmetry of synergistic movement of multiple segments of lower limbs, and thus kinematic synergy appears capable of discriminating gait asymmetry in children with DMD when conventional spatiotemporal parameters are unchanged.

Key points of development of motor skills in childhood embodied in gait parameters

ObjectiveTo observe changes of correlations of gait parameters of four sets of body in children aged 3–6. DesignA cross-sectional observational study. SettingDong Gang kindergarten in Suzhou, China. ParticipantsA total of 89 children between 3 and 6 years old. Main outcome measuresA total of 37 three-dimensional (3-D) gait parameters assessed with a wearable gait analysis system in 2-min walking test, for 3 times. ResultsThere were significant differences in gait speed, stride length and sagittal range of motion (ROM) of trunk among children of 3–6 years old (P < 0.05). The left and right toe out angle, sagittal ROM of waist, coronal ROM of trunk and arm swing velocity of male were significantly greater than those of female children (P < 0.05). Most gait parameters were symmetrical (P < 0.01). Canonical correlations of Upper Limbs Set vs. Trunk and Waist Sets increased by ages (P < 0.05). Canonical correlation of Trunk Set vs. Waist Set decreased by ages. Canonical correlations of Lower Limbs Set to any other sets were not significant (P > 0.05). ConclusionsValues and symmetry of gait parameters cannot reflect the development of motor skill during ages of 3–6. Proper trunk movement coordinating with upper limbs and isolating from waist is the key point of development of motor skill in walking. It is built during preschool period and girls develop better. Before the preschool period, lower limbs’ isolating movements from the other segments have already developed well. These key points of motor skills in walking should be considered when motor tasks for segment isolation and coordination are given to children with motor dysfunction.

Dribble Accuracy and Arm Coordination Pattern According to Motor Expertise and Tempo.

Skilled movements in motor learning result from efficiently controlling the many degrees of freedom in human movement. To acquire motor skills, harmonious coordination of body segments in time and space is crucial for accurate and consistent performance. The purpose of this study was to compare dribbling accuracy, consistency, and coordination patterns of body segments according to motor expertise and tempo. To achieve this, we had eight basketball experts and eight beginners perform static dribbling at three different speeds for 20 s. Force plates measured radial error while motion capture equipment measured the angular data of the right arm's fingers, wrist, and elbow. The measurements obtained from the force plate were used to analyze the participants' dribbling performance, including accuracy, consistency, and coordination patterns. The research results showed that there was no significant difference in dribbling accuracy according to skill level, but skilled players showed higher consistency in the anterior-posterior (AP) direction (p < 0.001). In the comparative analysis of coordination patterns, skilled players showed an in-phase structure, whereas beginners showed an anti-phase structure (elbow-wrist: p < 0.05; wrist-finger: p < 0.001; elbow-finger: p < 0.001). This study suggests that achieving proficiency in basketball dribbling requires a strategy that involves coordination of movements with an in-phase pattern for stability in performance.

The importance of relevant criteria of selection in ensuring the success of the national selection systems in athletics: A review

Scientific selection represents one of the most important concerns of contemporary sports, as evidenced by the major world investments made in order to identify unique combinations of physical and mental potential and abilities that can be developed towards human biological limits. Some countries have developed complex systems and programs aimed at identifying and especially transforming sports potential into performance, emphasizing the need to develop potentially talented performers and not just to early identify them. The critical analysis of the Romanian selection system in athletics highlights the shortcomings and allows corrections to be outlined. Athletics in particular is a complex sports discipline that requires a multitude of psychomotor and coordinative skills such as rhythm, tempo, balance, segmental coordination, space orientation, and laterality, skills recommended to be detected from the initial phase of the selection in order to foresee the motor endowment of the child and to guide him accordingly. The purpose of this review was to examine the discrepancies between the Romanian selection system in athletics and other successful national systems in order to emphasize the necessity of new perspectives regarding the selection criteria, which need to be relevant in detecting skills in the area of psychomotricity and coordination.

Changes in Coordination and Its Variability with an Increase in Functional Performance of the Lower Extremities

Clinical gait analysis has a long-standing tradition in biomechanics. However, the use of kinematic data or segment coordination has not been reported based on wearable sensors in "real-life" environments. In this work, the skeletal kinematics of 21 healthy and 24 neurogeriatric participants was collected in a magnetically disturbed environment with inertial measurement units (IMUs) using an accelerometer-based functional calibration method. The system consists of seven IMUs attached to the lower back, the thighs, the shanks, and the feet to acquire and process the raw sensor data. The Short Physical Performance Battery (SPPB) test was performed to relate joint kinematics and segment coordination to the overall SPPB score. Participants were then divided into three subgroups based on low (0-6), moderate (7-9), or high (10-12) SPPB scores. The main finding of this study is that most IMU-based parameters significantly correlated with the SPPB score and the parameters significantly differed between the SPPB subgroups. Lower limb range of motion and joint segment coordination correlated positively with the SPPB score, and the segment coordination variability correlated negatively. The results suggest that segment coordination impairments become more pronounced with a decreasing SPPB score, indicating that participants with low overall SPPB scores produce a peculiar inconsistent walking pattern to counteract lower extremity impairment in strength, balance, and mobility. Our findings confirm the usefulness of SPPB through objectively measured parameters, which may be relevant for the design of future studies and clinical routines.

Analysis of segmental coordination in the lower extremity using vector coding: a pilot return-to-play study of acute ankle sprain.

Purpose: Acute ankle sprain may affect ankle function during sport and daily activities. This study aimed to use vector coding technique to analyze the difference over time between injured and healthy lower limb during the first week of acute ankle sprain phase (P1) and post a 1-month recovery phase (P2) to understand the return-to-play coordination strategy in the lower extremity. Methods: Six females attended the gait experiments with attached 40 reflective markers using eight-camera Vicon motion capture system. All participants walked barefoot while turning in four directions (T0°, T45°, T90°, T135°) at their self-selected speed. Coordination patterns were classified as in-phase, anti-phase, proximal or distal dominancy between lower limb joints involving hip, knee, ankle, subtalar, metatarsophalangeal (MTP) joint and tarsometatarsal (TMT) joint. Results: P1 showed more proximal joint dominant in Hip-Knee coupling angles but P2 displayed more distal joint dominant in Knee-Ankle joint coordination pattern and mainly distal joint dominant in Ankle-MTP coupling angle mapping. The Ankle-TMT1 and Ankle-TMT5 coordination patterns matched best in straight walking but worst in T135 walking. Conclusions: Investigating inter-segmental coordination in different turning movements could provide insights into gait changes from acute ankle sprain from one-month return-to-play recovery. Knowledge of lower limb coordination pattern may provide clinical implications to improve dynamic balance and gait stability for individuals with acute ankle sprain.

Defining "Postural Control" in Interventions for Musculoskeletal Pain

<h3>Objective(s)</h3> To identify and describe how "postural control" is measured in therapeutic interventions for musculoskeletal pain, and to provide recommendations on assessment methods when "postural control" is a primary outcome measure. <h3>Data Sources</h3> PubMed and CINAHL were searched using terms encompassing concepts "postural control", "intervention", and "musculoskeletal pain" including MeSH terms and truncations. Limits were applied for human studies published in English. <h3>Study Selection</h3> 1,553 results were screened by title, then abstract to include only those studies providing an intervention to a human population experiencing musculoskeletal pain. Studies were included if they described a specific intervention or protocol, and identified a relevant keyword that could be related to "postural control." 136 articles were full-text reviewed to identify if a study had specific outcome measures for measuring postural control. Consensus was achieved between the first and last authors identifying a final list of 20 studies meeting inclusion criteria. <h3>Data Extraction</h3> Specific measurement tools for postural control and their methods of use were extracted from each study. Agreement on how "postural control" was measured in a study was achieved between at least two staff for each study. <h3>Data Synthesis</h3> Frequency counts were used to identify 3 measurement categories for "postural control": trunk sway or center of pressure during static standing, muscle activation or body position in response to or anticipating perturbation, and segmental coordination during movement. The most frequently used assessment was center of pressure during static standing, then velocity and amplitude of trunk sway, then relative joint angles. <h3>Conclusions</h3> Results indicate "postural control" is defined in multiple ways in musculoskeletal interventions for pain. Three broad concepts were identified as being measures of "postural control:" body position during static standing, anticipatory & reactive movements, and relative joint positions. Measures traditionally associated with "balance" were the most frequent measures of "postural control." Given the theoretical importance of postural control in musculoskeletal pain and it's multifaceted nature, we recommend including outcome measures that encompass reactive and dynamic activities to differentiate "postural control" from "balance." <h3>Author(s) Disclosures</h3> None to disclose.

Inter- and intra-limb coordination during initial sprint acceleration.

ABSTRACTIn complex movements, centre of mass translation is achieved through effective joint and segment rotations. Understanding segment organisation and coordination is therefore paramount to understanding technique. This study sought to comprehensively describe inter- and intra-limb coordination and assess step-to-step changes and between-individual variation in coordination during initial sprint acceleration. Twenty-one highly trained to world class male (100 m PB 9.89-11.15 s) and female (100 m PB:11.46-12.14 s) sprinters completed sprint trials of at least 20 m from which sagittal plane kinematics were obtained for the first four steps using inertial measurement units (200 Hz). Thigh-thigh, trunk-shank and shank-foot coordination was assessed using a modified vector coding and segment dominancy approach. Common coordination patterns emerged for all segment couplings across sexes and performance levels, suggesting strong task constraints. Between-individual variation in inter-limb thigh coordination was highest in early flight, while trunk-shank and shank-foot variation was highest in late flight, with a second peak in late stance for the trunk-shank coupling. There were clear step-to-step changes in coordination, with step 1 being distinctly different to subsequent steps. The results demonstrate that inter-limb coordination is primarily anti-phase and trailing leg dominant while ankle motion in flight and late stance appears to be primarily driven by the foot.