Ben Serrien

Differences in ball speed and three-dimensional kinematics between male and female handball players during a standing throw with run-up

BackgroundThe purpose of this paper was to examine differences in ball release speed and throwing kinematics between male and female team-handball players in a standing throw with run-up. Other research has shown that this throwing type produces the highest ball release speeds and comparing groups with differences in ball release speed can suggest where this difference might come from. If throwing technique differs, perhaps gender-specific coordination- and strength-training guidelines are in order.MethodsMeasurements of three-dimensional kinematics were performed with a seven-camera VICON motion capture system and subsequent joint angles and angular velocities calculations were executed in Mathcad. Data-analysis with Statistical Parametric Mapping allowed us to examine the entire time-series of every variable without having to reduce the data to certain scalar values such as minima/maxima extracted from the time-series.ResultsStatistical Parametric Mapping enabled us to detect several differences in the throwing kinematics (12 out of 20 variables had one or more differences somewhere during the motion). The results indicated two distinct strategies in generating and transferring momentum through the kinematic chain. Male team-handball players showed more activity in the transverse plane (pelvis and trunk rotation and shoulder horizontal abduction) whereas female team-handball players showed more activity in the sagital plane (trunk flexion). Also the arm cocking maneuver was quite different.ConclusionsThe observed differences between male and female team handball players in the motions of pelvis, trunk and throwing arm can be important information for coaches to give feedback to athletes. Whether these differences contribute to the observed difference in ball release speed is at the present unclear and more research on the relation with anthropometric profile needs to be done. Kinematic differences might suggest gender-specific training guidelines in team-handball.

The proximal-to-distal sequence in upper-limb motions on multiple levels and time scales

The proximal-to-distal sequence is a phenomenon that can be observed in a large variety of motions of the upper limbs in both humans and other mammals. The mechanisms behind this sequence are not completely understood and motor control theories able to explain this phenomenon are currently incomplete. The aim of this narrative review is to take a theoretical constraints-led approach to the proximal-to-distal sequence and provide a broad multidisciplinary overview of relevant literature. This sequence exists at multiple levels (brain, spine, muscles, kinetics and kinematics) and on multiple time scales (motion, motor learning and development, growth and possibly even evolution). We hypothesize that the proximodistal spatiotemporal direction on each time scale and level provides part of the organismic constraints that guide the dynamics at the other levels and time scales. The constraint-led approach in this review may serve as a first onset towards integration of evidence and a framework for further experimentation to reveal the dynamics of the proximal-to-distal sequence.

Analysis of 3D motion patterns with self-organising maps (SOM) and statistical parametric mapping (SPM): a methodological proposal.

Research in sports biomechanics using three-dimensional (3D) kinematics to study motion patterns is usually constrained by two main problems: (1) the study is limited to minima–maxima of certain variables (e.g. maximal shoulder internal rotation velocity) and their timing (e.g. 10ms before ball release) and (2) underlying non-linear relations among variables and between variables and the outcome are not taken into account. Statistical parametric mapping (SPM) takes care of the first problem (Pataky 2012), but the second is still not accounted for, because SPM is an extension on the general linear model. A method was described in literature to address the second problem (Bauer and Schöllhorn 1997). To analyse multidimensional kinematic chains in complex motions, self-organising maps (SOM, a class of neural networks) can be used to reduce the high dimensionality. However, we feel that this described methodology may be too datareductive: differences in motion patterns were reduced into one scalar quantity and then a cluster analysis was done. Therefore, we propose to combine both SOM and SPM (in this order) to analyse differences in motion patterns. We will apply this methodology to a data-set that we recently analysed in a more classic approach (Serrien et al. under review). We used multivariate analysis of variance to study gender differences in handball throwing techniques, and we found several statistical differences in kinematic and temporal variables between genders.

Systematic Review and Meta-Analysis on Proximal-to-Distal Sequencing in Team Handball: Prospects for Talent Detection?

Abstract The proximal-to-distal sequence has previously been discussed in the light of performance and injury prevention. Sports biomechanics literature in general, and in team handball in specific, has claimed to be of importance to inform coaches on what constitutes a ‘good’ technical performance. However, hitherto no prospective studies exist on how this information may be used and this may in part be due to the general small sample sizes. We therefore performed a systematic review and meta-analysis of proximal-to-distal sequencing in team handball throwing motions. A total of fourteen articles were included in the systematic review. Meta-analyses were performed for the timing of maximal angles and angular velocities as well as initiation of joint angular velocities in the penalty throw, the standing throw with run-up and the jump shot of experienced team handball players. For the initiation of joint angular velocities, the overall sequence was estimated to start with pelvis rotation, followed by trunk rotation, trunk flexion, shoulder internal rotation and elbow extension. For maximal velocities, the sequence started with pelvis rotation, followed by trunk rotation, trunk flexion, elbow extension, and shoulder internal rotation (post ball release). The obtained results were discussed in the light of talent identification purposes. Limitations to individual study methodology and of the present meta-analysis were also discussed. Much more research will be necessary, but at the very least, this review can provide a starting point for evidence-based discussions between movement scientists and team handball coaches to include proximal-to-distal sequencing as a measure of coordination to gauge early onset of talent.

The Uncontrolled Manifold Concept Reveals That the Structure of Postural Control in Recurve Archery Shooting Is Related to Accuracy

In this study, we examine the structure of postural variability in six elite-level recurve archers using the uncontrolled manifold concept. Previous research showed equivocal results for the relationship between postural control and shooting accuracy, but these studies were mainly limited to a descriptive approach to postural variability/stability and did not take the simultaneous movements of the upper limb joints into account. In this study, we show that the goal-equivalent variability which stabilizes the orientation of the arrow in space is significantly larger than that of the non-goal-equivalent variability in arrows of high accuracy (score 9 or 10). Conversely, arrows of lower accuracy (score 6, 7, or 8) failed to reach significant thresholds throughout the majority of the aiming phase. This analysis reveals that it is not necessary (or even possible) for elite archers to minimize the movements of all degrees of freedom during aiming, but rather that the structure of variability of the redundant kinematic chain is exploited so that the relevant performance variable (orientation of the arrow) is stabilized.

Evaluation of coordination hysteresis in a multidimensional movement task with continuous relative phase and Self-Organizing Maps

Hysteresis in the coordination of movement can be described in the language of coordination dynamics as an asymmetrical response of a systems order parameter with respect to opposite changes in a control parameter. For movement tasks involving a large number of active degrees-of-freedom, the order parameter can be modelled with a pattern recognition approach like Self-Organizing Maps (SOM). This study explored this method in a rope-skipping task, which involves the coordinated oscillation of several segments in the lower and upper limb and trunk and we compared the results to a classical order parameter like continuous relative phase. Five rope skippers completed a task which involved 30 s continuous forward rope-skipping during which the frequency (set by a metronome) increased linearly, immediately followed by 30 s during which the frequency decreased linearly. CRP was analyzed with statistical parametric mapping and a hysteresis measure for the SOM was calculated based on inter-trial variability. Both the CRP and the SOMs showed that the coordination patterns changed differently during the two conditions, signifying hysteresis. While the CRP captures only the relative coordination of two segments, the SOM is able to accommodate the whole-body multidimensional coordination. Hysteresis is often used as proxy for higher-order information about the movement system. While the low sample size in this study does not allow us to generalize the results, the present methodology can be used in further studies to advance our theoretical understanding of dynamical systems in complex whole-body movements.

A three-dimensional kinematical analysis of the handball jump shot, using the finite helical axis (FHA) approach

Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso. A three-dimensional kinematical analysis of the handball jump shot, using the finite helical axis (FHA) approach Autor(es): Deckers, Aiko; Serrien, Ben; Baeyens, Jean-Pierre Publicado por: Imprensa da Universidade de Coimbra URL persistente: URI:http://hdl.handle.net/10316.2/28387 DOI: DOI:http://dx.doi.org/10.14195/2182-7087_4_13