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  • Author: Matthieu Lenoir x
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Veerle Segers, Peter Aerts, Matthieu Lenoir, and Dirk De Clercq

The purpose of this study was to examine the kinetics of the walk-to-run transition (WRT) and run-to-walk transition (RWT), when accelerating or decelerating across transition speed (a = 0.17 m·s−2). Nine women performed gait transitions on a 50-m-long walkway. Vertical ground reaction forces (GRFs) and the center of pressure (COP) were examined in the range from 3 steps before to 3 steps after transition in order to identify the possible occurrence of a transition process, in order to facilitate the actual realization of transition. The actual transition is realized in one step, during WRT and RWT. This transition step was characterized by an outlying vertical GRF and COP trajectory (deviating from walking and running). Despite this clear discontinuity, a transitional adaptation period (process) appeared in both transitions. In the WRT, transition was prepared and kinetic adaptations were found in the last step before transition. The RWT was pre- and “post”-pared and only completed during the first walking step after transition. Thus, the WRT and RWT are two distinct phenomena, with different kinetics.

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Brigit De Wit, Dirk De Clercq, and Matthieu Lenoir

The purpose of this study was to investigate the influence of midsole hardness on both impact forces and rearfoot motion. Seven trained male long-distance runners were assessed with a Kistler force plate and with high-speed video, while running at 4.5 ± 0.1 m · s"1 with soft and hard shoe soles (EVA; soft shore Asker C40; hard shore Asker C65). The results showed smaller initial vertical impact peaks, occurring with a higher loading rate, and a significantly larger and faster initial eversion when subjects ran with hard shoes. Support is given to the concept that a more pronounced initial eversion offers an additional deceleration mechanism (Stacoff, Denoth, Kaelin, & Stuessi, 1988) also increasing the eccentric loading of the inverting muscles. On the other hand, during midstance soft shoe soles were found to produce a larger maximum eversion and pronation, also imposing an increased load on the same muscles. So, a good running shoe should be focused on a balance between reducing impact forces and reducing overpronation.

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Eva D’Hondt, Benedicte Deforche, Ilse De Bourdeaudhuij, and Matthieu Lenoir

The purpose of this study was to investigate gross and fine motor skill in overweight and obese children compared with normal-weight peers. According to international cut-off points for Body Mass Index (BMI) from Cole et al. (2000), all 117 participants (5–10 year) were classified as being normal-weight, overweight, or obese. Level of motor skill was assessed using the Movement Assessment Battery for Children (MABC). Scores for balance (p < .01) and ball skills (p < .05) were significantly better in normal-weight and overweight children as compared with their obese counterparts. A similar trend was found for manual dexterity (p < .10). This study demonstrates that general motor skill level is lower in obese children than in normal-weight and overweight peers.

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Liesbeth I.N. Mazyn, Gilles Montagne, Geert J.P. Savelsbergh, and Matthieu Lenoir

In the present study, the limits of human catching behavior were challenged to investigate quantitative and qualitative adaptations of the catching movement when performing under varying ball speeds, implying minor as well as severe temporal constraints. Nine male participants caught balls approaching at speeds ranging from 8.5 to 19.7 m/s with their preferred hand. Although a decrease in catching performance was undeniable, several quantitative adaptations provided the catcher with extra time and allowed to compensate the decrease in spatial accuracy with increasing speed. More importantly, changes in the coordination between hand, elbow, and shoulder emerged with increasing movement velocity. More demanding temporal constraints lead to a shift from relatively independent activity of each joint towards a mode in which several joints act as one unit. This reorganization of the coordination pattern of the catch is discussed in the context of Bernstein’s degrees of freedom problem.

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Philip W. Fink, Sarah P. Shultz, Eva D’Hondt, Matthieu Lenoir, and Andrew P. Hills

Multifractal analyses have been used in recent years as a way of studying balance, with the goal of understanding the patterns of movement of the center of pressure at different spatial scales. A multifractal detrended fluctuation analysis was used to compare obese and nonobese children to investigate the cause of previously demonstrated deficiencies in balance for obese children. Twenty-two children (11 obese and 11 nonobese), aged 8–15 years, performed 30-s trials of bilateral static balance on a plantar pressure distribution measuring device. Both the obese and nonobese groups demonstrated greater persistence for small fluctuations, but the effect was greater in the obese group. This was particularly evident with the eyes closed, where significant differences between the obese and nonobese were observed for small fluctuations. These results demonstrate that balance deficiencies in obese children may be the result of decreased proprioceptive abilities in obese children.

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Pieter Tijtgat, Jos Vanrenterghem, Simon J. Bennett, Dirk De Clercq, Geert J.P. Savelsbergh, and Matthieu Lenoir

The purpose of this study was to investigate postural adjustments in one-handed ball catching. Specifically, the functional role of anticipatory postural adjustments (APA) during the initial arm raising and subsequent postural adjustments (SPA) for equilibrium control and ball-hand impact were scrutinized. Full-body kinematics and kinetics allowed an analysis of the mechanical consequences of raising up the arm and preparing for ball-hand impact. APA for catching were suggested to be for segment stabilization. SPA had a functional role for equilibrium control by an inverted pendulum mechanism but were also involved in preparing for the impact of the ball on the hand, which was illustrated by an increased postural response at the end of the movement. These results were compared with raising up the arm in a well-studied reaction-time task, for which an additional counter rotation equilibrium mechanism was observed. Together, our findings demonstrate that postural adjustments should be investigated in relation to their specific functional task constraints, rather than generalizing the functional role of these postural adjustments over different tasks.

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Farid Bardid, Floris Huyben, Frederik J.A. Deconinck, Kristine De Martelaer, Jan Seghers, and Matthieu Lenoir

The aim of this study was to investigate the convergent and divergent validity between the Body Coordination Test for Children (KTK) and the Motor Proficiency Test for 4- to 6-Year-Old Children (MOT 4-6). A total of 638 children (5–6 yr old) took part in the study. The results showed a moderately positive association between the total scores of both tests (r s = .63). Moreover, the KTK total score correlated more highly with the MOT 4-6 gross motor score than with the MOT 4-6 fine motor score (r s = .62 vs. .32). Levels of agreement were moderate when identifying children with moderate or severe motor problems and low at best when detecting children with higher motor-competence levels. This study provides evidence of convergent and divergent validity between the KTK and MOT 4-6. However, given the moderate to low levels of agreement, either measurement may lead to possible categorization errors. Therefore, it is recommended that children’s motor competence not be judged based on the result of a single test.

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Frederik J. A. Deconinck, Dirk De Clercq, Geert J. P. Savelsbergh, Rudy Van Coster, Ann Oostra, Griet Dewitte, and Matthieu Lenoir

In the present study the walking pattern of 10 children with developmental coordination disorder (DCD) was investigated and compared to that of 10 typically developing, matched control children. All children walked at a similar velocity that was scaled to the length of the leg on a motor-driven treadmill. Three-dimensional kinematics were recorded with a motion capture digital camera system. The spatiotemporal parameters of the gait pattern revealed that children with DCD walked with shorter steps and at a higher frequency than the typically developing children. In addition, the children with DCD exhibited a body configuration that demonstrated increased trunk inclination during the entire gait cycle and enhanced during the entire gait cycle. At toe-off a less pronounced plantar flexion of the ankle was observed in children with DCD. In conclusion, it appeared that children with DCD make adaptations to their gait pattern on a treadmill to compensate for problems with neuromuscular and/or balance control. These adaptations seem to result in a safer walking strategy where the compromise between equilibrium and propulsion is different compared to typically developing children.

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Frederik J.A. Deconinck, Dirk De Clercq, Geert J.P. Savelsbergh, Rudy Van Coster, Ann Oostra, Griet Dewitte, and Matthieu Lenoir

One-handed catching behavior was studied in nine 6- to 8-year-old boys with Developmental Coordination Disorder (DCD) and nine matched typically developing boys. The participants performed a catching task under two conditions. In the first condition, one ball speed was used while three ball speeds were randomly presented in the second condition. Boys with DCD showed a significantly smaller maximal hand aperture and a lower maximal closing velocity in both the first and the second condition; however, the temporal structure of the catch as well as the adaptations to the varying ball speeds did not differ between groups. This leads to the suggestion that the motor problems of boys with DCD in one-handed catching are not primarily due to debilitated visuo-perceptual or planning processes but are more likely caused by problems at the execution level.

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Job Fransen, Thomas W.J. Lovell, Kyle J.M. Bennett, Dieter Deprez, Frederik J.A. Deconinck, Matthieu Lenoir, and Aaron J. Coutts

The aim of the current study was to examine the influence of restricted visual feedback using stroboscopic eyewear on the dribbling performance of youth soccer players. Three dribble test conditions were used in a within-subjects design to measure the effect of restricted visual feedback on soccer dribbling performance in 189 youth soccer players (age: 10–18 y) classified as fast, average or slow dribblers. The results showed that limiting visual feedback increased dribble test times across all abilities. Furthermore, the largest performance decrement between stroboscopic and full vision conditions was in fast dribblers, showing that fast dribblers were most affected by reduced visual information. This may be due to a greater dependency on visual feedback at increased speeds, which may limit the ability to maintain continuous control of the ball. These findings may have important implications for the development of soccer dribbling ability.