34 research outputs found
Sliding Allows Faster Repositioning during Tennis Specific Movements on Hard Court
No full textAbstractTennis game is nowadays getting faster and players have to show strong defensive skills in order to win points. This implies returning more balls and repositioning very fast to get ready for the next stroke. In order to achieve this speed demand especially on hard court, a few players are able to slide like on clay court. The purpose of this study was to determine whether sliding on hard court allows a faster repositioning during a tennis specific routine. A total of eighteen male, national level tennis players participated in this study. A new concept of shoe (NSh) was developed specifically to allow players to slide on hard court. The subjects were asked to play three series of ten balls sent by a ball machine, once with the new shoe and once with a regular shoe (RSh). They were instructed to move back quickly to the centre of the court between each stroke. The players’ displacements were videotaped (Casio Exilim FH25, Casio, Tokyo, Japan) at 120Hz from a rear-view in order to record the centre of gravity (CG) trajectories. The main results showed that time for repositioning – defined as the time separating ball contact and CG movement direction inversion - was reduced by up to 42% when wearing NSh compared to RSh. This gain of time resulted in a 1.10 m shorter distance covered by the players between the hit of the ball and the repositioning at the centre of the court. These results are suggesting that with Nsh, the players were able to better adjust their body position to play the strokes. Instead of doing multiple little adjustment steps, players did large lunges, slid, and hit the ball in an open stance position, then began the repositioning right after the stroke
Cutaneous stimulation at the ankle: a differential effect on proprioceptive postural control according to the participants’ preferred sensory strategy
No full textInternational audienc
Regular changes in foot strike pattern during prolonged downhill running do not influence neuromuscular, energetics, or biomechanical parameters
No full textResearch has suggested that a high variability in foot strike pattern during downhill running is associated with lower neuromuscular fatigue of the plantar flexors (PF). Given the popularity of trail running, we designed an intervention study to investigate whether a strategy with regular changes in foot strike pattern during downhill running could reduce the extent of fatigue on neuromuscular, energetics and biomechanical parameters as well as increase an uphill time- to-exhaustion trial (TTE) performance. Fourteen experienced trail runners completed two interventional conditions (separated by 15 days) in a pseudo-randomized and counter-balanced order that consisted of 2.5-h of treadmill graded running with (switch condition) or without (control condition) a change between fore- and rear-foot strike pattern every 30 s during the downhill sections. Pre and Post, neuromuscular tests were performed to assess PF central and peripheral fatigue. Energy cost of running was assessed using an indirect calorimetry system and biomechanical gait parameters were acquired with an instrumented treadmill. TTE was performed after both the graded running conditions. There were not significant condition × time interactions (P ≥ 0.085) for any of the variables considered, and TTE was not different between the two conditions (P = 0.755). A deliberate strategy to alternate between foot strike patterns did not reduce the extent of fatigue during prolonged graded running. We suggest that it is not the ability to switch between foot strike patterns that minimises fatigue; rather the ability to adapt foot strike pattern to the terrain and therefore a better running technique
Interactions between cadence and power output effects on mechanical efficiency during sub maximal cycling exercises
No full textA soft ankle brace increases soleus Hoffman reflex amplitude but does not modify presynaptic inhibition during upright standing
No full textInternational audienc
Individual physiological responses to changes in shoe bending stiffness: a cluster analysis study on 96 runners
No full textInternational audienceBackground Shoe longitudinal bending stiffness is known to influence running economy (RE). Recent studies showed divergent results ranging from 3% deterioration to 3% improvement in RE when bending stiffness increases. The variability of these results highlights inter-individual differences. Thus, our purpose was to study the runner-specific metabolic responses to changes in shoe bending stiffness. Methods After assessing their maximal oxygen consumption ( VO2 max) and aerobic speed (MAS) during a first visit, 96 het- erogeneous runners performed two treadmill 5 min runs at 75% VO2 max with two different prototypes of shoes on a second day. Prototypes differed only by their forefoot bending stiffness (17 N/mm vs. 10.4 N/mm). RE and stride kinematics were recorded during each trial. A clustering analysis was computed by comparing the measured RE and the technical measurement error of our gas exchange analyzer to identify functional groups of runners, i.e., responding similarly to footwear interventions. ANOVAs were then computed on biomechanical and morphological variables to compare the functional groups. Results Considering the whole sample (n = 96), there was no significant difference in RE between the two conditions. Cluster 1 (n = 29) improves RE in the stiffest condition (2.7 ± 2.1%). Cluster 2 (n = 26) impairs RE in the stiffest condition (2.7 ± 1.3%). Cluster 3 (n = 41) demonstrated no change in RE (0.28 ± 0.65%). Cluster 1 demonstrated 1.7 km•h -1 greater MAS compared to cluster 2 (p = 0.014). ConclusionThe present study highlights that the effect of shoe bending stiffness on RE is runner-specific. High-level runners took advantage of increased bending stiffness, whereas medium-level runners did not. Finally, this study emphasizes the importance of individual response examination to understand the effect of footwear on runner's performance.</div
SLIDING ON HARDCOURT SURFACE WITH SPECIFIC SHOES, PRELIMINARY RESULTS
No full textThe purpose of this study was to investigate the sliding characteristics of a new shoe (NSh) concept. The NSh has been developed with the specific aim of facilitating sliding on hard surface such as tennis players can do on clay or synthetic turf. Five young tennis players performed several trials on a walkway instrumented with seven force platforms synchronized with a motion capture system. Results revealed that the coefficient of friction was still higher for the NSh-hard surface condition than for the regular shoesynthetic turf condition but the players were able to obtain the same sliding length provided that approach velocity was higher
Additional file 1: of Cutaneous stimulation at the ankle: a differential effect on proprioceptive postural control according to the participants’ preferred sensory strategy
No full textData sets of the study. (XLSX 53 kb
