L’étude des forces de réaction au sol peut-elle être un indicateur de la stabilité de la chaussure lors de la locomotion ?

Objective

The aim of this study was to determine the influence of ground reaction forces on the footwear stability.

Material and methods

Twelve healthy men have walked on a treadmill ergometer ADAL with five different shoe models and in a barefoot condition. Here, the shoe called “shoe 1” is known for its capacity to stabilize the foot. Ground reaction forces (F_x, F_y, F_z) were recorded at constant speed (2, 4 and 6 km h⁻¹), and during transition phases (0 to 2, 0 to 4, 0 to 6 km h⁻¹). Two running conditions (8 km h⁻¹ at constant speed and 0 to 8 km h⁻¹ in transition) have completed this protocol. Then, each subject filled in a questionnaire to evaluate, for each shoe, different sensations: stability during walking and running, foot support, heightening of the rearfoot, width of shoe at the heel, general comfort, cushioning. At last, different geometrical parameters of each shoe were measured.

Results and discussion

The results show that, in all tested conditions (constant speed and transition phases, walking and running), medial force peaks are significantly more important in barefoot condition than all shod conditions, except for the shoe 1. As the barefoot condition is, according to the literature, the best condition of stability and as the shoe 1 is known for its capacity to stabilize the foot, these results could suggest that a better stability could be associated with more important medial force peaks.     

Sexe des joueurs et blessures en handball : influence de l’arbitrage ?

Introduction

The aim of this study was to examine whether refereeing may be evocated to explain why male handball players get injured more often than female players.

Synthesis of the facts

A total of 90 handball matches, both men's and women's, were observed focusing on transgression play against players in possession of the ball and the resulting refereeing decisions. The aggressive behavior and refereeing differ according to the sex of the players.

Conclusion

Female players are refereed more severely which may help to explain why they are less aggressive and get injured less frequently than their male counterparts.     

Le « syndrome des jambes lourdes » chez les athlètes surentraînés est-il le reflet de désordres hémorhéologiques ?

Introduction. – The aim of this work is to evaluate if the feeling of heavy legs in athletes is correlated with overtraining syndrome-related hemorheological disturbances.Results. – The subjects who quoted the item: “I have the feeling of heavy legs” had higher plasma viscosity and higher red cell aggregation parameters. The overtraining score was correlated positively with plasma viscosity, and aggregability parameters. The feeling of heavy legs was correlated with plasma viscosity and aggregability.Conclusion. – These findings suggest that the feeling of heavy legs in overtrained athletes is related to overtraining syndrome-related hemorheologic disturbances, namely mild plasma hyperviscosity and mild erythrocyte hyperaggregability.