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We aimed to clarify the effect of different futsal playing surface structural properties on the resultant change of direction (COD) performance, perceived traction and frictional properties. Twenty experienced male university soccer players performed a COD slalom-course test and perceived traction evaluation on three different types of playing surfaces (area-elastic: AE, point-elastic no.1: PE1 and point-elastic no.2: PE2). Frictional properties of these surfaces were mechanically evaluated against a futsal shoe, using a hydraulic moving force platform, and expressed as available friction coefficient (AFC). In the COD performance test, the participants performed significantly better on the point-elastic surfaces (PE1 and PE2) when compared to the area-elastic surface (AE) (p

Previous studies have compared slip resistance of commercially available footwear, however, often lacking the ability to isolate factors such as material and surface properties, or/and geometry. The aim of this study was to compare slip resistance of geometrically identical shoes with varying outsole materials. Three left Ecco Xpedition III shoes were constructed out of three different outsole materials: polyurethane (PU), thermoplastic polyurethane (TPU) and vulcanised rubber (RU). The shoes were tested for dynamic coefficient of friction (DCOF) on a steel and a tile surface, without contamination and with glycerine and canola oil as contaminants. The shoes were significantly (p < 0.001) different from each other across all surface/contaminant conditions/combinations, with the PU having a significantly 61–125% (p < 0.001) higher DCOF on contaminated surfaces compared to the RU outsole. Practitioner summary: Previous research has suggested the importance of studying individual parameters separately of footwear in relation to slip resistance. In this study, we managed to construct geometrically identical shoes and compare the slip resistance between three different outsole materials. We found that the polyurethane outsole was the least slippery choice of material for this specific footwear model on contaminated surfaces.

A heightened risk for lateral ankle sprain injuries has been associated with excessive shoe-surface friction. ‘Spraino’ is a novel product specifically designed towards preventing friction-related lateral ankle sprains. In a recent 510-athlete randomized controlled trial, allocation to this “low-friction” shoe-patch resulted in a 53% reduction of severe ankle sprain injuries. Until now, however, a theoretical explanation linking shoe-surface friction and lateral ankle sprain injury mechanism is missing, and the extent to which Spraino reduces shoe-surface friction remains unknown. Therefore, the purpose of this study was to present a theoretical link between lateral edge shoe-surface friction and the mechanism of lateral ankle sprain injuries, and ultimately establish the ability of Spraino to reduce lateral edge shoe-surface friction. In this paper, we present a theory on how ankle sprain mechanics are directly affected by the friction between shoe and surface, and why friction modifications might be a viable preventive strategy. When testing slip resistance in a modified mechanical test-setup, we detected a 63% reduction (0.83–0.31) in friction coefficient between the lateral edge of the outsole and the indoor sports floor when adding Spraino to the side of the shoe. Justified in our theory, and the previously established clinical effectiveness, this reduction in friction can mitigate both the risk and severity of lateral ankle sprain injuries. This suggests that reducing friction on the lateral edge of footwear can be an effective ankle sprain injury prevention strategy.

Sprains to the lateral ligaments of the ankle joint are the most common type of acute musculoskeletal injuries (Vuurberg et al., 2018). These injuries are especially prevalent in indoor sports wher...

PURPOSE: The sudden rise in the injury incidence during adolescence is also evident in soccer-related injuries to the groin. Submaximal passing applies high stress on the adductor muscles and pubic symphysis and is therefore likely to be connected to the occurrence of groin injuries. Therefore, the purpose of the study was to compare hip joint kinematics and adductor muscle forces of different adolescent age groups during submaximal soccer passing. METHODS: Sixty participants, in four groups, younger than 12, 15, 16. and 23 yr (U12, U15, U16, U23), were analyzed. A Footbonaut, equipped with a 3D motion capture system consisting of 16 cameras, was used to capture kinematic data of short passes. Inverse dynamic analysis was performed to calculate muscle forces of 10 passes of each subject. RESULTS: The U15 group showed reduced angular velocities. A rise in hip adductor muscle forces was evident from the youngest group up to the oldest groups. The largest increase (49%) was found between U12 and U15. Lower-limb mass was identified as the best predictor for the increasing adductor force. CONCLUSIONS: The reduced angular velocities of the U15 and the increase in muscle forces between all age groups were attributed to the increasing segment masses and length. This increases the moments of inertia of the leg segments thereby demanding higher forces to accelerate the segments. Most likely, the stress put upon the adductors apophyses increases during adolescence, as tendons are known to adapt slower than muscles, increasing the risk for overuse injuries. Coaches could use lower-limb mass as an indicator for fast increases in the force demand to identify players who would benefit from a reduced training volume.

Ankle injuries are among the most frequent injuries sustained in sports with approximately 75% being lateral sprains (Fong, Hong, Chan, Yung, & Chan, 2007). Prevention of ankle sprains is a broad f...

It has previously been speculated that the occurrence and severity of lateral ankle sprain injuries is linked to excessive shoe-surface friction. The purpose of this study was to assess the amount of lateral edge friction in indoor sports shoes, and evaluate the variation from the traditional forefoot traction test. Therefore, we modified the ISO:12387:2019 test for slip resistance and positioned the shoe on its lateral edge while simulating a sideways movement. All tests were conducted on an indoor surface. In general, we found that lateral edge friction on average was 22% lower than forefoot friction (p

It has previously been speculated that the occurrence and severity of lateral ankle sprain injuries is linked to excessive shoe–surface friction. Especially, the lateral parts of the shoe outsole are suggested to play an important role in such scenarios but have never been quantified in a systematic manner. Therefore, the purpose of this study was to investigate the variation of friction of indoor sport shoes with foot orientation and compare it to the traditional industry forefoot friction test standard. We modified the ISO:13287:2019 test for footwear slip resistance and positioned the shoe on its forefoot and lateral edge while replicating medio-lateral movements similar to previously reported ankle sprain incidents. All tests were conducted on an indoor vinyl/sport surface. The results from the modified setups were compared to those following the anterior-posterior orientated ISO standard. Medio-lateral friction was on average 17% lower and lateral edge friction 24% lower than anterior-posterior forefoot friction (p