The influence of gravimetric moisture content on studded shoe–surface interactions in soccer

It is desirable for the studs of a soccer shoe to penetrate the sport surface and provide the player with sufficient traction when accelerating. Mechanical tests are often used to measure the traction of shoe–surface combinations. Mechanical testing offers a repeatable measure of shoe–surface traction, eliminating the inherent uncertainties that exist when human participant testing is employed, and are hence used to directly compare the performance of shoe–surface combinations. However, the influence specific surface characteristics has on traction is often overlooked. Examining the influence of surface characteristics on mechanical test results improves the understanding of the traction mechanisms at the shoe–surface interface. This allows footwear developers to make informed decisions on the design of studded outsoles. The aim of this paper is to understand the effect gravimetric moisture content has on the tribological mechanisms at play during stud–surface interaction. This study investigates the relationships between: the gravimetric moisture content of a natural sand-based soccer surface; surface stiffness measured via a bespoke impact test device; and surface traction measured via a bespoke mechanical test device. Regression analysis revealed that surface stiffness decreases linearly with increased gravimetric moisture content (p = 0.04). Traction was found to initially increase and then decrease with gravimetric moisture content. It was observed that: a surface of low moisture content provides low stud penetration and therefore reduced traction; a surface of high moisture content provides high stud penetration but also reduced traction due to a lubricating effect; and surfaces with moisture content in between the two extremes provide increased traction. In this study a standard commercially available stud was used and other studs may provide slightly different results. The results provide insight into the traction mechanisms at the stud–surface interface which are described in the paper. The variation between traction measurements shows the influence gravimetric moisture content will have on player performance. This highlights the requirement to understand surface conditions prior to making comparative shoe–surface traction studies and the importance of using a studded outsole that is appropriate to the surface condition during play

Incorporating endoscope in middle ear surgery

We conducted a study to evaluate the use of a pediatric rigid otoendoscope for determining the extent of middle ear disease and for assessing ossicular integrity and mobility during tympanoplasty. Our study population was made up of 132 patients who were undergoing surgery for the treatment of chronic suppurative otitis media; of this group, 41 patients underwent otoendoscopy and 91 underwent scutum lowering for purposes of visualization. In the otoendoscopy group, the ossicles were successfully visualized and their mobility assessed in 34 patients; the remaining 7 patients subsequently underwent scutum lowering. A 30° endoscope allowed for complete visualization of the middle ear in almost all of the 34 cases. The mean duration of surgery for the 34 patients in the otoendoscopy group was 62.85 minutes (±15.57), which was significantly shorter than the duration of surgery (71.23 ± 15.65 min) for the 98 patients who underwent scutum lowering (p \u3c 0.005). A total of 50 patients required less than 60 minutes of surgical time-26 of 34 (76.5%) in the endoscopy group and 24 of 98 (24.5%) in the scutum-lowering group. Statistical analysis revealed that the possibility of completing a procedure in less than 60 minutes was 73.65% (±12.56%) when endoscopy was used and 58.62% (±12.60%) when scutum lowering was used-again, a statistically significant difference (p \u3c 0.005). We conclude that incorporation of an angled otoendoscope into middle ear surgery is a worthwhile alternative to scutum lowering