Does soccer cleat design influence the rotational interaction with the playing surface?

Non-contact injuries in soccer players may be related to the interplay between cleat type and playing surface, and bladed shoes were often blamed for non-contact injuries with no research support. The aim of this study was to compare the rotational resistance (stiffness and peak sustainable torque) among three types of soccer cleats (metal studs, molded rubber studs, and bladed) in a controlled laboratory environment. The shoes were tested on both natural and artificial turfs under a compressive preload of 1000 N and with internal and external rotations. The three shoe models showed comparable performances with a good repeatability for each individual test on both playing surfaces. A less stiff behavior was observed for the natural turf. A tendency toward highest peak torque was observed in the studded model on natural surface. The bladed cleats provided peak torque and rotational stiffness comparable to the other models. Studded and bladed cleats did not significantly differ in their interaction with the playing surface. Therefore, soccer shoes with bladed cleats should not be banned in the context of presumed higher risk for non-contact injuries.

Shoe Allergens: A Retrospective Analysis of Cross-sectional Data From the North American Contact Dermatitis Group, 2005-2018.

BACKGROUND: Shoe contact allergy can be difficult to diagnose and manage. OBJECTIVE: The aim of the study was to characterize demographics, clinical characteristics, patch test results, and occupational data for the North American Contact Dermatitis Group patients with shoe contact allergy. METHODS: This is a retrospective study of 33,661 patients, patch tested from 2005 to 2018, with a shoe source, foot as 1 of 3 sites of dermatitis, and final primary diagnosis of allergic contact dermatitis. RESULTS: Three hundred fifty-two patients met the inclusion criteria. They were more likely to be male (odds ratio = 3.36, confidence interval = 2.71-4.17) and less likely to be older than 40 years (odds ratio = 0.49, confidence interval = 0.40-0.61) compared with others with positive patch test reactions. The most common relevant North American Contact Dermatitis Group screening allergens were potassium dichromate (29.8%), p-tert-butylphenol formaldehyde resin (20.1%), thiuram mix (13.3%), mixed dialkyl thioureas (12.6%), and carba mix (12%). A total of 29.8% (105/352) had positive patch test reactions to supplemental allergens, and 12.2% (43/352) only had reactions to supplemental allergens. CONCLUSIONS: Shoe contact allergy was more common in younger and male patients. Potassium dichromate and p-tert-butylphenol formaldehyde resin were the top shoe allergens. Testing supplemental allergens, personal care products, and shoe components should be part of a comprehensive evaluation of suspected shoe contact allergy.

Escalators, rubber clogs, and severe foot injuries in children.

BACKGROUND: Reports in the media suggest that escalator-related foot injuries are on the rise. Trendy, bright-colored rubber clogs have been implicated in a significant number of these incidents involving children. We review the children who sustained severe foot injuries on escalators, were wearing rubber clogs at the time of injury, and who were admitted to hospital for emergency surgery. METHODS: A list of children who sustained foot injuries on escalators was generated from the hospital database and included for study. From clinical chart review, demographic data, footwear type, and injuries sustained were recorded. Inpatient or outpatient treatment rendered was also recorded for each patient. RESULTS: Between September 2006 and September 2008, we treated 17 children for escalator-related foot injuries. There were 10 boys and 7 girls who were between 2 and 9 years of age (mean: 5.5). Thirteen children (76.5%) from this group were wearing rubber clogs at the time of injury. Nine of these 13 (69.2%) children sustained severe foot injuries that required admission to hospital for emergency surgery and are the focus of this study. One child had an unsalvageable traumatic amputation of the great toe at the level of the interphalangeal joint. Two children sustained crush injuries to the great toe: 1 with severe degloving and the other with an open fracture of the proximal phalanx. One child had an open fracture-dislocation of the second metatarsophalangeal joint with a comminuted fracture of the second metatarsal. Five children sustained multiple deep lacerations in the foot and 2 of them had associated cut tendons that required repair. In the group not wearing rubber clogs, 3 of 4 children had severe foot injuries. In this series, 4 children with rubber clogs and another child with a different footwear sustained minor injuries; they were treated as outpatients. CONCLUSIONS: Escalator-related foot injuries involving rubber clogs can result in severe crushing of the foot and even traumatic amputation. The broad toe-box design may give a false perception of the distance between the foot and the side of the escalator, whereas the 'softness' of these rubber clogs makes them vulnerable to crush by moving escalator steps. This is the first report in the literature describing escalator-related severe foot injuries in children who were wearing rubber clogs. Injuries sustained can be significant and permanent. The potential dangers of escalators and rubber clogs must not be underestimated. LEVEL OF EVIDENCE: Level IV, Case Series.

The Effects of Heel Height on Head Position, Long-Term Average Spectra, and Perceptions of Female Singers.

Female singers often wear high heels for auditions and performances. Heel height research in non-singing contexts indicates that wearing heels can affect body alignment and head position. Studies in orthodontics, sleep apnea, and voice science suggest that head and neck positioning can alter the vocal tract. The purpose of this study was to assess the effects, if any, of heel height (barefoot, 10.16-cm stilettos) on three angles of singer head position (calculated from C7-tragus-nasion), long-term average spectra data, and perceptual data (questionnaire) acquired from female (N = 30) soloists during alternating periods of silence and singing. Results indicated that all participants (100%) significantly decreased head position angle measurements (inferior and posterior head and neck movement) when singing in high heels compared with singing barefoot. Participants, on average, significantly increased head position angle measurements (superior and anterior head and neck movement) when singing compared with standing silently, and did so to a greater degree when transitioning from silent heels to singing heels compared with transitioning from silent barefoot to singing barefoot. Long-term average spectra data indicated significant spectral energy differences between barefoot and high heel singing conditions across participants. Most participants (n= 21, 70.00%) indicated they felt comfortable and sang their best while barefoot. Results of this study, the second in a series of experiments addressing the effects of shoe heel height on female singers' vocal production, were discussed in terms of application to vocal pedagogy and directions for future research.

Use of new "barrier socks" in contact allergic dermatitis.

We present the case of a fifty-year-old construction worker with contact allergic dermatitis in his feet. Given the limited results obtained with a costly topical therapy, we tried, for first time, using completely breathable "barrier socks", which solved the persistent problem in a matter of days. In addition to the improvement in the patient's quality of life and the renewed possibility of his wearing protective shoes, a net reduction in the costs incurred with topical therapy was also obtained.

The effects of cycling shoe stiffness on forefoot pressure.

Plantar pressure data were recorded in two different shoe types to determine the effect of cycling shoe stiffness on peak plantar forefoot pressure in cyclists. Two pairs of shoes of the same size and manufacturer, identical except for outsole material and stiffness, were tested. Shoe stiffness measurements were collected under controlled conditions and in two different configurations using a dynamic hydraulic tensile testing machine. Measurements of plantar pressure were done using Pedar capacitive-based sensor insoles while subjects pedaled in a seated position at a controlled power output. Power output was set at a constant value of 400 W across all subjects by a magnetic resistance trainer unit. The pressure distribution in carbon-fiber-composite shoes during cycling was compared to cycling shoes made with plastic soles. Carbon fiber shoes presented stiffness values 42% and 550% higher than plastic shoes in longitudinal bending and three-point bending, respectively. The shoes made with carbon fiber produced peak plantar pressures 18% higher than those of plastic design (121 kPa vs. 103 kPa, p = .005). Competitive or professional cyclists suffering from metatarsalgia or ischemia should be especially careful when using carbon fiber cycling shoes because the shoes increase peak plantar pressure, which may aggravate these foot conditions.

Rubber foreign bodies in puncture wounds of the foot in patients wearing rubber-soled shoes.

We report 8 cases of puncture wound of the foot associated with rubber foreign bodies in patients who were wearing rubber-soled shoes. The difficulty in making the correct diagnosis and the complications arising from these injuries are reviewed. The morbidity associated with these seemingly innocuous puncture wounds can be serious. Infective complications resolved only with removal of all imbedded rubber foreign bodies. A history of wearing rubber-soled shoes during the injury and a high index of suspicion may prevent complications.

The effect of roughness, floor polish, water, oil and ice on underfoot friction: current safety footwear solings are less slip resistant than microcellular polyurethane.

Research over a period of about 18 years has shown that a microcellular polyurethane known as AP66033 is the most slip-resistant safety footwear soling material on oily and wet surfaces. In recent years it has been replaced in commercially available footwear by a dual density polyurethane (DDP) which has a dense outer layer and a soft microcellular backing. This research programme has compared the slip resistance of AP66033 with DDP and some rubber solings. In addition, data were obtained on the effects of soling and floor roughness, and floor polish on slip resistance. Some data were also obtained for walking on ice. The coefficient of friction (CoF) of the solings was measured on 19 water wet surfaces in three conditions: (I) when the solings were new, (II) following abrasion to create maximum roughness and (III) after polishing. The CoF was measured on four oily surfaces after each of 11 abrasion or polishing treatments. The profound effects of the roughening of all soles and of floor roughness on the CoF were demonstrated for both wet and oily surfaces. The superior slip resistance of AP66033 was confirmed for oily and wet conditions; however, some rubbers not suitable for safety footwear achieved higher CoF values on wet floors. All of the floor polishes reduced the CoF of all floors when contaminated with water. The mean CoF of DDP solings was lower than the mean for AP66033 on wet and oily surfaces. No safety footwear soling provided adequate grip on dry ice and the CoF was reduced by water on the ice. A rubber used for rock climbing footwear was one of the most slip-resistant solings on wet surfaces in the laboratory but recorded the lowest CoF on ice. It is concluded that the incidence of occupational injuries caused by slipping could be reduced by the following: (A) returning to safety footwear soled with the microcellular polyurethane AP66033; (B) abrading all new and smooth footwear solings with a belt sanding machine coated with P100 grit; (C) avoiding the use of floor polish; (D) informing the general public about the poor slip resistance of ordinary footwear on ice and the lowering of slip resistance in cold weather.

The effect of surface roughness and contaminant on the dynamic friction of porcelain tile.

Surface roughness affects friction, but it is not clear what surface roughness characteristics are better correlated with friction. The average of the maximum height above the mean line in each cut-off length (Rpm) and the arithmetical average of surface slope (deltaa) had the highest correlation with dynamic friction coefficient in a previous study. The previous study was expanded to two different footwear materials and four different contaminants on a porcelain tile in the current investigation. The results showed that dynamic friction decreased as the interface speed and glycerol content in the contaminant were increased due to the hydrodynamic lubrication effect. Deltaa had the highest correlation with friction for most of the test conditions with neolite. For Four S rubber, friction coefficient appeared to have the highest correlation with the parameters related to the surface void volume at 30% glycerol content, related to the surface slope at 70 and 85% glycerol contents, and related to the peak to valley distance at 99% glycerol content. A good indicator of surface slip resistance probably should consist of the surface parameters representing the surface slope, the surface void volume and the surface peak-to-valley distance with the coefficients determined by the system parameters.

[Dermatoses caused by footwear made of synthetic material: the rubber-boot syndrome]. / Dermatosis provocadas por calzado de material sintético: síndrome de las botas de goma.

One hundred patients, workers from a meat packing plant that wear rubber boots while working, were studied. Besides the well known allergic manifestations to rubber or other plastic materials used in footwear other pathologic findings included mycotic and bacterial lesions formed by plantar hyperhidrosis with the development of bromhidrosis and plantar xanthokeratoderma. These occupational dermatoses are a medical problem, but also have social and economical implications.

Shoe allergic contact dermatitis.

Foot dermatitis is a widespread condition, affecting men and women of all ages. Because of the location, this condition may present as a debilitating problem to those who have it. Allergic contact dermatitis involving the feet is frequently due to shoes or socks. The allergens that cause shoe dermatitis can be found in any constituent of footwear, including rubber, adhesives, leather, dyes, metals, and medicaments. The goal of treatment is to identify and minimize contact with the offending allergen(s). The lack of product information released from shoe manufacturers and the continually changing trends in footwear present a challenge in treating this condition. The aim of this study is to review the current literature on allergic contact shoe dermatitis; clinical presentation, allergens, patch testing, and management will be discussed. PubMed and MEDLINE databases were used for the search, with a focus on literature updates from the last 15 years.

p-tert-Butylphenol formaldehyde resin and its impact on children.

: p-tert-Butylphenol formaldehyde resin (PTBPFR) is widely used as an adhesive owing to its rapid onset of action, durability, flexibility, and heat resistance. Moreover, because of its tackiness, it is particularly useful as a glue component on both leather and rubber products. Sensitization to this resin has been increasing since the first cases of PTBPFR contact allergy in the late 1950s, and pediatric contact allergy to this resin is a significant problem. p-tert-Butylphenol formaldehyde resin has been reported as a leading cause of shoe-associated dermatitis internationally, as well as a cause of allergic contact dermatitis from its use in neoprene wet suits and sports equipment such as shin guards. In summary, patch test screening of both adults and children with PTBPFR is important, given the ubiquitous use of this chemical.