White Paper: functionality and efficacy of wrist protectors in snowboarding—towards a harmonized international standard

Repeatability of a bending stiffness test for snowboarding wrist protectors

Snowboarding wrist protectors are typically designed to limit impact forces and prevent wrist hyperextension. The standard for snowboarding wrist protectors (ISO 20320:2020) includes a test for measuring their bending stiffness, when fitted to a wrist surrogate. This test serves as a simple means of assessing the ability of wrist protectors to prevent wrist hyperextension. Wrist protector bending stiffness measurements have been shown to be influenced by surrogate design, protector strapping condition, and surrogate surface compliance. Currently, there is a lack of knowledge on the repeatability of bending stiffness measurements, as previous studies have conducted tests during one session. This study investigated the repeatability of a bending stiffness test, by testing two snowboarding wrist protectors (short and long) on two wrist surrogates (compliant and stiff), under three protector strapping conditions (loose, moderate, tight), across three repeated test sessions. Test session had a significant effect (p < 0.05) on torque values, with a large effect size ($$\eta_{{\text{p}}}^{2}$$ η p 2  > 0.14), indicating the test had limited repeatability between test sessions. Despite this limited repeatability, torque values increased with both wrist angle and strap tightness, as reported before, indicating consistent trends in results. The outer surface compliance of the surrogate did not significantly affect the protector’s sensitivity to test session nor strapping condition.

Effects of using rigid tape with bandaging techniques on wrist joint motion during boxing shots in elite male athletes

OBJECTIVES

To investigate the effects of bandaging techniques on wrist motion on impact during different shot types in elite male boxers.

DESIGN

Repeated-measures study.

SETTING

Field Experiment PARTICIPANTS: Two shot types, straight and bent arm, were assessed with 18 elite male boxers wearing either bandage only or bandage plus tape.

MAIN OUTCOMES MEASURES

Wrist motions and time to peak wrist angles, on impact, were measured with an electromagnetic tracking system.

RESULTS

Wrist motion on impact occurred concurrently in flexion and ulnar deviation for both shot types. For both motions, significant (p < 0.001) effects for bandaging techniques (η² = 0.580-0.729) and shot types (η² = 0.165-0.280) were observed. For straight and bent arm shots, wrist motion on impact occurred within 50% and 40% respectively of total active wrist motion for bandage only compared to within 20% and 15% for bandage plus tape. Time to peak wrist angle on impact increased significantly (p < 0.001) for both shot types when adding tape to bandage.

CONCLUSIONS

Adding tape provided an additional 25-30% reduction in wrist motion compared to bandage only, with a 1.2-1.4 increase in time to peak wrist angle, on impact for both shot types. This information could assist various individuals and organisations towards better hand-wrist protection.

Dental and general injuries among ski and snowboard instructors in Switzerland, Germany, and Austria-A questionnaire-based study

Objectives

Data on the injury rate of skiers and snowboarders are currently limited. The aim of this study was, therefore, to assess the frequency of general and dental injuries among snow sports instructors, to investigate the use of protective gear and mouthguards, and to evaluate snow sports instructors' dental first aid know‐how.

Material and Methods

A questionnaire‐based, cross‐sectional study comprising 603 ski and snowboard instructors from Austria, Germany, and Switzerland was conducted in the timeframe December 2019 to May 2020. The survey gathered data on general and dental injuries sustained by instructors, protective gear usage, and know‐how in dental first aid. The statistical analysis included χ² tests, Wilcoxon rank‐sum and Kruskal–Wallis tests, and linear regression analysis. The level of significance was set at α = .05.

Results

Out of the 603 instructors, 326 (54.1%) sustained an injury while skiing or snowboarding. Forty (6.6%) reported a snow sports‐related dental injury. The rates of injuries related to skiing and snowboarding showed no significant difference (p = .0952). Compared with snowboarding on slopes, backcountry snowboarding entailed fewer risks of injury for snowboard instructors (p = .012). Knowledge of dental first aid was limited, with 45.8% of instructors uninformed about the possibility of replanting avulsed teeth. 10.1% of instructors were familiar with tooth rescue boxes. None of the instructors surveyed had a tooth rescue box in their first aid equipment. Helmet usage was high (95.6%) among snow sports instructors, whereas mouthguard usage was rare (3.5%).

Conclusions

Protective gear usage among snow sports instructors is high. The risk of dental injury while skiing or snowboarding is lower compared with other sports. Dental first aid know‐how ought to be enhanced in snow sports communities to ensure that appropriate first aid is provided in case of a dental injury related to skiing or snowboarding.

Effect of Compressive Strain Rate on Auxetic Foam

Auxetic foams have previously been shown to have benefits including higher indentation resistance than their conventional counterparts, due to their negative Poisson’s ratio, making them better at resisting penetration by concentrated loads. The Poisson’s ratio and Young’s modulus of auxetic open cell foams have rarely been measured at the high compressive strain rates typical during impacts of energy absorbing material in sporting protective equipment. Auxetic closed cell foams are less common than their open cell counterparts, and only their quasi-static characteristics have been previously reported. It is, therefore, unclear how the Poisson’s ratio of auxetic foam, and associated benefits such as increased indentation resistance shown at low strain rates, would transfer to the high strain rates expected under impact. The aim of this study was to measure the effect of strain rate on the stiffness and Poisson’s ratio of auxetic and conventional foam. Auxetic open cell and closed cell polymer foams were fabricated, then compression tested to ~80% strain at applied rates up to 200 s−1, with Poisson’s ratios obtained from optical full-field strain mapping. Open cell foam quasi-static Poisson’s ratios ranged from −2.0 to 0.4, with a narrower range of −0.1 to 0.3 for closed cell foam. Poisson’s ratios of auxetic foams approximately halved in magnitude between the minimum and maximum strain rates. Open cell foam quasi-static Young’s moduli were between 0.02 and 0.09 MPa, whereas closed cell foams Young’s moduli were ~1 MPa, which is like foam in protective equipment. The Young’s moduli of the auxetic foams approximately doubled at the highest applied strain rate of 200 s−1.

Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system

The hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate (< 0.2°) and quasi-static testing (< 6°). Both systems showed a good intraclass coefficient of reliability (ICCs > 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexion–extension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system.

Hospital-Treated Snow Sport Injury in Victoria, Australia: A Summary of 2003-2012

INTRODUCTION

To determine the incidence rate and changes over time for ice and snow sports injury in Victoria, Australia, from 2003 to 2012 and describe the most common types and causes of these injuries.

METHODS

Retrospective data from the Victorian Injury Surveillance Unit describing hospital admissions and emergency department presentations were extracted for the 10-year period of 2003 to 2012 for all ice- and snow-related injury. Descriptive injury data and participation-adjusted trend analyses using log-linear regression modelling of data (statistical significance, P<0.05) from the Exercise, Recreation and Sport Survey 2003 to 2010 are presented.

RESULTS

Overall, there were 7387 ice- and snow-related injuries, with a significant increase in hospital-treated snowboard injuries and a (nonsignificant) decline in hospital-treated ski injuries over the 10 years. Skiing (39%) and snowboarding (37%) had the highest incidence of hospital-treated injury, with males aged 15 to 24 years injured most frequently in both sports. Falls were the most common cause of injury in both skiing (68%) and snowboarding (78%).

CONCLUSIONS

Patterns of snow sports injury in Australia during 2003 to 2012 remain similar to findings of national studies conducted decades earlier. More importantly, however, Australian injury patterns are comparable to international statistics and thus may be generalizable internationally. Head injuries, although infrequent, are associated with great injury severity due to a high frequency of hospitalization. Furthermore, research into the use of personal protective equipment and other injury prevention measures among Australian participants, particularly by young, male snowboarders, is required. Given the similar injury patterns, injury prevention measures implemented internationally could reasonably translate to an Australian setting.