How a wrist guard might have saved Katie Ormerod’s wrist in Pyeongchang

The winter Olympics haven’t even started and we already have injuries in the British camp. Britain’s medal hope, freestyle snowboarder Katie Ormerod, has fractured her wrist during training in Pyeongchang. Despite this setback she is still planning on competing in the slopestyle qualification on Sunday — less than a year after she fractured her L3 vertebra at the world championships last March.

Extreme sports carry an element of risk and snowboarding is no exception. Wrist fractures are the most common injury amongst snowboarders, with an estimated 95,000 wrist fractures worldwide every year. As both feet are fixed to the board with bindings, a moment of instability can make it very difficult to regain balance. The instinct is to throw out arms to break the fall and protect the head and torso. This impact can result in a compressive load through the carpals and hyperextension in the wrist joint resulting in a fracture.

fracture
An example of a radius fracture

These injuries are particularly common amongst beginners and adolescents, who are learning the sport for the first time and struggling to stay on their feet. Elite performers are also susceptible to this type of injury, due to travelling at high speeds and performing dangerous tricks, as was the case with Katie who slipped off a rail.

Wearing wrist protection has been shown to reduce the risk of wrist injuries.  There are a range of products on the market, which typically incorporate palmar and dorsal splints to stabilise the wrist joint and limit hyperextension. Palmar damping elements may be included to absorb the compressive impact load.

wrist protectors
Commercially available wrist protectors

Studies have shown that injury incidence is lower amongst those snowboarders that wear protection and laboratory studies replicating fall conditions have found that protectors do lower the impact force[1-4]. Yet there is no minimum performance standard that these products should meet, unlike ski helmets which are subject to both ISO and EN safety standards. To date, little research and development has gone into wrist protector characterisation, leaving consumers confused and misled about their safety.

In 2014 a call was made to implement a new international standard; a minimum set of performance requirements for snowboarding wrist protectors [5]. Researchers at the Centre for Sports Engineering (CSER) have been working alongside the International Standards Organisation and the Swiss council for accident prevention to develop a new test protocol.  Caroline Adams (CSER) has developed unique mechanical test methods that replicate injurious fall scenarios to compare the protective performance of wrist protectors. The test method has been validated against published fracture data as part of her PhD. The instrumented pendulum impactor can be tuned to replicate the mass and velocity of different fall scenarios.

impact rig.png
CSER Impact pendulum test rig

A key challenge when testing protective equipment is to keep the user central.  A simplified hand model (surrogate) based on the shape of a human forearm was built to replicate 50th percentile population. The surrogate was built to withstand repeated impacts but differentiate wrist guard performance. Commercially available protectors are mounted onto the instrumented surrogate and the impact force and wrist hyperextension angle are measured.

surrogate.png
A bespoke, instrumented surrogate based on 3D scan geometry

This tool will uniquely allow designers and manufacturers to understand how their products transfer and absorb impact energy and whether they will pass the proposed new standard. Ultimately reducing the risk of injury and enhancing consumer safety. Based on this body of work a standard has been prepared – “ISO 20320: Protective clothing for use in Snowboarding — Wrist Protectors — Requirements and test methods”[6]. It is currently at the draft review stage and will be released in the next year. Meaning all snowboarding wrist protectors will have to perform to a prescribed safe level before being commercially available.

We don’t know whether Katie was wearing a wrist protector when she slipped off the rail in training, but why take the risk? Manufacturers will soon be able to work with users and athletes to understand comfort and CSER to understand injury reduction.

[1] Hagel, B., Pless, I. B., & Goulet, C. (2005). The effect of wrist guard use on upper-extremity injuries in snowboarders. American Journal of Epidemiology, 162(2), 149–156.

[2]Greenwald, R. M., Janes, P. C., Swanson, S. C., & Mcdonald, T. R. (1998). Dynamic Impact Response of Human Cadaveric Forearms Using a Wrist Brace. The American Journal of Sports Medicine, 26(6), 2–7.

[3] Adams, C., James, D., Senior, T., Allen, T., & Hamilton, N. (2016). Development of a Method for Measuring Quasi-static Stiffness of Snowboard Wrist Protectors. Procedia Engineering, 147, 378–383.

[4] Kim, K.-J., Alian, A. M., Morris, W. S., & Lee, Y.-H. (2006). Shock attenuation of various protective devices for prevention of fall-related injuries of the forearm/hand complex. The American Journal of Sports Medicine, 34(4), 637–643

[5] Michel, F. I., Schmitt, K.-U., Greenwald, R. M., Russell, K., Simpson, F. I., Schulz, D., & Langran, M. (2013). White Paper: functionality and efficacy of wrist protectors in snowboarding—towards a harmonized international standard. Sports Engineering, 16(4), 197–210.

[6] International Organization for Standardization, 2016

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About csalauncher

PhD student at the Centre for Sports Engineering. Prone to injury having suffered both a wrist and an ankle fracture pole vaulting.

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