At the 2010 Winter Olympic Games, Amy Williams won a gold medal for Great Britain in the women’s skeleton event. An exceptionally talented and dedicated athlete like Amy, combined with word class coaching, sports science and medical support were, of course, key ingredients in any gold medal winning performance. But a key component in Amy’s success was her sled which was designed and built through a collaborative partnership between BAE Systems, UK Sport, University of Southampton and Sheffield Hallam University.
British Skeleton’s Performance Director, Andreas Schmidt, recognised that taking an innovative approach to the provision of kit and equipment could be the icing on the cake when attempting to take on and beat the world’s best winter sport nations. With this background, UK Sport and British Skeleton decided in 2006 to provide the British team with a radical new world-beating sled for the 2010 Winter Olympic Games in Vancouver.
As we now know, Amy Williams used this new sled in the Olympic Games to great effect, finishing a clear half second ahead of her nearest rivals (a considerable margin in the sport of skeleton). Now affectionately known as ‘Arthur’, the sled featured a range of radical new design features. The project team responsible for producing the new sled included Kelvin Davies and David Cocksedge from BAE Systems and Rachel Blackburn and James Roche from Southampton University. A key focus of this partnership was the application of ergonomic best practice to the sled design. Significant effort was put into understanding the requirements of the athletes, the interface between the athlete and the sled and the myriad of small usability refinements that, when combined, serve to provide Britain’s athletes with the incremental performance gains needed to win at international level.
The skeleton sled is far from being a passive vehicle. It is a complex machine, weighing in the order of 40kg. It must support the athlete on a steeply banked downhill track at speeds of up to 130km/h (80mph) and under stress levels of 4g or more. The sled frame is made of high grade steel and it is steered by the athlete through weight shifting and by direct steering inputs through the shoulders and feet. This frame is covered by padding on the top surface and an aerodynamic carbon fibre cowling on the lower surface. The runners on which the sled is supported are directly attached to the frame of the sled through a mechanism which allows them to be set up for different tracks and different ice conditions. The key adjustment is through the longitudinal pressure placed on the runners, which alters the amount of ‘bowing’ in the runner profile. (A concave form from front to back delivers a sled which tends to run in a straight line; a convex form provides a sled which is more agile in turning.)
The athlete rides the sled in a saddle, formed of two body contour shaped steel frames to left and right, serving both as push handles at the start and a support (both lateral and vertical) for the athlete during the high dynamic forces experienced during a skeleton run. There are a large number of ergonomic considerations in this complex mechanism including features related to riding the sled, setting up the sled and maintaining the equipment. It was these that were the focus of attention for the BAE Systems Advanced Technology Centre’s human factors team working on the sled design.
Kelvin Davies, who led the Human Factors review of the sled, commented: “All those who work in the fields of ergonomics and human factors know how critical user-centric design can be to the development of successful engineering systems. However it is rare to have the opportunity to demonstrate this more effectively to a global audience than through contributing to the design of as high profile a product as Amy Williams’ sled.”
The world-first design features on the new sled include adjustable components as well as interchangeable structural parts, allowing bespoke design to the individual athlete’s size and sliding style. This makes the sled more responsive to the athlete and provides greater steering control. The sled also features a ratchet mechanism to facilitate fast, precise and repeatable setup of the runners, allowing for the changing condition of the ice.
The ambition of UK Sport and the team assembled for the new sled programme in 2006/2007 was to provide the British skeleton team athletes with a ‘sled for life’. Skeleton is a highly professional sport in the UK with a very motivated team of athletes and coaches at its core (see ww.bobskeleton.org.uk). This professionalism is reflected in the success of the team over the past 10 years. In spite of the fact that the UK possesses no winter sliding sports facilities, the country is a world leader in the sport, and has won medals in the last three Olympics, culminating in a gold medal in Vancouver in 2010.
This professionalism was also reflected in the approach to building the ‘sled for life’. It was recognised early in the programme that the athletes’ requirements were key to designing the best equipment. During 2007 a full review was completed with the British skeleton team. All athletes and coaches participated in an extensive requirements capture and feedback session with BAE Systems’ human factors engineering team.
The review highlighted a number of clear areas for improvement. Amongst the key points were:
- Existing sleds were ‘one size fits all’. It was difficult to adjust the sled to fit the physique of each athlete, resulting in a poorer sled/athlete interface than the ideal. Athletes were critical of the existing saddle and stated that it was difficult to adjust and far from a ‘snug’ and comfortable fit. Without a good fit the sled/athlete system was compromised, steering was less precise and performance suffered.
- Sled maintenance was also found to be an issue. The more time it takes to maintain a sled, the less time available for training and racing. Therefore a focus was placed on ease of maintenance with good accessibility and a range of interchangeable parts.
- Sled set up is critical. The performance on a particular track is dependent on selecting the correct settings for the sled. In much the same way as for a Formula 1 car, there are a number of sled parameters that can be ‘tuned’ to the requirements of each track. In particular the runners on which the sled slides can be subjected to a varying degree of bowing to suit different tracks and athletes. However the existing procedure for adjusting the runners was rudimentary and precision and repeatability suffered.
Analysis of the results from this extensive process revealed key athlete requirements. In the design stage, the human factors engineers worked alongside skilled mechanical design engineers from BAE Systems and Southampton University to incorporate the key ergonomic requirements into the new sled design.
Only with this clear list of priorities and requirements from the athletes was it was possible to design a new sled that included those key innovations which took sled design to the next level. Key improvements to the sled include:
- Simple adjustability to the frame of the saddle to ensure that the sled can be accurately fitted to the body contours of individual athletes. This helps to improve the interface between the athlete and the sled. This improves comfort and enhances performance, particularly in respect to steering the sled with precision.
- Accuracy in the set up of the runners using a ratchet system to pre-stress the runners to provide a precise and repeatable configuration for the sled. It is worth noting that Amy Williams broke the track record a number of times during the 2010 competition. The precision available to her in runner set up would have supported her in achieving this, allowing her to set up her sled repeatedly in precisely the same configuration.
- Interchangeable parts to allow for quick and easy maintenance. As a high energy sport, skeleton sleds are prone to impact damage. With competitions across the globe, sleds may also be damaged in transit in spite of the precautions taken through using bespoke carrying cases. It is important that athletes are not distracted from the competition itself, therefore ease of sled maintenance is critical. This is greatly assisted through the design of the sled, the ease of access to the components and the use of interchangeable parts.
The quality of the ergonomic design, when combined with quality engineering and a world class athlete, was evident from the success achieved in Vancouver 2010. The new sled clearly demonstrated how well an integrated team can work together to deliver both innovative engineering and new technologies, and how these can contribute to making those vital fractions of a second difference on the skeleton track.
by Kelvin Davies
Kelvin Davies is Executive Human Factors Scientist at BAE Systems Advanced Technology Centre.