As the weather improves and the hedgerows turn green, the hard, health-related messages about the dire consequences of physical inactivity start to sink in. The efforts of ‘ordinary’ folk as well as the elite athletes in the London Marathon might also stir you from your comfy armchair. Running allows you to exercise from home on local roads or from the workplace for relatively little outlay and with low on-going costs. Whatever your level, this activity requires a careful choice of footwear and clothing, and attention to a range of ergonomic issues.
Running barefoot would now be regarded as unthinkable although participants in road races in many Asian and African countries still compete without wearing shoes. At top competitive level neither roads nor running tracks are sufficiently forgiving to the barefooted competitor, and cross-country performers need the competitive edge that spiked shoes offer. Abele Bikele from Ethiopia won the Olympic Games marathon running barefoot on Rome’s cobblestones in 1960; he retained his title in Tokyo in 1964, this time wearing running shoes. Bare-footed British runners who did reasonably well at this time included Frank Salvat, Bruce Tulloh and Jim Hogan but their barefooted endeavours were unsustainable as the last of the grass tracks were replaced by asphalt-based or tarmac surfaces. The last notable woman to run barefoot was Zola Budd in the 1980s although she experimented with running shoes when she immigrated to the UK.
A pair of running shoes was seen as a functional item of apparel, essential for protecting against bruising from contact with objects on the surface and cushioning the impact on landing. Runners generally had two sets of shoes, one set of lightweight shoes with embedded spikes for the track and a more robust, heavier shoe for the road. Choice was limited, the market being dominated by two or three manufacturers, one of which also specialised in football boots. The market changed considerably in the 1970s as the jogging craze spread in the USA, Japan and then to Europe, fuelled by the big city marathons, culminating in the first London marathon in 1981. By this time jogging was a socially accepted leisure activity, joggers swelled the entries at competitive road races and a new market emerged for sports clothing and footwear.
We reported an ergonomics study of marathon running at the Annual Conference of the Ergonomics Society in 1983. The increased participation in road running was accompanied by an increase in the incidence of injuries; overuse injuries were experienced by athletes on high training loads while joggers displayed an increase in soft tissue and lower back injuries when they increased the frequency of training abruptly. A range of factors predisposing to injury was revealed that included Morton’s foot (a disproportionately large second toe), discrepancy in leg length, genu valgus and genu varus (knock-knees and bow-legs). Shoe manufacturers recognised that their designs should meet the needs of the new market which now included women as well as men; the first women’s Olympic Games marathon was held in Los Angeles in 1984. Besides, runners from different racial backgrounds had different foot shapes.
A revolution in running shoe design was facilitated by new manufacturing processes and the availability of new composite materials. Novel vulcanisation methods and synthetic materials such as ethylvinylacetate (EVA) facilitated the replacement of leather as the base material. New companies were formed and new products became increasingly founded on ergonomics criteria that prioritised comfort, safety and performance. The criteria for ergonomics evaluation of running shoes were designed by Peter Cavanagh when working at Penn State University. Peter was a PhD student at Don Grieve’s laboratory in the Royal Free Hospital School of Medicine in 1970 where the first cohort of students on the MSc Ergonomics programme at University College London did their biomechanics modules. He continued his work on the biomechanics of gait at Penn State University funded in part by the running shoe industry. In his laboratory he tested a range of running shoes on the market and combined their performances on standard biomechanical tests into an overall rating. Results published in Runners World provided a Which?-like service to customers but antagonised the companies whose products did not match their marketing claims. The decade that followed was the golden age for those working on the ergonomic links between shoes, surfaces, the human foot and subject responses.
Designs of running shoes quickly incorporated ergonomic features. The shock absorption properties of the sole were improved by its composition of different characteristics in the outer and the midsole with a wedge in between at the back of the shoe. Enhanced shock absorption was provided in some shoe designs by incorporating an air bubble into the material. A heel counter provided rearfoot stability, important in decreasing the risk of Achilles tendinitis. An insole board provided the interface with the runner’s sock, and in some designs an ‘arch cookie’ midway along increased the flexibility of the shoe on plantar flexion at toe-off, a function that is fulfilled by the sole complex in current designs. Anti-pronation devices were built into other shoes to reduce the incidence of problems at the knees or the metatarsal heads related to excessive pronation on landing. This design feature has partly replaced the need for orthotics, which were moulded to the individual’s foot shape and, rather like benzodiazepenes for treating psychological stress, were being overprescribed. Indeed, authors in the current issue (March 2009) of the British Journal of Sports Medicine question the evidence base for prescribing running shoes with elevated cushioning and pronation control features, citing the lack of controlled clinical trials. This absence of preventative studies highlights a gap between the laboratory experiments and field trials quickly marketed by shoe companies and accepted by customers, and the prospective epidemiological studies that convinces sports medicine specialists.
Boundaries between shoe layers have also gained attention, including the stiffening of the mudguard tip on the toe box, padding on the tongue and collar, and the featherline between sole and upper. Rippled treading was incorporated into running shoes, allowing them to be used on multi-terrain surfaces. The design formula has been much improved due to laboratory studies and most recent attention is given to details such as the lacing patterns. Shoes that are too tight or too loose are uncomfortable. Higher lacing patterns ensure there is a firm coupling between foot and shoe, leading to a more effective function of the shoe.
Training and competing serve different purposes and for elite runners have totally separate requirements. Racing shoes are light in weight which aids performance but reduces the protection on impact. Training shoes are heavier, provide good protection although they lose their cushioning properties with mileage. The naïve customer seeking the ideal running shoe may be bewildered by the vast array of products available and might justifiably be confused by innovative features that are based on fashion rather than on ergonomics.
The first principle in selecting a shoe is to ensure it fits and feels comfortable. This means a satisfactory fit to the length, shape and width of the shoe. The length is probably the most important aspect and a thumb-wide distance at the toe should allow for movement of the foot in the longitudinal axis within the shoe. A sock similar to that to be used in training should be worn in a fitting trial. See the sidebar for more advice. Of course, there are other considerations such as your food and drink intake (preferably not alcohol!), and the type of clothing you wear during running.
Author: Professor Tom Reilly
Print 
PDF