The (Re-) Evolution Of Barefoot Running: Does It Reduce Injury?

The increase in popularity of barefoot running has led to research being conducted in the US as to the merits of this new trend.

By Paul Remy Jones, Christian Barton and Dylan Morrissey* W

hen working with clients you may have noticed the emergence of running shoes dedicated to protecting the feet of the wearer, whilst at the same time retaining the

perceived benefits of running without healed shoes.

Footwear has become a multi-billion pound industry and for the past 50 years has been attempting to enhance and optimise the running shoe for both performance and injury prevention. Now we’re asking whether we should run minimally shod, or even barefoot, with many arguing that the typical running shoe is part of the injury problem. Is this an industry-driven fashion or a back-to-nature scientific advance?

The popularity of running and prevalence of running injuries Running is one of the most simple and popular forms of exercise. It is estimated that 10–20% of the US population run regularly, and, in 2002 alone, almost 0.5 million competitors completed a marathon- length race within the United States (1). The health benefits of regular physical activity, such as running, are numerous and well documented (2). However, the greatest challenge to regular running is the associated high incidence of injury, which has been reported as 54.8% and 59% in two recent studies (3,4). Most running injuries are due to overuse. Common injuries include patellofemoral pain syndrome, iliotibial band friction syndrome, medial tibial stress syndrome, Achilles tendinopathy, plantar fasciitis and stress fracture (5). Despite the technological innovations of modern running shoes designed to reduce injury rates, incidence has remained steady (6). As a result, both clinicians and the general public have begun to question the validity of wearing often expensive running shoes, either to alleviate or prevent injury (7).

The development of running shoes and evidence for injury prevention Running-specific shoes were first introduced shortly after Charles Goodyear developed a method with which to vulcanise rubber in 1839, and consisted simply of a canvas slipper, a hardened rubber sole and some spikes under the forefoot for improved grip. Running shoes remained very much in this mould until Onitsuka Tiger (now Asics) introduced the cushioned heel in 1963. Since then, we have witnessed a rapid increase in running shoe technology, such as longitudinal arch support, stiffer heel cups and soles, multiple density soles, raised heels, and gel and air cushioning, designed to increase comfort, correct suboptimal running biomechanics and reduce injury.

The mainstay of treatment for many chronic running injuries has been 16

to prescribe ‘better’ running shoes incorporating one or more of these corrective features. However, the evidence supporting this practice is weak. A Cochrane Database systematic review, published this year, concluded that there was no evidence that prescribing running shoes based on assessment of foot type (eg. motion control shoes for those with a low arch) offered any protection from overuse injuries compared to standard (neutral) running shoes (8). Additionally, a recent systematic review found that the current practice of prescribing running shoes with supportive or correctional properties is not evidence-based and that the true effects of these shoes on the health and performance of runners remains unknown (9). Interestingly, a study by Taunton et al. found that runners training in shoes more than two years old reported lower injury rates than those wearing shoes less than 3 months old (10), which may question the practice of advising runners to change their shoes frequently in order to ensure consistent foot support and prevent injury (11).

The rationale behind running barefoot The notion that wearing shoes may contribute to injury and deformity is not new. In 1972 Stewart noted that men who lived unshod “… are free from the disabilities commonly noted among shod people – hallux valgus, bunions, hammer toe and painful feet…” (12). However, there has been a huge surge of interest of late in running barefoot due, in no small part, to the success of the bestselling book “Born to run: The hidden tribe, the ultra-runners and the greatest race the world has never seen (13)”. The book describes the Tarahumara people of Mexico, who regularly run distances up to 120 miles wearing no more than simple sandals on their feet, and reportedly rarely experience the running injuries common in modern societies. In addition, there is a small but increasing body of literature (14–16) suggesting that humans evolved to run long distances (likely for persistent hunting) and that many of our bodily adaptations, such as short toes (17) and enlarged gluteus maximus muscles (18), occurred to facilitate our running endeavours. Given that early man ran unshod and the possible benefits of this practice raised by McDougall’s book, recent research has sought to determine the potential advantages of running barefoot.

Lieberman et al. compared habitually barefoot with habitually shod runners and found that the barefoot runners tended to land on their forefoot (FFS – referred to in the present paper as ‘barefoot-style’) before bringing their heel down, whereas the shod runners landed hind foot first (RFS), thought to be facilitated by the built-up heels of their running shoes (19). The authors reported that the shod RFS runners experienced abrupt collision forces on contact with the ground, which were significantly reduced or absent in the barefoot- style group. They also noted greater vertical compliance, causing a lower rate of loading in the barefoot group. Given that the average

The REPs Journal 2013;27(May):16-18