Yesterday Guthrie found an article entitled “Feet hurt? Stop Wearing Shoes”. It begins;
“It took 4 million years of evolution to perfect the foot, and humans have been wrecking that perfection with every step since they first donned shoes…”
It then goes on to draw on the negative impact increased cushioning and heel height has on the foot’s structure and ability to support us. I’ve been digging around and discovered a number of web sites devoted to barefoot running and one particular article also titled Barefoot Running caught my eye.
Running barefoot is associated with a substantially lower prevalence of acute injuries of the ankle and chronic injuries of the lower leg in developing countries, but well-designed studies of the effects of barefoot and shod running on injury are lacking. Laboratory studies show that the energy cost of running is reduced by about 4% when the feet are not shod. In spite of these apparent benefits, barefoot running is rare in competition, and there are no published controlled trials of the effects of running barefoot on simulated or real competitive performance.
Many runners have suffered with plantar problems and the article makes a case that shoes, rather than provide support to relieve the problem, are in fact the cause and a perpetuating factor!
One of the most common chronic injuries in runners is planter fasciitis, or an inflammation of the ligament running along the sole of the foot. There is some evidence that the normally unyielding plantar fascia acts as the support for the medial longitudinal arch, and that strain on the proximal fascial attachment during foot strike leads to plantar fasciitis (Robbins and Hanna, 1987). Barefoot running may induce an adaptation that transfers the impact to the yielding musculature, thus sparing the fascia and accounting for the low incidence of plantar fasciitis in barefoot populations (Robbins and Hanna, 1987).
Chronic ailments such as shin splints, ilio-tibial band syndrome and peri-patellar pain are attributed variously to excessive pronation, supination, and shock loading of the limbs (Siff and Verkhoshansky, 1999, p.451). When running barefoot on hard surfaces, the runner compensates for the lack of cushioning underfoot by plantar-flexing the foot at contact, thus giving a softer landing (Frederick, 1986). Barefoot runners also land mid-foot, increasing the work of the foot’s soft tissue support structures, thereby increasing their strength and possibly reducing the risk of injury (Yessis 2000, p.124).
Wearers of expensive running shoes that were promoted as correcting pronation or providing more cushioning experienced a greater prevalence of these running-related injuries than wearers of less expensive shoes (Robbins and Gouw, 1991). In another study, expensive athletic shoes accounted for more than twice as many injuries as cheaper shoes, a fact that prompted Robbins and Waked (1997) to suggest that deceptive advertising of athletic footwear (e.g., “cushioning impact”) may represent a public health hazard. Anthony (1987) reported that running shoes should be considered protective devices (from dangerous or painful objects) rather than corrective devices, as their capacity for shock absorption and control of over-pronation is limited. The modern running shoe and footwear generally reduce sensory feedback, apparently without diminishing injury-inducing impact–a process Robbins and Gouw (1991) described as the “perceptual illusion” of athletic footwear. A resulting false sense of security may contribute to the risk of injury (Robbins and Gouw, 1991). Yessis (2000, p.122) reasoned that once the natural foot structures are weakened by long-term footwear use, people have to rely on the external support of the footwear, but the support does not match that provided by a well functioning foot.
Measurements of the vertical component of ground-reaction force during running provide no support for the notion that running shoes reduce shock. Robbins and Gouw (1990) reported that running shoes did not reduce shock during running at 14 km/h on a treadmill. Bergmann et al. (1995) found that the forces acting on the hip joint were lower for barefoot jogging than for jogging in various kinds of shoe. Clarke et al. (1983) observed no substantial change in impact force when they increased the amount of heel cushioning by 50% in the shoes of well-trained runners. Robbins and Gouw (1990) argued that plantar sensation induces a plantar surface protective response whereby runners alter their behavior to reduce shock. The less-cushioned shoe permitted increases in plantar discomfort to be sensed and moderated, a phenomenon that they termed “shock setting”. Footwear with greater cushioning apparently provokes a sharp reduction in shock-moderating behaviour, thus increasing impact force (Robbins and Hanna, 1987; Robbins et al., 1989; Robbins and Gouw, 1990). However, in these studies the subjects ran on treadmills or force platforms. Further studies are needed to establish how shoes affect impact force and shock-moderating behavior on natural surfaces such as road or grass.
Other features of footwear, such as arch supports and orthotics, may interfere with shock-moderating behavior and probably hinder the shock-absorbing downward deflection of the medial arch on landing (Robbins and Hanna, 1987). These features reportedly reduce pronation and supination or offer the wearer lateral and arch support. They may help some people with foot pathologies, but their benefit is uncertain for runners with healthy feet (Yessis, 2000, p.121).
Runners with diminished or absent sensation in the soles of the feet are particularly vulnerable to damage or infection when barefoot. Peripheral neuropathy is a common complication of diabetes mellitus and may result in the loss of protective sensations in the feet. Barefoot locomotion is therefore not recommended in this population (Hafner and Burg, 1999). Indeed, proper footwear is essential and should be emphasized for individuals with peripheral neuropathy (ACSM/ADA, 1999; ACSM, 2000).
It is also suggested that wearing shoes increases the energy cost of running!
Wearing shoes increases the energy cost of running. Burkett et al. (1985) found that oxygen consumption during running increased as the amount of mass they added to the foot increased; shoes and orthotics representing 1% of body mass increased oxygen consumption by 3.1%. Flaherty (1994) found that oxygen consumption during running at 12 km/h was 4.7% higher in shoes of mass ~700 g per pair than in bare feet. An increase in oxygen consumption of ~4% is of little importance to the recreational runner, but the competitive athlete would notice a major effect on running speed.
If you want to adapt to barefoot running…
Thirty minutes of daily barefoot locomotion is a recommended starting point to allow thickening of the sole of the foot and adaptation of muscles and ligaments (Robbins et al., 1993). Begin by walking barefoot at every reasonable opportunity then progress to jogging, gradually increasing the intensity and duration (Yessis 2000, p.124). After 3-4 weeks, the plantar skin eventually becomes robust and allows longer periods of barefoot running at higher average velocities (Robbins et al., 1993). To facilitate adaptation, perform progressive strengthening exercises for the foot and ankle, including foot inversion, toe flexion, and walking on the balls of the feet. Barefoot locomotion on uneven surfaces will also help stimulate the plantar surface and provide increased sensory feedback (Yessis 2000, p.125).
In conclusion:
Running in shoes appears to increase the risk of ankle sprains, either by decreasing awareness of foot position or by increasing the twisting torque on the ankle during a stumble.
Running in shoes appears to increase the risk of plantar fasciitis and other chronic injuries of the lower limb by modifying the transfer of shock to muscles and supporting structures.
Running in bare feet reduces oxygen consumption by a few percent. Competitive running performance should therefore improve by a similar amount, but there has been no published research comparing the effect of barefoot and shod running on simulated or real competitive running performance.
Research is needed to establish why runners choose not to run barefoot. Concern about puncture wounds, bruising, thermal injury, and overuse injury during the adaptation period are possibilities. [It took research to work this out!]
Running shoes play an important protective role on some courses, in extreme weather conditions, and with certain pathologies of the lower limb.
I don’t foresee a rush of runners gathering at start lines with their toes exposed however, it does seem that barefoot activity when practical (no need for insulation; no risk of crush injuries; social acceptability) deserves consideration since plantar sensory mediated protective adaptations seem optimized for this condition. Although this may run counter to notions prevalent when recounting dangers of barefoot activity and necessity of footwear even when barefoot activity is feasible, there is a strong belief that took much footwear design is guided by fashion rather than health considerations.
I may walk about the house and yard without shoes a bit more often but the thought of a 100 without good foot protection is a little hard to grasp!
