Barefoot running and running in minimalist shoes have received much attention in the scientific literature and media over the past few years. However, only 25%-30% of runners have reported using minimalist footwear on a regular basis 1, 2, and only 2% run barefoot on a regular basis 1. In fact, only 20% have reported trying to run barefoot 2.
Advocates of barefoot/minimalist-shoe running suggest that changes in mechanics, foot strength, and impact have a direct relationship to injury reduction. A March 2014 article in the British Journal of Sports Medicine 3 reviews current research regarding barefoot running, and concludes that running injuries are the result of many factors, and running without your shoes is least likely to be the mitigating factor.
But research and debate on barefoot and minimalist running are likely to continue, in light of various reported benefits.
The most common justifications for barefoot running are:
- It is the "natural" way of running.
- It prevents injury.
- It makes you run faster.
- It strengthens the muscles of your feet.
Are these claims supported by evidence?
Let's explore each one:
Natural Running
While it is likely that humans' gait mechanics have evolved over eons, the evidence of the relationship between shoes and these changes is lacking. Shoes have been worn for thousands of years. More recently, the running boom of the 1970s resulted in distinct changes in shoes. Interestingly, since the change in shoe construction has changed dramatically over the past 40 years, the rate of injuries among runners has not. It would seem possible that this is due to 2 potential reasons 3:
- Shoes are not related to the injuries, or
- The features of shoes are addressing the wrong factors.
These facts should not lead one to believe that no shoes are the answer.
Prevents Injury
The theory for how barefoot running will prevent injury are based on 2 primary findings:
- It reduces impact, and
- It reduces the load at the knee.
Both of the above claims presume changes in mechanics occur with barefoot running, that running without shoes should result in a midfoot or forefoot strike pattern, rather than a heel strike gait. However, only 40%-50% of individuals who run barefoot adopt a midfoot or forefoot strike pattern.
Impact has been associated with stress related injuries to the tibia. By changing the strike pattern, the impact is potentially removed from the lower leg, but those impact forces are likely moved to the foot as a result. In fact, foot stress fractures have been related to increased loads.
While midfoot or forefoot striking reduces the impact forces at the knee, it concurrently increases the demand on the ankle muscles. If the logic is that reducing load in 1 structure will decrease injury, then increasing load in another structure should increase risk of injury. It is yet to be determined if either of these is true.
Faster Running
This appears to be a classic case of backwards logic. Runners adopt more of a midfoot strike pattern as they run faster. In fact, 73% of competitive runners in the 800 m and 1500 m events have a midfoot or forefoot strike pattern 11. However, during a marathon or half marathon, 88.9% of runners are rearfoot strikers 12.
It is often suggested that midfoot or forefoot striking is more economical (uses less energy) so therefore, you can run farther and faster. However, research suggests that forefoot runners and heel-strike runners demonstrate the same running economy at various speeds 13. So, faster runners are more likely to adopt a midfoot or forefoot pattern, but adopting a midfoot or forefoot pattern does not necessarily make you faster.
Muscle Strength
Evidence suggests that short foot exercises do increase the size of the foot intrinsic muscles; however, there is no evidence to suggest that barefoot walking or running has the same effect. There is little rationale given as to the reason for the foot strengthening 14.
- Are stronger feet less likely to be injured? Or,
- Are stronger feet more likely to protect other structures in the lower extremities from injury?
It is also important to remember that there are muscles originating outside the foot (extrinsic muscles) that play a significant role in foot and ankle control during running and walking. These muscle are longer and have greater force-producing capabilities than the muscles originating inside the foot. Finally, recent findings suggest little change in foot intrinsic muscle activity after running (with or without shoes), and no difference between shoes on and shoes off 10.
Conclusion
Barefoot/minimalist running is a popular topic of discussion that is, in reality, not very prevalent among runners. There is little data to support its use as a training tool or treatment for injury. Continued study on the potential risks and benefits of this technique is necessary to determine its usefulness.
References
1. Goss DL, Gross MT. Relationships among self-reported shoe type, footstrike pattern, and injury incidence. US Army Med Dep J. 2012;Oct-Dec:25-30. Article Summary on PubMed.
2. Rothschild CE. Primitive running: a survey analysis of runners' interest, participation, and implementation. J Strength Cond Res. 2012;26(8):2021-2026. Article Summary on PubMed.
3. Tam N, Astephen Wilson JL, Noakes TD, Tucker R. Barefoot running: an evaluation of current hypothesis, future research and clinical applications. Br J Sports Med. 2014;48(5):349-355. Free Article.
4. Trinkaus E, Shang H. Anatomical evidence for the antiquity of human footwear: Tianyuan and Sunghir. J Archaeol Sci. 2008;35(7):1928–1933. Article Summary.
5. Willson JD, Bjorhus JS, Williams DS III, Butler RJ, Porcari JP, Kernozek TW. Short-term changes in running mechanics and foot strike pattern after Introduction to minimalistic footwear. PM R. 2014;6(1):34-43. Article Summary on PubMed.
6. Hatala KG, Dingwall HL, Wunderlich RE, Richmond BG. Variation in foot strike patterns during running among habitually barefoot populations. PLoS One. 2013;8(1):e52548. Free Article.
7. Lieberman DE, Venkadesan M, Werbel WA, et al. Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature. 2010;463(7280):531-535. Article Summary on PubMed.
8. Dixon SJ, Creaby MW, Allsopp AJ. Comparison of static and dynamic biomechanical measures in military recruits with and without a history of third metatarsal stress fracture. Clin Biomech (Bristol, Avon). 2006;21(4):412-419. Article Summary on PubMed.
9. Ridge ST, Johnson AW, Mitchell UH, et al. Foot bone marrow edema after a 10-wk transition to minimalist running shoes. Med Sci Sports Exerc. 2013;45(7):1363-1368. Article Summary on PubMed.
10. Williams DS III, Green DH, Wurzinger B. Changes in lower extremity movement and power absorption during forefoot striking and barefoot running. Int J Sports Phys Ther. 2012;7(5):525-532. Free Article.
11. Hayes P, Caplan N. Foot strike patterns and ground contact times during high-calibre middle-distance races. J Sports Sci. 2012;30(12):1275-1283. Article Summary on PubMed.