Barefoot running: Factors affecting performance and the implications for injury

Barefoot running and minimalist training shoes have been a hot topic for debate among both amateur and professional runners in recent years. With the emergence of headlines such as ‘Runners without shoes land more gently on the ground, avoiding impact injuries’ (Independent, 2010) there is little wonder as to why the craze has continued to grow. This article looks to explore the practice of barefoot running, deconstructing the myths that surround it whilst also giving some practical advice for performance and injury prevention.

The paper to spark this debate of the benefits to barefoot running was by Lieberman et al. (2010) suggesting that running shoes cause heel striking and that running barefoot would make for a flat/forefoot strike. It was thought that this forefoot strike would negate the impact peak of the heel strike that was frequently linked to running injuries and thus running with this style will not subject the body to the same impact loading. Ultimately, leading to the conclusion that running shoes cause impact shock and accommodate higher injury susceptibility. Perhaps a key result of this study was the introduction of minimalist training shoes such as Nike Free and Vibram Five Fingers, such trainers seek to emulate barefoot running since it was suggested that running shoe cushioning and heel lift were not beneficial. However, running both barefoot and whilst wearing minimalist training shoes result in higher impact force magnitudes and loading rates compared with traditional shod running (Squadrone and Gallozi, 2009). Both variables arguably possess a similar risk of injury as impact shock, thus highlighting flaws in the ‘safe’ and ‘gentle’ nature of running barefoot.

However it has been shown that the impact force acts as an external input to our system, allowing us to detect the nature of the surface and adjust our muscle activation accordingly (Nigg & Wakeling, 2001). Contradicting the notion that impact peak is associated with injury (Zadpoor & Nikooyan, 2011) and instead providing a means for runners to become more efficient in adjusting to different terrains. As opposed to examining ground reaction force data it has been suggested that the study of pressure variables would be more appropriate. This would allow for the identification of the area of the foot that first comes in contact with the ground providing more detail of what foot contact style is being adopted for different conditions (Nunns et al., 2012).

Current empirical evidence is equivocal regarding the potential benefits to barefoot running and running economy. Nevertheless there are a number of factors to consider that may affect oxygen consumption whilst running. The first of which being the affect of added mass, with each 100g shoe mass resulting in a 1% increase in oxygen consumption and with the average training shoe possessing a mass of 300g this could mean an O₂ uptake increase of up to 6%. On the other hand, due to the absence of footwear there is a metabolic cost associated with active cushioning. This takes places via changes in muscular activity in the supporting muscles, all of which is likely to result in a less efficient running performance. Lastly, during barefoot running there is a need for greater sensory feedback. Since the runners feet are coming into direct contact with the ground heightened proprioception is necessary and this may lead to gait alterations making for less efficient strides.
Although barefoot running may allow for the effective use of elastic energy in foot through a forefoot strike one’s strike pattern has not been proven to affect an individual’s running economy. So, forefoot striking offers no economical advantage over heel striking and given that runners naturally adopt their optimal stride type this could reduce their running economy.

 To conclude, barefoot running is not the miracle running practice that sporting professionals originally thought, making athletes more efficient and injury free. Instead it just causes individuals to load the associated joints in a different manner and changing their stride type, the effects of which can be equally as injury inducing. The notion that barefoot running also resulting in greater running economy can also be seen to be a myth as although it rids the exerciser of the added mass effect from trainers it does not account for the need of greater proprioception. Overall leading to gait alterations that would have already been at the optimal measures.