Barefoot Running: To Help or to Hurt?
Over the past ten years, barefoot running has taken off in strides as becoming a more prevalent approach to exercising without pain. Many opinions believe that barefoot running is able to change biomechanics back to natural movements of our ancestors. Similarly, barefoot running has been used in an attempt to correct or prevent injury in shod runners who suffer from chronic impact injuries associated with a rearfoot strike. Lastly, muscle activation has been connected to stability in the lower limb as usage increases. Brand names and athletes have been exploring the benefits and risks of minimizing shod footwear or ridding it all together. Efficiency, comfort, and correct movement have all come into question regarding the kinematics of barefoot running. However, inconsistency of findings had led the exercise science world still questioning positive and negative effects of the running methods when comparing barefoot and shod running. Thus, research on how barefoot running influences biomechanics, injury prevention and stability during exercise will be the main topics. Findings of this research will aid in conditioning programs, rehabilitation efforts, endurance training more if a consensus is reached. Therefore, the research in this blog will address if exercising barefoot is better for stability, injury prevention, and biomechanics in runners compared to shod performance.
Many studies have been performed to identify the differences in the forefoot strike of the barefoot runner and the rearfoot strike of the shod runner, and all are relatively similar in a few ways. Up to 93 percent of sub-elite marathon runners (habitual shod runners) are rearfoot strikers according to Munoz-Jimenez, Latorre-Roman, Soto-Hermoso, and Garcia-Pinillos (2015). It is notable to mention that prior to shoes, humans did not run heel-to-toe, simply because barefoot mechanics do not naturally allow that form. Endurance runners are known for chronic injuries of the lower limb, due to biomechanical repetition of mechanism of injury. Sinclair, Butters, and Stainton (2018) reviewed the stance phase to evaluate medial tibiofemoral joint loading in barefoot and shod runners and found knee adduction moment was larger in barefoot runners, as well as the instantaneous load rate. The load rate associated with rearfoot strikes, places the load on the tibiafemoral joint causing chronic injuries in the form of shin splints or low knee pain. Sinclair (2016) was able to associate a larger tibiofemoral load in running shoes than barefoot, which can contribute to overuse injuries and changes in biomechanics. Therefore, rearfoot strike patterns of habitual shod runners contribute to chronic pain more so than barefoot running, despite increase of stride frequency and stride velocity.
Hollander, Heidt, Van der Zwaard, Braumann, and Zech (2017) assessed foot morphology and arch structure to find connections between barefoot running and biomechanics differences. Hollander et al. (2017) found flat feet (low arch) could indicate a habitual barefoot runner, however limitations could also indicate differences in growth patterns or lifestyle. In agreement with Hollander et al., Maiwald, Grau, Krauss, Mauch, Axmann, and Horstmann (2008) tested a theory that plantar pressure can contribute to kinematics and footwear effects on biomechanics of the foot. Thus, if plantar pressure changes when the shoe is removed, a shift in biomechanics and channeling of activation in intrinsic foot muscles is caused. Maiwald et al (2008) also found plantar pressure to be much lower in the heel than the forefoot during a stride, despite increases of loading rate on the heel. In addition, muscle activation was not shown to differ between barefoot and shod runners, but did between forefoot and rearfoot runners (Ervilha, Mochizuki, Figueira, & Hamill, 2017). Therefore, biomechanical changes most greatly seen are the shift in strike and tibiofemoral loading.
When assessing the stability of the lower limb in relation to barefoot running, loading rate and stride frequency can have an effect on the fatigue and thus the integrity. Hashish Samarawickrame, Baker and Salem (2016) thought that reliance on muscles may have a reaction on stability and ground reaction forces. Providing a valid hypothesis to support barefoot running as a more stable activity based on muscle usage. Though it is widely debated that barefoot exercise can contribute to increased stability of the ankle and knee joints in hope of intrinsic muscle strengthening, De Villars and Venter (2014) found a substantial increase in medial-lateral and anterior-posterior stability after an 8-week barefoot training period. Specifically, in changing direction, ankle stability can prove to be an asset to performance in sports. (De Villars & Venter, 2014) tested a program which was progressive and gradual, increasing time each practice that athletes trained barefoot to allow athletes musculature to acclimate to barefoot demands. Thought it may be important to consider that sports with high frequency directional changes would require more ankle stability than long-distance running, therefore this article provides vital incite to the ability of barefoot exercise to be helpful rather than harmful.
Fatigue is thought to be a driving factor in injury as muscle tension increases, which reduces stability of the lower limb. Fatigue of muscles can reduce stability as the shoe is not there to provide sole support in barefoot runners. Thus, stability can also be connected to biomechanical changes as muscular involvement can compromise integrity of the kinematics. Intrinsic muscles of the foot are often supported so much in habitual shod runners that when barefoot running takes place, plantar pressure causes pain. Plantar pressure over time can create fatigue which can alter the biomechanics of the runner. Hazza Walaa Eldin and Mattes (2019) found that rearfoot strike runners showed higher values in the strength test, and lower fatigue values in the plantar flexors. In contrast, forefoot strike runners, the plantar flexor tired more than their dorsiflexors. Plantar pressure in both groups was lowered after fatigue (Hazza Walaa Eldin & Mattes, 2019). These findings prove that overtime, stability can be influenced in a beneficial way by barefoot running.
When identifying injury prevention causation Tam et al. (2017) was hoping to use the reduced load rate to also prove a reduced risk of injury with an alteration of foot strike. In another study by Thompson, Seegmiller, and McGowan (2016) load rates are used to then review acceleration and ground reaction forces by body segment to see if injury is a result of impact forces. Tam et al. (2017) found that in barefoot runners, after fatigue set in, could experience changed mechanics of joint angle (decreased flexion) and force absorption changes in response to knee stiffness which was decreased post-fatigue. Similarly, Thompson et al. (2016), found that although shoes do reduce tibial acceleration, barefoot runners can reduce impact acceleration by training plantarflexion. Musculoskeletal absorption within shod runners is still shown to be more consistent than in barefoot, as fatigue can then alter acceleration on impact and ground reaction forces. It is assumed that these acceleration differences are what could contribute to injury, but neither study found significant data to support that barefoot running would be beneficial. In fact, based on findings, both studies support that shod running is more beneficial for injury prevention due to consistent load rates and musculoskeletal acceleration.
Similarly, in conjunction with plantar pressure differences seen in biomechanics, stiffness of the ankle joint can be influenced by the barefoot mechanics as well. As the stiffness changes, the integrity of the foot is put at risk to injury. Chronic lower limb injuries in relation to stiffness and biomechanics has not been widely researched, but Sinclair, Atkins, and Taylor (2016) investigated how the stiffness of joints could correlate to injury prevention and performance. Joint stiffness was found to be increased during barefoot running, thought to be due to reduced limb compression (Sinclair et al. 2016). Furthermore, stiffness that is increased could contribute to “bone-related injuries,” yet also produce protection of soft tissues overtime (Sinclair et al. 2016). Because barefoot running can produce stiffness in all lower limb joints, multiple areas of the body could be affected by vertical loading. Together, plantar pressure and stiffness of joints caused by barefoot running has neither been confirmed nor denied as to be beneficial to injury prevention.
Injury prevention can also be influenced by type of shoe. Sinclair, Stainton, and Hobbs, (2018) found vertical ground forces were greater in barefoot and minimalist trials than in the trainers. Velocity was however reduced in barefoot trials along with a shorter stride time, despite increases of effective mass. Although adaptation of barefoot running takes time, forefoot strikes associated with barefoot running are the cause of such increased vertical ground forces. Findings by Sinclair et al. (2018) “indicate firstly, that effective mass has key implications for the generation of transient forces and, secondly, that running barefoot and in minimally shod footwear may place runners at increased risk from impact-related injuries compared to the traditional running shoes.” Thus, barefoot running could potentially pose risk for runners long-term if unsafely progressed into full-time barefoot habits.
Conclusions of this research show positive and negative effects surrounding barefoot running. Relating to biomechanics, barefoot running is beneficial to reducing tibiofemoral load but creates higher plantar pressure during a forefoot strike. In response to stability of the lower limb joint, despite increases of muscle activity that influence stability, fatigue of musculature can damage stability quickly altering the kinematics and potentially causing injury. Lastly, providing evidence for injury prevention during barefoot running, there was not enough support indicating that barefoot running is helpful more than harmful. In fact, barefoot running was shown to increase stiffness and vertical ground forces that could cause injury. In summary, this research displays that barefoot running is not beneficial in preventing injury or creating stability but may aid in correcting biomechanics to alter joint load for a short amount of time.
The FRF take- because barefoot running and shod running both show benefits, try them both out! It is no secret we are huge proponents of barefoot lifting (more on that to come!) But, if you happen to be on nice green grass or have a treadmill at home, give barefoot running a go and see how your body adapts. In most cases, it brings you more awareness to tendencies of your gait, stride, and ground contact to better help you choose a shoe, or style to support your needs!
References:
De Villiers, J. E., & Venter, R. E. (2014). Barefoot training improved ankle stability and agility in netball players. International Journal of Sports Science and Coaching, 9(3), 485-495.
Ervilha, U. F., Mochizuki, L., Figueira, A., & Hamill, J. (2017). Are muscle activation patterns altered during shod and barefoot running with a forefoot footfall pattern? Journal of Sports Sciences, 35(17), 1697–1703.
Hashish, R., Samarawickrame, S. D., Baker, L., & Salem, G. J. (2016). The influence of a bout of exertion on novice barefoot running dynamics. Journal of Sports Science and Medicine, 15(2), 327–334.
Hazzaa Walaa Eldin, A., & Mattes, K. (2019). Effect of local muscle fatigue and difference foot strike pattern on plantar pressure during barefoot running on treadmill. Biology of Exercise, 15(1), 87–102.
Hollander, K., Heidt, C., Van der Zwaard, B. C., Braumann, K. M., & Zech, A. (2017). Long-term effects of habitual barefoot running and walking: a systematic review. Medicine and Science in Sports and Exercise, 49(4), 752-762.
Maiwald, C., Grau, S., Krauss, I., Mauch, M., Axmann, D., & Horstmann, T. (2008). Reproducibility of plantar pressure distribution data in barefoot running. Journal of Applied Biomechanics, 24(1), 14–23.
Muñoz-Jimenez, M., Latorre-Román, P. A., Soto-Hermoso, V. M., & García-Pinillos, F. (2015). Influence of shod/unshod condition and running speed on foot-strike patterns, inversion/eversion, and vertical foot rotation in endurance runners. Journal of Sports Sciences, 33(19), 2035–2042.
Sinclair, J. (2016). The effects of barefoot and barefoot inspired footwear running on tibiofemoral kinetics. Human Movement, 17(3), 176–180.
Sinclair, J., Atkins, S., & Taylor, P. J. (2016). The effects of barefoot and shod running on limb and joint stiffness characteristics in recreational runners. Journal of Motor Behavior, 48(1), 79–85.
Sinclair, J., Butters, B., & Stainton, P. (2018). Acute effects of barefoot and minimalist footwear on medial tibiofemoral compartment loading during running: A statistical parametric mapping approach. Journal of Human Kinetics, 65(1), 35–44.
Sinclair, J., Stainton, P., & Hobbs, S. J. (2018). Effects of barefoot and minimally shod footwear on effective mass - implications for transient musculoskeletal loading. Kinesiology, 50(2), 165–171.
Tam, N., Coetzee, D. R., Ahmed, S., Lamberts, R. P., Albertus-Kajee, Y., & Tucker, R. (2017). Acute fatigue negatively affects risk factors for injury in trained but not well-trained habitually shod runners when running barefoot. European Journal of Sport Science, 17(9), 1220–1229.
Thompson, M., Seegmiller, J., & McGowan, C. P. (2016). Impact accelerations of barefoot and shod running. International journal of sports medicine, 37(05), 364-368.
