Impact Force Differences – Forefoot Strike vs Heel Strike

The touchdown phase is the most impactful phase of the running gait, suggesting that most injuries originate here, at initial foot-ground contact. The major advantage of forefoot running over heel strike running is less impact force variables and it is the reduction in impact that experts emphasize the suitability of forefoot running for clinical applications.

Impact Force Differences: Heel Strike vs Forefoot Strike

 

Impact Force Differences – Forefoot Strike vs Heel Strike

Indeed, both heel strike and forefoot running generates a vertical impact at touchdown, however the vertical impact in forefoot running is not present in the peak time domain. This means that forefoot running does not generate an impact peak of the vertical ground reaction force at touchdown, however heel striking does.

Less Impact force with forefoot running
No impact peak of the vertical ground reaction force in forefoot running. The absence of this impact peak prevents specific forces from giving rise to bone injuries.

Another impact variable that is lower in forefoot running is vertical loading. It is well documented that forefoot running results in less vertical loading as compared with heel strike running.

  • Shear forces increase when vertical loading and peak vertical impact are high.

Shear forces are harmful because they lead to bone fatigue, making the leg bones more susceptible to fracture during running [2-5].

Greater Impact Force with Heel Strike Running
A skeptic may say that there are several factors that contribute to lower leg injury in runners, however heel strike running adds unwanted impact to the body, and this is a fundamental issue in running.

This grim situation mirrors the fact that the body lacks the capacity to buffer impact during braking and acceleration in heel strike running.

Forefoot Strike-Related Impacts Are Friendly

Boyer et al., 2014 found that posterior and medial ground reaction forces were higher in forefoot running than in heel strike running. The researchers also found that peak instantaneous loading in the posterior and medial direction was higher in forefoot running than in heel strike running. Nonetheless, these impact variables are probably harmless because they are not emphasized as implicators to running-related injury the same degree as the impact variables of heel strike running are.

The Take Home Message

A common problem in constructing a running shoe designed to fully absorb impact is that the ground-body interactions in heel strike running are far too great. However, the protective properties of forefoot running lie in its ability to favor ground reaction forces, in the posterior and medial direction, that cancel-out shear forces.

More from Run Forefoot:

Forefoot Footwear – running shoes I like you to use for forefoot running.

Everything about Forefoot Running – The more you know about forefoot running, the more you’ll want to agree it’s the best way to run.

Heel Striking – Outlining the reasons runners are more likely to injure if they heel strike while they run.

Barefoot Running – Find out how barefoot running reinforces a better forefoot running technique.

Proprioception – Understand that the nerves in your feet are dedicated in helping you run with less impact, but to maximize proprioception you must wear barefoot shoes or run barefoot.


References:

[1]. Boyer E., Rooney BD and Derrick TR. Rearfoot and midfoot or forefoot impacts in habitually shod runners. Med Sci Sports Exerc, 2014; 46(7): 1384-1391.

[2]. Carter DR, Hayes WC. Fatigue life of compact bone—I. effects of stress amplitude, temperature and density. J Biomech. 1976;9(1):27–34.

[3]. Reilly DT, Burstein AH. The elastic and ultimate properties of compact bone tissue. J Biomech. 1975;8(6):393–405.

[4]. Schaffler MB, Radin EL, Burr DB. Mechanical and morphological effects of strain rate on
fatigue of compact bone. Bone. 1989;10(3):207–14.

[5]. Turner CH, Wang T, Burr DB. Shear strength and fatigue properties of human cortical bone determined from pure shear tests. Calcif Tissue Int. 2001;69(6):373–8.

Bretta Riches

Bretta Riches

"I believe the forefoot strike is the engine of endurance running..."

BSc Neurobiology; MSc Biomechanics candidate, ultra minimalist runner & founder of RunForefoot. I was a heel striker, always injured. I was inspired by the great Tirunesh Dibaba to try forefoot running. Now, I'm injury free. This is why I launched Run Forefoot, to advocate the health & performance benefits of forefoot running and to raise awareness on the dangers of heel striking, because the world needs to know.
Bretta Riches

P.S. Don't forget to check out the Run Forefoot Facebook Page, it's a terrific place to ask questions about forefoot running, barefoot running and injury. I'm always happy to help!

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