A forefoot strike is the best starting point at preventing running knee injuries.
At present, a long stride length and peak vertical forces contribute to knee stress in running. It is especially important to know that heel strike running is linked to increased knee stress as well.
However, adopting a forefoot strike landing, which can also involve a long stride, is enough to save the knees.
Using a Forefoot Strike Reduces Running Knee Injuries
Vannatta and Kernozek (2015) found that forefoot running reduced peak knee stress regardless of stride length and peak vertical forces.
The researchers investigated the effects of foot strike modification (from heel strike to forefoot strike) on knee stress during running. They also examined the effects of foot strike modification on other causal factors linked to knee stress, such as stride length and peak vertical forces.
The researchers noticed that heel strike runners who switched to forefoot running (transitioned forefoot runners), and maintained a long stride, had reduced knee stress despite increased peak vertical forces.
The researchers also repeatedly observed less peak quadricep force in the transitioned forefoot runners.
- The researchers speculated that a reduction in quadricep force in the presence of a high peak vertical force created greater force output on the soleus.
Thus, less work occurs at the knee and quads at the expense of more work at the ankle in forefoot running. Is this bad for the ankles? No, since the ankles are not as sensitive to injury as compared with the knee.
Nonetheless, the researchers found that high-pressure shock waves generated at heel strike were similar in magnitude to studies that showed heel strike impacts can distort the shape of the knee-joint.
How Heel Striking Causes Knee Running Pain
Many researchers ascribe most cases of running-related knee injuries to increased stride length and a high peak vertical force. However, the results from the current study indicate that knee stress arose from a heel strike landing, citing changes in peak patellofemoral joint stress and knee flexion angles similar to those seen from running-related knee injuries.
What is more is that the transitioned forefoot runners had less knee stress, despite producing a high peak vertical force, indicating that high peak vertical forces affect the knee in ways distinct from heel strike running.
The Take Home Message
Until recently, nobody seriously followed up on the heel strike-knee injury connection. Yet, the findings isolate a heel strike landing as the exact physical mechanism that exposes the knee to greater stress. Therefore, prevention of knee injuries in runners must extend beyond better shoe cushioning or other measures that protect the knee.
More From Run Forefoot:
Vannatta CN and Kernozek TW. Patellofemoral joint stress during running with alterations in foot strike pattern. Med Sci Sports Exerc, 2015;47(5):1001-1008.
Williams DSB 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):525–32.
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.
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