I’d like to point out another reason why heel striking is bad for running, especially for running performance, and a lot of it pertains to how heel strike running may cause your legs to move less efficiently.
In heel strike running, impact is so high that it causes soft tissue compartments and bones to vibrate, which affects motor nerve cell communication. So, what do nerve cells do in this case? They do nothing. In fact, nerve cell conduction velocity is reduced.
More Reasons Why Heel Striking is Bad
The heel strike impact, known as the impact transient, converts into a shock-wave that streams up the leg, into to the lower back and throughout the body, causing vibrations in soft tissue compartments. As a result, the soft tissue compartments vibrate at frequencies that initiate swelling and may disrupt neuromotor pathways.
Bongiovanni et al., reported that prolonged exposure to vibrations impaired motor firing and muscle contractions.
Normally, a nerve fires a strong, fast signal to other nerves for a movement to occur. For the signal to get from point A to point B quickly and efficiently, signal conduction must be strong and secure. The signal is disrupted by high vibrational frequencies which impair conduction, thus slowing signal transmission.
- when a tissue vibrates from impact, muscle fibers swell, thereby impairing nerve impulse conduction
Repeated vibrations in soft tissue compartments may cause ‘blips’ in nerve signalling and as a consequence, may impair, or weaken the strength of the neuromuscular signal, causing the body to move less efficiently.
However, a mechanism of the muscles known as muscle tuning minimizes the frequency of vibrations:
- Walkeling et al., discovered that heel strikers showed an increase in muscle activation of the lower leg which may help dampen soft tissue vibration in response to peak impact at heel strike
It is fair to assume that some heel strikers might better able to ‘deflect’ the impact associated with heel striking better than others. However, when fatigue sets in when running, movement naturally becomes slightly rigid, posture becomes stooped, and ground-contact time increases, and so does impact.
When a heel strike runner becomes fatigued, their form is altered which may increase soft tissue vibration duration occurring in a highly repetitive manner. This may be the breaking point of which muscle tuning cannot control, or dampen soft tissue vibrations.
More Injuries Linked to the Heel Strike-Transient Impact:
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Bongiovanni LG., Hagbarth KE and Stjernberg L.Prolonged muscle vibration reducing motor output in maximal voluntary contractions in man. Physiol (1990); 423:15-26.
Friesenbichler B., Stirling, LM., Federolf P and Nigg BM. Tissue vibration in prolonged running. J Biomech (2011);44(1):116-20.
Nigg, BM. Impact forces in running. Current Opinion in Orthopedics (1997); 43-47.
Wakeling, JM and Nigg, BM and Rozitis, AI. Muscle activity damps the soft tissue resonance that occurs in response to pulsed and continuous vibrations. J of Appli Physio (2002);93(3):1093-1103
Wakeling JM., Pascual SA and Nigg BM. Altering muscle activity in the lower extremities by running with different shoes. Med Sci Sports Exerc (2002); 34(9):1529-32.
Run forefoot, because you are faster than you think!
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.