There are a number of impact variables uniquely produced in heel strike running that accounts for nerve injuries in the feet and leg as compared with forefoot running.
In running, nerve injuries are the result of regular exposure to high repetitions of motions, high muscular forces and extreme foot positions [1], all of which are traits of heel strike running, not in forefoot running.
For a side note, optimal nerve health and function has a strong structural basis:
- conduction velocity is proportional to the diameter of the nerve fiber whereby soft tissue swelling perturbs the geometry of a nerve cell, interfering with conduction
- because a signal cannot pass stably under these conditions, movement efficiency is compromised and peripheral neuropathy may result [2]
Unlike forefoot strike running, heel strike running produces impacts that are enormous and more immediate that cause nerve injuries, such as nerve entrapment. The specific forces are patellofemoral and tibiofemoral compressive forces, intramuscular compartmental pressures, impact peaks and ground reaction forces as well as more overall mechanical loading on the musculoskeletal system [3-7].
Moreover, the adverse effects of heel strike running on peripheral nerve function surfaced in a study by Colak et al. [3]
The researchers examined and compared motor conduction velocities of the tibial and peroneal nerve and sensory conduction velocities of the medial and lateral plantar nerve, the sural and superficial peroneal nerve in habitual shod ( shoe) runners and non-runners (heel strike running is associated with habitual shod running*).
The researchers found that the habitual shod runners had delayed sensory conduction velocities in the lateral and medial plantar nerves as well as the sural nerve compared to the non-runners.
Interestingly, the researchers were shocked to find that running effected the sural nerve since isolated sural nerve injuries are rare. Likewise, it comes as no surprise that sural nerve function was impaired given the magnitude of bone strain cycles and relative greater loads associated with heel strike running.
Despite such findings, heel strike running should be officially recognized as the main risk factor for nerve injuries in running.
Regain Nerve Function with Forefoot Running
Humans evolved to use the same basic networks of brain parts and peripheral nerves that control basic motor parts for running, barefoot that is. Humans also evolved to use the same foot strike during running, a forefoot strike which has been disrupted by the modern running shoe.
Most running shoes inhibit the natural tendency to follow what the feet feel during running, forcing us to use abnormal foot mechanics (i.e. heel strike) that generate more impact. Researchers agree that running shoes with thickly, cushioned heels facilitates heel strike, and by running barefoot or at least in flatter shoes, a forefoot strike can be easily maintained.
In this regard, forefoot running cuts down on skeletal loading and therefore, does not interfere with the geometrical factors that influence nerve conduction velocity.
More From Run Forefoot:
Barefoot Running – Before running shoes, we ran barefoot. Learn about the wealth of health benefits of barefoot running.
Stretching Before You Run – Mounting evidence shows that stretching before running doesn’t mix well.
Another Reason to Avoid Heel Strike – Heel striking deforms the heel pad even when a cushioned heeled running shoe is worn!
Proper Running Shoes – If you hate the idea of running around barefoot, then run in running shoes that feel as if you are almost barefoot.
References:
[1]. Banarjee T, Koons DD. Superficial peroneal nerve entrapment: Report of two cases. J Neuro Surg 1981, 55:991-992.
[2]. Rask MR. Medial plantar neuropraxia Jogger’s foot): Report of 3 cases, Clin Orthop 1978, 134:193-195.
[3]. Colak et al. Comparison of nerve conduction velocities of lower extremities between runners and controls. J Sci Med Sport, 2005; 8(4):403-410.
[4]. Aminoff MJ. Tibial and sural neuropathies. In : Electromyography in Clinical Practice. 3 rd Ed. Churchill Livingstone. P 479-492.1998.
[5]. Jackson DL, Haglund B. Tarsal tunnel syndrome in athletes. Am J Sports Med 1991;19:61- 65.
[6]. Jackson DL, Haglund B. Tarsal tunnel syndrome in runners. Sports Med 1992; 13:146-149. Henricson AS, Westin NE. Chronic calcaneal pain in athletes: Entrapment of the calcaneal nerve? Am J Sports Med 1984; 12:152-54.
[7]. Leach RE, Purnell MB, Saito A. Peroneal nerve entrapment in runners. Am J Sports Med 1989; 17:287-291.
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