Although leg cramps when running has its own set of factors that contribute to its severity and complexity, one common culprit is fatigue failure in heel strike running.
Impact Transient Linked to Leg Cramps
Heel striking produces an impact transient, but forefoot strike running eliminates this force. The impact transient reflects loading on the leg where the higher the impact transient, the higher the loading.
- a study by Kirby and McDermott found that heel strike running increased anterior compartment pressure of lower leg and was most likely a result of greater loading. Increased anterior compartment pressure when running comprises circulation, resulting in muscle weakness and cramping.
A study by Diebal et al. found that anterior compartment pressure dramatically decreased in subjects who transitioned from heel strike to forefoot strike running and were able to increase running distance by 300% without leg cramps
The rate of overloading on the leg in heel strike running allows intramuscular pressure surrounding the tibia to accumulate of which may be exacerbating during foot rollover as well.
- the weight of the body transfers over the heel, over the arch, and on to the forefoot which increases overload on the calf muscles eccentrically, putting the legs at cramping risk
- calf cramps may also arise at toe-off as heel strikers use the forefoot to push forcefully against the ground to leap into flight
To lessen the load on the leg and prevent leg cramping during long runs, making the conscious effort to land on the front part of the foot (the forefoot) reduces knee extension and allows for a strike position closer to the body which in turn, engages the spring mechanism of the hind-leg to pull the foot off the ground automatically to initiate flight.
Toe-off is not required in forefoot running as the foot is ‘picked up’ off the ground by the tendons of the hind-leg after the weight of the body passes over the foot.
In forefoot running, the quick removal of the foot from the ground is controlled by the spring-action of the leg and is a reflexive response that may be under involuntary control -it just happens on its own, hence the term reflex.
Therefore, based on the principles of physics, forefoot running increases favorable mechanical conditions to eliminate the impact transient and loading-related leg cramps.
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- Avoid Stretching Before Running and Just Warm Up
Blackman, PG. (2000). A review of chronic exertional compartment syndrome in the lower leg. Med Sci Sports Exerc,32, SUPL:S4-10
Diebal et al., (2012). Forefoot Running Improves Pain and Disability Associated with Chronic Exertional Compartment Syndrome. Am J Sports Med,40(5):1060-7.
Gershuni et al., (1984) Ankle and knee position as a factor modifying intracompartmental pressure in the human leg. J Bone Joint Surg Am,66(9):1415-20.
Kirby and McDermott. (1983). Anterior tibial compartment pressures during running with rearfoot and forefoot landing styles. Arch Phys Med Rehabil, 64(7):296-9.
Tweed, JL and Barnes, MR. (2008) Is eccentric muscle contraction a significant factor in the development of chronic anterior compartment syndrome? Foot,18(3):165-70.
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.