In the running world there has been a lot of debate over whether a forefoot running style is better than a heel strike running style in terms of injury rates and efficiency. Shoe companies have been responsive in their action and heavily marketed the concept of barefoot style shoes, reduced heel ramp angles and even negative heels. But what can we justifiably reason to be the best style.
A Forefoot running style is one where the weight bearing component of the running cycle, called the support phase, is carried out with the front part of the foot hitting the ground first. A heel strike style of running is one where the initial contact of the support phase is conducted by the heel. The biomechanics of each running style are different of course and a quick description will give us some insight as to the potential issues that can arise.
During forefoot running, when your forefoot hits the ground first, the ankle begins to dorsiflex (ie the foot moves closer to the shin bone) and the heel approximates contact with the ground. The initial forces brought about by ground contact are absorbed by the muscles and joints of the foot, then the Achilles tendon and calf which decelerates rotational heel speed and mitigates any heel contact with the ground. Other torque is controlled by the quadriceps and gluteal muscles further up the kinetic chain. This forefoot striking process has the effect of dampening the rate at which the vertical forces are applied through your body.
During heel strike running, when your heel hits the ground first, the ankle starts to plantarflex (ie the foot moves away from the shin bone) and the front of the foot comes into contact with the ground. This is the opposite of forefoot running. The heel strike contact with the ground has little to no dampening effect of the foot and calf muscles and forces are transferred directly through your heel and lower leg bones at a much quicker rate.1 This can have an adverse effect on the joints of the ankle and knee and into the back. Shoe manufacturers are aware of this and make a percentage of their shoes with a larger heel to attenuate some of the ground reaction forces thereby limiting injury.
So examining the characteristics of both you might assume that forefoot running would be much better for you, but forefoot runners are not immune to injury either. The calf muscle has to work harder during forefoot running than heel striking and must control the rate at which the heel drops through an eccentric pattern. The duration and magnitude of forces acting on the Achilles tendon and other tendons located in the foot is now much greater and this can lead to tendinopathy. Secondly there is a change in the distribution of the forces that are associated with heel strike from the heel bone to the metatarsals during forefoot running, and bone stress injury may occur in this region. This is especially so if you are running barefoot or in minimalist shoes. Additionally, forefoot running is also more strenuous on the joints at the front of the foot and can result in metatarso-phalengeal (ball of the foot) joint pain.
At present their is limited evidence to suggest that one action is better than the other in terms of injury rates but given the biomechanics of fore foot running and its ability to attenuate shock it seems that forefoot running has greater potential to reduce injury rates.
As for efficiency there are multiple factors that that may contribute. For example the strength of muscles and their affect of maintaining efficient joint angles in the hip, knee and foot is very much a factor in determining the overall efficiency of the style. Another factor to consider is the horizontal component of the ground reaction force that occurs during foot strike. This is affected by the angle at which the foot strikes the ground. The more vertical that angle the less horizontal resistance occurs. In forefoot running this angle is more vertical than that of a heel striking runner resulting in a lower the horizontal component of the ground reaction force and a more fluent forward momentum than that of heel striking.
So again it would seem that forefoot running has the ability to be more efficient as well as reducing injury rates, but a word to the wise. If you have not been running with a forefoot striking motion previously, the lower limb will need time to adapt to the new forces that are occurring both from the ground and around the joints. So start slowly and give yourself time to recover in between sessions.
2Foot Bone Marrow Edema After a 10-wk Transition to Minimalist Running Shoes, Sarah T. Ridge et al. 2013. Med Sci Sports Exerc.;45(7):1363-1368.