While running is a simple sport — simple is not the same as easy — fads training programs and areas of focus are common.
After the release of the book Born to Run, barefoot running took center stage. While barefoot running can work for some people, it is hardly a universal superior running option.
But let’s say you want to run barefoot. Aside from needing to build up tolerance, you need to run with a fore- or mid-foot strike pattern. You will destroy your heel with a heel strike sans protection of a shoe.
Another reason for running with a mid- or forefoot strike is to increase running turnover or cadence. Heel striking slows you down. Try sprinting with a heel strike and see how well it works.
You can potentially run mid-distance — 800 or 1600 meters — with a heel strike, but it is rare among elite runners.
This begs the question — should all runners elect a fore- or mid-foot strike pattern?
Differences in impact forces
Some shoes are designed with added cushioning to increase shock absorption. These are intended for heel strikers and they are effective. They come with a cost, however. Cushoining adds weight to the shoe, impacting performance and injury risk.
The performance influence pertains to turnover rate. The injury influence pertains to impact forces, specifically the ground-reaction force. Here is where we reach a cross-road.
Cushioning reduces impact forces, but the impact forces are caused by heel-striking. Wouldn’t it stand to reason that fore- or mid-foot striking would be beneficial across the board? You can ditch the bulky shoe, increase your turnover rate, and reduce impact forces.
Research suggests the impact forces aren’t as big a deal as traditionally believed. We have conflicting evidence but a trend can be deciphered.
Relative to heel striking, forefoot striking reduces both the peak impact forces and the impact loading rates. Heel strikers can potentially even the playing field with a cushioned heel, but it comes with the consequences of increased stride length, decreased turnover, and changes in loading patterns. It is likely the cushion will impact the peak impact forces more than the loading rates, due to the nature of the heel strike and using the heel as a braking mechanism. Some studies indicate loading rates are more concerning than peak forces for injury occurrence.
One argument made against peak forces is the difference between sprinters and distance runners. While sprinters have significantly higher peak forces than distance runners, they do not have greater injury rates. The mileage and duration of running, however, are much lower for sprinters. Regardless, it appears forefoot striking does limit forces. The question is similar to the one concerning lifting and low back pain: how much stress is too much?
Conventional wisdom attributes increased risk of injury to the knee, hip, low back, and shin for heel strikers. The risk shifts to the Achilles tendon and plantar fascia when moving to a forefoot strike. But does the research support these claims?
Milner et al. demonstrated runners who have suffered from a tibial stress fracture display greater instantaneous and average vertical loading rates. Daoud et al. concluded runners who use a heel strike are more oft-injured than those using a mid and forefoot strike, but the sample size was small and in trained individuals (Division 1 Cross Country Collegiate Athletes). With differing workloads and intensities, a history of training, and access to coaches and dieticians, it is difficult to apply these findings to the general runner. The sample size also limits the ability to effectively break down injury types but here is what Daoud et al. concluded:
As hypothesized, the set of predicted rear-foot strike (RFS) injuries (hip pain, knee pain, lower back pain, tibial stress injuries, plantar fasciitis, and stress fractures of lower limb bones excluding the metatarsals) were between twofold and fourfold more frequent in RFS than in fore-foot strike (FFS) runners, with significantly lower rates of mild and moderate injuries in FFS runners (P = 0.0121 and P = 0.0014, respectively), and a significantly lower rate of moderate plus severe injuries in FFS runners (P = 0.0058). In contrast, the incidence of injuries predicted to be higher in FFS runners (Achilles tendinopathies, foot pain, and metatarsal stress fractures) was not significantly different between the two groups.
In studies with larger samples — keeping in mind they are still observational studies with significant limitations — the results are mixed. Adding a study by Hamil et al. to Milner and Daoud — ranging the sample sizes from 341 to 1203 runners — there were still no significant differences in overall injury rates between rearfoot and forefoot strikers.
When breaking down by injury type, two of the studies found midfoot dorsal pain, metatarsal stress fractures, Achilles tendinitis, and post tibial tendinitis were the most common injury type but there was no difference in rates between strike pattern.
In the end, cohort studies do not support the claims of specific foot strike patterns leading to specific injuries. Does this mean strike patterns don’t matter?
Again, it depends.
If heel striking is comfortable for you and you are not concerned with maximizing your race times, don’t worry about changing. If you are competing, however, you may want to consider a change. Bear in mind, the change will take weeks, maybe months. You can also change the severity of a heel strike, turning it into a borderline midfoot strike.
There are many ways to run. Don’t worry about doing it the “right” way.