Switching to a Forefoot Strike Over Winter? What Footstrike Research Shows

Every winter, some triathletes decide this is the year they fix their running form. Often that means getting off the heels and onto the forefoot, inspired by barefoot running books, slow-motion clips of elite runners or advice that heel striking is a braking, injury-causing habit. The off-season seems the ideal time, because there are no races to compromise.

It's worth checking the evidence before spending months on it. This article covers how most runners actually land, what studies show about footstrike, running economy and injury, and what really happens to your legs when you change. It stays on footstrike itself; TriForward's "Should You Raise Your Cadence?" covers step rate, which is often changed at the same time.

How most runners land

Footstrike is usually classified by which part of the foot touches the ground first:

• Rearfoot strike: the heel lands first.
• Midfoot strike: the heel and ball of the foot land at about the same time.
• Forefoot strike: the ball of the foot lands first, and the heel may or may not touch down afterwards.

Most distance runners heel strike. A 2011 study by Larson and colleagues in the Journal of Sports Sciences filmed 936 recreational and sub-elite runners at the 10 km point of a road race:

• 88.9% were rearfoot strikers.
• 3.4% were midfoot strikers.
• 1.8% were forefoot strikers.
• 5.9% landed differently on the left and right feet.

The researchers also tracked 286 of the runners to the 32 km point, where even more of them were heel striking. Several runners who were midfoot or forefoot striking at 10 km had switched to their heels by 32 km. Among marathon runners, footstrike wasn't significantly related to finishing time.

Inference: if you're a heel striker, you're in the large majority of age-group runners, and many runners who start a race on their forefoot end it on their heels. That's worth remembering for an Ironman marathon, where fatigue is the norm.

Why runners try to change

The case for switching usually rests on three claims:

1. Forefoot running is more economical, so you'll be faster at the same effort.
2. Forefoot running reduces impact, because it removes the sharp spike in force when the heel hits the ground.
3. Forefoot running reduces injury, because of the lower impact.

A 2017 review by Hamill and Gruber in the Journal of Sport and Health Science examined each claim and concluded that the evidence doesn't support any of them as a reason to switch. Switching doesn't improve running economy, doesn't remove impact forces from running, and hasn't been shown to reduce injury risk. The sections below look at the evidence behind those conclusions.

Running economy: no gain from switching

Running economy is the oxygen cost of running at a given speed. If forefoot running were more economical, it would be a strong argument for switching.

A 2013 study by Gruber and colleagues in the Journal of Applied Physiology tested this directly. It compared 19 habitual rearfoot strikers and 18 habitual forefoot strikers running on a treadmill at 3.0, 3.5 and 4.0 m/s, both in their own pattern and in the other pattern.

• In their habitual patterns, the two groups had the same economy.
• At the fastest speed, running with a forefoot pattern cost more oxygen than running with a rearfoot pattern.
• The authors concluded that a forefoot pattern is not more economical than a rearfoot pattern.

The largest analysis is a 2020 systematic review and meta-analysis by Anderson and colleagues in Sports Medicine, which included 53 studies:

• Habitual heel strikers and habitual non-heel strikers had similar economy at slow, moderate and fast speeds.
• When heel strikers switched to a non-rearfoot pattern, running became less economical at 10.8 and 12.6 km/h.
• The authors found no evidence that a non-rearfoot strike improves running economy.

Immediate switching isn't the same as switching after months of practice, and most of these studies tested the change on the day. But even the habitual forefoot strikers, who had run that way for years, weren't more economical. Inference: there's no economy gain waiting for you at the end of a footstrike transition.

Impact and loading rate: a real difference

The impact claim has more substance. Heel striking usually produces a distinct impact peak in the vertical ground reaction force shortly after landing, and forefoot striking usually doesn't.

The Anderson meta-analysis found limited to moderate evidence that non-rearfoot running produces lower average and peak vertical loading rates, meaning force rises more slowly after landing. But a lower loading rate isn't the same as lower total load. In the Stearne study described below, total lower-limb work and power didn't differ between habitual forefoot and rearfoot strikers; a forefoot strike changes where and how the load is handled.

Where the load goes

This is the most important point for a triathlete thinking about switching. Changing footstrike moves load between joints rather than removing it.

Knee down, ankle up

A 2013 study by Kulmala and colleagues in Medicine & Science in Sports & Exercise compared 19 female athletes who naturally forefoot strike with 19 female rearfoot strikers, pair-matched, running at 4 m/s.

• Patellofemoral contact force (behind the kneecap) was 4.3 body weights in forefoot strikers versus 5.1 in rearfoot strikers.
• The frontal-plane knee moment was also lower in forefoot strikers.
• The ankle plantarflexor moment (calf work) was higher in forefoot strikers: 3.12 versus 2.54 N·m/kg.
• Achilles tendon force was 6.3 body weights in forefoot strikers versus 5.1 in rearfoot strikers.

Inference: from those averages, forefoot strikers had about 16% less patellofemoral force and about 24% more Achilles tendon force. The authors suggested lower knee load might reduce knee injury risk, and higher ankle and Achilles load might increase the risk of foot and ankle injuries. Neither was tested.

The Anderson meta-analysis reached the same pattern across studies: non-rearfoot running reduced knee flexion and patellofemoral joint stress, and increased the peak ankle plantarflexor moment.

What happens when you switch on purpose

Habitual forefoot strikers have adapted over years. A 2014 study by Stearne and colleagues in Medicine & Science in Sports & Exercise looked at what happens when runners switch. It tested 16 trained male distance runners, 8 habitual rearfoot and 8 habitual forefoot strikers, at 4.5 m/s, running in both patterns.

When the rearfoot strikers switched to a forefoot strike:

• Their ankle internal rotation moment rose by 33%.
• Their knee abduction moment didn't fall to the level of the habitual forefoot strikers, so they didn't get the knee benefit.
• Their total positive lower-limb power rose by 17%, meaning their legs did more mechanical work.

The authors found no clear overall mechanical advantage for either pattern, and warned that switching moves loading between joints, which may have different injury implications. Inference: a heel striker who switches gets the extra calf and ankle load straight away, while the knee benefit seen in natural forefoot strikers may not appear, at least at first.

Injury: what the evidence can and can't show

The study most often quoted in favour of forefoot running is a 2012 paper by Daoud and colleagues in Medicine & Science in Sports & Exercise. It looked back at injury records from 52 runners on a collegiate cross-country team, 36 rearfoot and 16 forefoot strikers.

• About 74% had a moderate or severe injury each year.
• Rearfoot strikers had about twice the rate of repetitive stress injuries.
• Traumatic injuries didn't differ between groups.

This was a retrospective study of one team, with a small number of forefoot strikers, and footstrike wasn't the only factor linked to injury: sex, distance and weekly mileage were too. The authors were clear that they hadn't tested why.

The Anderson meta-analysis found that the only injury evidence comparing strike patterns is retrospective, and concluded that the link between footstrike and injury risk can't be determined. No prospective study has shown that switching from a heel strike to a forefoot strike reduces injury. That's why they concluded that changing strike pattern can't be recommended for an uninjured rearfoot runner.

When a change might make sense

None of this means footstrike never matters. The Anderson authors' recommendation was specifically about uninjured heel strikers. Inference: because forefoot running shifts load away from the knee, it may be one option for some runners with knee problems, as long as their ankles and Achilles can tolerate the extra load. That's a clinical decision, made with someone who has assessed you, not a general recommendation. TriForward's "Hips and Runner's Knee" covers the better-evidenced treatments for knee pain.

Equally, if you have a history of Achilles or calf problems, plantar heel pain or metatarsal stress fractures, a forefoot strike is likely to load exactly the tissues that have struggled before.

If you change anyway

Some triathletes will still want to experiment, or are changing on a clinician's advice. The following is inference from the loading research, not a tested transition programme:

• Build calf and Achilles capacity first. TriForward's "Calf and Achilles Capacity" covers progressive tendon loading.
• Introduce the change in small doses, such as short sections within easy runs, rather than whole runs.
• Expect calf soreness in the first weeks, and treat soreness that isn't easing as a sign to back off.
• Don't change shoes, footstrike and training volume at the same time. TriForward's "One Pair or Three?" covers shoe changes.
• Avoid making the change during a run-volume build, which is when many triathletes try it.
• Be patient. Habitual forefoot strikers adapted over years, not weeks.

Who was studied

The footstrike evidence base has some clear gaps that matter for age-group triathletes:

• Small samples. The key loading studies had 16 and 38 participants, and the economy study had 37.
• Single-sex groups. The Stearne study included only men, and the Kulmala study only women. The economy study and the injury study didn't report sex splits in their abstracts.
• Young and well-trained runners. Collegiate cross-country runners and trained distance runners are not typical age-group triathletes in their 40s and 50s.
• Fresh legs on a treadmill. Almost all the biomechanics was measured over short bouts, not late in a long run, and none after cycling.
• Retrospective injury data. The only injury comparisons ask people to recall past injuries, so they can't show cause and effect.

Inference: the most consistent finding, that forefoot striking adds load at the ankle and calf, appears in both men and women and in both habitual and switched runners. The knee benefit is less certain for runners who switch. The claims about speed and injury are where the evidence is weakest, and those are the claims that usually motivate a winter switch.

A triathlon scenario

The following example is illustrative, not drawn from a study. A 36-year-old triathlete finishes his first Ironman with a slow marathon and reads that heel striking was the problem. In November, he decides to switch to forefoot running, while also increasing his running from three to five sessions a week ahead of a spring half marathon.

Three weeks later, his calves are constantly sore and his Achilles is stiff every morning. His easy pace feels harder than it did, which fits the economy research.

A better plan, based on the evidence above, might be:

• Keep his natural footstrike, because there's no evidence it caused his slow marathon and no evidence that changing will make him more economical.
• Look at the more likely causes of a slow Ironman run: pacing, fuelling and run durability. TriForward's "Why the Ironman Marathon Falls Apart After 25 km" covers them.
• Build run volume gradually, and add calf and hip strength work through the winter.
• Revisit footstrike only with a clinician if he develops a specific problem, such as knee pain, where it might help.

Common mistakes

• Assuming heel striking is wrong. Most age-group and recreational runners heel strike, including many who finish races well.
• Changing footstrike to get faster. The evidence doesn't show an economy gain.
• Switching abruptly and running whole sessions on the forefoot from day one.
• Changing several things at once: shoes, footstrike, cadence and volume.
• Ignoring Achilles stiffness and calf soreness in the first few weeks.
• Copying elite runners' landing without their years of adaptation and their speeds.
• Focusing on the foot and ignoring overall training load, which has stronger links to injury.

What we don't know

• Whether changing footstrike prevents injury. There are no prospective trials in healthy runners.
• Long-term adaptation. Most studies tested a switch on the day, not after months of practice.
• Women. Several key studies were in men only; the knee-loading study was in women only.
• Triathletes. No study has looked at footstrike after cycling, or whether a forefoot strike holds up late in a long-course run.
• Who might benefit. Specific groups, such as runners with knee pain, may respond differently, but the evidence is thin.

References

• Anderson LM, Bonanno DR, Hart HF, Barton CJ. What are the benefits and risks associated with changing foot strike pattern during running? A systematic review and meta-analysis of injury, running economy, and biomechanics. Sports Medicine, 2020;50(5):885–917. doi:10.1007/s40279-019-01238-y
• Hamill J, Gruber AH. Is changing footstrike pattern beneficial to runners? Journal of Sport and Health Science, 2017;6(2):146–153. doi:10.1016/j.jshs.2017.02.004
• Larson P, Higgins E, Kaminski J, Decker T, Preble J, Lyons D, McIntyre K, Normile A. Foot strike patterns of recreational and sub-elite runners in a long-distance road race. Journal of Sports Sciences, 2011;29(15):1665–1673. doi:10.1080/02640414.2011.610347
• Gruber AH, Umberger BR, Braun B, Hamill J. Economy and rate of carbohydrate oxidation during running with rearfoot and forefoot strike patterns. Journal of Applied Physiology, 2013;115(2):194–201. doi:10.1152/japplphysiol.01437.2012
• Kulmala JP, Avela J, Pasanen K, Parkkari J. Forefoot strikers exhibit lower running-induced knee loading than rearfoot strikers. Medicine & Science in Sports & Exercise, 2013;45(12):2306–2313. doi:10.1249/MSS.0b013e31829efcf7
• Stearne SM, Alderson JA, Green BA, Donnelly CJ, Rubenson J. Joint kinetics in rearfoot versus forefoot running: implications of switching technique. Medicine & Science in Sports & Exercise, 2014;46(8):1578–1587. doi:10.1249/MSS.0000000000000254
• Daoud AI, Geissler GJ, Wang F, Saretsky J, Daoud YA, Lieberman DE. Foot strike and injury rates in endurance runners: a retrospective study. Medicine & Science in Sports & Exercise, 2012;44(7):1325–1334. doi:10.1249/MSS.0b013e3182465115