When you started running, you probably didn’t give much thought to how you ran; you just went faster than walking. But as you got more serious about the sport, you might have wanted to make changes to your technique for efficiency and speed.
Thanks to media hype and various articles around it for the past decade, foot strike (or where on your foot you land) is one of the popular targets for change. Running on your forefoot supposedly preserves knee and hip health, while landing on your heels brings all those impact forces up the leg and causes injury.
But the truth is more complex, and whether or not a forefoot strike is good for you depends on your goal.
For sprinters, adopting a forefoot strike is useful since they have a relatively short contact time and it makes them lighter on their feet, which is important for short-distance running. A forefoot strike allows sprinters to run more aggressively with much more force from each push-off that nets them more speed. Landing so far forward on the foot, sprinters rarely if ever touch their heels to the ground.
However, it’s a different story with long-distance running (and triathlon, which features long-distance running). Efficiency, more than raw power, is key. While striking with your forefoot provides lots of power, it comes at the cost of greater pressure and strain on your Achilles tendon and calf muscles. This compounds as the mileage goes up, increasing risk of injury. Because of this, forefoot striking isn’t as sustainable for long-distance running.
We see this happening when short-distance athletes migrate up towards Ironman; Alistair Brownlee runs with a very toe-y style for Olympic distance but has had to make changes to his run form for running marathons, landing flatter on his feet.
Not all heel strikes are created equal. It’s important to make a distinction between a “glancing” or “proprioceptive” heel strike, and a “braking” heel strike. The first one occurs when your foot lands under your center of mass, with the knee bent and a quick transfer of energy loading through the midfoot to toe-off; the second one is when you over-stride and your foot lands way in front of you in a braking motion. It’s this extreme, braking heel strike that transfers landing forces up your leg through knee and hip, courting injury.
If you’re a habitual heel-striker concerned about wrecking your knees and hips, you can adjust form towards a glancing heel strike much easier by shortening your stride and increasing your cadence/leg turnover.
In fact, coaching these days focuses more on preventing overstriding, rather than focusing on foot strike.
And check this out: a large study conducted on elite marathoners by Leeds Beckett University in partnership with the IAAF saw that most marathon runners at the 2017 IAAF World Championships were rearfoot strikers. The researchers concluded, “there is no one optimal foot-strike pattern with regard to performance and athletes should not be overly encouraged to alter what comes naturally to them.”