Trying to manipulate your footstrike while you’re running is like trying to change the tires on a moving car.
Your feet land where they must to keep you from falling down, and they’re put there by forces generated by your whole body. So in order to change your footstrike you have to change what you’re doing with your whole body.
When you overuse your flexor muscles – the ones that work together to curl you into a fetal position – your legs are pulled too much in front of you and your ankles are too dorsiflexed. This produces an overstriding heelstrike, causing you to “put on the brakes” with your heels in front of your body. It sends a jolt of force backwards into you that slows you down, feels unpleasant, and stresses your joints. Research by Daniel Lieberman and his colleagues at Harvard has persuaded many runners that they should try not to run this way in order to avoid injury.
If attempt to fix your footstrike by working on your running “posture,” trying to stop slouching and keep your back straight, it doesn’t change which muscles you’re using to run. It just adds another layer of effort on top of what you habitually do. This is why people say running with good technique is such hard work – they’re talking about making your technique look correct by adding an extra layer of muscle contractions to fight the way you habitually run. It’s not the same as having good technique to begin with.
If you try to change the part of your feet you touch the ground with or keep them from landing so far out in front of you, you still aren’t changing the forces that act on your foot, so you’re likely to increase the stress on your body. You’re also very unlikely to ever fully succeed, especially the minute your mind starts to wander.
Most importantly of all, your footstrike isn’t supposed to always stay the same. It changes a bit in every step as your speed, your energy, and the terrain you’re running on change. Fresh, fatigued, kicking, trotting, uphill, downhill, cambered, rocky, squishy… your nervous system needs to be free to regulate how you meet the ground anew in every footfall. You can’t do that if you’re busy tensing parts of your body to try to over-control your gait.
The solution is to learn to power your running through a healthy core action that balances the activity in your flexor and extensor muscles (the ones that stretch your body out). This balanced effort naturally regulates your footstrike so you avoid excessive overstriding, heelstriking, and exaggerated forefoot striking as well. Your footstrike and overall technique will become superbly responsive to your running conditions, your running will feel much easier and smoother, and you’ll stay healthier and perform better too.