Runners’ feet tend to get beat up during training. They swell, get blisters and calluses, and some even end up with discolored toenails. Runners call these black toenails. Black toenails are most common among runners participating in half, full or ultra-marathons. They occur under the nail from repetitive trauma of the top of the shoe striking the nail with each step or the toe sliding forward into the end of the shoe causing bruising or slight bleeding under the nail. These nail injuries are typically painless, though sometimes the nails do thicken. They usually heal once the intensity or volume decreases. There are, however, ways to prevent black toenails.
- Buy proper fitting shoes: Make sure when you get your shoes fitted, there is at least a half an inch between your longest toe and the front of the shoe when standing. Always wear the same socks you are going to run in when fitting your shoes.
- Keep your toenails clipped: Long nails shorten your distance to the front of the shoe which will cause undue pressure on your longest toe.
- Strengthen your hips and glutes: The stronger your hips and glutes are, the lighter you will run and the better your form will be. Strength training will lessen your chance of shuffling your feet towards the end of your training or race.
- Check your form during training: If you stop using your arms, you will start shuffling your feet. Continue to pump your arms through your run even when you are tired. It will cause you to not slump and keep you posture in check. Running is an entire body experience, not just the lower body.
Black toenails can be prevented if you pay attention to your feet. If your toenail color does not change within two weeks, contact your primary care provider.