Long-distance runners can also encounter this problem, although not from rapid changes of direction. In their case, it's due simply to the extreme number of repetitions of minor insult to the toenail with each stride.
In the worst case, blood emerges under the toenail, which quickly turns black, and then the toenail subsequently loosens from the nail bed and falls off. In a case with lesser damage, the toenail might only appear bruised, with blood under only part of the nail. Then it might heal, or later damage might lead to total loss of the toenail.
Unsightly while it is occurring, but not so bad, right? Wrong.
The loss of the toenail is usually accompanied by pain, which definitely hinders free movement about the court. The blood also has to drain somewhere, so you may notice involvement of your lymphatic system (e.g., lymph nodes in your groin).
In the 2004 Cleveland Squash Open, Graham Ryding, the second seed, had to take an injury time out at 7-2 in the third game when his toenail came off. The Canadian was clearly in pain and had been suffering difficulty throughout the match in moving to the front of the court. He went on to lose to the fourth seed, Dan Jenson, and the popped toenail definitely contributed to Graham's loss. In fact, after removing the popped toenail, he won only one more point in the match.
So how do you avoid popped toenails? The best advice I've gotten is this:
- buy shoes one half size larger
- trim your toenails tightly, especially on your big toes
- replace your shoes frequently, and try different makes and models until you find one that works best for you
- lose a bit of weight if you are overweight (it will lessen impacts)
- if you notice some toenail damage, and feel some pain, immediately stop playing.