When running my second toe (next to big toe) which is the longest toe is getting bruised under the toe nail. Is this a sympton that my sneakers are too small or is it related to my running style? I have been wearing the same model sneaker (Asics Kayano) for 3.5 years and have had “black toe” almost the entire time. However, the sneakers feel comfortable while running (even the toe).
As others said, sounds like shoes that are too small. You should have a thumb width from your longest toe to the end of the shoe to allo your foot to lengthen when it impacts the ground. Usually 1/2 a size up depending on the model will do it.