If you get a Cortisone Injection and then you race a week to 10 days later, where their is Drug Testing is this a problem?
I think the real question is where did you get the shot and should you be racing in 10 days. So, where was the needle inserted?
Totally unknowledgeable on the subject, but in ST tradition I’ll answer anyway. 
I think the answer is actually yes. I remeber during the Tour they were saying that the riders needed an exemption for cortisone. But this site has more info:
http://www.usantidoping.org/dro/search/status.aspx?BrandId=4272&UserTypeId=1&SportId=47&DisciplineId=-1
i have had a few where my IT Band inserts into the knee and 2 bits of advice i always recall…1st unless the pain changes your normal way of exercise keep doing what you are doing and secondly (More important in your case) it takes 10 to 14 days to take full affect
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