The last race I won was at school in the swimming baths* at the age of 16. After that none of the other 'swimmers'** wanted another race so I don't enter them.
* I took swimming as a main sport in the sixth form.
** These were the people*** I'd trailed in last to in all the running, jumping and throwing sports in the previous five and a half years.
***I'd sussed that these 'great sportsmen' were only interested in a race if they could win. So despite the fact that I'd been drilled in the 'Not the winning, but taking part' bullshit, I decided that in future they could beat someone else. I've never regretted this decision, in fact it made my last 18 months or so at school much more pleasant.