After the pivot the results data would look like this...

ID Result

-- ----------------

56 run, jump, scale

No, not really, it should look like:

ID Result

-- ----------------

56 run,jump,scale,

That's 15 characters long, and if the return statement was:

return substring(@value,1,LEN(@value)-1)

you could drop the comma at the end.  That's assuming your string including the last ',' character was 20 or under characters long.