im in the TA atm,
as for selection, just run, make sure you have a decent pair of running shoes and make sure your not last, just watch the guy in front.

also there's press up's and situp's.
not sure how old you are so the requirments are different.
the worst one is under 21 which is 44 press up's in 2 minute's (easy) and if i remember 50 sit up's in 2 minutes. there's also a chin up test, and a "clean and jerk" test, think i got that right...

also the TA is a great mob been in over a year now and going to Cyprus for 2 weeks in august courtasy of the tax-payer "for infantry tactics in the hottest time of the year"

but good luck and tell us how you get on