I could only wish to be able to do 10mins on the elliptical trainer :O I was at the gym today and had to literally PUSH myself to do 5mins

I can only do the treadmill for 10mins at a push and the bike for 20mins, so what I do is I'll start on the bike for 20mins, do 3 sets of 15 toning exercises, 10 minutes of treadmill, 3 sets ot 15 again and finish off on the elliptical

and I'ma keep doing it till it gets easier, don't let it put you off there is not a person on this earth who started out perfect everyone has to work at it
