I can do longer on my hands with arms straight than with elbows on the floor. Probably can do about 5 mins at a push with straight arms. Less than 2 minutes the elbow way!
I did it with all of my forearm on the floor, that way you have to use your stomach muscles more to keep them off of the floor and it's them I'm trying to tone.
I did 3 mins when my core strength was much better, prob get the shakes after as minute at the moment.
Over 2 mins is generally accepted as "very good".
Really jd? that's why auntie accused me of cheating when i said i used to be able to do 3 mins. But when I started shaking I used to try and get up to the next whole minute (you can't see the seconds on my alarm clock so it's hard to tell how long that'll be).