I'm in the Navy and we have a semiannual fitness test. We can ride an exercise bike for the cardio portion (so I do). It's twelve minutes and the scoring is basically a W/kg test.
We also do two minutes of push ups and sit ups but next Spring we will trade out the sit ups for planks. It's a better test of core strength. So it's a win/win for me. I'd do it for biking and now I can do it for the Navy.