modified push up question

[NightWanderer]

My hamstrings are too short/tight due to a disability so my legs are stuck more or less at a 90 degree angle (bent at the knee) as they would be if you were sitting on any couch or chair. So, when I do push ups, since I can't get my legs out straight behind me. Doing them from the knees is too easy for me so I do this: Get on a couch/chair/bench. Place your hands on the floor and walk yourself half off the couch with them, so the only part of your body touching the couch is your knees (provided your legs are bent). So at this point, most of your body weight is suspended by your arms. If you do push ups like these, are they harder or easier than a 'normal' push up for you? do they work your muscles differently? Are they working a different set of muscles altogether? Try for yourself and let me know if it's still not good enough! At which point I'll have to wear a back pack with weights or something...

[CHIQUITITA]

I've done something similar but with using one of those big swiss balls. I feel doing pushups off the ball forces your body to compensate and use more of your stabilizing core muscles as well as working the pecs. I.M.O., It definately makes the set feel harder.