I guess so.. I developed this out in the field where we dont always have access to a gym. As a bare minimum every day, whenever I have 10 minutes, I do
40x diamond pushups
30x jack-knife (lift legs and arms straight up while lying on back) sit-ups
75x Crunches (w/legs crossed in the air, pull in with legs and upper body)
30x cross-over crunches (touch elbow to opposite knee 30 each side)
40-60 wide-grip pushups
50-100 no-weight squats with a cross-over punch each time you come up
Pull-ups till failure
It takes a total of about 10 minutes at a quick pace. You can vary it by adding calf-raises at the top of each squat, and subbing out some ab work or pushups for reverse tricep pushups. This is what I do every day and I can post a pic or two of the results. You need to eat a chicken breast at every meal or fish, or some other lean protein. No supplements or shakes needed here. This will work if you want bruce-lee type build (small frame, dense lean muscle), but not if youre going for hulk hogan. Still, using only this workout type if I sit down at a bench, I can rep 175 10 times (I weigh 140-145). Good core and all-around workout.