Okay... who here knows Phys Ed?

[Nailzberg]

After a certain number of sit-ups, is it just a waste of time?

And why are squat thrusts even an exercise? They just give you gas.

[petronius]

1. I think you answered your own question about the squat thrusts;

gym teachers think it's funny to make the kids in the front of the class fart on the kids in the back. After all, these are usually the same guys who think nothing of turning a bunch of 8th graders loose in a room full of belt-sanders and arc-welders before heading down to the teachers lounge for a coffee and a shot...

(Just kidding - all my gym/shop teachers were very safety-conscious...)

[Nailzberg]

2. My gym teacher would never leave class for a shot

He used to drink his spiked coffee right there in front of us.

[datasuspect]

3. my gym teacher used to smoke

in the gym or out in the field when he was "teaching" us and ALWAYS had a cup of "coffee" nearby.

[HarukaTheTrophyWife]

4. Using proper form is more important than quantity.

You'll get more out of 25 "good" sit-ups than 100 half-assed ones.

Squat thrusts are a plyometric exercise. Plyometrics build up your explosive speed when done right, and I'm not talking about farting.

[seemunkee]

5. Try Janda situps

http://www.maxmuscle.com/index.cfm?fa=article&doc_id=271&subcat=strength_endurance
If those are too easy do them one legged http://www.dragondoor.com/articler/mode3/233/
This AM was abs day so I did three sets of these with some Saxon side bends

And squat thrusts or Burpees are a great cardio work out that can be done in limited space.