"I don't psyche myself up. I psych myself down. I think clearer when I'm not psyched up."
- Steve Cauthen

Dr. Wescott with on one versus multiple sets. The study he mentions here is, coincidentally, concerned with pull-ups and dips. http://www.naturalstrength.com/research/1enough.html


1 Pull-up
1 Dip
1 Sit-up
2 Pull-ups
2 Dips
2 Sit-ups
3 Pull-ups
3 Sit-ups
(get it?
Continue this sequence as far as you can for exactly 30 minutes.

Notes.

1. No "crappy" pull-ups, dips, or sit-ups. Perfect form, please.