http://www.charlespoliquin.com/Blog/tabid/130/EntryId/753/What-You-Need-to-Know-About-Rest-Intervals.aspx
 
A guiding principle when developing strength is that the rest interval should be long enough to permit the nervous system to recover almost completely but not so long that you lose what’s called the post-tetanic potentiation effect. That’s the phenomenon by which your contraction strength potential is increased for five to 10 minutes after a heavy set because of greater neural activation. This concept became popular in the English-language literature after I translated Dietmar Schmidtbleicher’s work from German in the early ’80s.
 
The peak effect – that is, greater potentiation – occurs about four minutes after a near-maximal contraction and then gradually wanes so that it’s gone by around the fifth minute. Consequently, when training for strength, you should rest about four minutes between sets of an exercise – that is, assuming we’re talking about a compound exercise. For isolation exercises three minutes of rest normally suffices. An individual’s maximal strength has an impact on the phenomenon, however. If you can curl 155 pounds for reps, you may need four minutes; if you curl only 75 pounds for reps, three minutes should suffice.

Eigen ervaring met post-tetanic potentiation is dat rond de drie minuten ook voor compound prima resultaat geeft. Langer dan 3 minuten geeft bij mij minder effect. 

Bij mij wisselt 't ook per oefening