Back in November, I wrote about why you should always lift fast. I stand by that post, though I should have made it more clear that what's important isn't the actual act of moving the bar with lots of speed, but the intent to do so. You're trying to throw the bar up as fast as possible, but the amount of weight on the bar means that you can't throw it around and it's actually moving at a reasonable, controlled speed. But I digress.
Last night, I started reading Power to the People by Pavel Tsatsouline. (The cover is horrific -- whoever designed that should be fired.) One of the very first assertions made in the book is that in order to get stronger, you have to lift SLOW. The idea is that strength is a product of muscle tension. When you lift something, the contraction of your muscles is the driving force. Pavel contends that lifting slow allows you to concentrate on contracting your muscles throughout the entire movement, leading to greater gains in strength.
The idea seems to be very similar to the concept of "time under tension," where bodybuilders lift slowly in order to maximize the amount of time their muscles are contracting, in theory leading to more hypertrophy. But Pavel claims that lifting slowly will give you strength WITHOUT gaining lots of muscle mass.
This is diametrically opposed to what Rippetoe and the guys at Westside Barbell preach. My previous post about lifting fast and power production is based on Rippetoe's analysis in Starting Strength, and the Westside guys split their training up into Max Effort (as heavy as you can go, 1-3 reps) and Dynamic Effort (lighter weight, as fast as you can go) days. These guys are at the top of the game when it comes to Strength Training, and they advocate lifting fast.
I'm interested to hear what Pavel has to say about lifting speed later on in the book, though. I don't think I could ever be convinced that slow lifting is inherently superior to fast lifting for strength training purposes, for the reasons in my previous post, but I'm willing to be convinced that the occasional "slow lift" day could be useful or that a week or two of slow lifting could help break through a plateau.