Some of you guys need to talk to Realgains (5'11 I believe, and got to a lean 250 or so. Never did volume). He will tell you all about HIT and HeavyDuty.
And Mike Mentzer never did one set only per body part, not while he was competing. He would do 2-6 work sets per part. You must remember this was at a time when most were training 6 days a week, sometimes twice a day, with up to 20 sets a body part. Mike's routines were a breath of fresh air.
I've always trained low volume, and Have gone from 144.5lbs at nearly 6'4 to 260lbs at a high point all within 4 years. The most I've done for a bodypart is 4-6 working sets. If anyone wants to call those type of gains, pussy, then so be it.
I'd like some people to tell Dorian Yates that HIT is pussy. Perhaps Casey Viator, or Tom Platz. Those guys along with Mike Mentzer trained with incredible intensity. They were HARD workers. Dante who does no more than one set per body part, a session, and is 300lbs, would laugh at such a statement.
Different strokes for different folks, but don't make such outlandish statements.