Less Is More in High Intensity Training

"Contrary to conventional wisdom, lengthy and frequent workouts are unnecessary and can even be detrimental. That's because you don't gain benefit from exercise when you exercise, you gain benefit from exercise when you rest and recover." - Fred Hahn, co-author of 'The Slow Burn Fitness Revolution'

Here's more:

"Working a muscle to exhaustion in as little as 60 to 90 seconds of slow but well-executed reps causes microscopic 'alterations' in the muscle. As the body repairs these microscopic alterations between workouts, the muscle gets stronger and adjusts to increasingly greater effort."