1. Wait too long between sets and you are working the same muscle fibers as the previous set….. Short rest periods between sets (30-60 seconds) result in lactic acid buildup and a larger increase in GH production
2. Studies show that even after 72 hours large muscle groups are not completely recovered, which makes me believe twice per week is not optimal
3. Higher volume has been proven superior and results in more damage to tissue hence more growth
Time under tension is still the most important factor for growth, yet most powerlifters rarely train with more than 5 reps. And still have a thickness and density to their muscles rarely seen even in good bodybuilders
4. Training to failure is superior for growth, but will fry your CNS with time. But you can't deny the relationship between strength and size.