is HIT legit? I've recently come across Drew Baye and Jay Vincent in Youtube. They claim: - You don't have to lift heavy or lift fast to recruit fast twitch muscle fibers. Fast twitch muscles are solely recruited by intense effort when the muscle comes close to failure. Therefore you don't need to lift fast on concentric part of the exercise. ​ -All you need is EXACTLY 1 SET AND EXACTLY 1 EXERCISE PER WEEK FOR EACH MUSCLE GROUP. That set is different than traditional sets though. They are 4-6 second concentric, 4-6 second eccentric to failure. 20-30 mins of hell. ​ -Going to failure in this fashion is extremely hard, beginners usually begin with drop sets because they can't really push it there. This one brutal set is not just all you need, but also all you can tolerate. Once you finish this brutal set you should not be able to rest and do a second set. That one brutal set is going to create all the damage and procedures we need for signaling muscle growth. ​ -Having 2 times in a week(upper and lower) in this fashion is going to have AT MINIMUM THE SAME(IF NOT BETTER) results than 3x-5x a week. ​ -Doing 3+ sets are completely unneccesary. Its a lie told by Reg Park and Arnold. Back in 1940-50s, people were doing 1 set per exercise. Reg Park wanted attention so he said doing more sets will stimulate better growth and then Arnold took it to a even more extreme levels and people followed Arnold (I don't remember the complete history, it roughly starts like that). ​ -Full ROM is not necessary AT ALL. You can get the same results by just isometric contractions. However, doing full ROM will have neural adaptations and its more fun to do. ​ There are many other claims, such as you don't need to train a sport-specific movement with resistance, all resistance training you need is performing basic muscle functions with resistance, then you learn the sport-specific movement without any resistance as a skill. All the strength you gain from lifting weights with basic exercises is going to be transferred as you learn the skill. ​ ​ However, only 1 set/muscle to failure, 2x times a week is the biggest claim. It got me real confused here. Is this a legit approach? If its so, why not everyone is doing it lol?