Mark Ottobre explains why complex lifts like deadlifts should never go to failure due to CNS demand, while isolation exercises like bicep curls can. Strength training uses reps in reserve to protect the nervous system, hypertrophy training pushes closer to failure to recruit more muscle fibers.
Talking about training to failure, one thing you also need to keep in mind is the central nervous system's involvement in the exercise. For example, something like a deadlift, you'd never take to failure because there's too much neural activity and also it's high skill. So basically any movement that is high skill, you don't take to failure. So like a clean, for example, you wouldn't take a clean to failure 'cause it's super high skill. But a bicep curl, calf raises, absolutely you take that to failure 'cause low skill. Reps in reserve makes sense when you're training for strength, but proximity to failure makes sense when training for hypertrophy. Now obviously there's a huge overlap because the stronger you get, the more neurally you're able to build muscle. So if you've got a 250-kilo deadlift, then you are neurologically more able to build muscle than someone who has a 200-kilo deadlift from a neural perspective. So strength certainly does have a place in building muscle, but it's also not to be overstated because it's not the only way to get there. It's just to say that the stronger someone is, the more capacity they have. That's why you do, you do want to get strong.
