Should You Train to Failure on Every Set
Training to failure has been a hotly debated topic in the bodybuilding world for decades. Science seems to be able to solve the problem but the truth is not conclusive as training to the point of failure can sometimes be beneficial depending on the circumstances.
There are advocates for NEVER training to failure who tell us that "Training to failure is training to fail." But then there are advocates like Arnold who tell us that no pain, no gain and say openly that "The last 3 or 4 reps is what makes the muscle grow."
There have been many different studies done on training to failure, proving to us that training to the point of failure comes along with a significant cost. One such study done by Dr. Mikel Izquierdo showed conclusively that when you train to the point of failure on every set done you will drastically increase your resting cortisol levels, which are your catabolic hormones suppressing important anabolic growth factors like IGF-1.
This specific study showed that taking every set to absolute failure will more than likely hinder any chance of long-term muscle growth. In another study that was done at the sports and research center in Pamplona, Spain, the researchers found training to the point of failure increased the levels of nucleotide adenosine monophosphate (AMP) dramatically when compared to all non-failure training.
An elevated AMP level is a sign that the muscle cell is drained of all energy which decreases protein synthesis. Despite the two studies mentioned above training to the point of failure is not something that you should never do. It can be a very effective tool for building muscle but it needs to be used strategically when appropriate.
Training to the point of failure can also be extremely anabolic when done in the right context. According to sports scientist Brad Schoenfeld, M.Sc., CSCS, the greater increases of lactic acid in the muscle are vitally important for muscle growth, because this lactic acid will trigger increases in the important intramuscular growth factors. Training to failure will increase lactic acid production a lot more than any non-failure training.
There is a second benefit of training to failure and that is when finishing the last 2 or 3 reps, just like Arnold said, that has now proven to fatigue all the smaller muscle fibers. Your body is then forced to use the remaining fast-twitch muscle fibers which are stronger and bigger.
I think we can conclude that even if you do train to failure it's best not to do it every sent of every workout, and it's good to have some workouts that you only use not to failure training.