Picture this. It’s leg day at the gym and you’ve been working up in weight on your squats. It’s your fourth set and you’re on your last two reps. Your quads are burning and it feels like gravity just keeps getting heavier. You have two more to go, but it feels like there’s nothing left in the tank. Do you go for the last two squats or put the bar back on the rack? That’s the dilemma behind the training to failure method. What creates more physical progress? Training within your limits or pushing yourself to complete muscle failure. 

The scientific explanation behind muscle failure is that during the lifting motion of a repetition, your muscles can’t create enough force to continue moving the weight upward, according to BodyBuilding.com. But the muscle tissue isn’t the only culprit responsible for our ability to perform. The central nervous system plays just as big a role in exercise and everything else our body does. 

Muscles contract because of electrical signals sent from the part of the brain responsible for motor function. These signals happen through neurons that travel all the way from the brain to the spinal tract to our muscle fibers, according to Science Daily. Not only does the nervous system tell our muscles when to move, but it also tells our muscles when to stop. The fascinating thing is, this urge to give up and drop the weights isn’t always because our muscles are tired. Studies show our nervous system starts to shut off these electrical signals to prevent us from sustaining long-term injury. It’s a kind of defense mechanism that ensures that we will be able to properly recover before our next workout. If you want to train to failure, it’s important to know the difference between muscular fatigue and central nervous system fatigue. Just like you can slowly increase the weight your lifting, you can slowly improve your neural responses to stress and push your failure barrier farther than before. 

Once you’ve nailed down the mental side of training to failure, it’s time to take a closer look at the physical. Researchers have found both benefits and consequences of this training method, but there seems to be one cohesive solution to reach the most success.

The concerns from physicians can be simplified down to “training to failure is training to fail”. One theory is based around the hormones that are released when we push our bodies past the point of comfort. Intensive exercise causes the body to release cortisol, the stress hormone, and human growth hormones. When you constantly train to failure every single set, your body may get in the habit of raising cortisol levels and suppressing growth hormones, which can make it harder for you to put on muscle, according to BodyBuilding.com. Adenosine monophosphate will also start pumping at higher levels, which tells your body that your cells are over-exerted and your body slows down protein-synthesis.

On the positive side, the longer your muscles are under stress, the more lactic acid that is produced. Elevated levels of lactic acid have shown direct correlation to muscle growth overtime, especially when the muscle is pushed to failure. But it has its limits. 

Yes, training to failure can produce results, but those results aren’t significantly better than other methods of training, according to Vice. In clinical trial studies, both training to failure and more manageable weight lifting showed about the same level of muscle growth overtime. It really comes down to your schedule, level of experience and what fits best with your routine. Training to failure can be a fast track to a quick, effective workout if your time is limited. But if you have time to spare and a stressful work day ahead, maybe scaling back your training is the better option.

Experts have found that the best course of action with the training to failure strategy is to find a safe middle ground. The method shows the most benefit in short doses, but can be damaging if you’re doing it too often. The general consensus is save the failure for the last set of every exercise. Get through a few rounds, warm up your muscles and then finish with a bang. This method of moderation gives you the best of both worlds and keeps your nervous system from getting too worn out. 

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Take it from me

Training to failure is a mental game to me. I’ve been lifting for less than two years at this point so I’m still learning my physical limits. Certain movements and muscle groups intimidate me more than others, pushing me to give up before I really need to. 

Training to failure works best for me with upper body exercises. I’m done when my muscles literally go limp. It doesn’t take much to push my biceps to failure so why not take advantage of that. My legs on the other hand are a totally different story. 

Leg exercises usually employ a multitude of muscle groups and it’s more difficult to pinpoint my exact fatigue level. When I squat, I can’t tell what hurts the most. My legs, back, core and traps are all under stress, not to mention my heart beating out of my chest. So I tend to give up long before I feel like I’m going to fall for my own safety. In those situations, I make my form the priority and put my level of fatigue on the back burner. No matter my method, I make sure that I’m working towards improvement in some area. That way, I always walk out of the gym proud of what I’ve accomplished and excited to try again.