There is definitely merit in training heavy, but if your goal is to add a lot of muscle, then the chances are that you are probably training TOO heavy. Most guys looking to put on a ton of size will tend to train like Bruce Lee and go all out every session like it’s their last. They want to kill it every time. A little hard work never hurt anyone, but in order to be effective, your workout needs to be as smart as it is hard.
If you’re serious about muscle growth, then you need to focus on mastering your technique on every lift you perform. This must be your #1 priority in every training session. You need perfect technique, full range of motion and continuous repetitions in the hypertrophy range (6 to 15 reps, preferably on the higher end of that number), where the tension never comes off the muscle. In order to train in this fashion you need to lift weights that you can control. That is likely a 10% decrease in poundage from what you are currently lifting.
I love working with motivated athletes where we get to perform explosive movements, plyometrics, mobility work and a lot of heavy lifts. This type of work will get you stronger and more agile for your chosen sport, but it is not going to do a lot to alter your overall physique. The physiques that are the most aesthetically pleasing to the eye rarely belong to those who lift the heaviest weights. These people choose weights they can control, train full body multi-joint movements, and keep rest periods short (60-90 seconds). Their training sessions are finished in 60 minutes or less.
Training mistakes happen with some of the most experienced trainees. There is very little tension created, no stretch and contract, tons of pausing, bouncing the weights for added momentum which places a ton of stress on the joint, and they are training beyond failure on every set. Failure is not when you can’t move the weight any more. It is when you can no longer move the weight with perfect technique. That is why you should always complete your sets by leaving one last rep in the tank.
The hardest sets to perform are the ones with explosive-like reps, constant maximal tension, and continuous movement with a slow negative on the descent. They get your heart pumping and your muscles burning. They are the type of sets that last between 40-70 seconds which are a lot harder than throwing up some dumbbells with zero tension, a pause at the top and bottom and you are done in 20 seconds or less. To perform sets that will really spur muscle growth is extremely hard work. Don’t let anyone try to convince you otherwise.
In order to grow your muscles, you need a sufficient amount of volume, but you can’t train to physical exhaustion every time. That is how you can get sick, injured and depressed. Listen closely to your body. Success leaves clues.