The importance of this principle is undeniably massive when it comes to building muscle and gaining strength. Most people either don't know of this or are too intimidated to practice it. I'm talking about progressive overload. Progressive overload is one of the 6 training principles. It simply states that in order for adaptation to occur, a greater demand (intensity or duration) is required in incremental stages.
In this post, I want to focus specifically on intensity. This would be how hard you make your exercise. i.e. continually increasing weight in resistance training. Now, you can increase the intensity of exercise by doing more repetitions with lighter weight... but there's a problem. See when we resistance train, or contract our muscles, muscle fiber recruitment occurs. We will only recruit enough muscle fibers needed per load. Simply put, if you lift X amount of weight, only X amount of muscle fibers will be recruited, period. So, the more weight you lift the more recruitment occurs. If you're only lifting lighter weight, you'll never recruit more muscle fibers.
Muscle fiber recruitment is a key part of progressive overload. The greater load placed on the muscles, the more we recruit. The more we recruit, the greater the adaptation, making your muscles grow bigger and stronger. Think logically. If you want to be stronger than you currently are, you have to lift more weight. Lifting the same weight over and over again won't increase your strength. It will just make you really good at lifting that particular weight.
Progressive overload causes muscle fibers to tear and breakdown. With proper recovery they will repair and grow back stronger. Lifting light weight that doesn't fall into progressive overload only pumps blood through the muscle fibers. This causes lactic acid buildup and that signature burn that you feel in the 10-12+ rep range. That style of resistance training is great for hypertrophy, but we're looking for strength.
How should you train for progressive overload? It's simple. Stick with compound movements (these are your squats, presses, deadlifts, rows). You'll work in the 4-8 rep range and do anywhere from 4-6 sets per exercise. Linearly move up in weight every set and take longer breaks between sets (1.5-3 min). YOU MUST TRACK WHAT YOU DO; OTHERWISE, HOW WILL YOU KNOW? The idea is to train towards failure while consistently moving up in weight. If you get all your reps, move up. If you fail before the minimum (4) go back down till you can build up to the rep range.
The thing that turns people away from weight training this way is because of the risk. One, heavy weight is dangerous so you may need a spotter or know how to bail out of an exercise. Two, we're uncomfortable with failure, but failure is O.K.! We actually need failure to grow. As mentioned above, training to failure is a necessary component of progressive overload and causing adaptation to occur.
You don't have to be a powerlifter or bodybuilder. If you want to be stronger or you find yourself in a plateau, give progressive overload a try. You may just see some fantastic results. I promise you'll become stronger than you ever have been.