If you want your muscles to grow, you need to challenge them. To really tear down those muscle fibers and force them to repair bigger and stronger, you need to expose your muscles to new stimulus, and you won’t accomplish that by curling 20lb dumbbells at the same tempo week after week.
Progressive overload means challenging your body to do something that it is not used to doing. When lifting weights, this can be accomplished either by adding weight to the bar, adding reps to your set, making your reps mechanically more difficult, or by combining these techniques. Planning your progressive overload correctly will allow you to continue progressing for longer without hitting a plateau.
The most straight-forward example of progressive overload is simply adding weight to the bar every week, or picking up the next heaviest set of dumbbells. For a lot of novice lifters, this method will keep you progressing easily for your first few months of lifting and is the quickest way to add poundage to your sessions. When you start to plateau, and you will, then it’s time to start thinking about moving to a different style of progressive overload that will allow you to keep the same weight for a few weeks, and overload your muscles through increased time under tension.
Most programs are written with an intended rep range for a given lift. These rep ranges are meant to assist you in planning how to overload your muscles. For example, if a program calls for four sets of bicep curls in the 6-8 rep range, you might be able to start on the first week with 6 reps with that 20lb dumbbell. The next week, you would shoot for 7 on all of your sets. Every week you try to push past your limits just a bit more until you can get all four sets with 8 reps each. When you can do that, you’d pick up the 25lb dumbbell and repeat the process, starting at 6 reps. This is a very sustainable progression that is most appropriate for isolation lifts, although it can also be used for compounds.
Another way to implement progressive overload is to think about increasing your time under tension via an extended descent. While you will always train to explode quickly out of the bottom of a lift, a slower descent can add a whole new challenge. Using the same weight from week to week, you would start with a relatively quick descent of one second for the first week. On the second week, increase that descent to two seconds, and on the third week, to three. This method works by increasing the total amount of time you spend under a given weight and therefore the amount of time that your muscles are exposed to strain and stimulus. The lift will become dramatically more difficult as you increase your descent time. By the time the fourth week comes, you’ll be able to throw another ten pounds on the bar and start the process over. This method is most useful when utilized on compound lifts.
Progressive overload is not limited to weight-loaded lifts. Mechanical overload of bodyweight movements is usually referred to as a calisthenic progression, or just progression, and the goal is a specific movement rather than a weight. If your end goal is to be able to accomplish a pistol squat, you would go through pistol squat progressions that would include standard bodyweight squats, “bottoms-up” pistol squats (starting from the bottom of the squat and driving up, removing the more difficult descent), and counter-weighted pistol squats before you are able to ultimately perform a pistol squat unassisted.
There is little more demotivating than a plateau that sticks, so avoid plateaus and train smarter by planning your progressive overload appropriately. If one method stops working for you, swap it out and keep driving. There is no real limit to your performance as long as you keep pushing. Make every single day a personal best!