Are Light Weights or Heavy Weights better for Muscle Growth? Find out which strategy works better based on science; light weights for high reps or heavy weights for low reps. You'll also learn the best volume to build muscle faster.
Should you use Light weight or Heavy weight to build muscle faster? How about to burn fat? Everyone seems to have their own opinion on this topic. Some believe that high reps and bodyweight calisthenic exercises are best, meanwhile others swear that low rep heavy weight training is best for faster muscle growth. So today I want to go over which style of training will lead to the best results for you personally based on scientific data rather than just another opinion.Â
To actually find out the answer, we first have to be clear on what training intensity is. In exercise science, training intensity refers to the percentage of your one-repetition maximum (%1RM) that you can train with. So if you were using 100% of your 1 rep max that would mean that you're using a weight load that's so heavy that you can only complete one rep and no more. On the other hand, 80 percent of your 1 rep max would be a weight load that you could probably rep for 7 to 8 reps before failure. And each training intensity level whether it's 70 percent, 80 percent, or 90 percent correlates with a certain rep count based on data gathered from many strength training studies, and you can see all that data simplified in the table that you see in front of you now (1) As you can see it's pretty obvious that If you train with less weight or a smaller percentage of your 1 rep max, you’ll be able to do more reps. But if you train with heavier weights or a larger percentage of your one-rep max, you'll only be able to perform fewer reps. Pretty straightforward. So let's see why some lifters claim that you should train with light weights if you want to maximize muscle growth and why they recommend that you perform anywhere from 15 to 25 reps per set.
Well, first the high rep crowd claims that light weights and high reps are better because they create a lot of metabolic stress, which is a physiological process that happens during resistance training as a response to low energy levels inside the cell that leads to metabolite accumulation, such as lactate, inorganic phosphate, and hydrogen ions. Second, training with high reps many times feels more effective. I mean, you get a huge pump and can see your muscles blow up when you look in the gym mirror. So, it must be the ideal training style, right? Well not necessarily. There is nothing magical about doing light weight, high-rep “pump training.” It’s not a bad strategy for muscle growth either, and many popular bodybuilders rely primarily on light weight training. But there’s nothing magical about it. For example, several studies found that you can build the same amount of muscle with low, moderate, and high reps. (2) Diving deeper into the data research shows that very high rep sets where you use only 30 percent of your 1 rep max can stimulate as much muscle growth as a traditional bodybuilding rep range where you use 80 percent of your 1 rep max. (3)
But please before you assume you can use any weight load or rep range to build muscle hear me out because it's not as simple in real life as these studies that are in a controlled lab setting would suggest. Specifically, there are three important things to keep in mind. First, very low-rep training, such as doing one or two reps per set, is very unlikely to be optimal for muscle growth. We can see this play out in a study that found that doing eight heavy sets of 1 rep max outs lead to worse results than eight sets of eight to twelve reps. (4) So make sure you select a weight load that allows you to squeeze out at least three reps per set if you want to optimize muscle growth. Second, training with very heavy loads for low reps happens to be much more stressful on your joints and connective tissues compared to training with a moderate or a high rep range. Even if you look at t he studies that found that people who trained with low reps gained the same amount of muscle, you also usually see that they had a higher injury rate. So very low-rep training might not be ideal if you have aches or pains in your joints or if there's some reason that makes you more susceptible to injuries. Also even if you like to train with a really heavy weight for a low amount of reps I wouldn’t recommend doing that for isolation exercises like bicep curls or lateral raises simply because it’s very difficult to maintain proper form when doing these isolation movements with heavy weights and you're much more likely to cheat and use momentum. Compound exercises like the squat, bench press, and deadlift, on the other hand, can be performed with heavier weight loads and for lower reps without issue as long as you maintain proper form...
