To understand how different forms of weight training affect the human body, you must first understand that there are different types of muscle fibers that are loaded.

There are two categories of muscle fibers: Fast and slow muscle fibers1and each of them serves a specific purpose.

According to the National Academy of Sports Medicine, fast-twitch muscle fibers support fast and powerful movements, while slow-twitch muscle fibers support endurance. You can think of fast and slow fibers like in a tortoise and a hare. Fast-twitch fibers tire as fast as they can move, while slow-twitch fibers maintain active activity and are much more resistant to fatigue.

According to celebrity trainer and founder of NWMethod, Nicole Winghoffer, you’ll see different results if you lift fewer reps with a heavier weight than if you do more reps with a lighter weight because you’re working different muscle fibers and training them differently. different

“Lifting heavier weights requires larger dominant muscle groups (such as biceps, triceps, quadriceps, and glutes) to do more work and recruit more muscle fibers to lift the load,” explains Winhoffer. This means that the target muscle groups will increase. When you lift more reps with less weight, you encourage slow-twitch muscle fibers and build more even tone over time.