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Building Muscle: The Right Approach to Reps and Weights

Updated: Aug 10, 2023


Building muscle is a goal shared by many people, and understanding the relationship between reps, weights, and muscle recruitment is essential to achieving optimal results. In this blog post, we'll dive into the discussion between Person A and Helder about the most effective approach for stimulating muscle growth.

1. The Importance of Motor Unit Recruitment:

As we embark on our fitness journey, one crucial factor that comes into play is motor unit recruitment. This concept involves the activation of high-threshold motor units in our muscles, which is vital for stimulating muscle growth. When we experience fatigue, motor unit recruitment increases, creating an environment conducive to muscle development.

2. Heavy Weights vs. Lighter Weights:

Person A raises an intriguing question: "If I go to failure, should I go heavy for fewer reps or lighter for more reps?" Helder suggests a preference for heavier weights in the range of 5 to 8 reps at 80% - 90% of one's 1 Rep Max. This approach aims to recruit all motor units effectively. Additionally, lifting heavy weights slows down movement, leading to a lower muscle fiber speed.

3. Muscle Building with Lighter Weights:

However, Helder acknowledges that building muscle is still possible with lighter weights. The key is to create enough fatigue within the muscle. Lighter weights engage fewer motor units until fatigue sets in. When lifting lighter or moderate weights, we can move more quickly, which means the muscle fiber shortening speed is fast, but the mechanical loading on each muscle fiber is small.

4. Reps and Volume:

To build muscle with lighter weights, one needs to increase the volume of repetitions. This approach can be effective, especially if you prefer a higher volume training style. However, it's essential to note that increasing the volume significantly may have diminishing returns if your primary goal is muscle building.

5. Personal Preference and Goals:

Ultimately, the choice between heavy and lighter weights depends on your preferences and goals. If you enjoy lifting heavier weights and want to maximise motor unit recruitment, the lower rep range may suit you. On the other hand, if you prefer lighter or moderate weights and are willing to increase volume for muscle fatigue, that's a valid approach as well.


In the realm of muscle building, there's no one-size-fits-all answer to the question of heavy vs. lighter weights. Both approaches have their merits, and it's crucial to align your training style with your goals. Whether you're aiming for maximal motor unit recruitment with heavy weights or planning to increase volume with lighter weights, consistency, and dedication to your chosen method are key to achieving the muscle growth you desire.

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