Introduction to Muscle Growth

Resistance training is an effective strategy for building muscle. Scientifically, the process of increasing muscle mass is known as skeletal muscle hypertrophy. Skeletal muscles, as their name suggests, are attached to the skeleton and form an integral part of the musculoskeletal system alongside bones, tendons, and connective tissues.

Building muscle mass is one of the most effective actions a person can take to improve health and promote healthy aging. Higher muscle mass and strength are associated with better physical function, greater independence later in life, and a reduced risk of metabolic diseases and physical disabilities.

The popularity of muscle-building has also created a large amount of misinformation, often leaving people who want to begin resistance training feeling overwhelmed by conflicting advice. In reality, building muscle is far less complicated than many believe. The most important step is simply to engage in resistance training consistently.

If you continue training regularly, even as little as once per week and about 5 sets, you can build muscle (PMID: 41343037). Will that be the optimal approach? Probably not. However, this article is not about the optimal or minimum effective dose of training. Instead, it focuses on the fundamental principle that drives continued muscle growth.

The Principle of Progressive Overload

Once a training routine has been established, the single most important factor for continued muscle growth is progressive overload. Progressive overload is a fundamental principle of resistance training program design that involves gradually increasing the demands placed on the neuromuscular system, thereby stimulating further adaptation and growth.

The primary stimulus for hypertrophy is training volume, which can be expressed as: Volume = Weight × Repetitions × Sets

In simple terms, training volume reflects the total amount of work performed during a workout.

Strategies for Progressive Overload

Two common strategies are used to progressively increase training volume:

• Increase repetitions while keeping the weight and number of sets constant.
• Increase weight while keeping the number of repetitions and sets constant.

Which Strategy is More Effective?

A study by Brad Schoenfeld (PMID: 36199287) examined this question in 43 resistance-trained participants. The LOAD group (13 men and 9 women) progressively increased the weight lifted while maintaining a constant repetition range. The REPS group (14 men and 7 women) progressively increased repetitions while keeping the load constant.

Participants performed four sets of four lower-body exercises twice per week over an eight-week training period. The researchers found that both approaches produced comparable improvements in muscle growth and muscular adaptations, suggesting that either strategy can be effective when progressive overload is maintained.

Summary

• Progressive overload refers to gradually increasing training demands over time.
• After establishing a consistent training routine, progressive overload is the most important factor for continued muscle growth.
• Progressive overload can be achieved by increasing either the weight lifted or the number of repetitions performed while keeping other variables constant.
• Current evidence suggests that both approaches are similarly effective for promoting muscle hypertrophy.