Many Roads Lead to Muscle Growth: New Strength Training Study

One of the most pervasive strength training myths in exercise science is the idea that the number of reps and amount of weight you lift determines whether you gain muscle size, muscle strength, or muscle endurance. In fact, every exercise physiology textbook written in the 1980s through 2015 has perpetuated this myth.

The long-standing rule of thumb has been:

• If the goal is stronger muscles: Perform 3–6 reps with a heavy weight.

• If the goal is bigger muscles (muscle hypertrophy): Perform 6–12 reps with a moderate weight.

• If the goal is muscle endurance and tone: Perform 12–20 reps.

But a brand-new study on rep ranges and muscle growth challenges this model. Published this month, authors of the study sought to understand the differences between lifting with lighter weights and performing more reps compared to lifting heavier weights and performing fewer reps.

Research participants were split into two groups:

• One group performed 3–5 reps of each exercise to muscle failure.

• One group performed 20–25 reps of each exercise to muscle failure.

The surprising results?
Both groups saw equal improvements in muscle strength and muscle hypertrophy.

Bottom line: The amount of weight we lift and the number of reps we perform do not selectively increase strength or muscle size. Instead, we have autonomy in choosing the rep ranges we prefer to train in and can have confidence that we are maximizing both strength and muscle hypertrophy. Many roads lead to Rome.