If you are looking for muscle growth, strategically changing your workout by increasing exercise variation to hit certain muscle groups can be beneficial. In contrast, changing exercise routines too frequently can hinder muscle growth.


  • Muscle confusion was a principle by Joe Weider.
  • Exercise variation was found to improve muscle growth in most of the studies. However, if exercise variation is too frequent, it can lead to reduced muscle growth.
  •       Moderate exercise variation is recommended, as frequent exercise changes can lead to less muscle growth.
  •       If the exercise variation is too frequent (e.g., different exercises every training session), this predisposes an individual to greater fatigue due to greater muscle damage due to an unfamiliar exercise. This can lead to an impaired muscle growth response.
  •       The inclusion of single-joint exercise can cause regional muscle hypertrophy of a muscle compared to multi-joint exercises. For example, it was found that the combination of leg extensions and squats resulted in greater increases in muscle growth of the rectus femoris compared to squats alone.
  •       Exercise variation should include strategic exercises to increase muscle growth of a specific muscle group rather than randomly changing an exercise for enjoyment.


In the early 80s, Joe Weider introduced the popular exercise principle, Muscle Confusion. According to this principle, a bodybuilder trains with a different exercise randomly each day. For instance, if you do bench press and cable flyes in one workout, you should switch to Incline Bench Press and dips in the next session.

The aim is to alternate exercises in every workout to stimulate muscle growth. People often vary their exercises for several reasons: they want to enjoy their workouts more, they aim to reduce the monotony of repeating the same exercises, and they want to engage different muscle fibers during their sessions. Muscle Confusion aims to stimulate muscle growth by presenting the body with a new workout challenge every gym session, preventing adaptation.


Exercise variation is a topic of debate for bodybuilders striving to increase muscle growth. Exercise variation can include the use of single (i.e., leg extensions) and multi-joint exercises (i.e., squats), one limb (i.e., one arm rows), and two limb exercises (i.e., bent over rows), and the use of various free weight and machines. Other variations include changing the angle movement (i.e., incline vs. flat bench), stance (i.e., close vs. wide grip stance), and range of motion (i.e., partial vs. a full range of motion).

A new meta-analysis by Kassiano et al. does a deep dive into the current literature by analyzing the data from studies that included exercise variation to those that did not include exercise variation.(1) The researchers set out to find if less or more exercise variation was better for muscle growth and strength.


1.         Kassiano W, Nunes JP, Costa B, Ribeiro AS, Schoenfeld BJ, Cyrino ES. Does Varying Resistance Exercises Promote Superior Muscle Hypertrophy and Strength Gains? A Systematic Review. The Journal of Strength & Conditioning Research. 2022;36(6):1753-62.

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