Does Varying Resistance Exercises Promote Superior Muscle Hypertrophy and Strength Gains? A Systematic Review
Journal of Strength and Conditioning Research: June 2022 - Volume 36 - Issue 6 - p 1753-1762 doi: 10.1519/JSC.0000000000004258
Fitness professionals routinely employ a variety of resistance training exercises in program design to enhance muscular adaptations. However, it remains uncertain whether that approach offers advantages over a fixed-exercise selection. The objective of this review was to evaluate the effects of exercise variation on muscle hypertrophy and strength.
A search of the literature was conducted using PubMed/MEDLINE, Scopus, and Web of Science databases. Eight studies were identified as meeting inclusion criteria. The combined total sample of the studies was 241 that comprised all young men. The methodological quality of included studies was considered “good” and “excellent” based on the Physiotherapy Evidence Database Scale.
Current evidence suggests that exercise variation can influence muscle hypertrophy and strength gains, either in a positive or negative manner.
These effects seem to be related both to the specific exercises selected and the frequency of exercise rotation.
Regarding muscle hypertrophy, programming should focus on targeting specific portions of a given muscle. Therefore, exercise variation should be done in a planned, systematized manner that applies biomechanical and anatomical principles.
To the contrary, variation of resistance exercises that provide a useless/redundant stimulus and a high frequency of change do not seem to help and may actually hinder hypertrophy.
For muscular strength, the specificity principle should be considered whereby the exercise desired for maximum strength increases should be trained with priority and kept in a regular rotation within the program.
Furthermore, the exercise variation can be focused on including exercises that have similar movement patterns to the main exercise while inducing muscle hypertrophy on prime movers.
Exercise variation should be approached systematically with a focus on applied anatomical and biomechanical constructs.
Opposingly, using different exercises that provide a useless/redundant stimulus and an excessive high frequency rotation of different exercises may actually hinder muscular adaptations.
IN PLAIN ENGLISH:
“Muscle confusion” is a specious argument for adding too much variety to a strength training program for maximum results. Yes, use some variety, but don’t add so much such that it hinders progressive training and accurate documentation of workout data. Construct six to 12 different workouts with some variety of exercises, their order of performance, and set/rep scripts and rotate them over the weeks of a two or three training days/week plan. That way you will be able to repeat each workout every few weeks yet have enough variety to keep from getting stagnant. Examples:
-- Multi-joint leg exercises @ rotate between leg press, dead lift, barbell squat, and squat machine on
-- Upper back exercises @ rotate between wide grip pulldown, seated row, close grip pulldown, and
bent-over row on different days.
Rotate between 1) do all upper body then all lower body exercises, 2) alternate an upper with a lower body exercise, or 3) alternate an upper push, upper leg, and lower body exercise.
High rep days, low to moderate rep days, combo rep days, circuits, and various overload protocols such as strip sets, isometric holds, 3 strikes & out, 50% reps, slow reps, or other.