This was one of the questions on our gym’s wall.
Firstly, switching up exercises is not only valid but recommended to encourage the different stimuli needed for the body to adapt and make strength and muscle gains…..now, how frequently can we switch these to make those optimum gains isn’t so straight forward.
Let’s look at 2 of the principles of strength training and hypertrophy (increasing muscle size) starting with:
Specificity - This principle makes sure that we make exercise selection based on our training goal. if we want bigger quads, there needs to be exercises included to cater for that eg high bar squat, leg press, split squats etc, and if we want to increase our deadlift 3 rep max then the exercises we choose must compliment that too. We wouldn’t work on our 10k run time to do this, as it doesn’t follow the principle of specificity.
So our exercise choices must be made with our training goal in mind.
Overload - This principle is well established and a BIG player when it comes to making muscle and strength gains.
Our body is always looking to keep in a balanced and stable internal environment (homeostasis). To force a big enough strength/muscle growth adaptation however , this balance must be disrupted through a training stimulus. The body then recovers, adapts and is better prepared for a similar type of work.
The principle of overload tells us that this workload MUST become harder over time (session by session, week by week, training block by training block) in order to continue muscle growth and strength gains.
There are other principles such as fatigue management, stimulus-recovery-adaption (SRA: the time in between training sessions where recovery and adaptation take place) and, the topic of the question (finally) variation.
Just by looking at specificity and overload we can answer the question better of how frequently variations can be made.
Before I go further, I’m fully aware of the the legendary work Louis Simmons does with his long list of savages at Westside Barbell.
But, I’m not Louis Simmons and Westside Barbell is like no other gym.
What works best for my guys (and for many other coaches) is tracking progress of an exercise for a number of weeks, increasing overload via more weight, more reps or more sets as well as using RPE (rate of perceived exertion). By keeping the exercises the same through each week, we see a good picture of how the trainer responds over the duration of a mesocycle (training block). In new trainers especially, keeping the same exercises also allows more time and exposures to technique practice.
At the end of that training block, we look at what needs to be worked on, and that influences future planning.
My reasons for switching exercises?
Progress has stopped. Adding more resistance or volume is no longer an option as fatigue has built up to a point where a de-load is needed.
Technique is too advanced for the trainer. If proper technique can’t be achieved then a regression is needed to continue in development. An exercise is only a tool, it’s movement that should be trained and loaded correctly.
Pain. If there is pain, it should be addressed. From my experience, pain doesn’t just go away from simply training harder.
You CAN make progress from switching exercises regularly but it’s more difficult to track with accuracy.
You CAN make progress from sticking to a handful of exercises for a few weeks and track how you overload them and how you progress.
There are very few absolutes in all walks of life, apart from you being a product of what you do CONSISTENTLY.