People who ask for exercise advice are usually looking for a simple answer. Do this on top of that. Do this a lot of this thing, for this long. Get those wins. In reality, things are never that simple.
This is certainly true for the age old question of how often to change up your exercise routine. Unfortunately, no perfectly designed study answers this question exactly. a lot depends on things like your fitness level, your goals, and how you train.
But if you’re thinking about changing up your routine, here are some things to consider.
Progressive overload and diminishing returns
The idea that you should mix up your exercise routine probably comes from the concepts of progressive overload (where you need a stimulus to achieve continuous improvements) and the principle of diminishing returns (where the more experienced you are at something, the less you progress with a stimulus).
One of the ways people try to incorporate these principles into training is through what’s called “periodization.”
This is where you manipulate certain aspects of a training program, such as exercise volume, intensity, and frequency.
Periodization models typically maintain consistent exercise selection for a designated period of time, usually an eight to 12 week program.
The two main patterns of periodization are linear and undulating. Linear periodization involves the gradual increase of a variable. For example, on an eight-week program, the loads may get heavier, but the number of sets or reps you do decreases.
Undulating periodization involves manipulating different variables (usually volume and intensity) on different days. So on Monday you could do some heavy lifting, then Tuesday you’ll focus on higher reps, then you’ll have explosive or speed priority for the next day.
Research shows that periodized programs seem surpass their non-periodized counterparts, with no difference between undulating and linear models.
Even if you’re not knowingly doing a periodized plan, most exercise programs tend to last eight to 12 weeks and incorporate some of the standard linear progressions mentioned above.
It depends on your goals
What about mixing the exercises themselves? Research has shown that people earn comparative or bigger muscle strength and size when opting for a variable exercise selection over a fixed exercise selection.
Variable exercise selection is where you don’t always stick to using the same exercise for the same muscle groups. For example, you can switch between a squat and a leg press the next session. Alternatively, the fixed selection means that for the duration of your program, you stay with the same exercise (for example, the squat).
And using a varied selection can improve motivation.
Conversely, excessive exercise rotation seems to have a negative influence on muscle gains.
When it comes to this, many moves are skill-based; by not practicing as much, you may not progress as fast. This probably only applies to complex multi-joint exercises such as those performed with a barbell (as opposed to, say, gym machines).
Is it important? If you have a performance related goal to lift a certain amount, or something similar, then this might be it. But if you train for health and wellness, that might not be a factor for you.
What about running?
Many of us walk the same loop, at the same pace, for weeks and years. Is it a problem?
Some researchers recommend increasing your training stimulus after six months of endurance exercise, as most benefits occur between three and six months and then tend to plateau without changing training regimens.
But is it enough for health? Our current national recommendations for physical activity do not mention the need to progress or vary the exercise. They simply indicate the amount, intensity and type of exercise for health benefits. Exercise for performance or continuous improvement seems to be a different story.
If you’re thinking about how often we should change exercises, consider how long it takes for the body to adapt after exercise.
Research has shown that muscle growth can occur as early as three weeks in a resistance training program and plateaus at about three months in previously untrained people.
Adaptations to cardiovascular fitness can occur as early as about one week in a training program, but it has been shown plateau in three weeks if no additional progressive overload is applied.
Even after a longer-term progressive aerobic program, measures of cardiovascular fitness tend to plateau around nine months Training.
Do what you love and can stick to it
So what do we do with all the evidence above?
Adaptation occurs rapidly, but also plateaus rapidly without continued stimulus.
However, we all have a “ceiling” of adaptation, beyond which it will be necessary to make significant efforts to progress.
It goes back to the principle of diminishing returns, where the more you practice, the less you are able to improve.
All things considered, the traditional approach of changing your program every 12 weeks might actually make sense in order to avoid plateaus. However, there is no hard and fast rule as to how often you should mix it.
Perhaps the best approach is to do what you are most likely to follow and enjoy the most.
After all, you can’t get any gains if you don’t actually do the work.
