A Theory About Exercise

I am not aware of any serious research on this idea, but I have noticed something that seems to hold true in my own personal experience...

Most of the benefits of exercise (weight loss, increased muscle mass, improved blood sugar control, increasing VO2 max, etc.) seem to be at their most pronounced levels when a person is undertaking something new. That is, when you first begin an exercise regimen, for the first, say, two or three weeks, one will notice major gains in muscle, major drops in body fat, major improvements in blood sugar, and so forth. But as that exercise regimen continues over 4, 5, 6 weeks, and beyond, the improvements become far less pronounced. In my personal observation, they even reverse in some cases.

To avoid losing out on all the progress I gain as I work out, I have taken to making major changes to my exercise regimen every two or three weeks. This might come in a variety of forms. For example, when I developed a case of tendonitis recently, I first switched to jump rope as my preferred cardiovascular exercise. When I reached the point of diminishing returns, though, I switched to a rowing machine and again started feeling good and healthy. Recently I reached the point of diminishing returns there, too, and so I've been focusing on interval workouts using an elliptical machine. Now I find I'm maxing out there, and my legs feel a lot better, so I am making plans to start running again.

For strength training, it's been the same way. I committed to making major changes to my weight lifting routine every week or two. The result is, at least so far, muscles that continue to get larger and better-toned, and stronger.

Of course, what I'm talking about here is basically the "muscle confusion" principle upon which P90X and other fitness programs are based. So there is at least a community of people out there who seem to have noticed the same thing I have.

But, I have no scientific evidence for this, and what evidence I have seen thus far looks more like marketing than exercise physiology. Perhaps I'll never know the answer to this question, but I can say at least this much: It seems to hold true for me.

What is your own experience with this phenomenon?


  1. I believe it's called diminishing marginal returns.

    1. Haha! You're telling me this was inevitable? Where were you 3 weeks ago? ;)

  2. I have witnessed the same (thought not in myself, but others in my accountability group). They are regularly told to expect the biggest changes in months 1-2 and smaller effects after that.

  3. I like shaking it up -- I like the feeling of having my body and mind have to adapt to a surprise. That's one reason I'm enjoying Crossfit right now. Instead of me thinking to myself, "Meh, the treadmill's getting easy, I'm going to switch to the stationary bike," I show up to the gym and someone else tells me what I'm going to work on. So there's no way to mentally prepare. My mind has to adapt as well. I don't get to comfortably choose what I'm going to do, I'm given a challenge that I don't know if I'll be able to complete. That adds another element to adapt to.

    What is your average time with any one activity before you feel like you've peaked or plateaued? And what do you think about extrapolating that concept over an entire year, into a "season" and an "off-season?"

    1. If I'm going just be "feel," then the plateau really gets noticeable after a month of one thing, unless I really make an effort to switch things up. If I'm going by my blood glucose it's gotta be 2 weeks or so. It's crazy.

      When I'm training for something, it's a little easier for me to deal with, because I can just increase mileage or speed (running) until it "does some good" again. But if we're just talking casual exercise and gym activity, what I've been doing lately is focusing on one set of muscle groups for an entire week, then changing to a new group the next week. And I try to force myself to do that every week. This helps me avoid doing the same stuff over and over every week ("Oh, it's arms day, so I'll do my Arms Day Workout...") by making sure that whatever series of exercises I might be doing, I only get to do them for a week.

      But I think you're right that it would be a better idea to go into it with a longer-range plan.

  4. Oh, I don't know if a longer-range plan would be better, necessarily... just wondered what your thoughts are on working out as if you had a "season" and "off-season" even if you really don't, and are just working out for fitness.

    And 2 weeks! Man, you are adaptive! :)

  5. The Goodlife classes I take exploit this phenomenon on a micro scale. That is in one workout, say biceps, they switch the exercises constantly just as your are simultaneously getting used to it and burning out. They call this muscle confusion as well. I have to say on this scale (seconds instead of weeks), it allows me to push my muscle group to absolute fatigue more easily than traditional weight training was able to. It is rare that I am not shaking like a leaf after a body pump workout. I know this is a little off topic, but I think the same principles are at work here on both the short term and long term scales. "Shaking it up" allows you to push hard, faster and further.