What’s your fitness routine? Have you found a particular activity that you like and only do that one thing, or do you try different classes and activities on a regular basis? This post is all about encouraging you to mix up your routine, and I’ll explain the science behind why you want to do that.


First, I want to introduce you to the SAID Principle. In physical rehabilitation and sports training, the SAID principle asserts that our bodies adapt to activities in a very particular way. Stressors on the human system, whether biomechanical or neurological, will result in a Specific Adaptation to Imposed Demands (SAID).


We can use the SAID Principle to help us improve. As an example, if you are training for a marathon, you should do a lot of running. If that same marathon runner stopped all their running in favor of yoga classes, their performance in their next race would likely suffer. They are no longer imposing the required demands on their body in order to see the specific adaptation they desire.


We can also use the SAID principle to understand why we sometimes hit a plateau in our fitness levels. Say you want to be able to hold a 60-second plank. You start at 10 seconds and every day you add 1 second to that total. In less than 2 months, you can hold your plank for 60-seconds, and a 10-second plank is easy-peasey. Then you continue to do that 60-second plank every day and after another 2 months you wonder why that 60-second plank is still pretty hard. Your body has adapted to holding a plank for 60-seconds max. If I told you to start adding 1 second every day again, by the end of 2 more months, a 2-minute plank would be challenging, but that 1 minute plank would now be much easier.


Looking at it another way, perhaps you’ve been coming to dance fitness classes for a few years. At first, classes were really challenging and left you exhausted that night, sore the next day, and you lost 5 pounds in the first month or two. Now, you wouldn’t categorize classes as easy, but you definitely don’t feel them like you did when you first started. And those 5 pounds? They’re back. You’ve adapted to your routine and haven’t provided any other challenge to your body that would force a change.


Too much of any one thing can be really detrimental, too. As a ballet dancer, from the outside it looked like I was in great shape. But because that’s all I did physically, I suffered from some repetitive use injuries. I had achilles tendinitis and torn cartilage in my knees. At 19 I needed surgery! How about those of you who type much of your day and have carpal tunnel. Our bodies CRAVE different activities and THRIVE when they get them.


Let’s revisit that marathon runner. If she ADDED a yoga class to her weekly routine (instead of switching her routine entirely), she’d likely see a different kind of improvement. Her recovery after a long run might be shorter due to adding some muscular endurance and flexibility work.


There are multiple components of physical fitness, and in order to be the healthiest versions of ourselves, we need to work them all! These are the components of physical fitness:

  • Cardiovascular and Cardiorespiratory
  • Muscular Strength
  • Muscular Endurance
  • Flexibility
  • Balance
  • Nutrition


Current recommendations are:

  • 150 minutes of cardio total weekly (less time is needed if the workout is very intense)
  • Muscular Strength Training, 2 times per week
  • Muscular endurance, balance and flexibility weekly

Increased benefits are seen with increased time.


There’s something for all components of fitness at Fitness with Rachel, but I don’t want you to think I’m just trying to get you to take more classes (though I won’t complain if you do). I truly want you all to be the healthiest version of you that you possibly can be. If I’ve convinced you that you should mix things up, but you don’t know where to start, grab me before or after class sometime for a quick (and free) consultation, and I’ll help you figure out what’s missing in your routine and give you some options about how to fill those gaps.


And just so you know, at Fitness with Rachel:

  • Positive Groove is Cardio (and Balance to a lesser degree)
  • Tabata Express is Muscular Strength (and Cardio to a lesser degree)
  • Foam Roll Stretching is Flexibility
  • Pelvicore Balance is Muscular Endurance and Balance
  • Fun and Fit classes are a mix of all components, varying in degree
  • Meal Plans address nutrition