I find both of these concepts to be helpful in different ways.
There are times when I need to take a break due to my chronic illness and the craziness of life. I may not be able to do dedicated exercise for a week (YIKES!)
Muscle memory assists with regaining strength and size much quicker than the first time around. Our brains and muscle fibers recall the repetitive motions! So when I resume my training it’s not as difficult as when I first began. I often can get back to the same weight and run pace in a matter of days after sometime off. Even improving my personal best!
Muscle confusion is the idea that by constantly change your workouts you “confuse” your muscles and increase the stimulation. It’s a fun and challenging way to train. I tend to get bored with the same routines so changing it up helps.
However, I’ve been perpetually sore for a few weeks now due to overtraining. I am not a professional athlete I work my body safely and do a wide variety of workouts. Use caution here because I believe it’s easier to cause injury doing workouts that vary so much.
After consulting with a athletic trainer I realized I’m not allowing myself recovery time, hence the constant aches and pains. I have a chronic illness, my weight, joint pain, and age to consider when it comes to recovery.
I think it’s amazing what our mind and bodies can do.