Why can't you perform the things you do from your (fake) memories?

Why can't you fly?

Seriously. Why can't you just lift yourself off the ground and fly around in the air?

Haven't you ever had a dream where you were flying without the assistance of some mechanical device? I know I have. More importantly, I remember having those dreams, and I remember some of the content of those dreams. So... since I remember (a key point to your question) flying, why can't I fly now? If, as you postulate, my mind can remember how and what my body has done, shouldn't I be able to do that again?

The problem with that postulate, is the following assumption:

if your mind can remember how and what your body has done

There is absolutely NO PROOF or even speculation within the Total Recall canon that the memory of how you did what you did was implanted in your memory. You were simply given the memories of having done those things. You are not given the memories of the years of training and the years of experience a spy received in addition to the two weeks of the life of a spy that you paid for, when you purchase a two week "Life of a Spy" vacation package. You are only given those two weeks. So, you were never given the memory of how something was done, just that it was done.

There are countless real world examples of people looking back at personal experiences, and not being able to recall how they did something even immediately after doing it. Those are people who actually did do something, and still can't remember how or actually be able to repeat the action. On a related note, there are also a large number of people who can repeat actions without being able to explain how they do them, because of their training. They can respond almost instinctively without applying conscious thought.

Because you do not actually get the training, practice and experience which are required to actually build these skills. You simply have the memory of having had this training and the memory of having applied it. Hence you do not really know if, you simply have a recollection of having known it.

Also, I vividly remember fighting 3 people at the same time when I was 18 to pass a martial art grading (that actually happened) - that does not mean I can walk up to any three people and fight them all at the same time and expect to win. Even if you have a memory of something real, it was specific to that exact situation at that exact time and does not mean that those skills will work in the same way the next time.