Exercise Repetition Question....

I have to say I don't agree. I am a runner and run about 5-6 days a week and have been for over a year. It's still working and still making a difference. I do believe your body gets used to it to some degree, and maybe with more strength type exercises your body needs to change up the intensity for more results.

I am not sure I agree either unless you are targeting a specific part of the body. It would seem to me that any time you are exercising you are burning calories, so if your goal is weight loss, that would be sufficient. The exception would be like I said if you are focusing on a particular part of the body - stomach, arms, legs, back, etc. - then she may be right.

There is no magic number. Your body adapts to what you are doing so if you do the same thing all the time without increasing intensity, there will come a day when you don't burn as many calories doing it (because you aren't working as hard) or you are only maintaining your muscle strength and not improving it. But it takes way longer than 3 times and it's going to happen at a different point for everyone.

Well played.

To add to that: eventually, the body will adapt to just about anything, and It retains a lot of that adaptation even when you stop doing the activity. Studies have been done that show that people who did regular strength training for several years when they were younger, still test higher than those who have never trained even 10-15 years later. The idea that you can do a certain movement for a few sessions, switch to other movements, then come back to that movement after a couple of weeks and "confuse" the body is patently absurd. Here is the fact: if you CAN introduce a movement that is so different that it results in a mechanical inefficiency ("muscle confusion") that will actually be enough to cause you to burn more calories, then the inefficiency will also be enough to prevent you from exerting yourself to the best of your fitness levels--thus lowering your caloric expenditure.

Yes, the body needs variety, and you need to follow a varied training schedule. But this current concept of "muscle confusion" as espoused by P90X infomercials is a gross oversimplification and distortion of basic principles (that's why it's in an infomercial). What is always disappointing is how many supposedly "experienced" fitness people take the cynical and lazy way out and just echo the current buzz words, pretending they are "guidelines". It's this conscious intermingling of self-marketing BS with real science that robs the industry of so much of its credibility.

I think what she meant was more along the lines of toning and strength training. You can burn calories doing a lot of stuff, but you will eventually get good at something and more conditioned to it, so that you don't burn as many calories during it as well. However, when you are trying to tone your muscle groups, then you have to keep pushing a little futher each session to keep seeing results. She said that ANY exercise is better than no exercise at all. She also isn't a big advocate for walking and nothing else. She feels it should all be done in conjunction with strength training.

No -- what happens when you "get good at something and more conditioned to it" is that you can work harder at it--and thus burn more calories, not fewer. Again, you need variety in your routines--both strength and cardio--but for training purposes--not because of any reduced calorie burn.