 Basic exercise fail. Plank held incorrectly. Ouch. Often, people have really low hips, they're kind of sinking down here. Or they're cheating and their hips are really high and that's not hard either. They put their arse in the air, like a little mountain. Get it flat, put the tension on your stomach. A lot of people put their bum up in the air and now it's taking tension off your abs. And also if you're sagging, you're basically resting on the floor. You want to be bang in the middle, like this, and just hold. Start by tucking the tailbone under and kind of sucking your belly button towards your spine. So you're kind of making that position. And then you want to make sure your hips are in line with your shoulders and then all the way down to your ankles. So if you drew a straight line from my shoulders to my hips to my ankles, it would be straight. I'm not sinking down or pushing up. I'm in a straight line here. One of the worst mistakes I see people make is rounding their back when they do a body weight squat. So what people will tend to do is kind of tuck their bum under like this and squat down. Now this is going to put a lot of pressure on the lower area of your back and instead you should be trying to arch your back and stick your bum out and sit back into your hips. That will prevent any unwanted back pain and make sure you're using the right muscles. One exercise I see people make mistakes on is to press up. I see a lot of people doing this. What is that? That's not a press up. This is a press up. You go down and then up, down and then up. Your nose and your chest goes down to the floor as well as your hips. So none of this and more of this straight line up and down.