Guys I wonder what do you think about mixing the squats and sit ups? I mean which is better option to start with the squats and continue with the sit ups or reverse? For instance for me it is almost impossible to achieve a good result when making push ups after the two exercises I mentioned above. Your abs are burning, you legs are shaking. When I do sit ups after squats my thighs are in pain, but when I do squats after sit ups I feel weak my core. So what do you think about the mix of these exercises?