Many people ignore any form of warm ups thinking it’s a waste of time. Wrong. Even a short and easy warm up can increase the blood flow to the muscles, which decreases muscle stiffness and decreases risks of injury. You will feel better and you will perform better so please, don’t neglect warm ups! This video is a great example of a short pre-workout warm up. If you plan to do Tabata or HIIT or any form of intense cardio, I encourage you to devote a couple of minutes for an additional warm up, or perform first couple minutes slower with much less intensity. If you plan to lift weights, also allow some time for an extra warm up. Personally, I like to do first round with a set of light weights before reaching for heavy dumbbells.  I feel better and it helps me to push myself harder later into my workout.