Contraindications are simply a condition or symptom that keeps you from or medically requires you not to do something else. For example, someone with a broken leg has a contraindication for using a jump rope. Of course it can be more subtle than that, but it doesn’t mean the negative effects of ignoring a contraindication will be subtle. So, it’s important to listen to your doctor and fitness professional when they advise you not to partake in particular activities and take it seriously.