Yes. Even though your clients sign consent forms acknowledging the possible risks they face by participating in your workout classes, you still require business insurance to protect yourself from third-party allegations and lawsuits of wrongdoing, negligence, or misconduct, or if they are injured by your exercise routine. Although a waiver or consent form can be helpful, they cannot prevent one of your clients from suing you. If they do, and you do not have business insurance, you are still responsible to pay for your legal defence costs.