CrossFit is an evidence-based fitness programCrossFit is an evidence-based fitness program. Meaningful statements about safety, efficacy and efficiency the three most important and interdependent facets of any fitness program can be supported only by measurable, observable, and repeatable facts, (i.e., data). The CrossFit methodology depends on full disclosure of methods, results and criticisms, and we have employed the Internet as our primary means to support these values. Our charter is open source, making co-developers out of participating coaches, athletes and trainers through a spontaneous and collaborative online community.CrossFit is empirically driven, clinically tested and community developed. We offer the worlds most useful definition of fitness: increased work capacity across broad time and modal domains. Capacity is the ability to do real work, which is measurable using the basic terms of physics (force, distance and time).