Times has an article comparing tai chi to crossfit.

“It holds up when compared to other more strenuous types of exercise. “Over time, we see people who do tai chi achieve similar levels of fitness as those who walk or do other forms of physical therapy,” Irwin says. One study in theAmerican Journal of Epidemiology concluded that tai chi was nearly as effective as jogging at lowering risk of death among men. Another review inPLOS One found that the practice may improve fitness and endurance of the heart and lungs, even for healthy adults.”