The Tai Chi classics always say you should not do strength training with tai Chi, but you have to look at that in context. The classes were written in a very different time when life was more physical than today.
Thirty-percent of ambulatory seniors over the age of 65 living in a community fall every year. Another 50% of the same age group living in long-term care facilities suffer from at least one fall annually. One in 10 of these falls in turn results in a fracture.1 Falls represent the leading cause of death for people over 65 and the number of fall-related deaths continues to increase with every passing year.