Therapeutic benefits of Tai Chi exercise: research review

Just found this scientific review paper published in the Wisconsin Medical Journal 2006, (Volume 105, No. 7.42), entitled "Therapeutic benefits of Tai Chi exercise: research review". I'm very pleased to see proper scientific review papers like this. Here is the summary:

"The majority of studies on Tai Chi conducted between 1996 and 2004 had focused on health and well-being of Tai Chi exercise for senior adults. The results showed that Tai Chi may lead to improved balance, reduced fear of falling, increased strength, increased functional mobility, greater flexibility, and increased psychological well-being, sleep enhancement for sleep disturbed elderly individuals, and increased cardio functioning. Wang, Collet and Lau did a systematic review of Tai Chi research and found some limitations or biases in existing in some of the studies and it was difficult to draw firm conclusions about the benefits reported. Therefore, more well-designed studies are needed in the future.
    They need to be studies on the effects on younger and middle-aged people. More longitudinal studies are needed, since time is an important factor of physical and psychological interventions. Studies on the effect of Tai Chi on the immune system and bone loss reduction are still very exploratory and will be especially useful for arthritis patients and others with immune disorders. Future studies should investigate outcomes associated with Tai Chi training as a function of different instructional techniques, different Tai Chi styles, different diagnostic groups and different age groups.
    It is not yet clear which of the components in Tai Chi makes the exercise form especially effective for seniors. Tai Chi exercise is a relatively "low tech" approach to preventing disability and maintaining physical performance in older adults. The positive effects of Tai Chi may be due solely to its relaxing, meditative aspects. The current data suggest that Tai Chi can influence all the individuals' functioning and well-being and provide some appreciation for why this exercise for has been practised by older Chinese for more than three centuries."

To my mind this confirms my feeling that although there are clearly benefits and widespread anecdotal understanding of the therapeutic benefits of Tai Chi, this is a long way from being scientifically accepted. This is not to say that I don't think there are benefits, but the crucial thing is that scientifically speaking, these benefits need to be demonstrated relative to a control group. The point I'm trying to make, is that of course there are benefits of doing Tai Chi - exercise is good and relaxation is good, no argument there. But relatively, is doing Tai Chi better than going for a regular daily relaxing walk of a similar duration, or sitting quietly watching the ducks say? The answer to that is very far from clear.