Both tai chi and Iyengar yoga are good choices for improving strength, balance and confidence in older adults. A total of 48 healthy participants aged over 60 were divided into a tai chi group, an Iyengar yoga group and a control group by Chinese researchers. While the former two undertook 16-week exercise programmes, the control group received general education. Both programmes improved all measures of strength and balance significantly, with tai chi being more effective for increasing knee flexor and extensor strength, and activity-specific balance confidence, while yoga was more effective for improving static and dynamic balance.

Comparisons of tai chi and Iyengar yoga intervention effects on muscle strength, balance, and confidence in balance. J Sports Med Phys Fitness. 2021 Oct;61(10):1333-1338.