Long-term practice of tai chi can improve muscular strength in the lower body, particularly around the knees and ankles, as much as long-term jogging, according to a study published in the British Journal of Sports Medicine (2006; , 50–54). This is good news for older adults looking for gentle movement alternatives that provide powerful conditioning benefits.
Researchers recruited 61 participants, including long-term tai chi practitioners, long-term joggers and inactive individuals. Assessors measured the isokinetic strength of muscles at the knee and ankle joints and the endurance of knee flexors and extensors in all subjects. Slight differences in conditioning resulted from the nature of the different activities. For example, comparing joggers with tai chi practitioners, the former developed slightly stronger concentric strength in the knee extensors and flexors, whereas the latter attained greater muscular endurance in the knee extensors. The benefits of both jogging and tai chi on lower-body muscular strength and endurance were clear—and significantly better than no exercise.
Investigators suggested that tai chi could be effective in increasing muscular endurance because the movements are slow, continuous, smooth and well controlled. This type of training may be most beneficial for conditioning slow-twitch muscle fibers, which when trained have a greater resistance to fatigue (than fast-twitch fibers) because of their high capacity for aerobic metabolism. More research is needed to explore these mechanisms of action and to appreciate the broad range of benefits, especially for older adults, of long-term tai chi practice.