Differences in the effects of different TC exercise programs and times on BMD improvement
skeletal muscle contraction, BMD loss
The present study revealed that each TC exercise program exhibited significant disparities in BMD changes across several skeletal regions including the L2-L4 lumbar vertebrae, Ward's triangle, femoral neck, and greater trochanter in comparison to CG, at various time points. These differences were particularly pronounced at select time points and may be attributable to the biomechanical characteristics of the body, as influenced by the movements performed during TC training. Such characteristics could conceivably impact skeletal muscle contraction and joint movement, ultimately impacting BMD. Our findings further suggest that the 24TCC exercise program is especially effective at mitigating BMD loss in the L2-L4 lumbar vertebrae over short-term training. Nonetheless, the training effects progressively converged with those of CG during the 8th, 12th, and 16th weeks of systematic training. This trend is consistent with the results of Cheng et al., who observed a more robust effect on BMD in the early phase of TC exercise, with a weaker effect in the later phases [The inherent adaptability of bone structure enables it to respond to mechanical stimuli, leading to the development of advantageous structural features in the mature skeleton through physical activity, such as enhanced cross-sectional area, BMD, and moment of inertia [The current study elucidates significant disparities in BMD changes in various skeletal regions, including L2-L4 lumbar vertebrae, Ward's triangle, femoral neck, and greater trochanter, during TC exercise programs compared to CG. These disparities were notably prominent at specific time points, potentially attributable to biomechanical characteristics of the body influenced by TC exercise, which could affect skeletal muscle contraction, joint movement, and ultimately, BMD. 24TCC demonstrates particular efficacy in mitigating BMD loss in L2-L4 lumbar vertebrae during short-term training, but training effects converge with those of CG over longer durations (i.e., 8th, 12th, and 16th weeks). This temporal variation in TC exercise efficacy on BMD improvement aligns with Cheng et al. [