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This study aimed to investigate the co-contraction and pre-activation of agonistic and antagonistic muscles in experienced Tai Chi (TC) practitioners during normal walking (NW) and brush-knee twist-step (BKTS). The electromyographic activities of rectus femoris, biceps femoris, and tibialis anterior and lateral gastrocnemius muscles were collected during BKTS and NW in 28 TC practitioners. The pre-activation of knee and ankle joints before initial landing of left foot, and the co-contraction of knee and ankle joint in double-stance phase I (DSI), single-stance phase (SS), double-stance phase II (DSII), and swing phase (SW) were calculated during BKTS and NW. Ankle co-contraction significantly increased during DSI and SS in BKTS movements than compared with that in NW. For DSI and SW, SS and DSII, and DSII and SW, a significant difference was found in BKTS. The pre-activation of knee joint significantly decreased in BKTS and NW. This study indicated greater ankle joint muscle co-contraction in DSI and SS of stance phase and lower knee joint muscle co-contraction and pre-activation than in NW in BKTS movement. In addition, greater ankle joint muscle co-contraction was observed in the DSI, SS, and DSII of stance phase than those of swing phase in BKTS movement. [ABSTRACT FROM AUTHOR]

Diffusion tensor imaging (DTI) measures the displacement of water molecules across tissue components and thus provides information on the microstructure of brain white matter. This study examined the effect of Tai Chi and the relation of Tai Chi experiences and skills with brain white matter. Fractional anisotropy (FA) was obtained from the DTI magnetic resonance images of two group participants, namely, the long-term Tai Chi practitioners and sedentary counterparts. Whole-brain voxel-based analysis showed that the Tai Chi group had higher FA in the splenium of corpus callosum (p = 0.015) than the control group. Rank correlation analysis revealed that in the Tai Chi group, the FA value of the splenium of corpus callosum was moderately related with exercise duration (r = 0.45, p = 0.045) but highly related with skill level (r = 0.699, p = 0.001). Long-term Tai Chi practice could benefit to the brain white matter, and these impacts were correlated with exercise duration and skill level. [ABSTRACT FROM AUTHOR]

This study evaluates the effects of training and detraining on ankle proprioception in terms of kinesthesia in adult women. Sixty participants were randomly assigned to three groups. Tai Chi and Brisk Walking Groups went through a 16-week training period followed by an eight-week detraining period. The ankle plantar-flexion, dorsal-flexion, inversion, and eversion kinesthesia were measured every four weeks. The ankle kinesthesia in plantar/dorsal flexion of both exercise groups decreased, but the Tai Chi Group decreased more and sooner than the Brisk Walking Group. The training effects of Tai Chi exercise were retained but diminished during the detraining. The training effects of Brisk Walking exercise were not retained. The kinesthesia of ankle inversion and eversion remained unchanged after training. The results suggest that Tai Chi exercise is more effective in training ankle proprioception in plantar and dorsal flexion and in retaining the training effects compared with Brisk Walking exercise. [ABSTRACT FROM PUBLISHER]