Tai Chi Can Improve Postural Stability as Measured by Resistance to Perturbation Related to Upper Limb Movement Among Healthy Older Adults

Purpose: The aim of the study was to examine the effects of Tai Chi (TC) training on postural control when upright standing was perturbed by upper limb movement. Methods: Three groups, TC, Brisk walk (BW), and sedentary (SE), of thirty-six participants aged from 65 to 75 years were recruited from local community centers. Participants performed static balance task (quiet standing for 30 s with eyes open and closed) and fitting task (two different reaching distances X three different opening sizes to fit objects through). During tasks, the COP data was recorded while standing on the force plate. Criteria measures calculated from COP data were the maximum displacement in anterior-posterior (AP) and medial-lateral (ML) directions, the 95% confidence ellipse area (95% area), and the mean velocity. Results: No significant effect was observed in the static balance task. For fitting tasks, the group effect was observed in all directions on COP 95% area (p \u3c 0.05) and the TC group showed reduced area. The tests of subject contrasts showed significant trends for reaching different distances and fitting different openings conditions in all directions, the 95% area, and the mean velocity (p \u3c 0.05). Conclusion: Compared to the other two groups, long-term TC exercise helps in reducing the effects of upper body perturbation as measured by posture sway

Tai Chi Can Improve Postural Stability as Measured by Resistance to Perturbation Related to Upper Limb Movement among Healthy Older Adults

Purpose. The aim of the study was to examine the effects of Tai Chi (TC) training on postural control when upright standing was perturbed by upper limb movement. Methods. Three groups, TC, Brisk walk (BW), and sedentary (SE), of thirty-six participants aged from 65 to 75 years were recruited from local community centers. Participants performed static balance task (quiet standing for 30 s with eyes open and closed) and fitting task (two different reaching distances X three different opening sizes to fit objects through). During tasks, the COP data was recorded while standing on the force plate. Criteria measures calculated from COP data were the maximum displacement in anterior-posterior (AP) and medial-lateral (ML) directions, the 95% confidence ellipse area (95% area), and the mean velocity. Results. No significant effect was observed in the static balance task. For fitting tasks, the group effect was observed in all directions on COP 95% area (p<0.05) and the TC group showed reduced area. The tests of subject contrasts showed significant trends for reaching different distances and fitting different openings conditions in all directions, the 95% area, and the mean velocity (p<0.05). Conclusion. Compared to the other two groups, long-term TC exercise helps in reducing the effects of upper body perturbation as measured by posture sway

Sensitization of Glioma Cells to Tamoxifen-Induced Apoptosis by Pl3-Kinase Inhibitor through the GSK-3β/β-Catenin Signaling Pathway

Malignant gliomas represent one of the most aggressive types of cancers and their recurrence is closely linked to acquired therapeutic resistance. A combination of chemotherapy is considered a promising therapeutic model in overcoming therapeutic resistance and enhancing treatment efficacy. Herein, we show by colony formation, Hochest 33342 and TUNEL staining, as well as by flow cytometric analysis, that LY294002, a specific phosphatidylinositide-3-kinase (PI3K) inhibitor, enhanced significantly the sensitization of a traditional cytotoxic chemotherapeutic agent, tamoxifen-induced apoptosis in C6 glioma cells. Activation of PI3K signaling pathway by IGF-1 protected U251 cells from apoptosis induced by combination treatment of LY294002 and tamoxifen. Interference of PI3K signaling pathway by PI3K subunit P85 siRNA enhanced the sensitization of U251 glioma cells to tamoxifen -induced apoptosis. By Western blotting, we found that combination treatment showed lower levels of phosphorylated AktSer473 and GSK-3βSer9 than a single treatment of LY294002. Further, we showed a significant decrease of nuclear β-catenin by combination treatment. In response to the inhibition of β-catenin signaling, mRNA and protein levels of Survivin and the other three antiapoptotic genes Bcl-2, Bcl-xL, and Mcl-1 were significantly decreased by combination treatment. Our results indicated that the synergistic cytotoxic effect of LY294002 and tamoxifen is achieved by the inhibition of GSK-3β/β-catenin signaling pathway

Tai Chi Can Improve Postural Control During Upper Limb Movement for Healthy Elderly

Purpose: Aim of the study was to examine the effects of Tai Chi (TC) training on postural control when upright standing was perturbed by upper limb movement. Methods: Three groups, TC, Brisk walk (BW), and Sedentary (SE), of thirty-six participants aged form 65 to 75 years old were recruited from local community centers. Participants performed six different upper extremity fitting tasks (two different reaching distances X three different opening sizes to fit through). During fitting tasks, the COP data was recorded while standing on the force plate. Three-way ANOVA with repeated measure used to examine the effects of group, reaching distances and opening sizes. Criteria measures calculated from COP data were distance in anterior-posterior (DAP) and medial-lateral directions (DML), 95% area (AREA) and average velocity (VEL). Results: Significant linear trends (P\u3c.05) observed for reaching different distances and fitting different openings for variables reported in Table 1 & 2. TC group were least effected by upper body motion in both reaching for further distance and fitting object to smaller openings. Conclusions: Long-term TC exercise helps reduce the effects of upper body perturbation as measured by posture sway, comparing to the other two groups

Long-term Tai Chi Exercise Lead to Enhanced Resistance Postural Perturbation Among Older Adults

PURPOSE: The purpose of this study was to examine the influences of performing precision fitting task on the dynamics of postural sway among older adults. METHODS: Three groups (12 each) participants aged 65 to 75 years recruited for the project: habitual Tai Chi practitioners (TC, body mass (M) = 64.4 ± 9.3 kg, height (H) = 162.5 ± 6.9 cm), long term brisk walkers (BW, M = 62. 8 ± 6.6 kg, H = 163.5 ± 6.5 cm), and sedentary (SE, M = 68.3 ± 7.0 kg, H = 163.9 ± 7.0 cm). Participants were asked to stand on a force plate (Kistler 9287C, Kistler Corporation, Switzerland) with their feet forming a 30° angle and their heels 8% body height apart. Participants were required to fit a 90 * 90 mm block into three different openings (small: 100 * 100, medium: 115 *115, and large: 130 * 130 mm) with two different distances (1 and 1.3 times arm’s length). The task time and base of support were recorded by optical gate and reflective markers using Vicon system (Vicon Corporation, UK) synchronized with force plate data collection. The average time-to-contact (TTC) measures were used to examine the dynamic of posture sway during fitting task. Two two-way ANOVAs were used to assess the effects of group by size for average TTC at the two reaching distances. RESULTS: There was no group by size interaction observed for either distance (p \u3e .05). Significant differences were detected for group (close: F2,99 = 11.567, p \u3c .00; far: F2,99 = 13.549, p \u3c .00) and size (close: F2,99 = 49.228, p \u3c .00, far: F2,99 = 36.296, p \u3c .00) for both distances. LSD Post Hoc revealed that TTC for TC was significantly less than that of the SE and BW at both close (2.30±0.56 vs. 2.81±0.71 vs. 2.61±0.71 s, p \u3c .05) and far distance (1.82±0.31 vs. 2.30±0.61 vs. 2.11±0.58 s, p \u3c .05). Additionally, TTC of small fitting size was significantly longer than that of the middle and lager fitting sizes, while TTC of middle size also was longer than that of the larger size at both close (3.25±0.75 vs. 2.46±0.43 vs. 2.14±0.28 s, p \u3c .05) and far (2.52±0.57 vs. 1.98±0.42 vs. 1.74±0.30 s, p \u3c .05) distances. CONCLUSIONS: Small fitting opening provided greater perturbation to postural control lead to longer TTC. However, postural control of the TC revealed having greater resistance to the perturbation lead to shorter TTC. Therefore, Tai Chi training have the potential for resist postural perturbation and prevent fall among older adults

Long-term Tai Chi Exercise Lead to Enhanced Resistance Postural Perturbation among Older Adults

PURPOSE: The purpose of this study was to examine the influences of performing precision fitting task on the dynamics of postural sway among older adults. METHODS: Three groups (12 each) participants aged 65 to 75 years recruited for the project: habitual Tai Chi practitioners (TC, body mass (M) = 64.4 ± 9.3 kg, height (H) = 162.5 ± 6.9 cm), long term brisk walkers (BW, M = 62. 8 ± 6.6 kg, H = 163.5 ± 6.5 cm), and sedentary (SE, M = 68.3 ± 7.0 kg, H = 163.9 ± 7.0 cm). Participants were asked to stand on a force plate (Kistler 9287C, Kistler Corporation, Switzerland) with their feet forming a 30° angle and their heels 8% body height apart. Participants were required to fit a 90 * 90 mm block into three different openings (small: 100 * 100, medium: 115 *115, and large: 130 * 130 mm) with two different distances (1 and 1.3 times arm’s length). The task time and base of support were recorded by optical gate and reflective markers using Vicon system (Vicon Corporation, UK) synchronized with force plate data collection. The average time-to-contact (TTC) measures were used to examine the dynamic of posture sway during fitting task. Two two-way ANOVAs were used to assess the effects of group by size for average TTC at the two reaching distances. RESULTS: There was no group by size interaction observed for either distance (p \u3e .05). Significant differences were detected for group (close: F2,99 = 11.567, p \u3c .00; far: F2,99 = 13.549, p \u3c .00) and size (close: F2,99 = 49.228, p \u3c .00, far: F2,99 = 36.296, p \u3c .00) for both distances. LSD Post Hoc revealed that TTC for TC was significantly less than that of the SE and BW at both close (2.30±0.56 vs. 2.81±0.71 vs. 2.61±0.71 s, p \u3c .05) and far distance (1.82±0.31 vs. 2.30±0.61 vs. 2.11±0.58 s, p \u3c .05). Additionally, TTC of small fitting size was significantly longer than that of the middle and lager fitting sizes, while TTC of middle size also was longer than that of the larger size at both close (3.25±0.75 vs. 2.46±0.43 vs. 2.14±0.28 s, p \u3c .05) and far (2.52±0.57 vs. 1.98±0.42 vs. 1.74±0.30 s, p \u3c .05) distances. CONCLUSIONS: Small fitting opening provided greater perturbation to postural control lead to longer TTC. However, postural control of the TC revealed having greater resistance to the perturbation lead to shorter TTC. Therefore, Tai Chi training have the potential for resist postural perturbation and prevent fall among older adults

The Effect of Tai Chi Exercise on Postural Time-to-Contact in Manual Fitting Task among Older Adults

Background A fall would impact elderly population’s quality of life, which associate with diminished physical and psychological function, and can even be life-threatening. Tai Chi has been used to improve age-related postural instability in locomotion. However, it does not fully explain the mechanism of a lower risk of falling among the Tai Chi population compared to other healthy older adults. Research question The maintenance of postural stability is more complicated than minimizing postural movements. Postural time to contact is an important temporal measure of postural stability under fitting tasks, which might further clarify the benefits of long term Tai Chi exercise. Methods Participants were required to fit a block (90 × 90 mm) through two different openings (130 × 130 mm and 100 × 100 mm) at two different distances (arm’s length or 130 % of arm’s length). Kistler forceplate and Vicon system were used to collect center of pressure and kinematic data, respectively. Postural time to contact was used to assess instantaneous perturbation for postural system. Results Tai Chi group exhibited significant longer postural time to contact in quiet standing and shorter postural time to contact in fitting tasks, expecting for close-small condition, compared to the brisk walking and sedentary groups (p \u3c .05). In addition, both large and small opening condition, Tai Chi group showed a shorter postural time to contact than brisk walking and sedentary groups (p \u3c .0001). Significance Long term Tai Chi exercise would promote the regulation of posture and decrease the postural constrain to increase the overall stability when performing fitting tasks. Therefore, Tai Chi exercise can be considered as a feasible method to enhance postural control and stability in older adult

The Effects of Habitual Foot Strike Patterns on the Morphology and Mechanical Function of the Medial Gastrocnemius–Achilles Tendon Unit

As a crucial and vulnerable component of the lower extremities, the medial gastrocnemius–Achilles tendon unit (gMTU) plays a significant role in sport performance and injury prevention during long-distance running. However, how habitual foot strike patterns influence the morphology of the gMTU remains unclear. Therefore, this study aimed to explore the effects of two main foot strike patterns on the morphological and mechanical characteristics of the gMTU. Long-distance male runners with habitual forefoot (FFS group, n = 10) and rearfoot strike patterns (RFS group, n = 10) and male non-runners (NR group, n = 10) were recruited. A Terason uSmart 3300 ultrasonography system was used to image the medial gastrocnemius (MG) and Achilles tendon, Image J software to analyze the morphology, and a dynamometer to determine plantar flexion torque during maximal voluntary isometric contractions. The participants first performed a 5-minute warm up; then, the morphological measurements of MG and AT were recorded in a static condition; finally, the MVICs test was conducted to investigate the mechanical function of the gMTU. One-way ANOVA and nonparametric tests were used for data analysis. The significance level was set at a p value of p p Conclusion: Long-term running with a forefoot strike pattern could significantly affect the FL and PA of the MG. A forefoot strike pattern could lead to a longer FL and a smaller PA, indicating an FFS pattern could protect the MG from strain under repetitive high loads