The objectives of this study were to examine whether elderly Tai Chi practitioners have developed better knee joint proprioception and standing balance control than control subjects. Tai Chi and control subjects (N = 21 each, aged 69.4 +/- SD 5.5 and 72.3 +/- 6.1 yr, respectively) were matched with respect to age, sex, and physical activity level. Passive knee joint repositioning was used to test joint proprioceptive acuity. Control of body sway during static standing and subjects' intentional weight shifting to eight different spatial limits of stability within their base of support were conducted using force platform measurements. Tai Chi practitioners were found to have better knee joint proprioceptive acuity, in that they made less absolute angle error (2.1 +/- 1.2 degrees ) than control subjects (4.0 +/- 3.4 degrees, with P = 0.023) in passive knee joint repositioning. No significant difference was found in the anteroposterior and mediolateral body sway during static standing (P > 0.05). However, Tai Chi practitioners initiated voluntary weight shifting in the limits of stability test more quickly (reaction time: 0.8 +/- 0.2 s for Tai Chi practitioners) than control subjects (1.1 +/- 0.3 s; P = 0.008). Moreover, they could lean further without losing stability (maximum excursion: 5.2 +/- 0.6% for Tai Chi practitioners and 4.6 +/- 0.5% for control subjects; P = 0.001) and showed better control of their leaning trajectory (directional control: 75.9 +/- 10.0% for Tai Chi practitioners and 68.5 +/- 6.9% for control subjects; P = 0.008). These results demonstrate that long-term Tai Chi practitioners had improved knee joint proprioception and expanded their limits of stability during weight shifting in stance.

TSANG, W. W. N., and C. W. Y. HUI-CHAN. Effect of 4- and 8-wk Intensive Tai Chi Training on Balance Control in the Elderly. Med. Sci. Sports Exerc., Vol. 36, No. 4, pp. 648–657, 2004.PurposeThe objective of this study was to examine whether 4 and/or 8 wk of intensive Tai Chi practice could i

A cross-sectional study of the balance control in adolescents with idiopathic scoliosis. OBJECTIVE.: To investigate the relationship among somatosensory function, balance control, and adolescent idiopathic scoliosis (AIS). Balance control requires the contribution of somatosensory, visual, and vestibular inputs. Previous studies have shown that abnormal somatosensory evoked potentials (SSEPs) were associated with AIS. A total of 105 girls with AIS and 57 normal girls aged 11-14 years entered the study, and were evaluated with bilateral tibial nerve evoked cerebral SSEPs and standing balance control under reduced or conflicting sensory conditions (i.e., the sensory organization test). One-way analysis of variance was conducted to evaluate the effects of scoliosis and somatosensory function tested by SSEPs on the performance of sensory organization test. There were 15 patients with AIS who had abnormal SSEPs. Postural sway was measured on all subjects under normal, reduced, or conflicting somatosensory, visual, and vestibular conditions. One-way analysis of variance indicated no significant effect of spinal deformity or SSEPs on the balance control when there was an increased reliance on the somatosensory, visual, and vestibular systems during stance (P > 0.05). However, in the patients with abnormal SSEPs, a significant effect was found when subjects had to rely on somatosensory input for their balance control (P = 0.023). The effect of scoliosis by itself was not found to be significant (P = 1.0). The finding of significantly larger difference in bilateral SSEP latencies in patients with AIS indicated the association of abnormal SSEPs with AIS. The finding of a significant effect of SSEPs on the balance control further indicated the presence of abnormal somatosensory function in a subgroup of patients with AIS.

TSANG, W. W. N., and C. W. Y. HUI-CHAN. Effects of Exercise on Joint Sense and Balance in Elderly Men: Tai Chi versus Golf. Med. Sci. Sports Exerc., Vol. 36, No. 4, pp. 658–667, 2004.PurposeOur previous studies showed that experienced Tai Chi practitioners had better joint proprioception and

Falls are common after total hip arthroplasty (THA) and total knee arthroplasty (TKA). While previous studies have investigated various risk factors for falls in patients following THA and TKA, no systematic reviews have summarized these risk factors. Therefore, the current systematic review aimed to summarize evidence regarding risk factors for falls in patients after THA and/or TKA. MEDLINE, EMBASE, CINAHL, SPORTDiscus, and Physiotherapy Evidence Database (from inception to June 30, 2018) were searched. The methodological quality and quality of evidence of the included studies were assessed by two independent reviewers. Relevant data regarding participants' characteristics, study design, follow-up time points, and identified risk factors were extracted. Meta-analyses and narrative syntheses were performed. Twelve studies with a total of 1,292,689 participants were included. Twenty-nine identified risk factors for post-THA/TKA falls were classified into either inpatient or post-discharge risk factors. Key risk factors for both post-THA and/or post-TKA inpatient falls that showed moderate level of evidence included: postoperative complications or comorbidities and revision THA/TKA. Likewise, risk factors for post-discharge falls after THA and/or TKA that demonstrated moderate level of evidence included: medications, psychiatric diseases, living alone, prior history of TKA, falls history and female gender. The quality of the included studies varied and sample sizes were not justified. This review summarized both non-modifiable and modifiable risk factors for post-THA/TKA falls. Our findings highlight the importance of developing strategies to lower the falls risk among patients following THA/TKA.