Objective: Stand-to-sit task is an important daily function, but there is a lack of research evidence on whether knee osteoarthritis (knee OA) affects the postural balance during the task. This study aimed to compare individuals with knee OA and asymptomatic controls in postural balance and identify kinematic and lower extremity muscle activity characteristics in individuals with knee OA during the stand-to-sit task.Methods: In total, 30 individuals with knee OA and 30 age-matched asymptomatic controls performed the 30-s Chair Stand Test (30sCST) at self-selected speeds. Motion analysis data and surface electromyography (sEMG) were collected while participants performed the 30sCST. To quantify postural balance, the displacement of the center of mass (CoM) and the peak instantaneous velocity of the CoM were calculated. The kinematic data included forward lean angles of the trunk and pelvic, range of motion (RoM) of the hip, knee, and ankle joints in the sagittal plane. The averaged activation levels of gluteus maximus, vastus lateralis, vastus medialis, rectus femoris, biceps femoris (BF), tibialis anterior (TA), and medial head of gastrocnemius muscles were indicated by the normalized root mean square amplitudes.Results: Compared with the asymptomatic control group, the knee OA group prolonged the duration of the stand-to-sit task, demonstrated significantly larger CoM displacement and peak instantaneous CoM velocity in the anterior-posterior direction, reduced ankle dorsiflexion RoM, greater anterior pelvic tilt RoM, and lower quadriceps femoris and muscles activation level coupled with higher BF muscle activation level during the stand-to-sit task.Conclusion: This study indicates that individuals with knee OA adopt greater pelvic forward lean RoM and higher BF muscle activation level during the stand-to-sit task. However, these individuals exist greater CoM excursion in the anterior-posterior direction and take more time to complete the task. This daily functional activity should be added to the rehabilitation goals for individuals with knee OA. The knee OA group performs reduced ankle dorsiflexion RoM, quadriceps femoris, and TA activation deficit. In the future, the rehabilitation programs targeting these impairments could be beneficial for restoring the functional transfer in individuals with knee OA.

BackgroundEvidence from quantitative studies suggest that Tai Chi produces a variety of health-related benefits, but few qualitative studies have investigated how older adults perceive the benefit of Tai Chi. The objective of the current study was to qualitatively evaluate the perceived benefits of Tai Chi practice among community older population.MethodsThis study was conducted with participants from a trial examining the effects of a 12-week Tai Chi training on ischemic stroke risk in community older adults (n = 170). A total of 20 participants were randomly selected from a convenience sample of participants who had completed 12-week Tai Chi training (n = 68) were interviewed regarding their perceived benefit on physical and mental health and whether Tai Chi exercise was suitable for the elderly.ResultsAll participants agreed that Tai Chi training could relax their body and make them comfortable. Most of them thought Tai Chi training could promote physical health, including relieving pain, enhancing digestion, strengthening immunity, enhancing energy and improving sleep quality, enhancing their mental and emotional state (e.g. improving mood and reducing anxiety, improving concentration and promoting interpersonal relationship). Most of participants also agreed that Tai Chi exercise was appropriate for community older people. Three primary themes emerged from content analysis: Improving physical health; Enhancing mental and emotional state; Conforming with the request of the elderly.ConclusionThe findings indicate that regular Tai Chi exercise may have positive benefits in terms of improved physical health and mental state among community elderly population, and may be useful and feasible body-mind exercise to community elderly population for its positive effects and advantages.Trial registration ChiCTR ChiCTR-TRC-13003601. Registered 23 July 2014.Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-017-1694-3) contains supplementary material, which is available to authorized users.

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This study investigated the effects of Tai Chi compared with no exercise control on the cerebral hemodynamic parameters and other health-related factors in community older adults at risk of ischemic stroke. A total of 170 eligible participants were randomly allocated to Tai Chi or control group. The cerebral hemodynamic parameters and physical fitness risk factors of cardiovascular disease were measured at baseline, 12 weeks, and 24 weeks. After the 12-week intervention, Tai Chi significantly improved the minimum of blood flow velocity (BFVmin); BFVmean; pulsatility index and resistance index of the right anterior cerebral artery; and BFVmax, BFVmin, and BFVmean parameters of the right middle cerebral artery. Tai Chi training also decreased triglyceride, fasting blood glucose, and homocysteine levels, and improved balance ability. Therefore, the supervised 12-week Tai Chi exercise had potential beneficial effects on cerebral hemodynamics, plasma risk factors, and balance ability in older community adults at risk of ischemic stroke.

IntroductionControlling risk factors with regular exercise is effective and cost-effective for the primary prevention of ischaemic stroke. As a traditional Chinese form of exercise, Tai Chi might be beneficial in decreasing ischaemic stroke, but the evidence remains insufficient. We hypothesise that elderly community adults with risk factors for ischaemic stroke will decrease their ischaemic stroke risk by improving cerebral haemodynamic parameters, cardiopulmonary function, motor function, plasma risk indices, physical parameters or psychological outcomes after receiving 12 weeks of regular Tai Chi training compared with those who maintained their original physical activities. Therefore, we designed a randomised controlled trial that will systematically evaluate the protective effects of Tai Chi exercise on ischaemic stroke risk in an elderly community population with risk factors for ischaemic stroke.Methods and analysisA total of 170 eligible participants were randomly allocated into either the Tai Chi training group or the usual physical activity group. This paper reports on the design, intervention development and baseline characteristics of the participants. There were no significant differences between comparison groups in demographic characteristics or the baseline data of primary or secondary outcomes. Participants in the Tai Chi training group will receive 12 weeks of Tai Chi training with a frequency of 5 days/week and 60 min/day, while those in the usual physical activities group will maintain their original activities. Primary and secondary outcomes will be measured at the 12-week and 24-week follow-ups.Ethics and disseminationEthical approval has been obtained from the Medical Ethics Committee of The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine (number 2013-020-02). The findings of this study will be communicated to healthcare professionals, participants and the public through peer-reviewed publications or scientific conferences.Trial registration numberChiCTR-TRC-13003601; Pre-results.