Increased hip adductor activation during sit-to-stand improves muscle activation timing and rising-up mechanics in individuals with hemiparesis.

Long sit-to-stand (STS) time has been identified as a feature of impaired functional mobility. The changes in biomechanics of STS performance with simultaneous hip adductor contraction have not been studied, which may limit indications for use of hip adductor activation during STS training. Ten individuals with hemiplegia (mean age 61.8 years, injury time 29.8 ± 15.2 months) performed the STS with and without squeezing a ball between two legs. The joint moments, ground reaction force (GRF), chair reaction force and movement durations and temporal index of electromyography were calculated from the control condition for comparison with those from the ball squeezing condition. Under the squeeze condition, reduced peak vertical GRF during the ascension phase with increased loading rate was observed in the nonparetic limb, and the peak knee extensor moment occurred earlier in the paretic. Earlier activation of tibialis anterior and gluteus maximus, and gluteus medius were found in squeeze STS. Squeezing a ball between limbs during STS increased the contraction timing of tibialis anterior, gluteus maximus, gluteus medius, and soleus as well as a more symmetric rising mechanics encourage the use of squeezing a ball between limbs during STS for individuals with hemiparesis.

Relationship Between Shoulder Pain and Joint Reaction Forces and Muscle Moments During 2 Speeds of Wheelchair Propulsion.

The purpose of this study was to determine shoulder joint reaction forces and muscle moments during 2 speeds (1.3 and 2.2 m/s) of wheelchair propulsion and to investigate the relationship between joints reaction forces, muscle moments, and shoulder pain. The measurements were obtained from 20 manual wheelchair users. A JR3 6-channel load sensor (±1% error) and a Qualisys system were used to record 3-dimensional pushrim kinetics and kinematics. A 3-dimensional inverse dynamic model was generated to compute joint kinetics. The results demonstrated significant differences in shoulder joint forces and moments (P < .01) between the 2 speeds of wheelchair propulsion. The greatest peak shoulder joint forces during the drive phase were anterior directed (Fy, 184.69 N), and the greatest joint moment was the shoulder flexion direction (flexion moment, 35.79 N·m) at 2.2 m/s. All the shoulder joint reaction forces and flexion moment were significantly (P < .05) related to shoulder pain index. The forces combined in superior and anterior direction found at the shoulder joint may contribute to the compression of subacromial structure and predispose manual wheelchair users to potential rotator cuff impingement syndrome.

Immediate video feedback on ramp, wheelie, and curb wheelchair skill training for persons with spinal cord injury.

We hypothesized that the effects of immediate video feedback (IVF) on training ramp, wheelie, and curb wheelchair skills for persons with spinal cord injury (SCI) would be equivalent to or better than the traditional wheelchair skill training. Participants were manual wheelchair users with recent SCI (thoracic 1-lumbar 1) who were matched (9 pairs) on motor function level, age, and sex and randomly assigned to a control group (conventional training) or an experimental group (IVF training). Participants learned three wheelchair skills and then went through the wheelchair skill competency test, retention test, and transfer test. Paired t-tests were used to examine the differences in training time (minutes), spotter intervention needed (counts), and successful rate in performance between the two groups. A 2 (groups) x 3 (skills) x 3 (tests) repeated-measures analysis of variance and Bonferroni adjustment test were used to examine differences between groups on wheelchair skills and tests. No differences were found between two groups in training times (minutes) on three wheelchair skills (experimental vs control: ramp 14.92 +/- 5.80 vs 11.69 +/- 7.85; wheelie 17.79 +/- 6.03 vs 19.92 +/- 13.42; and curb 38.35 +/-23.01 vs 48.59 +/- 15.21). This study demonstrated that IVF for training manual wheelchair skills may produce similar results as the conventional training and may be an alternative training method for wheelchair skills.

An instrumented wheel system for measuring 3-D pushrim kinetics during racing wheelchair propulsion.

The purpose of this study was to design and validate an instrumented wheel system (IWS) that can measure 3-dimensional (3-D) pushrim forces during racing wheelchair propulsion. Linearity, precision, and percent error were determined for both static and dynamic conditions. For the static condition, the IWS demonstrated a high linearity (0.91

Fundamental locomotive activity time efficiency with differently positioning drive-axis wheelchairs among elders.

This study examined time efficiency in wheelchair locomotive activities among four different wheelchairs propelled by elders with arms and/or legs. Sixteen elder manual wheelchair users propelled her/his own wheelchair and three wheelchairs (the main drive-axis wheels positioning in front, middle, and rear, respectively) in the test of seven wheelchair locomotive activities of daily living. A Mixed-Model ANOVA and Bonferroni post hoc test (p < .05) were employed to determine the time efficiency among four wheelchairs and three groups. The results demonstrated better time efficiency resulted from propelling the mid drive-axis and/or rear drive-axis wheelchairs; using arms and legs simultaneously propelling wheelchairs was more time efficient than using the arms or legs only in the selected locomotive activities.

Effects of Tai Chi exercise on physical and mental health of college students.

The purpose of this pilot study is to examine the effects of Tai Chi Quan, a body-mind harmony exercise, on college students' perceptions of their physical and mental health. A three-month intervention of Tai Chi exercise was administered to college students, and multidimensional physical (PHD) and mental (MHD) health scores were assessed using the SF-36v2 health survey questionnaire before and after the intervention. Thirty college students participated in a 1-hour-long Tai Chi exercise intervention twice a week for 3 months. Each practice session included 10 minutes of breathing and stretching exercises followed by 50 minutes of Tai Chi Quan 24-form practice. PHD including physical function (PF), role physical (RP), bodily pain (BP), general health (GH), and MHD including social function (SF), role mental/emotion function (RE), vitality (VT), perceptions of mental health (MH) were assessed. The normalized scores of each variable and the combined PHD or MHD scores before and after the Tai Chi intervention were examined by paired t-test (p < 0.05). Physical measures of BP and GH, and mental measures of RE, VT and MH were significantly improved after Tai Chi exercise intervention. When the overall PHD or MHD scores were evaluated, the MHD had increased significantly. In conclusion, Tai Chi exercise had positive effects on the self-assessed physical and mental health of college students. Scores on the mental health dimension appeared to be particularly sensitive to change. Colleges/universities might consider offering Tai Chi as a component of their ongoing physical activity programs available to students.