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[Purpose] To explore the differences in bilateral trunk muscle activation between chronic stroke patients and healthy controls, this study investigated the symmetry index and cross-correlation of trunk muscles during trunk flexion and extension movements. This study also assessed the differences in trunk reposition error between groups and the association between trunk reposition error and bilateral trunk muscle activation. [Subjects and Methods] Fifteen stroke patients and 15 age- and gender-matched healthy subjects participated. Bilateral trunk muscle activations were collected by electromyography during trunk flexion and extension. Trunk reposition errors in trunk flexion and extension directions were recorded by a Qualisys motion capture system. [Results] Compared with the healthy controls, the stroke patients presented lower symmetrical muscle activation of the bilateral internal oblique and lower cross-correlation of abdominal muscles during trunk flexion, and lower symmetry index and cross-correlation of erector spinae in trunk extension. They also showed a larger trunk extension reposition error. A smaller trunk reposition error was associated with higher cross-correlation of bilateral trunk muscles during trunk movements in all subjects. [Conclusion] Trunk muscle function during symmetrical trunk movements and trunk reposition sense were impaired in the chronic stroke patients, and trunk position sense was associated with trunk muscle functions. Future studies should pay attention to symmetrical trunk movements as well as trunk extension position sense for patients with chronic stroke.

[Purpose] The purposes of this study were to investigate differences between patients with chronic stroke and age matched healthy controls in trunk stability, by assessing the kinematics of the center of mass and moving body segments during voluntary limb and trunk movement, and the relationship between trunk stability and clinical measurements. [Subjects and Methods] Fifteen stroke patients and 15 age- and gender-matched healthy subjects participated. Each subject performed flexion of the hip and shoulder of the non-paretic or matched side as fast as possible, as well as trunk flexion and extension at a self-selected speed. A Qualisys motion system was employed to track the kinematics of the trunk and limbs. [Results] Patients presented larger mediolateral displacement of the center of mass during all limb and trunk movements, and larger velocity of center of mass during hip flexion movement. Healthy subjects showed greater movement velocity during shoulder flexion, trunk flexion and extension. Patients' clinical measurements only correlated with movement characteristics during voluntary trunk motions. [Conclusion] Trunk stability in patients with chronic stroke was compromised during voluntary trunk as well as non-paretic limb movements, and the voluntary trunk movements reflected the trunk deficits measured using clinical measurements. Rehabilitation of patients with chronic stroke should include programs to improve trunk stability.

Aging is widely considered to be associated with limited balance capacity. It is not clear if forward reach ability is also affected by aging. The purpose of this study was to determine if aging was associated with reduced ability of forward reach or changes in movement patterns. Thirty-three young and 31 older adults were instructed to reach forward as far as possible without losing balance. A motion analysis system was used to record the body kinematics to calculate the joint angle and estimate the motion of center of mass (COM) using a five-segment model. Reach distance (measured from the finger marker), COM displacement, and the distance that the COM exceeded the 2nd toe marker (COM-toe) were used to represent reach performance. The movement patterns were classified as hip, ankle or mixed strategies based upon joint kinematics. It was found that the initial location of the COM was significantly more anterior in the older adults. Older adults were found to have significantly smaller COM displacement and greater hip flexion, but did not differ from young adults in reach distance or COM-toe. Older adults overwhelmingly adopted a hip strategy, but none adopted an ankle strategy. The distribution of the different strategies also differed significantly between groups. These findings suggest that aging appears to be associated with modifications in movement patterns, but not necessarily with a reduction in the ability to approach the boundary of stability. Clinically, balance training for older adults may include the exploration and instruction of atypical movement patterns.

A prospective longitudinal study.Diastasis recti abdominis (DRA) is defined as an increase in the inter-recti distance (IRD), or width of the linea alba. It is a common occurrence in women postpartum. Little information exists on the short- and long-term recovery of IRD and the relationship between changes in IRD and the functional performance of the abdominal muscles.To investigate the natural recovery of IRD and abdominal muscle strength and endurance in women between 7 weeks and 6 months postpartum, and to examine the relationship between IRD and abdominal muscle function.Forty postpartum (25-37 years of age) and 20 age-matched, nulliparous females participated. IRD was measured at 4 locations (upper and lower margin of the umbilical ring, and 2.5 cm above and below the umbilical ring) with a 7.5-MHz linear ultrasound transducer. Trunk flexion and rotation strength and endurance were measured with manual muscle testing and curl-ups. Evaluation was conducted at 4 to 8 weeks and 6 to 8 months after childbirth in postpartum women, and only once for the nulliparous female controls.During follow-up, the IRD at 2.5 cm above the umbilical ring and at the upper margin of the umbilical ring decreased (P = .013 and P = .002, respectively). The strength and static endurance of the abdominal muscles improved over time (P.05). A negative correlation between IRD and abdominal muscle function at 7 weeks and 6 months postpartum was found (r = 0.34 to 0.51; P.05, except for trunk flexion strength at 6 months postpartum [P = .064]). In addition, IRD changes between 7 weeks and 6 months postpartum were correlated with improvement in trunk flexion strength (Spearman rho = 0.38, P = .040). At 6 months after childbirth, postpartum women had greater mean ? SD IRDs at all 4 locations (from cranial to caudal: 1.80 ± 0.72, 2.13 ± 0.65, 1.81 ± 0.62, and 1.16 ± 0.58 cm) than those of nulliparous females (0.85 ± 0.26, 0.99 ± 0.31, 0.65 ± 0.23, and 0.43 ± 0.17 cm) (all P.001). All abdominal strength and endurance measurements were less than those of nulliparous females (all P.001).The IRD and abdominal muscle function of postpartum women improved but had not returned to normal values at 6 months after childbirth. Future research is essential to explore the need for intervention and, if needed, the effectiveness of specific intervention to reduce the size of IRD in postpartum women.

Deterioration in the function of the sensorimotor system is often seen in patients with diabetes and could be related to balance impairments. The purpose of this study was to determine the association between sensorimotor function and forward reach ability in patients with diabetes. Thirty-one patients with Type 2 diabetes went through a monofilament test of plantar touch-pressure threshold, an ankle joint reposition test for joint position sense, and a series of strength tests of the lower leg. These patients also performed the forward reach test in standing to measure the reach distance and displacement of the center of mass (COM), using a motion analysis system. Correlational and regressional analyses were conducted to determine the association between sensorimotor and balance parameters. It was found that greater reach distance and COM displacement were significantly correlated with lower plantar touch-pressure threshold and greater plantarflexion strength. Regression analysis showed that after controlling the variance in the subject characteristics, plantar touch-pressure threshold was a significant predictor for reach distance and COM displacement, while plantarflexion strength was also a significant predictor for COM displacement. These findings highlight the importance of the assessment of plantar sensitivity and the need for detailed balance or fall risk assessment for patients with impaired plantar insensitivity.

In recent years many multimedia services, such as voice over IP and videoconferencing, have been developed and applied popularly over the Internet. These multimedia services become key applications in home networks, but the bandwidth requirements for these multimedia services grow up rapidly. Thus how to provide a certain degree of Quality of Services (QoS) for the multimedia applications in edge routers is an important issue. The framework of differentiated services (DiffServ) is able to provide QoS by means of packet classifications, flow aggregation and scheduling mechanisms. In the paper a DiffServ edge router is implemented on the Intel IXP425 network processor platform. Network processors are emerging as a programmable alternative to the traditional ASIC-based solutions in scaling up the user-plane processing of network services. The performance of the implemented DiffServ edge router is evaluated by experiments. Experimental results demonstrate the validation of the implemented system.

The functional reach test (FRT) is a reliable and frequently used test to measure dynamic balance ability clinically. However, it is not clear if reach strategy would affect the association between reach distance and dynamic balance. The purpose of this study was to investigate the extent to which reach distance reflected dynamic balance in different reaching strategies. Thirty-three healthy young adults performed the FRT that required subjects to stand with the feet shoulder width apart and one arm raised to 90 degrees , and then reach forward as far as possible without moving the feet or losing balance. Two additional instructions were given to induce different strategies: keeping the raised arm at 90 degrees throughout the test, and reaching toward a shoulder-height target. The kinematics was recorded using a Vicon motion system, and the hip, ankle and mixed strategies were identified. The results showed that subjects adopted different strategies during the FRT. Significant correlations were found between reach distance and center of mass displacement in the ankle, and mixed strategies. Reach distance, hip posterior displacement and angular displacement of the trunk, hip and ankle were significantly different between the hip and ankle strategies. These findings show that the extent to which reach distance reflected dynamic balance was affected by the reach strategy adopted. It is suggested that clinically, both reach distance and movement patterns should be given special attention when conducting the FRT.