Influence of the Hawthorne effect on spatiotemporal parameters, kinematics, ground reaction force, and the symmetry of the dominant and nondominant lower limbs during gait.

The Hawthorne effect is a change in behavior resulting from awareness of being observed or evaluated. This study aimed to determine whether awareness of being evaluated or presence of an observer influence gait. Twenty-one young women were asked to walk in three conditions. In the first condition (unawareness of evaluation; UE), participants were aware that it was a practice trial, and there was no observer. In the second condition (awareness of evaluation; AE), participants were aware that their gait was being evaluated. The third condition (AE + researcher observation; RO) was similar to the second condition except that an additional researcher observed the participant' gait. The spatiotemporal, kinematic, ground reaction forces, and ratio index (symmetry of both lower limbs) were compared among the three conditions. A higher ratio index indicated a relative increase in the value on left versus right. Gait speed (P = 0.012) and stride length (right and left; P = 0.006 and 0.007, respectively) were significantly increased in the AE + RO than in UE. Range of motion of the right hip and left ankle was significantly greater in AE than in UE (P = 0.039 and 0.012, respectively). The ratio index of ground reaction force during push-off was significantly higher in AE and AE + RO conditions than in UE (P < 0.001 and P = 0.004, respectively). The Hawthorne effect (awareness of being evaluated or presence of an observer) potentially influences gait. Thus, factors that influence gait analysis should be considered when evaluating normal gait.

Comparison of screw-home movement between patients with knee osteoarthritis and normal adults.

BACKGROUND: Tibial rotation accompanying sagittal movement contains the phenomenon of screw-home movement (SHM) of the knee, which plays an important role in knee stability during extension. OBJECTIVE: This study aimed to investigate the change of SHM in patients with knee osteoarthritis (OA). METHODS: Thirty-one sex-matched patients with knee OA and 31 normal subjects were recruited. The total tibial rotation was obtained during knee sagittal movement (extension and flexion) using an inertial measurement unit. The acquired angle of tibial rotation was divided into eight periods. The total tibial rotation and the variation of each period were compared between the OA and control groups. The difference in tibial rotation according to Kellgren-Lawrence (KL) grade was compared. RESULTS: The total tibial rotation of the OA group decreased compared with the control group during knee extension and flexion (P< 0.001). Variations of tibial rotation were significantly different between groups in all periods (P< 0.001) except for knee extension at 70∘ to 45∘ (P= 0.081). There was no significant difference in tibial rotations among the KA grades of OA patients. CONCLUSION: We found a reduction in the total tibial rotation and loss of the SHM in the unloaded OA knee. It could be predicted that reduced SHM appeared early in knee OA.

Correlation of eccentric strength of the knee extensors and knee proprioception with dynamic postural control.

BACKGROUND: It is important for clinicians and researchers to perform dynamic postural control evaluation for predicting musculoskeletal conditions, injury prevention, and rehabilitation. OBJECTIVE: The purpose of this study was to investigate the relationship (1) between the eccentric strength of the knee extensors and star excursion balance test (SEBT), and (2) between the knee proprioception and SEBT. METHODS: Forty healthy young adults participated in this study. The eccentric peak torque (EPT) of the knee extensors, joint position sense, and force sense were measured. The participants also performed SEBT. Pearson's product-moment correlation and multiple linear regression analysis were used to determine the relationship between the variables and SEBT. RESULTS: The posteromedial direction of the SEBT was positively and strongly correlated with EPT (r= 0.74, P< 0.01). The anterior and posterolateral directions were positively and moderately correlated with EPT (r= 0.46, P< 0.01, and r= 0.69, P< 0.01, respectively.). However, knee proprioception was not correlated with all the directions of SEBT (P> 0.05). According to the results of multiple linear regression analysis, EPT of the knee extensors significantly predicted SEBT reach distances. CONCLUSION: The eccentric strength of the knee extensors seems to be an essential factor in dynamic postural control. However, the knee proprioception did not show a significant correlation with SEBT.

Effect of trunk stabilization exercise on abdominal muscle thickness, balance and gait abilities of patients with hemiplegic stroke: A randomized controlled trial.

BACKGROUND: Trunk stability has been identified as an important prerequisite of functional movement. OBJECTIVE: To investigate the effectiveness of core muscle contraction training on abdominal muscle thickness, balance, and gait ability in stroke patients. METHODS: Thirty patients with stroke were randomly assigned to two experimental groups and a control group. All groups received conventional therapeutic exercise program for six weeks. The experimental groups additionally trained trunk stability exercise with abdominal hollowing or bracing maneuvers within training time. Primary outcome measures were evaluated abdominal muscle thickness using the sonography. Secondary outcome measures were evaluated by the Functional Reach Test (FRT), Berg Balance Scale (BBS), 10-meter walk test (10MWT), and Timed Up and Go test (TUG). RESULTS: Compared with the control group, the effect of trunk stability training for the experimental groups on the abdominal muscles thickness change was observed (p < 0.05). The values in balance and gait measures, BBS, FRT, 10MWT, and TUG, showed significant improvement after the intervention periods (p < 0.05), although no significant differences were found in scores of gait and balance scales among groups. CONCLUSIONS: Trunk stability training with selective abdominal muscles activation has beneficial effects on abdominal muscles, balance, and mobility in stroke patients. Our findings might provide support for introducing stroke rehabilitation.

Association between Cigarette Smoking Frequency and Health Factors among Korean Adults.

BACKGROUND: Recently, there has been a trend that cigarette smoking rate in Asian and Africa adults has increased while the age group to start smoking has decreased gradually. This study aimed to investigate the relationships between lifetime smoking and hypertension, diabetes, obesity, waist measure, fasting blood pressure and food consumption, in order to look into health status depending on smoking status in Koreans. METHODS: Totally, 1075 men and 697 women with no disease participated in this study, in which one-way ANOVA was conducted by using SPSS version 18.0 for statistical process. The level of statistical significance was 0.05. RESULTS: As a result of analysis on relationship between lifetime smoking and hypertension, obesity and diabetes, statistically significant differences were revealed.Lifetime smoking was found to be significantly associated with increased waist measure, higher level of fasting blood sugar, and more ingestion of nutrients (carbohydrate, fat, and protein). CONCLUSION: Increased amount of lifetime cigarette smoking was shown to negatively influence various health factors, which might become to be a drive to cause diseases. Therefore, method to improve health factors must be sought for via education and campaign to control an amount of cigarette smoking in Korean adults.

Atomic layer deposition of GeSe films using HGeCl3 and [(CH3)3Si]2Se with the discrete feeding method for the ovonic threshold switch.

The ovonic threshold switch (OTS) based on the voltage snapback of amorphous chalcogenides possesses several desirable characteristics: bidirectional switching, a controllable threshold voltage (V th) and processability for three-dimensional stackable devices. Among the materials that can be used as OTS, GeSe has a strong glass-forming ability (∼350 °C crystallization temperature), with a simple binary composition. Described herein is a new method of depositing GeSe films through atomic layer deposition (ALD), using HGeCl3 and [(CH3)3Si]2Se as Ge and Se precursors, respectively. The stoichiometric GeSe thin films were formed through a ligand exchange reaction between the two precursor molecules, without the adoption of an additional reaction gas, at low substrate temperatures ranging from 70 °C-150 °C. The pseudo-saturation behavior required a long time of Ge precursor injection to achieve the saturation growth rate. This was due to the adverse influence of the physisorbed precursor and byproduct molecules on the efficient chemical adsorption reaction between the precursors and reaction sites. To overcome the slow saturation and excessive use of the Ge precursor, the discrete feeding method (DFM), where HGeCl3 is supplied multiple times consecutively with subdivided pulse times, was adopted. DFM led to the saturation of the GeSe growth rate at a much shorter total injection time of the Ge precursor, and improved the film density and oxidation resistance properties. The GeSe film grown via DFM exhibited a short OTS time of ∼40 ns, a ∼107 ON/OFF current ratio, and ∼104 selectivity. The OTS behavior was consistent with the modified Poole-Frenkel mechanism in the OFF state. In contrast, the similar GeSe film grown through the conventional ALD showed a low density and high vulnerability to oxidation, which prevented the OTS performance. The ALD method of GeSe films introduced here will contribute to the fabrication of a three-dimensionally integrated memory as a selector device for preventing sneak current.