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The accumulation of a large amount of amyloid-β (Aβ42) in brain neurons is one of the debilitating characteristics of Alzheimer's disease. In this study, we determined the effects of peroxisome proliferator-activated receptor alpha (PPARα) activation on neuronal degeneration using a model of Aβ42-induced cytotoxicity. We found that 0.5 μM Aβ42 induced DNA damage and apoptosis in NT2N cells after 6 h of treatment. Co-treatment of Aβ42-treated cells with Wy14643, a PPARα ligand, significantly increased cell viability after 24 h compared with cells treated with Aβ42 alone. There were no differences in the protein levels of caspase-3, Bcl-2/Bax or p53 between cells treated with Aβ42 alone and those treated with both Aβ42 and Wy14643. However, the addition of Wy14643 significantly suppressed the Aβ42-induced upregulation of Endo G and AIF protein levels. Immunohistochemical analyses further demonstrated that Wy14643 reduced the expression of Endo G and AIF translocated from the cytoplasm into the nucleus, which occurred concomitantly with the decrease in DNA damage in Aβ42-treated cells. Our data clearly show that PPARα activation prevents DNA damage and neuronal cell apoptosis by decreasing the expression and translocation of AIF/Endo G to the nucleus in a caspase-3- and p53-independent pathway in the NT2N cell model. This role of PPARα in promoting neuron survival suggests a possible clinical application in treating Aβ42-associated neurotoxicity in Alzheimer's disease.

Push Hand is an advanced training technique for the Yang-style old frame 108 forms Tai Chi Chuan. It is performed by two practitioners. To clarify how people use forces during Push Hand training, it is important to review the ground reaction force (GRF). Here, we quantify the characteristics of the GRF during Push Hand training. Kinematic data and GRF data from 10 Tai Chi Chuan practitioners (29.9 ± 7.87 years) were synchronously recorded using a three-dimensional motion analysis system (200 frames · s(-1)) and three-dimensional force plates (1000 Hz). The resultant GRF for both feet for the 0%, 50% and 100% phases of attack and defence were compared to body weight using a paired-samples t-test. The differences in the resultant GRF between the 0%, 50% and 100% phases of attack and defence were tested by one-way repeated-measures ANOVA. The significance level was set to 0.05. The total resultant GRF was almost equal to the participant's body weight in push hand. This result was consistent throughout the entire push hand process. Our results revealed that the GRF was comparable to the body weight, implying that practitioners do not push or resist their opponents during the push hand process.

The purpose of this study was to determine the effect of Tai Chi Chuan on the strategies of obstacle-crossing behavior in older adults aged over 65 years. Fifteen Tai Chi group (TCG) participants were compared with 15 general group (GG) participants. Kinematic parameters (by Vicon motion analysis system) and ground reaction forces (by Kistler force plates) were synchronously recorded. A two-way mixed-design ANOVA (α = 0.05) was used to test the effects of the group and the obstacle height. The TCG performed significantly faster stride velocities, longer stride lengths, and shorter stride times than GG while crossing the obstacles. TCG could also produce significantly larger forward ground reaction forces to propel the body and were able to make a significantly greater flexion angle of the hip of the leading leg compared with the GG. It was concluded that the TCG adopted a different strategy with GG to cross the obstacles and completed the crossing behavior more effectively.

Objectives. To evaluate the effects of anterior thermal capsulorrhaphy of the glenohumeral joint by monitoring changes of magnitudes of the anterior and posterior displacements of the humeral head and ranges of motion of abduction and rotation in fresh cadaver shoulders. Design. Single session repeated-measures design. Background. Following thermal shrinkage anterior and posterior displacements of the head of humerus were decreased. However, no studies were focused on the ranges of motion of abduction and rotation of the shoulder joint immediately. The mobility of abduction and rotation are also important indexes for glenohumeral function. Methods and measures. Nine fresh frozen shoulder specimens were used. The dorsal and ventral displacements of humeral head and ranges of motion of abduction and rotation of glenohumeral joint before and after thermal capsulorrhaphy were performed and monitored. Changes after thermal treatment in these linear and angular displacement variables were calculated as outcome measures. Results. After anterior thermal capsulorrhaphy, significant (P

Single-session repeated-measures design.To define the resting position of the glenohumeral joint by investigating the magnitude of the anterior and posterior displacements of the humeral head and medial and lateral rotation ranges of motion (ROMs) of the glenohumeral joint at different abduction angles in cadaver specimens.The resting position of a joint is the position in the joint's ROM at which the joint capsule has its greatest laxity. It is frequently chosen as the position for assessing and treating joints with dysfunction. However, no study has been conducted to determine the resting position of the glenohumeral joint.Seven freshly frozen cadaver shoulder specimens (age at time of death [mean +/- SD] was 66.9 +/- 2.5 years) were studied. Specimens were mounted on a system that uses computer-controlled hydraulics and motors to induce and monitor translation and rotation movements of the glenohumeral joint. The magnitudes of total displacement (DTotal) of the head of the humerus and total ROM (RTotal) of the glenohumeral joint were measured in the plane of the scapula at 0 degrees (neutral), 30 degrees, 40 degrees, 50 degrees, 60 degrees, and the end range of glenohumeral joint abduction. The resting position was determined as the midpoint of the shared range of the 95% to 99.9% confidence intervals of the predicted abduction position where the peaks of displacement and rotation occurred.The DTotal measurements (mean +/- SD) at 0 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, and the end range of glenohumeral joint abduction were 30.53 +/- 9.35, 44.87 +/- 7.34, 45.35 +/- 8.53, 43.99 +/- 10.02, 39.63 +/- 9.85, and 23.80 +/- 10.42 mm, respectively. The RTotal measurements (mean +/- SD) for the same positions were 67.15 degrees +/- 15.87 degrees, 95.64 degrees +/- 24.26 degrees, 98.88 degrees +/- 29.56 degrees, 97.08 degrees +/- 30.17 degrees, 90.91 degrees +/- 28.73 degrees, and 63.48 degrees +/- 25.93 degrees, respectively. The resting position was located at 39.33 degrees +/- 4.37 degrees of glenohumeral abduction (45.13% +/- 7.58% of the available abduction ROM). The resting position (Y) varied linearly with the maximum available abduction ROM (X) (Y = 0.607X - 13.120, R2 = 0.679, F = 10.61, P = 0.023). There was a main effect of joint position on both displacement (P0.001) and rotation ROM (P0.001).In the plane of the scapula, the resting position of the glenohumeral joint (angle measured between the scapula and humerus) occurred at 39 degrees of abduction (45% of the maximum available abduction ROM) and varied linearly with the amount of available abduction ROM. This finding suggests that in patients with glenohumeral joint hypomobility the resting position is located closer to neutral and that evaluation and treatment should be initiated accordingly at a smaller angle of abduction than the traditional resting position. Our data were derived from cadaver specimens, therefore, caution should be taken when generalizing the results of the present study to a patient population.

Hsu A-T, Ho L, Chang J-H, Chang G-L, Hedman T. Characterization of tissue resistance during a dorsally directed translational mobilization of the glenohumeral joint. Arch Phys Med Rehabil 2002;83:360-6. Objectives: To quantify forces applied by therapists during dorsal glide translational mobilization of the glenohumeral joint, to determine the relationship of tissue resistance to the load-displacement relation of the glenohumeral joint, and to determine the safety of the forces applied by the therapists during dorsal glide translational mobilization. Design: A fresh cadaver shoulder specimen mounted on a 6-axis load cell was used to register forces applied by therapists during dorsal glide translational mobilization of the glenohumeral joint in a test-retest pattern. Setting: Biomechanics laboratory. Participants: Twelve experienced orthopedic physical therapists. Intervention: Not applicable. Main Outcome Measures: Forces exerted by therapists during passive dorsal glide translational mobilization in the loose-packed position and in the end range of abduction, with different grades of movements. The movements did not include any manipulation or thrust-type procedures. Simulated dorsal glide procedures were performed by the material testing system to construct the load-displacement curve of the glenohumeral specimen. The corresponding locations of the forces applied by therapists were interpolated and plotted on the load-displacement curve. Results: The peak force values measured during mobilization were characterized by large intertherapist variability: coefficients of variation ranged from 40.97% to 77.49%. Test-retest reliability for intrasession measures was high (ICC 2,1 range,.90–.94); intersession reliability was poor (ICC 2,1 range,.01–.54). The mean forces ranged from 18.36 to 38.76N. When interpolated to the load-displacement curve, the mean peak forces obtained fell mostly in the toe and the linear elastic regions of the load-displacement curve. Conclusion: Force parameters measured during dorsal glide mobilization were characterized by large intertherapist variability with high intrasession and poor intersession test-retest reliability. The mobilization forces applied by experienced orthopedic physical therapists fall safely in the toe and the linear elastic regions of the load-displacement curve. © 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Background More than 1000 scientific papers have been devoted to flatfoot issue. However, a bimodal distribution of flatfoot indices in school-aged children has never been discovered. The purposes of this study were to establish a new classification of flatfoot by characteristic in frequency distribution of footprint index and to endue the classification with discrepancy in physical fitness. Methods/principal findings In a longitudinal survey of physical fitness and body structure, weight bearing footprints and 3 physical fitness related tests were measured in 1228 school-aged children. Frequency distribution of initial data was tested by Kolmogorov-Smirnov test for normality and a unique bimodal distribution of footprint index was identified. The frequency distribution of footprint index manifests two distinct modes, flatfoot and non-flatfoot, by deconvolution and bootstrapping procedures. A constant intersection value of 1.0 in Staheli's arch index and 0.6 in Chippaux-Smirak index could distinguish the two modes of children, and the value was constant in different age, sex, and weight status. The performance of the one leg balance was inferior in flatfoot girls (median, 4.0 seconds in flatfoot girls vs. 4.3 seconds in non-flatfoot girls, p = 0.04, 95% CI 0.404-0.484). Discussion The natural bimodality lends itself to a flatfoot classification. Bimodality suggests development of the child's foot arch would be a leap from one state to another, rather than a continuous growth as body height and weight. The underlying dynamics of the human foot arch and motor development will trigger research prospects.

Two methods have been used to produce a maximal voluntary isometric contraction (MVIC) of the superficial quadriceps femoris muscles for normalization of electromyographic (EMG) data. The purposes of this study were to compare the myoelectic activity of MVIC of manual muscle testing (MMT) versus Cybex maximal isometric testing. Eighteen normal subjects were recruited. MMT and Cybex testing for MVIC of the dominant leg were performed. EMG activities of the vastus medialis, vastus lateralis and rectus femoris were recorded during MMT and Cybex trials. EMG amplitude and median frequency obtained from the two methods (MMT and Cybex testing) were used for statistical analysis of these three muscles. Statistically, the difference in the mean of the EMG signal amplitude and median frequency between MMT and Cybex testing were not significant. Considering cost and time, MMT for MVIC technique appears to be reliable and highly valuable.

The axial distraction mobilization techniques are frequently employed for treating patients with joint hypomobility. However, there is a lack of basic biomechanical studies and description of this procedure. The purpose of this study was to analyze humeral head displacement while performing an axial distraction mobilization of the glenohumeral joint. Twelve experienced orthopedic physical therapists participated. Distraction mobilization techniques were performed in three different positions of glenohumeral abduction on a fresh cadaveric specimen. Outcome measures were displacements of the humeral head center during distraction mobilization. Result indicated that displacement of the humeral head was largest in the resting position (27.38 mm) followed by the neutral (22.01 mm) and the end range position (9.34 mm). There were significant differences for both the displacement of the humeral head (p

Background and Purpose. Translational mobilization techniques are frequently used by physical therapists as an intervention for patients with limited ranges of motion (ROMs). However, concrete experimental support for such practice is lacking. The purpose of the study was to evaluate the effect of simulated dorsal and ventral translational mobilization (DTM and VTM) of the glenohumeral joint on abduction and rotational ROMs. Methods. Fourteen fresh frozen shoulder specimens from 5 men and 3 women (mean age=77.3 years, SD=10.1, range=62–91) were used for this study. Each specimen underwent 5 repetitions of DTM and VTM in the plane of scapula simulated by a material testing system (MTS) in the resting position (40° of abduction in neutral rotation) and at the end range of abduction with 100 N of force. Abduction and rotation were assessed as the main outcome measures before and after each mobilization procedure performed and monitored by the MTS (abduction, 4 N·m) and by a servomotor attached to the piston of the actuator of the MTS (medial and lateral rotation, 2 N·m). Results. There were increases in abduction ROM for both DTM (X̄=2.10°, SD=1.76°) and VTM (X̄=2.06°, SD=1.96°) at the end-range position. No changes were found in the resting position following the same procedure. Small increases were also found in lateral rotation ROM after VTM in the resting position (X̄=0.90°, SD=0.92°, t=3.65, P=.003) and in medial rotation ROM after DTM (X̄=0.97°, SD=1.45°, t=2.51, P=.026) at the end range of abduction. Discussion and Conclusion. The results indicate that both DTM and VTM procedures applied at the end range of abduction improved glenohumeral abduction range of motion. Whether these changes would result in improved function could not be determined because of the use of a cadaver model.