Abstract Objective The aims of this study were to determine whether the application of vibration on a postural lower limb muscle altered the sensorimotor control of its joint as measured by isometric ...force production parameters and to compare present findings with previous work conducted on trunk muscle. Methods Twenty healthy adults were asked to reproduce submaximal isometric plantar flexion under 3 different conditions: no vibration and vibration frequencies of 30 and 80 Hz on the soleus muscle. Time to peak torque, variable error, as well as constant error and absolute error in peak torque were calculated and compared across conditions. Results Under vibration, participants were significantly less accurate in the force reproduction task, as they mainly undershot the target torque. Applying an 80-Hz vibration resulted in a significantly higher negative constant error than lower-frequency vibration (30 Hz) or no-vibration condition. Decreases in isometric force production accuracy under vibration influence were also observed in a previous study conducted on trunk muscle. However, no difference in constant error was found between 30- and 80-Hz vibration conditions. Conclusion The results suggest that acute soleus muscle vibration interferes with plantar flexion torque generation by distorting proprioceptive information, leading to decreases in accuracy of a force reproduction task. Similar results in an isometric trunk extension force reproduction task were found with vibration applied on erector spinae muscle. However, high-frequency vibration applied on soleus muscle elicited higher force reproduction errors than low-frequency stimulation.
Abstract Purpose The aim of this study was to determine the accuracy in measuring the pelvic orientations of a phantom model using the PosturePrint method. Methods In the Université du Québec à ...Trois-Rivières biomechanics laboratory, Trois-Rivières, Quebec, Canada, a mannequin was fixed on a rotating platform. For a set of 3 photographs (left lateral, anterior to posterior, right lateral) of each position, the mannequin pelvis was placed in 68 different postures on a stand, 61 cm from a wall, in front of a digital camera. The camera was at 83.8 cm in height and at 3.35 m from a calibrated wall grid. Mannequin postures were in 5 degrees of freedom: lateral translation (Tx), lateral flexion (Rz), axial rotation (Ry), flexion-extension (Rx), and anterior-posterior translation (Tz). Average errors were the differences of the positioned postures to the PosturePrint computed values. Results Mean and SD of computational errors for rotation displacements were Rx = 0.5° ± 0.8°, Ry = 1.3° ± 0.8°, and Rz = 0.5° ± 0.3°, and for translation, Tz = 1.2 ± 0.6 mm and Tx = 0.9 ± 0.5 mm. Conclusions The PosturePrint system allowed for accurate postural measurement of rotations and translations of a mannequin pelvis. The next step in evaluation of this product would be a reliability study on human subjects.
Abstract Objective This study examines whether there is a relationship between clinical correlates of osteoarthritic changes of the cervical spine and changes in postural stability. Methods This was ...a control group study with repeated measures. Twenty-three patients were recruited from the chiropractic University Clinic to participate in this study. The presence and severity of osteoarthritic changes of the cervical spine were determined radiologically. Balance control was evaluated by testing subjects' postural stability on a force platform with and without vision. A general clinical assessment of the neuromusculoskeletal system was performed to screen for any physical condition that could affect postural stability. Participants' characteristics were compared between each group using a 1-way analysis of variance for independent samples, and postural stability variables were submitted to a 2-way repeated measures analysis of variance. Results Subjects with signs of osteoarthritis of the cervical spine showed an increased range of sway, a faster sway speed, and a greater excursion than control subjects. They also showed a larger degree of lower limb neuropathy than control subjects. Conclusion The postural instability shown by the osteoarthritic group may be due to the effects of the lower limb peripheral neuropathy alone or due to a combination of both cervical degenerative changes and peripheral changes. Further research is needed to clearly isolate the effects of the degeneration of the cervical spine on postural control.
Abstract Objective The purpose of this study is to describe and evaluate the validity/accuracy of the computerized system PosturePrint for measuring head posture. Methods Computer analysis was ...compared with 125 measured positions of a mannequin head in 5 degrees of freedom. For each mannequin position, 3 digital photographs were obtained (left lateral, anteroposterior, and right lateral) and were processed through the PosturePrint computer system. For the head analysis, a headgear with 3 reflective markers was placed on a subject; and there were additional click-on markers at the ear tragus, upper lip, acromioclavicular joints, and episternal notch. Head postures were calculated as lateral translation ( T x ), lateral flexion ( R z ), axial rotation ( R y ), flexion-extension ( R x ), and anterior-posterior translation ( T z ). For an error analysis, PosturePrint algorithm calculations were compared with the true mannequin head positions. Furthermore, average head posture was determined in student volunteers (n = 40). Results Mean computational errors were R x = 1.3° (SD 0.6°) and T z = 1.1 mm (SD 0.5 mm) for sagittal displacements and R y = 1.1° (SD 0.7°), R z = 0.6° (SD 0.4°), and T x = 1.1 mm (SD 0.5 mm) for frontal view displacements. For the normal group, mean head displacements were 1.1° or less for all rotations and 1 mm or less for lateral translations ( T x ); and forward head posture ( T z ) averaged 3 cm. Conclusion From the mannequin positions, small mean errors indicate that the PosturePrint system is accurate. In the future, statistical research determining the correlation between head displacements, neck pain, function, and health status should be performed.
Abstract Objective This study correlates changes in trunk isometric force parameters and trunk muscle recruitment strategies in subjects with low back pain (LBP) and healthy participants. Methods A ...control group study with repeated measures was performed. Study participants included 15 control subjects and 14 patients with LBP. Participants were required to exert 50% and 75% of their maximal trunk flexion and extension. In a learning phase, feedback was provided, after which study participants were asked to perform 10 trials without any feedback. Spatiotemporal parameters of muscular activity and force production were recorded. Dependent variables included time to peak force, peak force variability, absolute error in peak force, electromyogram (EMG) burst duration for agonist muscles, and normalized integrated EMG. Results Average time to peak force was significantly longer for subjects with LBP than for healthy subjects. Subjects with LBP showed longer burst duration for all 4 muscles recorded. No group difference was noted in normalized integrated EMG. Conclusions We suggest that the observed changes in trunk motor control and trunk muscle recruitment strategies are not only mediated by a neurophysiologic adaptation to chronic pain but also by cognitive adaptations modulated by fear of movement and fear of reinjury.
Abstract Introduction No questionnaire is available to evaluate disability levels in French-speaking patients suffering from tennis elbow. Purpose of the Study To perform a cross-cultural adaptation ...of the English version of the Patient-rated Tennis Elbow Evaluation (PRTEE) into Canadian French. Methods The PRTEE was cross-culturally adapted to Canadian French according to well-established guidelines. Thirty-two patients with tennis elbow completed the prefinal version of the PRTEE. The construct validity, longitudinal validity, and responsiveness were assessed through comparisons with the Visual Analog Scale (VAS) measuring pain and the pain-free grip (PFG) at baseline, six weeks and three months. The internal consistency was assessed by Cronbach's alpha and the item-total correlations. Results The adaptation process resolved the discrepancy between the forward and back translation. The scores of PRTEE were adequately distributed without floor or ceiling effect. Item completion was good. The correlation between the PRTEE and the VAS was moderate to high ( r = 0.64–0.77) and statistically significant. There was also a low but significant correlation between the PRTEE and PFG ( r = −0.38 to −0.48). For the longitudinal construct validity, the correlation with the VAS was moderate to high and statistically significant ( r = 0.68 and 0.88, p < 0.01). The effect size (0.8; 1.0) and the standardized response mean (0.9; 1.0) were high and at least as good as the other outcomes. Internal consistency of the total score was high (Cronbach alpha = 0.93) and item-total correlations were substantial for all items (0.58–0.85). Conclusions This study supports linguistic and conceptual equivalence of our Canadian French version. Because this version of the PRTEE demonstrated good acceptability, construct validity, internal consistency, and responsiveness, it may be used in both research and clinical setting. Level of Evidence N/A.
Abstract Objective The purpose of this study was to evaluate the effect of augmented soft tissue mobilization (ASTM) on the treatment of lateral epicondylitis. Methods This randomized clinical study ...assessed 27 subjects (12 men and 15 women) with lateral epicondylitis and were divided randomly into 2 groups. The experimental group (n = 15) received ASTM twice a week for 5 weeks. The subjects of the control group (n = 12) received advice on the natural evolution of lateral epicondylitis, computer ergonomics, and stretching exercises. Patient-rated outcome was assessed at baseline and after 6 weeks and 3 months using a visual analog scale and the Patient-Rated Tennis Elbow Evaluation. The function was assessed using the pain-free grip strength at baseline and after 6 weeks. Results Both groups showed improvements in pain-free grip strength, visual analog scale, and Patient-Rated Tennis Elbow Evaluation. Sample size for larger future randomized clinical trial was 116 participants. Conclusion A larger study investigating the same hypothesis is warranted to detect difference in the effects of these treatments strategies. The study design is feasible, and minor improvements will help to minimize the potential bias.
