Relationship between scapular elevation exercises with different alignments and activity of the trapezius and levator scapulae muscles.

[Purpose] This study aimed to examine whether scapular elevation exercises in sitting positions with different alignments lead to contractions of the trapezius and levator scapulae muscles. [Participants and Methods] The participants were 25 males, measured in four sitting positions with different alignments. Spine alignment was assessed by measuring the head protrusion, upper thoracic spine tilt, and pelvic tilt angles. Upper limb alignment was evaluated using the scapula tilt angle, scapula rotation angle, and distance between scapular spinous processes. Scapular elevation exercises were measured, and the thickness of the trapezius and levator scapulae muscles were measured in resting and elevated positions, with changes in muscle thickness. [Results] The trapezius muscle thickness was greater in the sitting position with less thoracic spine tilt and scapula tilt angles. Conversely, the levator scapulae muscle thickness was greater in the sitting position with more thoracic spine tilt and scapula tilt angles. [Conclusion] Scapular elevation exercises induce separate contractions of the trapezius and levator scapulae muscles by modifying the alignment of the spine and upper limbs.

Relationship between the bilateral ratios of the thoracic shape and electromyographic activity of the thoracic and lumbar iliocostalis muscles during thoracic lateral translation.

[Purpose] This study aimed to determine the relationship between thoracic lateral deviation, the bilateral ratio of the thoracic shape, and the bilateral ratio of the thoracic and lumbar iliocostalis muscles during resting sitting and thoracic lateral translation. [Participants and Methods] We included 23 healthy adult males in the study. The measurement tasks were resting sitting and thoracic lateral translation relative to the pelvis. The thoracic lateral deviation and bilateral ratio of the upper and lower thoracic shapes were measured using three-dimensional motion capture. The bilateral ratio of the thoracic and lumbar iliocostalis muscles were measured using the surface electromyographic recording. [Results] The bilateral ratio of the lower thoracic shape was significantly positively correlated with the thoracic translation distance and the bilateral ratio of the thoracic and iliocostalis muscles. In addition, the bilateral ratio of the thoracic iliocostalis muscles was significantly negatively correlated with the bilateral ratios of the lower thoracic shape and lumbar iliocostalis muscles. [Conclusion] Our findings showed that the asymmetry of the lower thoracic shape is associated with left lateral deviation of the thorax at rest and thoracic translation distance. In addition, the thoracic and lumbar iliocostalis muscle activity differed between the left and right translations.

Relationship between the thoracic asymmetry in standing position and the asymmetry of ankle moment in the frontal plane during gait.

[Purpose] We aimed to investigate the relationship of thoracic asymmetry in standing position with asymmetry of the internal ankle moment in the frontal plane during gait. [Participants and Methods] The following measurements were recorded in 22 healthy adult males using a 3D motion analyzer and force plates: thoracic lateral deviation, asymmetrical ratios of the upper and lower thoracic shape, internal ankle moment in the frontal plane, mediolateral deviations of the center of mass and center of pressure. [Results] In the standing position, the thorax was deviated to the left relative to the pelvis, and the upper and lower thoracic shapes were asymmetrical. During gait, significant lateralities were observed in the internal ankle moment in the frontal plane, mediolateral deviations of the center of mass and the center of pressure. Significant positive correlations were observed between the asymmetrical ratio of the lower thoracic shape and both the asymmetry of the internal ankle moment in the frontal plane and the mediolateral deviation of the center of pressure. [Conclusion] These results suggest that thoracic asymmetry is associated with mediolateral control of the ankle during gait.

Analysis of the asymmetry of thoracic shape at rest: relationship with lateral thoracic deviation.

[Purpose] We analyzed the relationship between the degree of asymmetry in the shape of the thorax and postural changes in the frontal plane, and examined the mechanism that creates an asymmetry in the thoracic shape. [Participants and Methods] The participants included 19 healthy young males. We calculated the thoracic volume and lateral deviation from the amount of displacement of reflective markers attached to the thoracic area using the Vicon MX 3D-analysis system. [Results] Left-right differences were shown in each area of the thorax, and positive and negative correlations were found with the amount of lateral deviation of the thorax, which captured postural changes in the frontal plane. [Conclusion] The results of this study suggest that postural changes in the frontal plane are factors involved in the mechanism of left-right asymmetry formation in the thoracic shape.

Effects of the posterior pelvic tilt sitting posture on thoracic morphology and respiratory function.

[Purpose] We investigated how differences in pelvic angle in the posterior pelvic tilt sitting posture simultaneously affect the thoracic morphology and the respiratory function. [Participants and Methods] The participants were 18 healthy young males. We positioned the pelvis at 0°, 10°, 20°, and 30° of posterior tilt, following which the thoracic expansion volume ratio, thoracic spine tilt angle, and respiratory function were measured. We calculated the thoracic volume and thoracic spine tilt angle by measuring the amount of displacement of reflective markers attached to the thoracic area using the Vicon MX 3D-analysis system. Respiratory function was measured by spirometry. [Results] The expansion volume ratio decreased significantly in response to 10-30° posterior pelvic tilt sitting at the mid-thorax and 30° posterior pelvic tilt sitting at the lowest thorax. The upper thoracic spine level showed a change in anterior tilt at 10-30° posterior pelvic tilt sitting, whereas the lower thoracic spine level showed a change in posterior tilt at 30° posterior pelvic tilt sitting. Respiratory function was significantly lower at 30° posterior pelvic tilt sitting than at 0° posterior pelvic tilt sitting. A positive correlation between thoracic expansion volume ratio and respiratory function was found at 30° posterior pelvic tilt sitting. [Conclusion] Changes in thoracic spine tilt angle due to posterior pelvic tilt sitting may restrict the expansion of thoracic motion during respiration, thereby affecting respiratory function.

Humeral Head Morphometry Can Predict the Presence of Subacromial Spurs: Measurements of Dried Bones from Human Shoulder Girdles.

OBJECTIVE: To clarify the relationship between the morphological characteristics of the bones of the shoulder girdle and the presence of subacromial spurs (SS). METHODS: The bones of 36 cadaveric shoulder girdles were measured. After dividing the bone specimens into SS present and absent groups, various bone parameters between the two groups were statistically compared. Logistic regression analysis was conducted to assess the significance of each parameter as a predictor of SS formation. A receiver operating characteristic curve analysis was used to determine the cut-off point and to assess the sensitivity and specificity of the parameters showing significant differences. RESULTS: SS were found in 16 scapulae. The values for five parameters of the examined shoulder girdles were significantly different between the two groups. The presence of SS depended on the humeral head ratio, which was calculated by dividing the length of the greater tubercle of the humerus by the length of the lesser tubercle. A cut-off value of 1.97 was suitable for discriminating between the presence and absence of SS (sensitivity, 75%; specificity, 80%). CONCLUSION: The presence of SS is related to several morphological characteristics of the shoulder girdle and, the presence of SS can be predicted using humeral head morphometry.

Effect of forward head posture on thoracic shape and respiratory function.

[Purpose] This study investigated the effect of forward head posture on upper and lower thoracic shape in adults to better understand the relationship between a forward head posture and respiratory function. [Participants and Methods] Fifteen healthy males were recruited after obtaining informed consent from all participants. All participants were instructed to respire in both the forward and neutral head postures while seated. Respiratory function was assessed using spirometry. Thoracic shape during respiration was assessed using 23 markers on both the upper and the lower thorax and compared between the 2 postures. [Results] Forced vital capacity, expiratory and inspiratory reserve volumes, forced expiratory volume at 1 second, and the peak flow rate observed with the forward head posture were significantly lower than that with the neutral head posture. The upper thorax showed a greater forward shift and the lower thorax showed a greater forward and inward shift with the forward head posture than with the neutral head posture. No significant difference in upper thoracic mobility was observed during respiration between the forward head posture and the neutral head posture. However, mobility of the lower thorax during respiration was significantly reduced with the forward head posture. [Conclusion] The forward head posture causes expansion of the upper thorax and contraction of the lower thorax, and these morphological changes cause decreased respiratory function.

Instantaneous changes in respiratory function induced by passive pelvic suspension in the supine position in relation to increased diaphragm excursion.

[Purpose] This study aimed to introduce an approach of pelvic suspension (PS) using sling cords and to obtain evidence for changes in respiratory function of healthy subjects. [Subjects and Methods] Subjects were 25 healthy men. In the supine position, with hip and knee joints flexed at 90°, the subjects' pelvises were suspended with sling belts. Diaphragm excursion, respiratory function, and respiratory comfort in these postures were measured using ultrasonography, respirometry, and visual analog scale (VAS), respectively. [Results] When the pelvis was passively suspended with sling cords, the diaphragm moved 5 mm cranially and diaphragm excursion showed an instantaneous increase compared with the control. The tidal volume (VT) showed an increase and the respiration rate (RR) showed a decrease. The extent of diaphragm excursion was correlated with changes in VT under the control and PS conditions. Independent measurements of pulmonary function revealed that PS reduced the expiratory reserve volume, being correlated positively and negatively to increases in vital and inspiratory capacities, respectively. Furthermore, VAS values for respiratory ease were greater with PS than with the control. [Conclusion] These results suggest that PS effectively changed diaphragm excursion and respiratory function, leading to ease of breathing (i.e., deep and slow respiration).

The relationship between thoracic configuration and changes in volumes of hemithoraces in upright sitting.

[Purpose] Some patients with respiratory disease exhibit asymmetrical movement of the thorax. The purpose of this study was to investigate the relationship of thoracic configuration with changes in thoracic volume in 13 sedentary healthy men. [Subjects and Methods] In upright sitting, 84 reflective markers were placed on the anterior and posterior aspects of the trunk to record thoracic volume during quiet and volitional deep breathing. Using a three-dimensional motion analyzer, the difference in volume within the upper and lower hemithoraces was measured. For calculation of the thoracic volume six imaginary hexahedra were visualized for the upper and lower thorax using four reflective markers for each on the anterior and posterior aspects of the thorax. Each hexahedron was then divided into three imaginary triangular pyramids to calculate positional vectors. Finally, the volume for both the hexahedra and triangular pyramids was calculated. Four thoracic volumes were obtained. [Results] The findings showed that the left upper and right lower hemithorax yielded significantly larger thoracic volumes. [Conclusion] In conclusion the left upper and right lower hemithoraces were found to expand more than their corresponding sides. Understanding the characteristics of thoracic excursion during quiet and volitional deep breathing could be of value in assessment and instruction of breathing techniques to patients.

Immediate effects of thixotropy conditioning of inspiratory muscles on chest-wall volume in chronic obstructive pulmonary disease.

INTRODUCTION: Thixotropy is a passive property of the skeletal muscle that depends on the muscle's immediate history of contraction and length change. Inspiratory-muscle thixotropy affects the end-expiratory position of the rib cage in normal subjects. OBJECTIVE: To determine whether a reduction in end-expiratory chest-wall volume occurs after thixotropy conditioning of inspiratory muscles in patients with chronic obstructive pulmonary disease. METHODS: Ten male subjects with chronic obstructive pulmonary disease (mean +/- SD forced expiratory volume in the first second 70+/-20% of predicted) showed an increased ratio of residual volume to total lung capacity (49 +/- 4.7%). The subjects conducted inspiratory muscle thixotropy conditioning maneuvers at 3 different chest-wall volumes (end-expiratory volume of baseline breathing, residual volume plus 40% of expiratory reserve volume, and residual volume) and with 3 levels of inspiratory effort (0%, 30%, and 100% of maximal inspiratory mouth pressure at each volume), with airway-closure, in the sitting position. Using respiratory induction plethysmography, we measured the effect of effort-intensity and volume at the time of the conditioning maneuver on the end-expiratory chest-wall volume of the 5 respiratory cycles immediately following the conditioning maneuver. RESULTS: There was a reduction in end-expiratory chest-wall volume after the conditioning maneuver, except when conditioning was performed at end-expiratory baseline with 0% effort. The reduction increased as effort intensity increased (p = 0.011) and as volume decreased (p < 0.001), and the reduction was attained by rib-cage movement rather than abdominal movement. CONCLUSIONS: Thixotropy conditioning of inspiratory muscles, at a reduced chest-wall volume, decreased end-expiratory chest-wall volume in the 5 subsequent breaths in patients with chronic obstructive pulmonary disease.