Effect of different trunk postures on scapular muscle activities and kinematics during shoulder external rotation

[Background]Shoulder external rotation at abduction (ER) is a notable motion in overhead sports because it could cause strong stress to the elbow and shoulder joint. However, no study has comprehensively investigated the effect of different trunk postures during ER. This study aimed to investigate the effect of different trunk postures on scapular kinematics and muscle activities during ER. [Methods]Fourteen healthy men performed active shoulder external rotation at 90° of abduction with the dominant arm in 15 trunk postures. At maximum shoulder external rotation in 15 trunk postures, including 4 flexion-extension, 6 trunk rotation, and 4 trunk side-bending postures, as well as upright posture as a control, scapular muscle activities and kinematics were recorded using surface electromyography and an electromagnetic tracking device, respectively. The data obtained in the flexion-extension, trunk rotation, and trunk side-bending postures were compared with those obtained in the upright posture. [Results]In the flexion-extension condition, scapular posterior tilt and external rotation significantly decreased, but the muscle activities of the lower trapezius and infraspinatus significantly increased in maximum trunk flexion. Moreover, scapular upward rotation and the activity of the serratus anterior significantly increased in maximum trunk extension. In the rotation condition, scapular posterior tilt and external rotation significantly decreased, but the activity of the serratus anterior significantly increased in the maximum contralateral trunk rotation posture. In the trunk side-bending condition, scapular posterior tilt and the external rotation angle significantly decreased. [Conclusio]Trunk postures affected scapular kinematics and muscle activities during ER. Our results suggest that different trunk postures activate the lower trapezius and serratus anterior, which induce scapular posterior tilt

A First View of the Effect of a Trial of Early Mobilization on the Muscle Strength and Activities of Daily Living in Mechanically Ventilated Patients With COVID-19

Objective: To retrospectively investigate the effect of early mobilization on the muscle strength and activities of daily living in patients with COVID-19 under mechanical ventilation. Design: This was a single-center, retrospective, observational study. Setting: Inpatient rehabilitation care in Japan. Participants: The study subjects were divided based on the onset of mobilization: under mechanical ventilation (n=17; aged 68.5±11.9, 13 male) and after extubation (n=11; aged 59.7±7.1, 6 male; N=28). Interventions: Mobilization, including dangle sitting, standing, walking, and muscle strengthening exercises. Main Outcome Measures: The outcome measures were Barthel Index, Medical Research Council Manual Muscle Test, and intensive care unit Mobility Scale. Results: The difference in the Barthel Index, Medical Research Council Manual Muscle Test, and intensive care unit Mobility Scale scores pre- and postintervention were not statistically significant between the 2 groups, but all significantly improved after the intervention. Conclusion: This small sample size study found no difference in the functional recovery of patients with severe COVID-19 who underwent early mobilization under mechanical ventilation relative to when it was begun after extubation

Effects of periodic robot rehabilitation using the Hybrid Assistive Limb for a year on gait function in chronic stroke patients

Using a robot for gait training in stroke patients has attracted attention for the last several decades. Previous studies reported positive effects of robot rehabilitation on gait function in the short term. However, the long-term effects of robot rehabilitation for stroke patients are still unclear. The purpose of the present study was to investigate the long-term effects of periodic gait training using the Hybrid Assistive Limb (HAL) on gait function in chronic stroke patients. Seven chronic stroke patients performed 8 gait training sessions using the HAL 3 times every few months. The maximal 10-m walk test and the 2-minute walking distance (2MWD) were measured before the first intervention and after the first, second, and third interventions. Gait speed, stride length, and cadence were calculated from the 10-m walk test. Repeated one-way analysis of variance showed a significant main effect on evaluation time of gait speed (F = 7.69, p < 0.01), 2MWD (F = 7.52, p < 0.01), stride length (F = 5.24, p < 0.01), and cadence (F = 8.43, p < 0.01). The effect sizes after the first, second, and third interventions compared to pre-intervention in gait speed (d = 0.39, 0.52, and 0.59) and 2MWD (d = 0.35, 0.46, and 0.57) showed a gradual improvement of gait function at every intervention. The results of the present study showed that gait function of chronic stroke patients improved over a year with periodic gait training using the HAL every few months

Swimmers With Low Back Pain Indicate Greater Lumber Extension During Dolphin Kick and Psoas Major Tightness

Context: In competitive swimming, many swimmers experience low back pain (LBP). Lumbar hyperextension may cause LBP, and tight hip-flexor muscle may cause lumbar extension during swimming. Objective: The purpose of this study was to clarify the features of the elastic moduli of the muscles and the lumbar extension when swimmers with LBP perform a dolphin kick (DK). Design: Cross-sectional study. Setting: Single center. Other Participants: Eleven male college swimmers were enrolled as the LBP group (who have LBP when swimming and during a lumbar extension), and 21 male college swimmers were recruited as the control group (no LBP). Interventions: The elastic moduli of the psoas major, iliacus, teres major, latissimus dorsi, pectoralis major, and pectoralis minor were measured through ultrasonic shear wave elastography. The lumbar and hip extension angles during a DK were measured using a video camera. The passive hip extension and shoulder-flexion range of motion (ROM) were measured using a goniometer. Main Outcome Measures: Muscle elastic moduli and lumbar extension angles during DK. Results: The characteristics, muscle elastic moduli, DK motion, and ROM were compared between the 2 groups. LBP group demonstrated significantly higher elastic modulus of the psoas major and lower modulus of pectoralis minor compared with the control group. Also, LBP group showed greater lumbar extension during a DK and less hip extension ROM than the control group. Conclusions: The higher elastic modulus of the psoas major and greater lumbar extension during a DK may be related to the LBP in swimmers

Association of Physical Activity and Nutritional Intake with Muscle Quantity and Quality Changes in Acute Stroke Patients

[Objectives] To evaluate longitudinally the muscle properties of acute stroke patients and examine the association between physical activity and nutritional intake. [Materials and methods] This study enrolled 21 stroke patients (72.7±10.4 years). Muscle quantity (fat-free mass, appendicular skeletal muscle mass) and quality (extracellular water/intracellular water ratio, phase angle) were assessed using a bioelectrical impedance device at baseline (within three days) and two weeks after stroke onset. Physical activity and sedentary were calculated from the accelerometer data. Total energy and protein intake were calculated from the dietary surveys as nutritional intake. The association of physical activity, sedentary, and nutritional intake with the rate of changes in muscle properties was examined. [Results] The fat-free mass significantly decreased (from 43.4±8.0 to 42.2±7.6 kg), and the skeletal muscle was unchanged (from 17.8±4.2 to 17.7±4.0 kg) after two weeks. The extracellular water/intracellular water ratio significantly increased (from 0.63±0.02 to 0.65±0.03) and the phase angle significantly decreased (from 5.1±0.6 to 4.9±0.8°), suggesting that the muscle quality have declined. Correlation analysis showed that the extracellular water/intracellular water ratio was significantly associated with physical activity [metabolic equivalents (ρ=-0.61)] and sedentary (ρ=0.67) and that the phase angle was significantly associated with physical activity [metabolic equivalents (ρ=0.69)], sedentary (ρ=-0.68), and nutritional intake [total energy (r=0.45), protein (r=0.45)]. [Conclusions] The fat-free mass and muscle quality (extracellular water/intracellular water ratio and phase angle) declined two weeks after stroke. Physical activity and nutritional intake were lower in patients with decreased muscle quality, suggesting the importance of exercise and nutrition in the acute phase