OBJECTIVE: This study aimed to explore the association between arm elevation and neck/shoulder pain, and trunk forwarding bending and low back pain among home care workers.
METHODS: Home care workers (N = 116) from 11 home care units in Trondheim, Norway, filled in pain assessment and working hours questionnaire, and wore 3 accelerometers for up to 7 consecutive days. Work time was partitioned into upright awkward posture, nonawkward posture, and nonupright time, i.e. sitting. Within a compositional approach framework, posture time compositions were expressed in terms of log-ratio coordinates for statistical analysis and modeling. Poisson generalized linear mixed models were used to analyze the relationship between arm elevation in upright postures and neck/shoulder pain, and between trunk forward bending in upright postures and low back pain, respectively. Isotemporal substitution analysis was used to investigate the association of pain assessment with the reallocation of time spent in the different postures.
RESULTS: Time spent in awkward postures was modest, especially for the more extreme angles (60° and 90°). Adjusting for age, gender, and body mass index, our study suggested that the compositions of time spent by home care workers in awkward postures were significantly associated with pain assessment (P < 0.01). Isotemporal substitution analysis showed that reallocating 5 min from upright posture with arms elevated below to above 60° and 90° was associated with a 6.8% and 19.9% increase in the neck/shoulder pain score, respectively. Reallocating 5 min from a forward bending posture while upright below to above 30°, 60°, and 90° was associated with 1.8%, 3.5%, and 4.0% increase in low back pain, respectively.
CONCLUSIONS: Although the exposure to awkward postures was modest, our results showed an association between increased time spent in awkward postures and an increase in neck/shoulder pain and low back pain in home care workers. As musculoskeletal pain is the leading cause of sickness absence, these findings suggest that home care units could benefit from re-organizing work to avoid excessive arm elevation and trunk forward bending in workers.

Measuring the quality of movement is a need and a challenge for clinicians. Jerk, defined as the quantity of acceleration variation, is a kinematic parameter used to assess the smoothness of movement. We aimed to assess and compare jerk metrics in asymptomatic participants for 3 important movement characteristics that are considered by clinicians during shoulder examination: dominant and non-dominant side, concentric and eccentric contraction mode, and arm elevation plane. In this pilot study, we measured jerk metrics by using Xsens® inertial measurement units strapped to the wrists for 11 different active arm movements (ascending and lowering phases): 3 bilateral maximal arm elevations in sagittal, scapular and frontal plane; 2 unilateral functional movements (hair combing and low back washing); and 2 unilateral maximal arm elevations in sagittal and scapular plane, performed with both arms alternately, right arm first. Each arm movement was repeated 3 times successively and the whole procedure was performed 3 times on different days. The recorded time series was segmented with semi-supervised algorithms. Comparisons involved the Wilcoxon signed rank test (p < 0.05) with Bonferroni correction. We included 30 right-handed asymptomatic individuals [17 men, mean (SD) age 31.9 (11.4) years]. Right jerk was significantly less than left jerk for bilateral arm elevations in all planes (all p < 0.05) and for functional movement (p < 0.05). Jerk was significantly reduced during the concentric (ascending) phase than eccentric (lowering) phase for bilateral and unilateral right and left arm elevations in all planes (all p < 0.05). Jerk during bilateral arm elevation was significantly reduced in the sagittal and scapular planes versus the frontal plane (both p < 0.01) and in the sagittal versus scapular plane (p < 0.05). Jerk during unilateral left arm elevation was significantly reduced in the sagittal versus scapular plane (p < 0.05). Jerk metrics did not differ between sagittal and scapular unilateral right arm elevation. Using inertial measurement units, jerk metrics can well describe differences between the dominant and non-dominant arm, concentric and eccentric modes and planes in arm elevation. Jerk metrics were reduced during arm movements performed with the dominant right arm during the concentric phase and in the sagittal plane. Using IMUs, jerk metrics are a promising method to assess the quality of basic shoulder movement.

Objective: To analyze the mechanism of invasive blood pressure change in radial artery caused by arm elevation by observing pressure, velocity and diameter of radial artery. Methods: Twenty-six hemodynamically stable hepatobiliary surgery patients admitted to the intensive care unit from June to December 2018 after general anesthesia in Tsinghua Changgung Hospital were selected. When the arm was raised, the invasive blood pressure was recorded, and the inner diameter and blood flow velocity of the radial artery were measured by Doppler ultrasound. The data following a normal distribution were compared with paired t test. Results: After arm elevation for 30 s, systolic blood pressure of radial artery decreased and diastolic blood pressure increased significantly((107±16) mmHg vs (120±17) mmHg, (75±6) mmHg vs (71±9) mmHg, t=25.0, -12.6, both P<0.05), but there was no significant difference in mean arterial pressure ((87±10) mmHg vs (87±11) mmHg, t=1.1, P>0.05). The peak velocity, end-diastolic velocity and resistance index of the radial artery increased significantly, and the transverse and longitudinal inner diameters of the radial artery decreased significantly after the arm was elevated for 30 s (t=-63.4, -14.6, -22.5, 31.4, 25.3, all P<0.01). Conclusions: Kinetic pressure compensation and vascular resistance compensation may be the main mechanism of radial artery pressure change when the arm is elevated. Arm elevation can be used as a vascular resistance response test clinically.
目的： 通过观测桡动脉压力、流速、直径等指标，分析抬高上肢导致桡动脉有创血压改变的流体力学机制。 方法： 选择2018年6至12月期间入住清华长庚医院重症监护病房（ICU）的血流动力学稳定的肝胆外科全身麻醉手术后患者26例。分别在抬高上肢前和抬高上肢时，记录有创血压数值，并以多普勒超声测量桡动脉置管处的动脉血管内径和血流速。符合正态分布的数据比较采用配对t检验。 结果： 与抬高上肢前相比，抬高上肢30 s后桡动脉收缩压下降、舒张压上升，分别为（107±16) mmHg比（120±17) mmHg和（75±6) mmHg比（71±9) mmHg，差异均有统计学意义（t=25.0、-12.6，均P<0.05)，但平均动脉压变化差异无统计学意义[(87±10) mmHg比（87±11) mmHg，t=1.1，P>0.05]。与抬高上肢前相比，抬高上肢30 s后桡动脉收缩期峰流速、舒张期末流速和阻力指数均显著增加，而桡动脉横径与纵径则显著减小，前后比较差异均有统计学意义（t=-63.4、-14.6、-22.5、31.4、25.3，均P<0.01)。 结论： 动压代偿和血管阻力代偿可能是抬高上肢时桡动脉压力改变的主要机制，抬高上肢可以作为血管阻力反应性试验在临床应用。.