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This study evaluated the effects of the promotion of active breaks and postural shifts on new onset of neck and low-back pain during a 6-month follow-up among high-risk office workers. A 3-arm cluster-randomized controlled trial with 6-month follow-up was conducted among healthy but high-risk office workers. Participants were recruited from six organizations in Bangkok, Thailand (N=193) and randomly assigned at cluster level into active break intervention (N=47), postural shift intervention (N=46), and control (N=100) groups. Participants in the intervention groups received a custom-designed apparatus to facilitate designated active breaks and postural shifts during work. Participants in the control group received a placebo seat pad. The primary outcome measure was new onset of neck and low-back pain during 6-month follow-up. Analyses were performed using Cox proportional hazard models. One-hundred and eighty-six (96%) predominantly female participants were successfully followed up over six months. New onset of neck pain during the 6-month follow-up occurred in 17%, 17%, and 44% of the participants in the active break, postural shift, and control groups, respectively. For new onset of low-back pain, these percentages were 9%, 7%, and 33%, respectively. Hazard rate (HR) ratios after adjusting for biopsychosocial factors indicated a protective effect of the active break and postural shift interventions for neck pain [HRadj 0.45, 95% confidence interval (CI) 0.20-0.98 for active break and HRadj 0.41, 95% CI 0.18-0.94 for postural shift] and low-back pain (HRadj 0.34, 95% CI 0.12-0.98 for active break and HRadj 0.19, 95% CI 0.06-0.66 for postural shift). Interventions to increase either active breaks or postural shifts reduced new onset of neck and low-back pain among high-risk office workers.

The purpose of this study was to determine the biomechanical mechanisms driving passengers’ lower-limb postural shifts during seated sleep on a flight to prevent negative effects on passengers’ physical health. Twenty subjects participated in an observational study and a subsequent experiment on fatigue development and tissue oxygenation changes during seated sleep in an economy-class aircraft seat. Three of the most frequently used postures, which involved four targeted muscles of the legs and the thigh-buttock region, were selected and examined in the experiment with the following measures: muscle electromyogram, tissue oxygenation, and body contact pressure distribution. The results showed that the fatigue of the tibialis anterior and gastrocnemius and the compression of the region under the medial tuberosities were relieved by alternations among the three positions—position 1 (placing the shanks forwards), position 2 (placing the shanks neutrally), and position 3 (placing the shanks backwards). This research reveals the mechanical properties of the biomechanical factors functioning in lower-limb postural shifts during seated sleep and provides design optimization strategies for economy-class aircraft seats to reduce the negative effects on passenger health.

OBJECTIVE: This study evaluated the effectiveness of the promotion of postural shift intervention using a dynamic seat cushion on the 6-month incidence of neck and low-back pain among high-risk office workers. METHODS: In a cluster-randomized controlled trial (RCT), 133 office workers were randomly assigned, at cluster level, to intervention (N=67) and control (N=66) groups. The intervention group received a dynamic seat cushion to encourage postural shifts during sitting, while the control group received a placebo seat pad. Primary outcomes were 6-month incidence of neck and low-back pain. Secondary outcomes included sitting discomfort, pain intensity, disability, and trunk muscle performance. Analyses utilized Cox proportional hazard models. RESULTS: During the 6-month period, 15% of participants in the intervention group developed neck pain and 10% developed low-back pain. For the control group, this was 65% and 59%, respectively. Hazard rate (HR) ratios, after adjusting for biopsychosocial factors, indicated a protective effect of the intervention for neck pain [HR adj 0.19, 95% confidence interval (CI) 0.09–0.39, P<0.001] and low-back pain (HR adj 0.16, 95% CI 0.07–0.35, P<0.001). The intervention group demonstrated a significant reduction in sitting discomfort and improvement in trunk muscle performance compared to the control group (P<0.05). However, the intervention did not reduce pain and disability in individuals experiencing pain compared to the control group. CONCLUSIONS: The dynamic seat cushion effectively reduced the incidence of neck and low-back pain by promoting postural shifts. These findings suggest that the key factor in reducing the risk of developing neck and low-back pain is the facilitation of postural shifts during sitting, which can potentially be achieved with other dynamic interventions designed to reduce prolonged and static sitting among office workers.

Background Neck and low back pain are prevalent issues among office workers due to prolonged sitting, necessitating effective interventions. Dynamic seat cushion, designed to promote postural shifts, have emerged as promising solutions to address this concern. This study aims to evaluate the effectiveness of a dynamic seat cushion on recovery and recurrence of neck and/or low back pain in office workers. Methods This study used 6-month follow-up data of a randomized controlled trial, involving 66 office workers who reported neck and/or low back pain during the trial. At baseline, participants were cluster-randomized into an intervention group, which received a dynamic seat cushion designed to encourage postural shifts, or a control group, which received a placebo seat pad. Health outcomes included recovery duration and recurrence of pain. Analyses utilized log rank test and Cox proportional hazard models. Results The recovery rate from neck and/or low back pain was 100% for the intervention group, and 86% for the control group. The median recovery duration of participants who reported pain during the 6-month period was 1 month in the intervention group and 3 months in the control group. The intervention group had a higher probability of recovery compared to the control group (HR adj 4.35, 95% CI 1.87–10.11; p  < 0.01). The recurrence rate of neck and low back pain was 27% in the intervention group, which was 75% in the control group. The Hazard Ratio, after adjustment, for the intervention group compared to the control group was 0.50 (95% CI = 0.11–2.12). Conclusions A dynamic seat cushion that encourages postural shifts shortened recovery duration of neck and low back pain among office workers. Due to small numbers, a potentially relevant reduction in the recurrence of neck and low back pain could not be statistically confirmed. A power analysis was not conducted for this secondary analysis, and future studies should be designed with adequate sample sizes to explore the recurrence of pain with greater statistical power. Trial registration This trial is retrospectively registered under the Thai Clinical Trials Registry: TCTR20230623002 (23/06/2023).

A novel and fun exercise robot (LOCOBOT) was developed to improve balance ability. This system can control a spherical robot on a floor by changing the center of pressure (COP) based on weight-shifting on a board. The present study evaluated leg muscle activity and joint motion during LOCOBOT exercise and compared the muscle activity with walking and sit-to-stand movement. This study included 10 healthy male adults (age: 23.0 ± 0.9 years) and examined basic LOCOBOT exercises (front–back, left–right, 8-turn, and bowling). Electromyography during each exercise recorded 13 right leg muscle activities. Muscle activity was represented as the percentage maximal voluntary isometric contraction (%MVIC). Additionally, the joint motion was simultaneously measured using an optical motion capture system. The mean %MVIC differed among LOCOBOT exercises, especially in ankle joint muscles. The ankle joint was primarily used for robot control. The mean %MVIC of the 8-turn exercise was equivalent to that of walking in the tibialis anterior, and the ankle plantar flexors were significantly higher than those in the sit-to-stand motion. Participants control the robot by ankle strategy. This robot exercise can efficiently train the ankle joint muscles, which would improve ankle joint stability.

Background Changes in head position are thought to cause a degree of brain shift in the intracranial cavity. However, little is known on the concurrent shift of the cerebral veins. The present study aimed to investigate the positional shift of the cerebral veins that accompanies brain shift. Methods Sagittal T2-weighted magnetic resonance imaging was performed on 21 consecutive patients lying in the supine and prone positions, using the same sequence. For each patient, imaging data were obtained for the two positions as a pair of images with morphologically best-matched cerebral contours. Results The subarachnoid spaces in the parasagittal frontal convexity showed variable reductions related to a postural change from a supine to a prone position, with a mean percent reduction (%Δ) of 17.8 ± 11.7%. Additionally, cerebral cisterns ventral to the brainstem and upper cervical cord were reduced in most patients when lying in a prone position, with a mean %Δ of 16.6 ± 8.7%. In contrast, none of these 130 pairs of identical venous segments located in the parasagittal cerebral convexity showed positional shift. Cadaveric dissections found that the major cortical veins were superficially upheld by the arachnoid membranes. Conclusions The parasagittal major cortical and bridging veins do not seem to show positional shifts. Positional change in the posterior–anterior direction causes a shearing between the frontal cortices and the distributing veins and can be a risk factor for acute subdural hemorrhage, in case of severe head trauma.

In the literature on inter-limb coordination, the coordination among ‘‘focal’’ body parts (i.e., the two limbs) directly engaged in a pendulum swinging task has been studied by immobilizing other body parts to reduce “noise,” while putting aside questions of how one maintains posture while performing the task. However, in practical performance of musical instruments, for example, performers must coordinate different body parts in sync with the music while maintaining the whole body’s balance. This study demonstrates the effectiveness and necessity of understanding inter-limb coordination in whole-body coordination. Participants were asked to move two pendulums either in sync or alternatively with metronome beeps under two conditions: immobile (fixed forearms) and mobile (forearms not fixed). The explorative analyses focused on whether and how coordinative structures emerged and whether the degree of task achievement differed according to the phase mode, frequency, and mobility conditions. The motion similarity and phase difference between different parts and the pendulums showed that task-specific coordinative structures emerged in both immobile and mobile conditions. In the in-phase mobile condition, the emergent coordinative structure may have improved task achievement, shown by the phase difference between the left and right pendulums. These findings suggest that the global coordinative structure is involved in achieving the local pendulum swinging task.

The use of vibration as a feedback modality to convey motion of the body has been shown to improve measures of postural stability in some groups of patients. Because individuals using transtibial prostheses lack sensation distal to the amputation, vibratory feedback could possibly be used to improve their postural stability. The current investigation provided transtibial prosthesis users (n = 24, mean age 48 yr) with vibratory feedback proportional to the signal received from force transducers located under the prosthetic foot. Postural stability was evaluated by measuring center of pressure (CoP) movement, limits of stability, and rhythmic weight shift while participants stood on a force platform capable of rotations in the pitch plane (toes up/toes down). The results showed that the vibratory feedback increased the mediolateral displacement amplitude of CoP in standing balance and reduced the response time to rapid voluntary movements of the center of gravity. The results suggest that the use of vibratory feedback in an experimental setting leads to improvements in fast open-loop mechanisms of postural control in transtibial prosthesis users.

Age-related balance impairments, particularly in mediolateral direction (ML) may cause falls. Sufficiently sensitive and reliable ML balance tests are, however, lacking. This study is aimed to determine (1) the effect of age on and (2) the reliability of ML balance performance using Center of Mass (CoM) tracking. Balance performance of 19 young (26±3 years) and 19 older (72±5 years) adults on ML-CoM tracking tasks was compared. Subjects tracked predictable and unpredictable target displacements at increasing frequencies with their CoM by shifting their weight sideward. Phase-shift (response delay) and gain (amplitude difference) between the CoM and target in the frequency domain were used to quantify performance. Thirteen older and all young adults were reassessed to determine reliability of balance performance measures. In addition, all older adults performed a series of clinical balance tests and conventional posturography was done in a sub-sample. Phase-shift and gain dropped below pre-determined thresholds (-90 degrees and 0.5) at lower frequencies in the older adults and were even lower below these frequencies than in young adults. Performance measures showed good to excellent reliability in both groups. All clinical scores were close to the maximum and no age effect was found using posturography. ML balance performance measures exhibited small but systematic between-session differences indicative of learning. The ability to accurately perform ML-CoM tracking deteriorates with age. ML-CoM tracking tasks form a reliable tool to assess ML balance in young and older adults and are more sensitive to age-related impairment than posturography and clinical tests.

Objective Coronal balance and shoulder balance affect the results of surgical treatments. Numerous studies on these topics in moderate scoliosis have been reported. However, the risk factors and the association between coronal imbalance and shoulder imbalance in complex spinal deformity remain unknown. The purpose of this study is to investigate whether shoulder imbalance as well as other radiographic factors could predict ultimate coronal imbalance in severe and rigid scoliosis. Methods A retrospective study was conducted at our hospital between January 2009 and December 2018. Fifty‐one patients with severe and rigid thoracic/thoracolumbar scoliosis (main curve Cobb angle > 80° and flexibility < 25%) were recruited. Patients were divided into the Coronal balance (CB) group (C7PL‐CSVL ≤ 20 mm) and the Coronal imbalance (CIB) group (C7PL‐CSVL > 20 mm). Then, the patients in the CIB group were stratified based on the aggravation of C7PL‐CSVL for further subgroup analysis. Potential risk factors for coronal imbalance and decompensation, including shoulder height data and various radiographic parameters, were analyzed between groups and summarized in a quantitative predictive equation. Results Of all patients, 43.1% (22/51) showed coronal imbalance at the last follow‐up. Univariate analysis showed that the following parameters were significantly greater in CIB group: shoulder height data including immediately postoperative radiographic shoulder height (RSH, p = 0.001), postoperative clavicle angle (CA, p = 0.000), and postoperative C7PL‐CSVL (p = 0.000). Logistic regression identified that immediately postoperative CA [odds ratio (OR) = 6.837, p = 0.008] and C7PL‐CSVL (OR = 1.071, p = 0.010) were the independent risk factors for ultimate coronal imbalance. The predictive equation was Risk Index = −5.277 + 1.922 × postoperative CA + 0.068 × postoperative C7PL‐CSVL, with positive and negative predictive values of 86.7% and 85.7%, respectively. Conclusions The prevalence of coronal imbalance at the last follow‐up remained high in severe and rigid scoliosis. Postoperative shoulder imbalance and residual trunk shift could be used as predictors for ultimate coronal imbalance. The aggravation of coronal imbalance might represent a possible compensatory response to shoulder imbalance, as suggested by the observed adverse trends. However, this interpretation should be considered hypothetical, since a direct causal relationship could not be verified yet. Surgeons should pay attention to restore an appropriate relationship between curves in surgical planning for better results. The prevalence of coronal imbalance remained high in severe and rigid scoliosis. Postoperative shoulder imbalance and residual trunk shift could be used as predictors for ultimate coronal imbalance. The aggravation of coronal imbalance might be a compensation, trying to level the imbalanced shoulder and attain a truncal global balance.