Impact of posture and axial loading on lumbar intervertebral disc dimensions investigated by transabdominal ultrasound.

PURPOSE: To use transabdominal ultrasound (US) to investigate the impact of posture and axial loading on the lumbar intervertebral disc (IVD) dimensions in healthy adults. METHOD: For this single-center, prospective cross-sectional study 54 healthy volunteers (mean age 23.76 ± 3, 26 men) underwent transabdominal US. Lumbar IVD dimensions (height, length, width) at the levels L3/4 and L4/5 were assessed in three test conditions: supine, standing, and standing position with additional axial load of 50 % body weight (standing+50%). Success rates for the longitudinal and transverse US acquisitions and IVD dimension measurements were determined. IVD dimensions were compared across test conditions using two-way repeated measures analysis of variance and post-hoc pairwise t-tests with Bonferroni correction. RESULTS: The success rate for longitudinal and transverse US acquisition was 100 %. The overall success rate for IVD dimension measurement was 96.4 %, it was highest for IVD height (99.2 %) and lowest for IVD length (93.3 %). IVD height at L4/5 decreased significantly from the supine to standing position (p < 0.05) and from the supine to standing+50% position (p < 0.01). IVD width at L3/4 increased significantly from the supine to standing+50% position (p < 0.05). No significant differences were found for IVD length. CONCLUSIONS: Transabdominal US is a feasible tool to investigate IVD dimensions at L3/4 and L4/5 in different postures and with axial loading. Posture and axial loading significantly influence IVD height and width, but not length.

Defining the glenohumeral range of motion required for overhead shoulder mobility: an observational study.

Background: Recovery of overhead mobility after shoulder surgery is time-consuming and important for patient satisfaction. Overhead stretching and mobilization of the scapulothoracic and glenohumeral (GH) joints are common treatment interventions. The isolated GH range of motion (ROM) of flexion, abduction, and external rotation required to move above 120° of global shoulder flexion in the clinical setting remains unclear. This study clarified the GH ROM needed for overhead mobility. Methods: The timely development of shoulder ROM in patients after shoulder surgery was analyzed. Passive global shoulder flexion, GH flexion, abduction, and external rotation ROM were measured using goniometry and visually at 2-week intervals starting 6-week postsurgery until the end of treatment. Receiver operating characteristic curves were used to identify the GH ROM cutoff values allowing overhead mobility. Results: A total of 21 patients (mean age 49 years; 76% men) after rotator cuff repair (71%), Latarjet shoulder stabilization (19%), and arthroscopic biceps tenotomy (10%) were included. The ROM cutoff value that accurately allowed overhead mobility was 83° for GH flexion and abduction with the area under the curve (AUC) ranging from 0.90 to 0.93 (p < 0.001). The cutoff value for GH external rotation was 53% of the amount of movement on the opposite side (AUC 0.87, p < 0.001). Conclusions: Global shoulder flexion above 120° needs almost full GH flexion and abduction to be executable. External rotation ROM seems less important as long as it reaches over 53% of the opposite side.

Exercise- and education-based prehabilitation before total knee arthroplasty: a pilot study.

OBJECTIVE: To determine the feasibility and estimates of effects of a supervised exercise- and education-based prehabilitation programme aiming to improve knee functioning compared with usual care in patients awaiting total knee arthroplasty. DESIGN: A randomized controlled pilot study. SUBJECTS: Patients receiving primary, unilateral total knee arthroplasty. METHODS: Patients randomized to the intervention group participated in a personalized 4-8-week prehabilitation programme before surgery. Feasibility of the intervention and self-reported knee functioning, pain, physical performance and hospital stay were assessed at baseline, immediately preoperatively, 6 and 12 weeks after surgery. RESULTS: Twenty patients (mean age 72.7±5.95 years) were enrolled in this study. The personalized prehabilitation programme was found to be feasible and safe, with an exercise adherence of 90%. Significant medium interaction effects between groups and over time favouring prehabilitation were reported for the sport subscale of the Knee Osteoarthritis Outcome Score (F(3/54) = 2.895, p = 0.043, η² = 0.139) and Tegner Activity Scale (F(2.2/39.1) = 3.20, p = 0.048, η² = 0.151). CONCLUSION: The absence of adverse events and high adherence to the programme, coupled with beneficial changes shown in the intervention group, support the conduct of a full-scale trial investigating the effectiveness of prehabilitation.

Lunar and mars gravity induce similar changes in spinal motor control as microgravity.

Introduction: Once more, plans are underway to send humans to the Moon or possibly even to Mars. It is therefore, important to know potential physiological effects of a prolonged stay in space and to minimize possible health risks to astronauts. It has been shown that spinal motor control strategies change during microgravity induced by parabolic flight. The way in which spinal motor control strategies change during partial microgravity, such as that encountered on the Moon and on Mars, is not known. Methods: Spinal motor control measurements were performed during Earth, lunar, Mars, and micro-gravity conditions and two hypergravity conditions of a parabola. Three proxy measures of spinal motor control were recorded: spinal stiffness of lumbar L3 vertebra using the impulse response, muscle activity of lumbar flexors and extensors using surface electromyography, and lumbar curvature using two curvature distance sensors placed at the upper and lower lumbar spine. The participants were six females and six males, with a mean age of 33 years (standard deviation: 7 years). Results: Gravity condition had a statistically significant (Friedmann tests) effect spinal stiffness (p < 0.001); on EMG measures (multifidus (p = 0.047), transversus abdominis (p < 0.001), and psoas (p < 0.001) muscles) and on upper lumbar curvature sensor (p < 0.001). No effect was found on the erector spinae muscle (p = 0.063) or lower curvature sensor (p = 0.170). Post hoc tests revealed a significant increase in stiffness under micro-, lunar-, and Martian gravity conditions (all p's < 0.034). Spinal stiffness decreased under both hypergravity conditions (all p's ≤ 0.012) and decreased during the second hypergravity compared to the first hypergravity condition (p = 0.012). Discussion: Micro-, lunar-, and Martian gravity conditions resulted in similar increases in spinal stiffness, a decrease in transversus abdominis muscle activity, with no change in psoas muscle activity and thus modulation of spinal motor stabilization strategy compared to those observed under Earth's gravity. These findings suggest that the spine is highly sensitive to gravity transitions but that Lunar and Martian gravity are below that required for normal modulation of spinal motor stabilization strategy and thus may be associated with LBP and/or IVD risk without the definition of countermeasures.

Earth-vertical motion perception assessment using an elevator: a feasibility study.

A feasible, inexpensive, rapid, and easy-to-use method to measure vestibular vertical movement perception is needed to assess the sacculus-mediated low-frequency otolith function of dizzy patients. To evaluate the feasibility of reaction time assessment in response to vertical motion induced by an elevator in healthy young individuals. We recorded linear acceleration/deceleration reaction times (LA-RT/LD-RT) of 20 healthy (13 female) subjects (mean age: 22 years ± 1 SD) as a measure of vertical vestibular motion perception. LA-RT/LD-RT were defined as the time elapsed from the start of elevator acceleration or deceleration to the time at which subjects in a sitting position indicated perceiving a change in velocity by pushing a button with their thumb. The light reaction time was measured as a reference. All 20 subjects tolerated the assessment with repeated elevator rides and reported no adverse events. Over all experiments, one upward and four downward rides had to be excluded for technical reasons (2.5%). The fraction of premature button presses varied among the four conditions, possibly related to elevator vibration (upward rides: LA-RT-up 66%, LD-RT-up 0%; downward rides: LA-RT-down 12%, LD-RT-down 4%). Thus LD-RT-up yielded the most robust results. The reaction time to earth-vertical deceleration elicited by an elevator provides a consistent indicator of linear vestibular motion perception in healthy humans. The testing procedure is inexpensive and easy to use. Deceleration on upward rides yielded the most robust measurements.

Typical Cockpit Ergonomics Influence on Cervical Motor Control in Healthy Young Male Adults.

INTRODUCTION: Neck pain and injury are common problems in military high-performance aircraft and helicopter aircrews. A contributing factor may be the reclined sitting position in cockpits. This study aimed to determine the effect of typical cockpit ergonomics on cervical proprioception, assessed by using the cervical joint position error (cJPE).METHODS: A total of 49 healthy male military employees (mean age 19.9 ± 2.2 yr) were examined. Measurements of the cJPE were obtained in the flexion, extension, and rotation directions in an upright and in a 30°-reclined sitting position. Each condition comprised three trials, with an additional 3-kg head load to mimic real world working conditions.RESULTS: A smaller cJPE was noted in the 30°-reclined sitting position (mean cJPE = 3.9 cm) than in the upright sitting position (mean cJPE = 4.6 cm) in the flexion direction. The cJPE decreased significantly in all movement directions across the three trials; for example, in the flexion direction in the 30°-reclined sitting position: Trial 1/2/3 mean cJPE = 5.0/3.8/3.1 cm.CONCLUSION: It seems that a reclined seating position has a positive influence on cJPE. However, the result is weak. In both sitting positions and all three directions, the first tests of the cJPE showed the highest values. Already after one or two further measurement runs, a significantly reduced cJPE was observed. This rapid improvement might indicate that an exercise similar to the cJPE test may improve the pilots' cervical proprioception and possibly reduce the risk of injury or pain.Heggli U, Swanenburg J, Hofstetter L, Häusler M, Schweinhardt P, Bron D. Typical cockpit ergonomics influence on cervical motor control in healthy young male adults. Aerosp Med Hum Perform. 2023; 94(3):107-112.

The association of fear of movement and postural sway in people with low back pain.

Background: Fear of movement is thought to interfere with the recovery from low back pain (LBP). To date, the relationship between fear of movement and postural balance has not been adequately elucidated. Recent findings suggest that more specific fears need to be assessed and put in relation to a specific movement task. We propose that the fear to bend the trunk in a certain direction is distinctly related to the amount of postural sway in different directions. Therefore, our aim was to investigate whether fear of movement in general and fear of bending the trunk in a certain plane is related to postural sway. Methods: Data was collected from participants with LBP during two assessments ~3 weeks apart. Postural sway was measured with a force-platform during quiet standing with the eyes closed. Fear of movement was assessed with an abbreviated version of the Tampa Scale of Kinesiophobia (TSK-11) and custom items referring to fear of bending the trunk in the sagittal and the frontal plane. Results: Based on data from 25 participants, fear of bending the trunk in the frontal plane was positively related to displacement in the sagittal and frontal plane and to velocity in the frontal plane (χ 2 = 4.35, p = 0.04; χ 2 = 8.15, p = 0.004; χ 2 = 9.79, p = 0.002). Fear of bending the trunk in the sagittal plane was not associated with any direction specific measure of sway. A positive relation of the TSK-11 with velocity of the frontal plane (χ 2 = 7.14, p = 0.008) was found, but no association with undirected measures of sway. Discussion: Fear of bending the trunk in the frontal plane may be especially relevant to postural sway under the investigated stance conditions. It is possible that fear of bending the trunk in the frontal plane could interfere with balance control at the hip, shifting the weight from side to side to control balance. Conclusion: For the first time the directional relationship of fear of movement and postural sway was studied. Fear of bending the trunk in the frontal plane was positively associated with several measures of postural sway.

Responsiveness of the German version of the Neck Disability Index in chronic neck pain patients: a prospective cohort study with a seven-week follow-up.

BACKGROUND: The need for an efficient and feasible strategy to deal with neck pain has a high priority for many countries. Validated assessment tools like the Neck Disability Index (NDI) to evaluate the functional status of a neck pain patient are urgently needed to treat and to follow-up patients purposefully. A German version (NDI-G) was shown to be valid and reliable, but has so far not been tested for responsiveness. The aim of this study was to evaluate the NDI-G`s responsiveness. METHODS: This was a prospective cohort study with a seven-week follow-up. Fifty chronic neck pain patients filled out NDI-G twice. Additionally, the Patients' Global Impression of Change score (PGIC) was assessed at follow-up. Wilcoxon and Spearman tests were used to assess direction and strength of the association between the change in NDI-G and PGIC. The receiver operating characteristics method and the area under the curve (AUC) were calculated to assess sensitivity and specificity of the NDI-G change over time. RESULTS: The Wilcoxon test showed statistically significant differences for NDI-G at baseline and follow-up in the total sample, the "clinically improved" and "clinically not improved" subgroups as indicated in the PGIC. Spearman test resulted in a moderate correlation between the NDI-G and the PGIC (rS = -0.53, p = 0.01) at follow-up. AUC showed an acceptable discrimination [AUC = 0.78 (95% confidence interval 0.64 - 0.91)] of the NDI-G, with a cutoff score of 1.5, between clinically improved and clinically not improved patients, based on the PGIC. CONCLUSIONS: The NDI-G is responsive to change in chronic neck pain. Together with the results of a previous study on its validity and reliability, the NDI-G can be recommended for research and clinical settings in patients with neck pain in German speaking countries. TRIAL REGISTRATION: NCT02676141. February 8, 2016.

Prehabilitation Improves Knee Functioning Before and Within the First Year After Total Knee Arthroplasty: A Systematic Review With Meta-analysis.

OBJECTIVE: To assess whether prehabilitation influenced knee functioning before and within the first year after total knee arthroplasty (TKA) surgery. DESIGN: Intervention systematic review with meta-analysis. LITERATURE SEARCH: The authors searched the MEDLINE/PubMED, EMBASE, CINAHL, Cochrane Library, Physiotherapy Evidence Database, Web of Science, and Scopus databases from their inception until March 2022. STUDY SELECTION CITERIA: The authors included peer-reviewed articles comparing preoperative, short-, mid- or long-term effects of exercise-based physical therapy before primary unilateral TKA with TKA without prehabilitation. DATA SYNTHESIS: We assessed bias using the Cochrane Risk-of-Bias tool (ROB 2.0) and therapeutic validity using the i-CONTENT tool. Standardized mean differences (Hedges' g) and 95% confidence intervals (CIs) were calculated for knee functioning. Certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. RESULTS: Sixteen trials (968 participants) were included; 14 qualified for meta-analysis. Low to very low certainty of evidence favored prehabilitation over no intervention for improving knee functioning before (g = 1.23; 95% CI: 0.49, 1.97) and up to 3 months after TKA (short-term: 1 day to 1 month, g = 0.90; 95% CI: 0.18, 1.61; mid-term: 6 weeks to 3 months, g = 0.45; 95% CI: 0.06, 0.84). There were no significant between-group differences at long-term follow-up (6-12 months, g = 0.07; 95% CI: -0.17, 0.30). CONCLUSION: There was low to very low certainty of evidence that prehabilitation promotes superior knee functioning before and up to 3 months after TKA, compared to TKA alone. The long-term postoperative effects were inconclusive. J Orthop Sports Phys Ther 2022;52(11):709-725 Epub: 20 September 2022. doi:10.2519/jospt.2022.11160.

Feedback on Trunk Movements From an Electronic Game to Improve Postural Balance in People With Nonspecific Low Back Pain: Pilot Randomized Controlled Trial.

BACKGROUND: Postural balance is compromised in people with low back pain, possibly by changes in motor control of the trunk. Augmenting exercising interventions with sensor-based feedback on trunk posture and movements might improve postural balance in people with low back pain. OBJECTIVE: We hypothesized that exercising with feedback on trunk movements reduces sway in anterior-posterior direction during quiet standing in people with low back pain. Secondary outcomes were lumbar spine and hip movement assessed during box lift and waiter bow tasks, as well as participant-reported outcomes. Adherence to the exercising intervention was also examined. METHODS: A randomized controlled trial was conducted with the intervention group receiving unsupervised home exercises with visual feedback using the Valedo Home, an exergame based on 2 inertial measurement units. The control group received no intervention. Outcomes were recorded by blinded staff during 4 visits (T1-T4) at University Hospital Zurich. The intervention group performed 9 sessions of 20 minutes in the 3 weeks between T2 and T3 and were instructed to exercise at their own convenience between T3 and T4. Postural balance was assessed on a force platform. Lumbar spine and hip angles were obtained from 3 inertial measurement units. The assessments included pain intensity, disability, quality of life, and fear of movement questionnaires. RESULTS: A total of 32 participants with nonspecific low back pain completed the first assessment T1, and 27 (84%) participants were randomized at T2 (n=14, 52% control and n=13, 48% intervention). Intention-to-treat analysis revealed no significant difference in change in anterior-posterior sway direction during the intervention period with a specified schedule (T2-T3) between the groups (W=99; P=.36; r=0.07). None of the outcomes showed significant change in accordance with our hypotheses. The intervention group completed a median of 61% (55/90; range 2%-99%) of the exercises in the predefined training program. Adherence was higher in the first intervention period with a specified schedule. CONCLUSIONS: The intervention had no significant effect on postural balance or other outcomes, but the wide range of adherence and a limited sample size challenged the robustness of these conclusions. Future work should increase focus on improving adherence to digital interventions. TRIAL REGISTRATION: ClinicalTrials.gov NCT04364243; https://clinicaltrials.gov/ct2/show/NCT04364243. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/26982.

Effects of increasing axial load on cervical motor control.

To investigate the effects of increasing axial load on cervical motor control. Surrogates of cervical motor control were active cervical range of motion (C-ROM) and joint position error (JPE) assessed in flexion, extension, lateroflexion and rotation directions in 49 healthy young men (mean age: 20.2 years). All measurements were executed with 0-, 1-, 2-, and 3-kg axial loads. Linear mixed models were used to assess the effects of axial loading and cervical movement-direction on C-ROM and JPE. Post-hoc analysis was performed to compare load levels. Axial loading (p = 0.045) and movement direction (p < 0.001) showed significant main effects on C-ROM as well as an interaction (p < 0.001). C-ROM significantly changed with 3-kg axial load by decreaseing extension (- 13.6%) and increasing lateroflexion (+ 9.9%). No significant main effect was observed of axial loading on JPE (p = 0.139). Cervical motor control is influenced by axial loading, which results in decreased C-ROM in extension and increased C-ROM lateroflexion direction.

Exergaming Using Postural Feedback From Wearable Sensors and Exercise Therapy to Improve Postural Balance in People With Nonspecific Low Back Pain: Protocol for a Factorial Pilot Randomized Controlled Trial.

BACKGROUND: Physical exercise is a common treatment for people with low back pain (LBP). Wearable sensors that provide feedback on body movements and posture during exercise may enhance postural balance and motor control in people with LBP. OBJECTIVE: This study aims to investigate whether physical exercising with postural feedback (EPF) improves postural balance, motor control, and patient-reported outcomes in people with LBP. METHODS: The study was an assessor-blinded 2×2 factorial trial. We planned to recruit 80 participants with nonspecific LBP who did not receive treatment for LBP. In addition, we aimed to recruit 40 patients with chronic, nonspecific LBP who were receiving exercise therapy (ET) at the University Hospital Zurich. Both ET patients and participants without treatment were randomized to receive either an additional EPF intervention or no additional intervention. This resulted in four different combinations of interventions: ET+EPF, ET, EPF, and no intervention. The participants underwent outcome assessments at inclusion (T1); 3 weeks later, at randomization (T2); after an intervention period of 3 weeks with a predefined exercise schedule for participants receiving EPF (T3); and after an additional 6 weeks, during which participants assigned to the EPF groups could exercise as much as they wished (T4). Patients receiving ET completed their regularly prescribed therapies during the study period. Balance was assessed during quiet standing on a force platform, and motor control was assessed during a lifting task and a waiter's bow task. Physical activity was recorded using an activity tracker and the participants' mobile phones during the study. The predefined EPF schedule consisted of nine sessions of 20 minutes of exercise with a tablet and inertial measurement unit sensors at home. Participants performed a series of trunk and hip movements and received feedback on their movements in a gamified environment displayed on the tablet. RESULTS: The first participant was recruited in May 2019. Data collection was completed in October 2020, with 3 patients and 32 eligible people without therapy who passed the eligibility check. CONCLUSIONS: Although it will not be possible to investigate differences in patients and people without other therapies, we expect this pilot study to provide insights into the potential of EPF to improve balance in people with LBP and adherence to such interventions. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/26982.

In vivo measurements of spinal stiffness according to a stepwise increase of axial load.

BACKGROUND: The spine has a complex motor control. Its different stabilization mechanisms through passive, active, and neurological subsystems may result in spinal stiffness. To better understand lumbar spinal motor control, this study aimed to measure the effects of increasing the axial load on spinal stiffness. METHODS: A total of 19 healthy young participants (mean age, 24 ± 2.1 years; 8 males and 11 females) were assessed in an upright standing position. Under different axial loads, the posterior-to-anterior spinal stiffness of the thoracic and lumbar spine was measured. Loads were 0%, 10%, 45%, and 80% of the participant's body weight. RESULTS: Data were normally distributed and showed excellent reliability. A repeated-measures analysis of variance with a Greenhouse-Geisser correction showed an effect of the loading condition on the mean spinal stiffness [F (2.6, 744) = 3.456, p < 0.001]. Vertebrae and loading had no interaction [F (2.6, 741) = 0.656, p = 0.559]. Post hoc tests using Bonferroni correction revealed no changes with 10% loading (p = 1.000), and with every additional step of loading, spinal stiffness decreased: 0% or 10-45% loading (p < 0.001), 0% or 10-80% loading (p < 0.001), and 45-80% (p < 0.001). CONCLUSION: We conclude that a load of ≥ 45% of the participant's body weight can lead to changes in the spinal motor control. An axial load of 10% showed no significant changes. Rehabilitation should include high-axial-load exercise if needed in everyday living.

Influence of Axial Load and a 45-Degree Flexion Head Position on Cervical Spinal Stiffness in Healthy Young Adults.

Background: Neck pain is a major cause of disability worldwide. Poor neck posture such as using a smartphone or work-related additional cervical axial load, such headgear of aviators, can cause neck pain. This study aimed at investigating the role of head posture or additional axial load on spinal stiffness, a proxy measure to assess cervical motor control. Methods: The posterior-to-anterior cervical spinal stiffness of 49 young healthy male military employees [mean (SD) age 20 ± 1 years] was measured in two head positions: neutral and 45-degree flexed head position and two loading conditions: with and without additional 3 kg axial load. Each test condition comprised three trials. Measurements were taken at three cervical locations, i.e., spinous processes C2 and C7 and mid-cervical (MC). Results: Cervical spinal stiffness measurements showed good reliability in all test conditions. There was a significant three-way interaction between location × head position × load [F(2, 576) = 9.305, p < 0.001]. Significant two-way interactions were found between measurement locations × loading [F(2, 576) = 15.688, p < 0.001] and measurement locations × head position [F(2, 576) = 9.263, p < 0.001]. There was no significant interaction between loading × head position [F(1, 576) = 0.692, p = 0.406]. Post hoc analysis showed reduction of stiffness in all three measurement locations in flexion position. There was a decrease in stiffness in C2 with loading, increase in stiffness in C7 and no change in MC. Discussion: A flexed head posture leading to decreased stiffness of the cervical spine might contribute to neck pain, especially if the posture is prolonged and static, such as is the case with smartphone users. Regarding the additional load, stiffness decreased high cervical and increased low cervical. There was no change mid cervical. The lower spinal stiffness at the high cervical spine might be caused by capsular ligament laxity due to the buckling effect. At the lower cervical spine, the buckling effect seems to be less dominant, because the proximity to the ribs and sternum provide additional stiffness.

Microgravity and Hypergravity Induced by Parabolic Flight Differently Affect Lumbar Spinal Stiffness.

The objective of this study was to determine the response of the lumbar spinal motor control in different gravitational conditions. This was accomplished by measuring indicators of lumbar motor control, specifically lumbar spinal stiffness, activity of lumbar extensor and flexor muscles and lumbar curvature, in hypergravity and microgravity during parabolic flights. Three female and five male subjects participated in this study. The mean age was 35.5 years (standard deviation: 8.5 years). Spinal stiffness of the L3 vertebra was measured using impulse response; activity of the erector spinae, multifidi, transversus abdominis, and psoas muscles was recorded using surface electromyography; and lumbar curvature was measured using distance sensors mounted on the back-plate of a full-body harness. An effect of gravity condition on spinal stiffness, activity of all muscles assessed and lumbar curvature (p's < 0.007) was observed (Friedman tests). Post hoc analysis showed a significant reduction in stiffness during hypergravity (p < 0.001) and an increase in stiffness during microgravity (p < 0.001). Activity in all muscles significantly increased during hypergravity (p's < 0.001). During microgravity, the multifidi (p < 0.002) and transversus abdominis (p < 0.001) increased significantly in muscle activity while no significant difference was found for the psoas (p = 0.850) and erector spinae muscles (p = 0.813). Lumbar curvature flattened in hypergravity as well as microgravity, albeit in different ways: during hypergravity, the distance to the skin decreased for the upper (p = 0.016) and the lower sensor (p = 0.036). During microgravity, the upper sensor showed a significant increase (p = 0.016), and the lower showed a decrease (p = 0.005) in distance. This study emphasizes the role of spinal motor control adaptations in changing gravity conditions. Both hypergravity and microgravity lead to changes in spinal motor control. The decrease in spinal stiffness during hypergravity is interpreted as a shift of the axial load from the spine to the pelvis and thoracic cage. In microgravity, activity of the multifidi and of the psoas muscles seems to ensure the integrity of the spine. Swiss (BASEC-NR: 2018-00051)/French "EST-III" (Nr-ID-RCB: 2018-A011294-51/Nr-CPP: 18.06.09).

Preoperative exercise in patients undergoing total knee arthroplasty: a pilot randomized controlled trial.

BACKGROUND: The purpose of this study was to assess the effect of preoperative physiotherapy (PT) on functional, subjective and socio-economic parameters after total knee arthroplasty (TKA). METHODS: 20 patients (mean ± SD: age 67 ± 7 years) scheduled for TKA at Balgrist University Hospital between July 2016 and March 2017 were randomly assigned to a control (CG) or intervention (IG) group. 3 to 4 weeks prior to surgery the IG completed 5 to 9 sessions of PT containing proprioceptive neuromuscular facilitation (PNF) techniques, endurance training and individually indicated interventions. Measurements were executed at baseline, preoperative and 3 months after TKA. The primary outcome measure was the Stair Climbing Test (SCT), secondary outcome measures were the knee range of motion (ROM) and the level of physical activity using Lysholm Score (LS) and Tegner Activity Scale (TAS). The subjective and socio-economic parameters were the Patients' Global Impression of Change (PGIC) scale, inpatient rehabilitation time, preoperative pain levels and metabolic equivalent (MET), postoperative intake of analgesics and overall costs. RESULTS: No difference between IG and CG was found for SCT (F (2/36) = 0.016, p = 0.984, η2 = 0.004). An interaction between group and time was shown for TAS (F (18/1) = 13.890) with an increase in the IG (p = 0.002, η2 = 0.536). The sub-item "pain" within the LS presented a higher pain-level in CG (F (18/1) = 4.490, p = 0.048, η2 = 0.974), while IG showed a higher preoperative MET compared to CG (p = 0.035). There were no other significant changes. The CG produced 21.4% higher overall costs, took more analgesics and showed higher preoperative pain levels than the IG. CONCLUSIONS: Findings show that preoperative therapy improved the level of physical activity before and after TKA and resulted in a clinically relevant gain in TAS. TRIAL REGISTRATION: ClinicalTrials.gov Identifier; NCT03160534. Registered 19 May 2017.

Exergaming With Integrated Head Turn Tasks Improves Compensatory Saccade Pattern in Some Patients With Chronic Peripheral Unilateral Vestibular Hypofunction.

Background: This study aimed to determine whether vestibular rehabilitation using active video games (Exergames), including promoted head turns and unsupported locomotion, may facilitate vestibular compensation and gait in subjects with one-sided chronic peripheral vestibular hypofunction (cPVH). Methods: 12 patients with cPVH (mean age of 65 ± 12 years, 8 male) were recruited for this study. The study consisted of a four-week baseline control period T1-T2 followed by a four-week intervention period T2-T3. The intervention included exergames that required physical tasks such as steps, weight shifts or balance control to cognitive challenges, in a virtual environment to play the game. The subjects participated in a total of 176 min of exergaming in eight sessions. Because of the changing projection direction of the game to the wall, the subjects had to turn their heads constantly while playing the game. Dynamic visual acuity (DVA) was assessed. Vestibulo-Ocular reflex (VOR) gain deficit and cumulative overt saccade amplitude (COSA) were measured with the video head-impulse test. Additionally, the functional gait assessment (FGA), Extended Timed Get-Up-and-Go (ETGUG), and the Dizziness handicap inventory (DHI), were assessed. Results: DVA showed no significant group level change (p = 0.475, z = -0.714, d = 0.295) with a small effect size and improvements in five out of 12 subjects. Ipsilesional VOR gain did not improve (p = 0.157, z = -1.414, d = 0.481) on group level while there was an intermediate effect size and improvements in six out of 12 subjects. COSA got significant smaller (p = 0.006, z = -2.746, d = 1.354) with improvements in seven out of 12 subjects. The contralesional sides did not change. The FGA for the group significantly improved with an intermediate effect size (p < 0.001, z = -3.08, d = 1.617) and five individuals showed clinically relevant improvements. The ETGUG group value improved significantly with a strong effect size (p < 0.001, z = -2.67, d = 1.030), with seven individuals contributing to this change. The DHI showed no change (p = 0.172, z = -1.381, d = 0.592) neither on the group nor on the individuals' level. The game scores of the subjects improved during the intervention period of the intervention for every game. Conclusion: The results of this study demonstrate that exergaming with promoted head turns facilitates vestibular compensation in some subjects with cPVH. This is the first study that shows an improvement in cumulative overt saccade amplitude after exergaming in chronic vestibular subjects.

Influence of body position and axial load on spinal stiffness in healthy young adults.

PURPOSE: This study aimed at investigating the effects of different body positions and axial loads on spinal stiffness to better understand spinal stabilisation mechanisms. METHODS: The posterior-to-anterior lumbar and thoracic spinal stiffness of 100 young healthy adults (mean age 23 years; 50 females) were measured in three test situations: prone, standing and standing while carrying a load equal to 50% of the subject's body weight. Each test situation comprised three trials. RESULTS: Spinal stiffness in all test situations showed good reliability. Repeated measures analysis of covariance showed significantly higher spinal stiffness in standing than in the prone position [F(1/1694) = 433.630, p < 0.001]. However, spinal stiffness was significantly lower when standing while carrying a load of 50% of the body weight than when standing without additional load [F(1/1494) = 754.358, p < 0.001]. CONCLUSION: This study showed that spinal lumbar and thoracic stiffness increases when body position is changed from prone to standing. Additional axial load of 50% of the subject's body weight results in reduced spinal stiffness during standing. These slides can be retrieved under Electronic Supplementary Material.

Cervical Spine Disability in Correlation with Subjective Voice Handicap in Patients With Voice Disorders: A Retrospective Analysis.

OBJECTIVE: Neck muscle dysfunction has been considered as risk factor or consequence of voice disorders. This study investigates the correlation between neck and voice-related subjective symptoms in patients with voice disorders. STUDY DESIGN: Retrospective case-control study. METHODS: 100 adult patients (59 female and 41 male) over 18 years with a mean age of 50.01 years (SD 16, range 24-87), of which 68 were under 60 years, were included. 50 patients had organic voice pathologies and 50 functional dysphonia. Outcome measures were the Voice Handicap Index 9 international (VHI-9i) and the Neck Disability Index (NDI-G). Spearman rank order coefficient was applied to determine the correlation between overall and single item VHI and NDI results. Subanalyses were done for functional vs. organic disorder, gender and age ± 60 years. RESULTS: Mean overall VHI-9i (13.93, SD = 7.81, range = 0-31) and mean NDI-G (6.07, SD = 7.71, range = 0-43) showed a significant mild correlation (rs = 0.220, P = 0.02). Split into subgroups the relation was stronger in patients with organic pathologies (rs = 0.297, P = 0.03), but not significant in functional disorders (r = 0.148, P = 0.30). There was a moderate relation in men (rs = 0.317, P = 0.04). Single item correlation was highest between VHI-9i item P4 (physiological) and NDI-G item reading (cognitive functioning) (rs = 0.480, P = 0.002). CONCLUSION: Specifically patients with organic voice disorders showed increased voice symptoms with the presence of neck dysfunction. This indicates a risk for a functional imbalance of the muscles surrounding the larynx, which in extreme cases may hinder functional voice rehabilitation even after phonosurgery. Therefore, neck dysfunction should be considered in voice diagnostics.