Search

CC-BY Applied Ergonomics, 2021, March https://www.journals.elsevier.com/applied-ergonomics Purpose: To analyze progression of changes in kinematics and work physiology during progressive lifting in healthy adults.Methods: Healthy participants were recruited. A standardized lifting test from the WorkWell Functional Capacity Evaluation (FCE) was administered, with five progressive lifting low series of five repetitions. The criteria of the WorkWell observation protocol were studied: changes in muscle use (EMG), heart rate (heart rate monitor), base of support, posture and movement pattern (motion capture system). Repeated measures ANOVA’s were used to analyze changes during progressive workloads.Results: 18 healthy young adults participated (8 men, 10 women; mean age 22 years). Mean maximum weight lifted was 66 (±3.2) and 44 (±7.4) kg for men and women, respectively. With progressive loads, statistically significant (p < 0.01) differences were observed: increase in secondary muscle use at moderate lifting, increase of heart rate, increase of base of support and movement pattern changes were observed; differences in posture were not significant.Conclusions: Changes in 4 out of 5 kinematic and work physiology parameters were objectively quantified using lab technology during progressive lifting in healthy adults. These changes appear in line with existing observation criteria.

BACKGROUND: Many patients visiting physiotherapists for musculoskeletal disorders face psychosocial challenges which may form a large barrier to recover. There are only a limited number of evidence based psychosocial therapies, but they are mainly based on breathing exercises.OBJECTIVE: to study which respiration frequency would lead to the highest relaxation, reflected in vagal tone derived from the heart rate variability (HRV) in healthy subjects.METHODS: A randomized controlled cross sectional study was performed. Respiration cycles of four, five, six, seven and eight breaths per minute (BPM) were delivered in randomized order for two minutes each. HRV metrics were measured during the sessions with electrocardiogram (ECG). Repeated Measures ANOVA's were performed to analyze differences between breathing frequencies.RESULTS: 100 healthy volunteers were included (40 male). Standard Deviation of inter beat intervals (SDNN) values were significantly highest at 5 BPM, whereas the Root Mean Square of Successive Differences (RMSSD) values appeared highest at 7 breaths per minute (p < 0.01). High Frequency (HF) power was lowest at 4 BPM, whereas Low Frequency (LF) power was not significantly influenced by respiration frequency.CONCLUSIONS: Breathing at a frequency of 5 to 7 breaths per minute leads to highest HRV values, but there is no single respiration ratio that maximizes all metrics. Physiotherapists may use five to seven BPM as guidance to determine ideal breathing frequencies.

Duchenne muscular dystrophy (DMD) is a genetic disorder that results in progressive muscular degeneration. Although medical advances increased their life expectancy, DMD individuals are still highly dependent on caregivers. Hand/wrist function is central for providing independence and robotic exoskeletons are good candidates for effectively compensating for deteriorating functionality. Robotic hand exoskeletons require the accurate decoding of motor intention, typically via surface electromyography (sEMG). Traditional low-density sEMG was used in the past to explore the muscular activations of individuals with DMD, however it cannot provide high spatial resolution. This study characterized for the first time, the forearm high-density electromyograms of three individuals with DMD while performing seven hand/wrist related tasks and compared them to eight healthy individuals (all data available online). We looked into the spatial distribution of HD-sEMG patterns by using principal component analysis (PCA), and also assessed the repeatability and the amplitude distributions of muscle activity. Additionally, we used a machine learning approach, to assess DMD individuals’ potentials for myocontrol. Our analysis showed that although participants with DMD were able to repeat similar HD-sEMG patterns across gestures (similarly to healthy participants), a fewer number of electrodes was activated during their gestures compared to the healthy participants. Additionally, participants with DMD activated their muscles close to maximal contraction level (0.63±0.23) whereas healthy participants had lower normalized activations (0.26±0.2). Lastly, participants with DMD showed on average fewer principal components (3) explaining 90% of the complete gesture space than the healthy (5). However, the ability of the DMD participants to produce repeatable HD-sEMG patterns was unexpectedly comparable to that of healthy participants and the same holds true for their offline myocontrol performance, disproving our hypothesis and suggesting a clear potential for the myocontrol of wearable exoskeletons. Our findings present evidence for the first time, on how DMD lead to progressive alterations in hand/wrist motor control in DMD individuals compared to healthy. The better understanding of these alterations can lead to further developments for the intuitive and robust myoelectric control of active hand exoskeletons for individuals with DMD.

Background The aim of this study was to test the inter- and intrarater reliability and the concurrent validity of the Gyko Microgate for the assessment of lumbar range of motion. Methods A cross-sectional study was carried out with two groups of healthy participants. The first group, consisting of 91 subjects, was tested to determine the inter- and intrarater reliability. Concurrent validity was assessed with comparisons with an optical motion system (Vicon) in a second group of 20 subjects. Lumbar range of motion in flexion, extension, left and right lateral flexion were performed. Intraclass correlation coefficient (ICC) was calculated for both analyses. Measurement error was calculated with standard error of the measurement (SEM), smallest detectable change (SDC) and Limits of Agreement (LoA). ICCs were considered good when ICC ≥0.80 and excellent with ICC ≥0.90. Results Interrater reliability was good to excellent with ICCs ranging from 0.82 to 0.94. Intrarater reliability was good to excellent with ICCs ranging from 0.84 to 0.95. Concurrent validity was excellent with ICCs varying from 0.90 to 0.95. LoA were highest in interrater reliability and smallest in concurrent validity. SEM ranged from 2.2 to 4.0° in lateral flexion left and flexion respectively. SDC varied from 6.1 to 11.1°. Conclusion Gyko has good inter- and intrarater reliability and excellent concurrent validity compared to the optical motion system for lumbar range of motion. Gyko may be considered as objective measure to measure range of motion for clinical purposes, however trials with patients are currently lacking.

Duchenne muscular Dystrophy (DMD) is a progressive degenerative muscle disease, affecting, among others, the upper extremities. Effective hand rehabilitation can improve the hand function of people with DMD. To reach this goal, we first need to gain more insight into the hand cognitive-motor performance of people with DMD. This is the first study employing a systematic analysis on multi-finger, cognitive-motor performance of people with DMD. For this purpose, we propose an active dynamic visuo-motor task. The task employed six visual stimuli, a subset of which was activated at each trial. The stimuli were activated with a frequency of 1, 2, 3 and 4 Hz. Eight healthy participants and three participants with DMD performed the task. Additionally, the healthy participants performed seven sessions, and we assessed the training effects. Task-related cognitive-motor performance was evaluated using information transfer rate (ITR) and perceived workload. Regarding ITR, healthy participants performed significantly better than DMD participants; however, this was more evident for trials involving more than three fingers. Workload showed no difference between the healthy and the DMD groups. Healthy participants significantly improved their performance during training. Our results suggest that hand rehabilitation of people with DMD should consider multi-finger dynamic training. However, additional research with more people with DMD is needed for further generalization of our conclusions.

Contains fulltext : 196887.pdf (Publisher’s version ) (Open Access) The human hand is important for the performance of activities of daily living which are directly related to quality of life. Various conditions, such as Duchenne muscular dystrophy (DMD) can affect the function of the human hand and wrist. The ability to assess the impairment in the hand and the wrist by measuring the range of motion (ROM), is essential for the development of effective rehabilitation protocols. Currently the clinical standard is the goniometer. In this study we explore the feasibility and reliability of an optical sensor (Leap motion sensor) in measuring active hand/wrist ROM. We measured the hand/wrist ROM of 20 healthy adults with the goniometer and the Leap motion sensor, in order to check the agreement between the two methods and additionally, we performed a test-retest of the Leap motion sensor with 12 of them, to assess its reliability. The results suggest low agreement between the goniometer and the leap motion sensor, yet showing a large decrease in measurement time and high reliability when using the later. Despite the low agreement between the two methods, we believe that the Leap motion sensor shows potential to contribute to the development of hand rehabilitation protocols and be used with patients in a clinical setting.

Item does not contain fulltext OBJECTIVE: To evaluate the construct validity and interrater reliability of 4 simple antigravity tests in a small group of patients with facioscapulohumeral muscular dystrophy (FSHD). DESIGN: Case-control study. SETTING: University medical center. PARTICIPANTS: Patients with various severity levels of FSHD (n=9) and healthy control subjects (n=10) were included (N=19). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: A 4-point ordinal scale was designed to grade performance on the following 4 antigravity tests: sit to stance, stance to sit, step up, and step down. In addition, the 6-minute walk test, 10-m walking test, Berg Balance Scale, and timed Up and Go test were administered as conventional tests. Construct validity was determined by linear regression analysis using the Clinical Severity Score (CSS) as the dependent variable. Interrater agreement was tested using a kappa analysis. RESULTS: Patients with FSHD performed worse on all 4 antigravity tests compared with the controls. Stronger correlations were found within than between test categories (antigravity vs conventional). The antigravity tests revealed the highest explained variance with regard to the CSS (R(2)=.86, P=.014). Interrater agreement was generally good. CONCLUSIONS: The results of this exploratory study support the construct validity and interrater reliability of the proposed antigravity tests for the assessment of functional capacity in patients with FSHD taking into account the use of compensatory strategies. Future research should further validate these results in a larger sample of patients with FSHD.

Item does not contain fulltext To better understand postural and movement disabilities, the pattern of total body muscle fat infiltration was analyzed in a large group of patients with facioscapulohumeral muscular dystrophy. Additionally, we studied whether residual D4Z4 repeat array length adjusted for age and gender could predict the degree of muscle involvement. Total body computed tomography scans of 70 patients were used to assess the degree of fat infiltration of 42 muscles from neck to ankle level on a semi-quantitative scale. Groups of muscles that highly correlated regarding fat infiltration were identified using factor analysis. Linear regression analysis was performed using muscle fat infiltration as the dependent variable and D4Z4 repeat length and age as independent variables. A pattern of muscle fat infiltration in facioscapulohumeral muscular dystrophy could be constructed. Trunk muscles were most frequently affected. Of these, back extensors were more frequently affected than previously reported. Asymmetry in muscle involvement was seen in 45% of the muscles that were infiltrated with fat. The right-sided upper extremity showed significantly higher scores for fat infiltration compared to the left side, which could not be explained by handedness. It was possible to explain 29% of the fat infiltration based on D4Z4 repeat length, corrected for age and gender. Based on our results we conclude that frequent involvement of fat infiltration in back extensors, in addition to the abdominal muscles, emphasizes the extent of trunk involvement, which may have a profound impact on postural control even in otherwise mildly affected patients.

Item does not contain fulltext BACKGROUND: Although it is known that muscle weakness is a major cause of postural instability and leads to an increased incidence of falls in patients with neuromuscular disease, the relative contribution of lower extremity and trunk muscle weakness to postural instability has not been studied well. METHODS: We determined the relationship between muscle fatty infiltration and sagittal-plane balance in ten patients with facioscapulohumeral muscular dystrophy. Sagittal-plane platform translations were imposed in forward and backward directions on patients with facioscapulohumeral muscular dystrophy and healthy controls. Stepping thresholds were determined and kinematic responses and center-of-mass displacements were assessed using 3 dimensional motion analysis. In the patients, magnetic resonance imaging was used to determine the amount of fatty infiltration of trunk and lower extremity muscles. FINDINGS: Stepping thresholds in both directions were decreased in patients compared to controls. In patients, significant correlations were found for fatty infiltration of ventral muscles with backward stepping threshold and for fatty infiltration of dorsal muscles with forward stepping threshold. Fatty infiltration of the rectus abdominis and the back extensors explained the largest part of the variance in backward and forward stepping thresholds, respectively. Center-of-mass displacements were dependent on intensity and direction of perturbation. Kinematic analysis revealed predominant ankle strategies, except in patients with lumbar hyperlordosis. INTERPRETATION: These findings indicate that trunk muscle involvement is most critical for loss of sagittal-plane postural balance in patients with facioscapulohumeral muscular dystrophy. This insight may help to develop rehabilitation strategies to prevent these patients from falling.

The aim of this pilot study was to investigate the effects of an intervention consisting of mental coaching combined with either electro encephalogram (EEG) alpha power feedback or heart rate variability (HRV) feedback on HRV, EEG outcomes and self-reported factors related to stress, performance, recovery and sleep quality in elite athletes. A prospective pilot study was performed with two distinct cohorts. Soccer players were provided with four sessions of mental coaching combined with daily HRV biofeedback (Group A); track and field athletes were provided with four sessions of mental coaching in combination with daily neurofeedback (Group B). Measurements were performed at baseline, post intervention and at 5 weeks follow-up. Objective measures: EEG and ECG. Subjective measures: Numeric Rating Scale for performance, Pittsburgh Sleep Quality Index, Rest and Stress Questionnaire and Sports Improvement-60. Group characteristics were too distinct to compare the interventions. Linear mixed models were used to analyze differences within groups over time. In Group A, significant changes over time were present in alpha power at 5 of 7 EEG locations (p

Mechanically well-defined stabilization systems have only recently become available, providing standardized conditions for studying the role of the mechanical environment on mouse bone fracture healing. The aim of this study was to characterize the time course of strength recovery and callus development of mouse femoral osteotomies stabilized with either low or high flexibility (in bending and torsion) internal fixation plates. Animals were euthanized and femora excised at 14, 21, and 28 days post-osteotomy for microCT analysis and torsional strength testing. While a larger mineralized callus was observed in osteotomies under more flexible conditions at all time points, the earlier bridging of the mineralized callus under less flexible conditions by 1 week resulted in an earlier recovery of torsional strength in mice stabilized with low flexibility fixation. Ultimate torque values for these bones were significantly higher at 14 and 21 days post-osteotomy compared to bones with the more flexible stabilization. Our study confirms the high reproducibility of the results that are achieved with this new implant system, therefore making it ideal for studying the influence of the mechanical environment on murine fracture healing under highly standardized conditions.

Item does not contain fulltext Patients with FSHD suffer from progressive skeletal muscle weakness, which is associated with an elevated fall risk. To obtain insight into fall mechanisms in this patient group, we aimed to assess dynamic stability during level walking and obstacle crossing in patients at different disease stages. Ten patients with at least some lower extremity weakness were included, of whom six were classified as moderately affected and four as mildly affected. Ten healthy controls were also included. Level walking at comfortable speed was assessed, as well as crossing a 10cm high wooden obstacle. We assessed forward and lateral dynamic stability, as well as spatiotemporal and kinematics variables. During level walking, the moderately affected group demonstrated a lower walking speed, which was accompanied by longer step times and smaller step lengths, yet dynamic stability was unaffected. When crossing the obstacle, however, the moderately affected patients demonstrated reduced forward stability margins during the trailing step, which was accompanied by an increased toe clearance and greater trunk and hip flexion. This suggests that during level walking, the patients effectively utilized compensatory strategies for maintaining dynamic stability, but that the moderately affected group lacked the capacity to fully compensate for the greater stability demands imposed by obstacle crossing, rendering them unable to maintain optimal stability levels. The present results highlight the difficulties that FSHD patients experience in performing this common activity of daily living and may help explain their propensity to fall in the forward direction.

Item does not contain fulltext Facioscapulohumeral muscular dystrophy is a slowly progressive hereditary disorder resulting in fatty infiltration of eventually most skeletal muscles. Weakness of trunk and leg muscles causes problems with postural balance and gait, and is associated with an increased fall risk. Although drop foot and related tripping are common problems in FSHD, gait impairments are poorly documented. The effect of ankle plantarflexor involvement on gait propulsion has never been addressed. In addition to ankle plantarflexion, gait propulsion is generated through hip flexion and hip extension. Compensatory shifts between these propulsion sources occur when specific muscles are affected. Such a shift may be expected in patients with FSHD since the calves may show early fatty infiltration, whereas iliopsoas and gluteus maximus muscles are often spared for a longer time. In the current study, magnetic resonance imaging was used to assess the percentage of unaffected calf, iliopsoas and gluteus maximus muscles. Joint powers were analyzed in 10 patients with FSHD at comfortable and maximum walking speed to determine the contribution of ankle plantarflexor, hip flexor and hip extensor power to propulsion. Associations between muscle morphology, power generation and gait speed were assessed. Based on multivariate regression analysis, ankle plantarflexor power was the only factor that uniquely contributed to the explained variance of comfortable (R(2)=80%) and maximum (R(2)=86%) walking speed. Although the iliopsoas muscles were largely unaffected, they appeared to be sub-maximally recruited. This submaximal recruitment may be related to poor trunk stability, resulting in a disproportionate effect of calf muscle affliction on gait speed in patients with FSHD.

Item does not contain fulltext Objectives: To investigate whether spinal cord stimulation (SCS) has a negative effect on static balance and gait, which is implicated by the increased incidence of falls leading to frequently occurring lead migrations. Materials and Methods: A controlled trial is performed with 11 subjects (four female, seven male) with a mean age of 46 years old. A baseline measurement consisting of static balance and gait tests was performed. Within two weeks after implantation of a spinal cord stimulator, subjects performed the same tests with both stimulation switched on and off. Static balance was assessed with eyes open and eyes closed on hard surface and foam surface. The velocity of the center of pressure and weight symmetry were the main outcome parameters. Kinematics and spatiotemporal outcome parameters were used to analyze gait. ANOVAs were used to compare between baseline, stimulation on, and stimulation off. Results: Spinal cord stimulation resulted in significant pain relief as scored on a Visual Analog Scale (p < 0.001). Gait width decreased and this change (indicative of improvement in balance) was significant (p = 0.007). No other significant group differences were found between stimulation baseline and post-surgery measurements. SCS did not influence static balance or gait when group effects were analyzed. Four subjects showed significant differences in static balance between stimulation on and off. Conclusions: The lack of group differences in normal gait and static balance cannot explain the increased incidence of falls. However, four subjects showed an effect of SCS on static balance. Further research to clarify why only a part of the subjects experienced balance problems is recommended and assessments of more demanding balance and gait tasks are desirable. 01 mei 2013