Normally, when the patient's functional recovery involves partial weight-bearing aided walking using forearm crutches, it is not possible to control the amount of weight-bearing objectively that the individuals carry out and its progression. This leads to significant errors in accuracy and, consequently, complications and after effects in pathologies. To compensate for this deficiency, we have set out to design and validate a measurement system and a computerized record of the loads exerted on Canadian crutches in aided walking as well as incorporating a mechanism for acoustic and visual biofeedback that will inform the subject if said charges are correct, so that they are able correct their errors and avoid problems in their recovery. We analyzed the validity and reliability of the system through a concordance study with the AMTI OR6-7-2000 force plate, extensively validated previously, while finding a correlation coefficient of 0.99 with a significance (p<0.001). We have designed and developed a measurement system with a computerized record, analysis and wireless graphical display of real-time data, incorporating a mechanism for acoustic and visual biofeedback to measure the loads exerted on forearm crutches during aided walking. The device, called "GCH System 1.0" is a reliable and valid instrument.
This work had the objective to analyze the values of the vertical and anteroposterior components of the ground reaction force (GRF) during the aquatic gait and the influence of the speed and the upper limb position on the GRF components values.
Sixty subjects, with average height between 1.6 and 1.85m and average age of 23 years, were divided in three groups according to the immersion level. The citizens walked over a walking platform, which had two force plates attached. The platform was located at a depth of 1.3m. The subjects walked over the platform in four different situations, with speed and upper limb position variations. For data analysis, descriptive and inferential statistics were used.
For the vertical component, the force values varied between 20% and 40% of the subjects' body weight according to the different data collection situations. For the anteroposterior component, the force values reached between 8% and 20% of the subjects' body weight corporal, also according with the data collection situation. INTERPRETATION (DISCUSSION): It was noted that for a given immersion level, the forces can vary according to the request that is imposed to the aquatic gait. It was concluded that either the speed as well as the position of the upper limb influence the values of the GRF components. An increase in the gait speed causes increase of the anteroposterior component (Fx), while an increase in the corporal mass out of the water causes increase mainly of the vertical component (Fy). Knowing the value of these alterations is important for the professional who prescribes activities in aquatic environment.
Physical performance measures predict health and function in older populations. Walking speed in particular has consistently predicted morbidity and mortality. However, single brief walking measures may not reflect a person's typical ability. Using a system that unobtrusively and continuously measures walking activity in a person's home we examined walking speed metrics and their relation to function. In 76 persons living independently (mean age, 86) we measured every instance of walking past a line of passive infra-red motion sensors placed strategically in their home during a four-week period surrounding their annual clinical evaluation. Walking speeds and the variance in these measures were calculated and compared to conventional measures of gait, motor function and cognition. Median number of walks per day was 18±15. Overall mean walking speed was 61±17 cm/s. Characteristic fast walking speed was 96 cm/s. Men walked as frequently and fast as women. Those using a walking aid walked significantly slower and with greater variability. Morning speeds were significantly faster than afternoon/evening speeds. In-home walking speeds were significantly associated with several neuropsychological tests as well as tests of motor performance. Unobtrusive home walking assessments are ecologically valid measures of walking function. They provide previously unattainable metrics (periodicity, variability, range of minimum and maximum speeds) of everyday motor function.
A basic aspect of the neuronal control of quadrupedal locomotion of cat and of bipedal stance and gait of humans concerns the antigravity function of leg extensors. In humans proprioceptive reflexes involved in the maintenance of body equilibrium depend on the presence of contact forces opposing gravity. Extensor load receptors are thought to signal changes of the projection of body's centre of mass with respect to the feet. According to observations in the cat, this afferent input probably arises from Golgi tendon organs and represents a newly discovered function of these receptors in the regulation of stance and gait. From these experiments it can be concluded that during locomotion there is a closing of Ib inhibitory and an opening of Ib extensor facilitatory paths. In humans evidence for a significant contribution of load receptor contribution to the leg muscle activation came from immersion experiments. Compensatory leg muscle activation depends on the actual body weight. Also during gait the strength of leg extensor activation during the stance phase is load dependent. In patients with Parkinson's disease there is a reduced load sensitivity and decreased leg extensor activation, which might contribute to the movement disorder. Recent experiments in paraplegic patients show that the beneficial effects of a locomotor training critically depends on the initial degree of body unloading and reloading during the course of the training period.
Standard gait analysis reports knee joint rotations in the three anatomical planes without addressing their different levels of reliability. Most clinical studies also restrict analysis to knee flexion-extension, because knee abduction-adduction and axial rotation are small with respect to the corresponding amount of measurement artefact. This study analyses a set of 11 motor tasks, in order to identify those that are adequately repeatable and that can induce greater motion at the knee than walking. Ten volunteers (mean ± SD age: 29 ± 9 years) each underwent three motion analysis sessions on different days with a standard gait analysis system and protocol. In each session they performed normal walking, walking with sidestep and crossover turns, ascent onto and descent off a step, descent with sidestep and crossover turns, chair rise, mild and deep squats, and lunge. Range and repeatability of motions in the three anatomical planes were compared by ANOVA. The sidestep turns showed a range of axial rotation significantly larger than that in walking (about 8°), while maintaining similar levels of repeatability. Ascent, chair rise, squat, and lunge showed greater flexion ranges than walking; among these, ascent was the most repeatable. The results show that turning increases knee axial rotation in young subjects significantly. Further, squats and lunges, currently of large interest in orthopaedics and sports research, have smaller repeatability, likely accounted for to the smaller constraints than in the traditional motor tasks.
Analysis of pedobarographical data requires geometric identification of specific anatomical areas extracted from recorded plantar pressures. This approach has led to ambiguity in measurements that may underlie the inconsistency of conclusions reported in pedobarographical studies. The goal of this study was to design a new analysis method less susceptible to the projection accuracy of anthropometric points and distance estimation, based on rarely used spatio-temporal indices. Six pedobarographic records per person (three per foot) from a group of 60 children aged 11-12 years were obtained and analyzed. The basis of the analysis was a mutual relationship between two spatio-temporal indices created by excursion of the peak pressure point and the center-of-pressure point on the dynamic pedobarogram. Classification of weight-shift patterns was elaborated and performed, and their frequencies of occurrence were assessed. This new method allows an assessment of body weight shift through the plantar pressure surface based on distribution analysis of spatio-temporal indices not affected by the shape of this surface. Analysis of the distribution of the created index confirmed the existence of typical ways of weight shifting through the plantar surface of the foot during gait, as well as large variability of the intrasubject occurrence. This method may serve as the basis for interpretation of foot functional features and may extend the clinical usefulness of pedobarography.
The aim of this study was to acquire static and dynamic foot geometry and loading in childhood, and to establish data for age groups of a population of 1-13 year old infants and children. A total of 10,382 children were recruited and 7788 children (48% males and 52% females) were finally included into the data analysis. For static foot geometry foot length and foot width were quantified in a standing position. Dynamic foot geometry and loading were assessed during walking on a walkway with self selected speed (Novel Emed X, 100Hz, 4 sensors/cm(2)). Contact area (CA), peak pressure (PP), force time integral (FTI) and the arch index were calculated for the total, fore-, mid- and hindfoot. Results show that most static and dynamic foot characteristics change continuously during growth and maturation. Static foot length and width increased with age from 13.1±0.8cm (length) and 5.7±0.4cm (width) in the youngest to 24.4±1.5cm (length) and 8.9±0.6cm (width) in the oldest. A mean walking velocity of 0.94±0.25m/s was observed. Arch-index ranged from 0.32±0.04 [a.u.] in the one-year old to 0.21±0.13 [a.u.] in the 5-year olds and remains constant afterwards. This study provides data for static and dynamic foot characteristics in children based on a cohort of 7788 subjects. Static and dynamic foot measures change differently during growth and maturation. Dynamic foot measurements provide additional information about the children's foot compared to static measures.
In the last years it has become possible to regain some locomotor activity in patients suffering from an incomplete spinal cord injury (SCI) through intense training on a treadmill. The ideas behind this approach owe much to insights derived from animal studies. Many studies showed that cats with complete spinal cord transection can recover locomotor function. These observations were at the basis of the concept of the central pattern generator (CPG) located at spinal level. The evidence for such a spinal CPG in cats and primates (including man) is reviewed in part 1, with special emphasis on some very recent developments which support the view that there is a human spinal CPG for locomotion. Copyright 1997 Elsevier Science B.V.
Lower limb rotational profile in children may cause great concern to parents and relatives. In order to give parents clear information, there is a need for referential studies giving normative data of lower limb rotational profile and its normal changes expected over growth. Our aim was to collect a large clinical series of healthy children, out of a clinic, selected from a non-consulting population and to analyse Tibial Torsion and Femoral Anteversion according to age and gender. One thousand three hundred and nineteen healthy children underwent a clinical evaluation. Tibial Torsion was assessed using the method described by Staheli and Engel, whereas Femoral Anteversion was assessed using the method described by Netter. Our results showed that there was a significant difference between males and females in Femoral Anteversion, whereas there was no significant difference between the right side and the left side. Femoral Anteversion was higher in females, and was markedly correlated with age in both genders. There was no significant difference between males and females in Tibial Torsion, nor significant difference between the right side and the left side. Tibial Torsion was slightly correlated with age in both genders. Normative data were statistically defined in this work using the +/-2S.D. range. To our knowledge, there is no large and comprehensive series in the English speaking literature that gives normative data of Femoral Anteversion. Concerning Tibial Torsion, our results compared to those published in the literature.
The purpose of this study was to use three-dimensional gait analysis to describe the gait status of adults with spastic diplegia who underwent selective dorsal rhizotomy (SDR) in childhood. Outcome measures were the gait deviation index (GDI), non-dimensional temporal-distance parameters, and kinematics of the lower limbs. A total of 31 adults with spastic diplegia who had previously undergone SDR were eligible and participated in current study (SDR group). These participants had a median age of 26.8 years (range 21-44 years) with a mean time between surgery and assessment of 21.2±2.9 years (range 17-26 years). For comparison purposes, 43 typically developed adults also participated (CONTROL group), with a median age of 28.3 years (range 21-45 years). More than 17 years after SDR 58% of the SDR group showed improved GMFCS levels, while none of them deteriorated. The participants in the SDR group walked with a mild crouch gait, although there was a loading response, adequate swing-phase knee flexion, adequate swing-phase plantarflexion, reasonable speed and cadence. The gait status of the SDR group more than 17 years after SDR was similar to what has been reported in short-term follow-up studies, as well as our earlier 20 year follow-up study that did not include 3D gait analysis. Appropriate orthopaedic intervention was required in 61% of the study cohort. Whether the types and numbers of orthopaedic interventions are positively affected by SDR remains an open question. Further studies examining this question are warranted. In addition, long-term follow-up studies focused on other interventions would also be of clinical relevance.
Standing turns are associated with an increased risk for falls and fall-related injuries in the elderly. The purpose of this study was to test the (null) hypothesis that age has no effect on the kinematics of the 180 degrees turn. Ten young and 10 older healthy women were asked to complete a series of 180 degrees turns in a standing posture after picking up a light bowl with both hands. Foot-ground reactions, insole pressures and body segment kinematics were recorded in 62 trials at 100 Hz. Turning strategies were analyzed for effects of both age and turn direction on linear and angular foot kinematics, as well as pelvic axial rotation. The older women (OW) used a preparatory stepping strategy more often (170%, p < 0.002), and employed a lower average pelvic rotation rate (21%, p < 0.011) than the younger controls. The minimum foot separation distance for OW was less in their non-preferred than in their preferred turn direction (29%, p < 0.038), thereby increasing their risk of foot-foot interference and falling when turning in their non-preferred direction. The older women were more variable in their turn execution, particularly in minimum foot separation distance (55%, p < 0.022) and the maximum rate of pelvic rotation (82%, p < 0.035). Despite the fact that these healthy older women were careful to employ a preparatory stepping strategy and slower average rotational velocities, they were also more variable in their turn execution than the young.
In order to determine the influence of somatosensory impairments, due to the loss of large myelinated fibres, on the postural stability of Charcot-Marie-Tooth 1A (CMT) patients, a cross-sectional balance assessment was done. Nine CMT patients were compared with eight patients with a distal type of Spinal Muscular Atrophy (SMA), and 11 healthy control subjects. The balance assessment consisted of four tasks: quiet barefoot standing on a stable versus compliant surface, with eyes opened or closed. Force plate signals were used to calculate the velocity of the centre of pressure of the ground reaction forces. The patients' distal muscle force (MRC scale), vibration detection threshold (Rydel-Seiffer tuning fork) and superficial tactile sensation (Semmes-Weinstein monofilaments) were clinically assessed. Compared to the healthy subjects, postural stability of both patient groups was seriously impaired, however, increased visual dependency was only found in the CMT patients. The postural instability of the CMT patients correlated significantly with decreased vibration sense only. The strength of the correlation increased with task complexity. It is concluded that somatosensory deficits substantially contribute to impaired postural stability and increased visual dependency in CMT patients.
The growing popularity of endurance sports activities is associated with a growing number of metatarsal stress fractures in recreational runners. Excessive foot loading has been suggested as a potential cause for these problems [Bennell, K, Matheson G, Meeuwisse W, Brukner P. Risk factors for stress fractures. Sports Med 1999;28(2):91-122]. Therefore, the question arises whether long distance running affects foot loading characteristics like ground reaction forces and peak pressure in specific areas of the foot.
To investigate the effects of long distance running on plantar pressure patterns before and after a marathon race.
Repeated measurements of recreational runners before and after a marathon race.
Two hundred participants of the third Muenster marathon, 2004, were measured before and after the race with plantar pressure measurements during barefoot walking on a capacitive platform. The ratio between forefoot and toe loading was calculated to assess a suggested loading shift between these areas.
The results of the whole group of participants revealed a significant difference in foot loading characteristics before and after the race. Post-race peak pressure and impulse values were higher in the forefoot regions and reduced under the toes.
The increased peak pressure under the metatarsal heads after the race indicates a load shift from the toes to the metatarsal heads. This suggests an increased loading of the metatarsal bones and could explain the increased incidence of metatarsal stress fractures in long distance runners.
The purpose of this study was to evaluate the test–retest reliability of an instrumented walkway system (the GAITRite® mat) for the measurement of temporal and spatial parameters of gait in young and older people. Thirty young subjects (12 males, 18 females) aged between 22 and 40 years (mean 28.5, S.D. 4.8) and 31 older subjects (13 males, 18 females) aged between 76 and 87 years (mean 80.8, S.D. 3.1) walked at a self-selected comfortable walking speed across the pressure-sensor mat three times and repeated the process approximately 2 weeks later. Intra-class correlation coefficients (ICC), coefficients of variation (CV) and 95% limits of agreement were then determined. For both groups of subjects, the reliability of walking speed, cadence and step length was excellent (ICCs between 0.82 and 0.92 and CVs between 1.4 and 3.5%). Base of support and toe in/out angles, although exhibiting high ICCs, were associated with higher CVs (8.3–17.7% in young subjects and 14.3–33.0% in older subjects). It is concluded that the GAITRite® mat exhibits excellent reliability for most temporo-spatial gait parameters in both young and older subjects, however, base of support and toe in/out angles need to viewed with some caution, particularly in older people.
Twenty-four women divided into three groups: control, exercise and nutrition, have been involved in a -6 degrees head down bed rest (HDBR) experiment for 60 days. The objective was to analyse the effects of microgravity on balance function regulation. Group comparisons assessed the efficiency of countermeasures (specific exercises and in particular diet) on the deleterious effects of simulated microgravity. Measurements of orthostatic and dynamic balance were taken 9 and 2 days prior to the experiment, on the first day of getting up, the following day and 4 and 10 days after, under two visual conditions: eyes open and eyes closed. The results confirmed that, as in any other test performed with ordinary subjects, the postural balance performances are better with eyes open than with eyes closed. The static and dynamic postural performances were impaired on the first day of recovery (R0) following HDBR. This impairment lasted up to 4 days after getting up and, afterwards the volunteers recovered their initial performances. The exercise group recovered static postural performances more quickly than the other groups whereas there were no differences in the recovery of the dynamic balance performances.
Before making interpretations on the effects of interventions or on the features of pathological gait patterns during stair ambulation, the day-to-day consistency of the investigated variables must be established. In this article, the day-to-day consistency was determined for kinematic variables during barefoot stair ambulation. Ten healthy athletes performed two gait analysis sessions, at least one week apart, utilizing a marker set of 47 skin markers, and a functional joint center/axes determination. Being found on limits of agreement and mean differences between the repeated stair ambulation sessions, totally 43 ranges of motions were examined at the hip, knee, ankle, and midfoot joints. The day-to-day consistency was generally in the magnitude of three degrees, irrespective of test condition, investigated joint, or regarded cardinal body plane. The reported values of the day-to-day consistency provide guidelines to distinguish between pathological and healthy gait patterns, and thresholds to determine minimal effects of interventions during stair ambulation.
The purpose of this study was to examine the 3-dimensional kinematics of 'normal' walking gait in young children. A cross sectional study using nine children aged between 10 and 24 months, filmed whilst walking at natural speed, was undertaken using two gen-locked video cameras. The children were at different stages of walking development (from 0.5 to 10 months of independent walking (IW)). Repeated measures were taken from two of the children at 10 and 17 months of age and then at 18 and 24 months respectively. 3-dimensional video digitisation techniques utilising the DLT algorithm were used to obtain variables of the gait cycle. The position and movement of the arms were identified as potential motor development patterns. Ranges of movement and motion patterns observed in other variables are useful to determine 'normal' walking gait in such young children. The knees and hips were flexed throughout the gait cycle. Inter-limb asymmetries were observed for the knee angle pattern and for the stance and swing phase time. The mean stance phase time and double support time were 4 and 15% (respectively) greater than in adult's gait. The findings of this study are useful as a guide to research, teaching and clinical professions in this area of biomechanics. Copyright 1998 Elsevier Science B.V.
Morphology and step-time parameters were recorded in 100 children between 15 and 36 months to investigate the relation between morphology and the walking pattern. A footfall method was used to register step-time parameters. Next, the differences in step-time parameters between four morphological classes were assigned with a multiple analysis of variance. We also performed stepwise linear regressions with a correction for walking experience, to examine the relation between detailed morphological measurements and step-time parameters. The results of these regressions show a significant relation between pelvis span/ankle spread ratio and the relative radii of gyration in the frontal plane of head and pelvis. It is hypothesized that the morphology of the head and pelvis plays a role in the coordination of the walking pattern.
The purpose of the present case report is to show the potential for use of 3D gait analysis as an assessment method of feigned muscle weakness. We describe a patient complaining of right leg pain and weakness. Physical examination showed severe quadriceps muscle weakness in a highly abnormal gait pattern context. Conventional diagnostic workup did not show any relevant findings. Three-dimensional (3D) gait analysis was performed with a 3D motion capture system. Joint angles, internal moments and powers were computed from the motion data. Lower leg muscle surface-electromyography was also performed. During the late stance phase, flexor moment and negative power peaks (indicating eccentric knee extensor activity) were generated in the knee, together with relevant Rectus femoris activity. All findings were highly inconsistent with true quadriceps weakness and gave objective ground to suspect insincerity of patient complaints. 3D gait analysis might be a valuable clinical assessment tool in suspected feigned lower limb muscle weakness.
Repeatability studies on 3D multi-segment foot models (3DMFMs) have mainly considered healthy participants which contrasts with the widespread application of these models to evaluate foot pathologies. The current study aimed at establishing the repeatability of the 3DMFM described by Leardini et al. in presence of foot deformities. Foot kinematics of eight adult participants were analyzed using a repeated-measures design including two therapists with different levels of experience. The inter-trial variability was higher compared to the kinematics of healthy subjects. Consideration of relative angles resulted in the lowest inter-session variability. The absolute 3D rotations between the Sha-Cal and Cal-Met seem to have the lowest variability in both therapists. A general trend towards higher σ(sess)/σ(trial) ratios was observed when the midfoot was involved. The current study indicates that not only relative 3D rotations and planar angles can be measured consistently in patients, also a number of absolute parameters can be consistently measured serving as basis for the decision making process.
Short-leg walking boots offer several advantages over traditional casts. However, their effects on ground reaction forces (GRF) and three-dimensional (3D) biomechanics are not fully understood. The purpose of the study was to examine 3D lower extremity kinematics and joint dynamics during walking in two different short-leg walking boots. Eleven (five females and six males) healthy subjects performed five level walking trials in each of three conditions: two testing boot conditions, Gait Walker (DeRoyal Industries, Inc.) and Equalizer (Royce Medical Co.), and one pair of laboratory shoes (Noveto, Adidas). A force platform and a 6-camera Vicon motion analysis system were used to collect GRFs and 3D kinematic data during the testing session. A one-way repeated measures analysis of variance (ANOVA) was used to evaluate selected kinematic, GRF, and joint kinetic variables (p<0.05). The results revealed that both short-leg walking boots were effective in minimizing ankle eversion and hip adduction. Neither walker increased the bimodal vertical GRF peaks typically observed in normal walking. However, they did impose a small initial peak (<1BW) earlier in the stance phase. The Gait Walker also exhibited a slightly increased vertical GRF during midstance. These characteristics may be related to the sole materials/design, the restriction of ankle movements, and/or the elevated heel heights of the tested walkers. Both walkers appeared to increase the demand on the knee extensors while they decreased the demand of the knee and hip abductors based on the joint kinetic results.
Children with spina bifida (SB) can exhibit excessive arm swing, trunk sway, and pelvic tilt during walking. To understand the relationship between abnormal low back forces (LBF) and gait disorders in SB, we derived a mathematical model for evaluating LBF in this population. One unimpaired child and a child with SB were tested. A 3D motion analysis system and force plate were used to collect kinematic and ground reaction force data during walking. A mathematical model created using MATLAB software was used to calculate LBF for each child. The LBF for the child with SB was three times greater in the medio-lateral direction than for the unimpaired child. In the anterior-posterior direction, the LBF for the child with SB acted mostly towards the anterior trunk. In addition, the LBF of the child with SB increased by 24.5% of body weight at the fastest walking speed.
Characterization of gait pattern is of interest for clinical gait assessment. Past developments of ambulatory measurement systems have still limitations for daily usage in the clinical environment. This study investigated the potential of 3D angular accelerations of foot, shank, and thigh to characterize gait events and phases of ten healthy and ten hemiparetic subjects. The key feature of the system was the use of angular accelerations obtained by differential measurement. Further, the effect of sensor position and walking cadence on the signal was investigated. We found that gait phases are characterized as modulated amplitudes of angular accelerations of foot, shank, and thigh. Increasing the gait cadence from 70steps/min to 100steps/min caused an amplitude increase of the magnitude of the vector, summing all 3D angular accelerations on the sensor position (p<0.001). Comparison of healthy and hemiparetic gait showed a lower mean of the magnitude of the vector during the loading response in the hemiparetic gait (p<0.05), while during pre-swing and swing no significant differences between healthy and hemiparetic gait were observed. A comparison of the tangential acceleration component in the frontal plane showed no statistically significant difference between healthy and hemiparetic gait. Further, no statistically significant difference between the tangential components was found for both groups. This method demonstrated promising results for a possible use for gait assessment.
Gait data need to be reliable to be valuable for clinical decision-making. To reduce the impact of marker placement errors, the Optimized Lower Limb Gait Analysis (OLGA) model was developed. The purpose of this study was to assess the sensitivity of the kinematic gait data to a standard marker displacement of the OLGA model compared with the standard Vicon Clinical Manager (VCM) model and to determine whether OLGA reduces the errors due to the most critical marker displacements. Healthy adults performed six gait sessions. The first session was a standard gait session. For the following sessions, 10mm marker displacements were applied. Kinematic data were collected for both models. The root mean squares of the differences (RMS) were calculated for the kinematics of the displacement sessions with respect to the first session. The results showed that the RMS values were generally larger than the stride-to-stride variation except for the pelvic kinematics. For the ankle, knee and hip kinematics, OLGA significantly reduced the averaged RMS values for most planes. The shank, knee and thigh anterior-posterior marker displacements resulted in RMS values exceeding 10°. OLGA reduced the errors due to the knee and thigh marker displacements, but not the errors due to the ankle marker displacements. In conclusion, OLGA reduces the effect of erroneous marker placement, but does not fully compensate all effects, indicating that accurate marker placement remains of crucial importance for adequate 3D-gait analysis and subsequent clinical decision-making.
The purpose of this study was to evaluate side-to-side differences in three-dimensional clavicle kinematics in normal shoulders during dynamic scapular plane elevation using model-image registration techniques. Twelve healthy males with a mean age of 32 years (range, 27-36 years old) were enrolled in this study. Clavicle rotations were computed with bilateral fluoroscopic images and CT-derived bone models using model-image registration techniques and compared between dominant and nondominant shoulders. There was no difference in retraction between both shoulders. The clavicle in dominant shoulders was less elevated during abduction than in nondominant shoulders (P=0.03). Backward rotation angles of dominant shoulders were significantly smaller than those of nondominant shoulders throughout the activity (P=0.03). Clavicular kinematics during scapular plane abduction were different according to hand-dominance.
A new method of scoring systems for the functional assessment of the shoulder is presented. 3D accelerometers and gyroscopes attached on the humerus were used to differentiate a healthy from a painful shoulder. The method was first tested on 10 healthy volunteer subjects with no shoulder pathology. The system was then tested on 10 patients with unilateral shoulder pathology (rotator cuff disease, osteoarthritis) before and after surgery (3, 6 months). In order to evaluate the system, nine tests based on the Simple Shoulder Test (SST) were performed on each shoulder for each patient. Three scores were defined: the P score was based on the angular velocities and accelerations of the humerus; the RAV score was based only on the angular velocities of the humerus; the M score was based on the sum of all moments of the humerus. Our kinematic scores indicated significant differences between baseline and follow-up (p<0.05) and differentiated between patients with varying severity of the same condition. We demonstrated a reliable technique of evaluating shoulder pathology and the results of surgery.
This study aimed to use the plantar pressure insole for estimating the three-dimensional ground reaction force (GRF) as well as the frictional torque (T(F)) during walking. Eleven subjects, six healthy and five patients with ankle disease participated in the study while wearing pressure insoles during several walking trials on a force-plate. The plantar pressure distribution was analyzed and 10 principal components of 24 regional pressure values with the stance time percentage (STP) were considered for GRF and T(F) estimation. Both linear and non-linear approximators were used for estimating the GRF and T(F) based on two learning strategies using intra-subject and inter-subjects data. The RMS error and the correlation coefficient between the approximators and the actual patterns obtained from force-plate were calculated. Our results showed better performance for non-linear approximation especially when the STP was considered as input. The least errors were observed for vertical force (4%) and anterior-posterior force (7.3%), while the medial-lateral force (11.3%) and frictional torque (14.7%) had higher errors. The result obtained for the patients showed higher error; nevertheless, when the data of the same patient were used for learning, the results were improved and in general slight differences with healthy subjects were observed. In conclusion, this study showed that ambulatory pressure insole with data normalization, an optimal choice of inputs and a well-trained nonlinear mapping function can estimate efficiently the three-dimensional ground reaction force and frictional torque in consecutive gait cycle without requiring a force-plate.
In spite of the importance of stair-climbing (SC) as an activity of daily living, 3D spinal motion during SC has not been investigated in association with low back pain (LBP). The purpose of this research is to investigate the differences of the spinal motions during SC between an LBP group and a healthy control group, in order to provide insight into the LBP effect on the spinal motions. During two types of SC tests (single and double step SCs), we measured 3D angular motions (flexion/extension, lateral bending, and twist) of the pelvis, lumbar spine and thoracic spine using an inertial sensing-based, portable spinal motion measurement system. For the nine motion variables (i.e. three anatomical planes × three segments), range of motions (ROM) and movement patterns were compared to determine the differences between the two groups. It was found that the only variable having the p-value of a t-test lower than 0.05 was the flexion/extension of the lumbar spine in both SCs (i.e. the LBP group's ROM<the control group's ROM). Although the strength of this finding is limited due to the small number of subjects (i.e. 10 subjects for each group) and the small ROM differences between the groups, the comparison result of the t-test along with the motion pattern shows that the effect of LBP during SC may be localized to the lumbar spinal flexion/extension, making it an important measure to be considered in the rehabilitation and treatment of LBP patients.
This study aims at giving an insight into the causative forces of walking in toddlers. Therefore, joint angle, moment and power profiles of 10 toddlers with less than 6 months of walking experience are compared to the stereotype adult patterns. In general, joint moments are small, which can be explained both by the small size of toddlers and differences in walking strategy. Also mass specific powers are reduced due to the low average walking speed. Balance problems in toddlers lead to a dominance of hip and knee extending moments throughout stance. The joint moment profiles are characterized by a reduced complexity, which might suggest an immature control of movement. Another feature of toddler gait is that virtually no power is generated at the ankle joint prior to foot-off (no active push-off). We also examined the effect of walking experience on the toddler gait pattern. In general, an evolution towards a more mature gait becomes evident after 4 months of independent walking. Changes are observed in step-time parameters, ankle dorsiflexing moment and power absorption at the hip joint.
The purpose of this study was to construct a 3D dynamic model to quantify low back load during single person dependent transfer, and to compare the effects of wearing style of a low back belt on low back loading. Of the nine subjects participating in this study, eight adopted the role of caregiver and one was a simulated patient. Tasks were general transfer without either subject wearing a low back belt (WB), transfer with the patient wearing a low back belt (BP), transfer with both subjects wearing low back belts (BB), and transfer with the caregiver wearing a low back belt (BC). Low back lateral and extension moments in BB and BC transfers showed the significantly smaller values than those in WB transfers (p<0.01). The results suggest that the wearing of a low back belt by caregivers would reduce low back joint moment during transfers.
Evaluative quantification of gait disorder minimizing time-consuming and cost-intensive laboratory installations remains a challenging task in movement analysis. We examined the criterion validity of global gait mechanics assessed by trunk accelerometry. Eight female and four male volunteer subjects (mean age, 27.5 years; S.D., 5.1 years; weight, 68.7+/-11.3kg; height, 1.74+/-0.08m) without gait dysfunction participated in the study. They walked barefoot over two adjacent force-platforms at self-selected speeds. In addition to ground reaction forces, vertical, anterior-posterior and medio-lateral accelerations of the trunk were simultaneously measured by means of a light tri-axial accelerometer. Mean acceleration cycles of the trunk and the body centre of mass were calculated. Acceleration vectors were integrated twice to obtain velocity and displacement vectors of the trunk and the centre of mass, respectively. Temporal boundaries of right and left functional stance phases were defined by the two intermediate moments between maximum anterior-posterior velocity and minimal vertical displacement. Cross-correlations of the kinematics of the trunk and the centre of mass were determined. External work and corresponding symmetry indicators were computed for both methods. Centre of mass anterior-posterior displacement lagged behind the trunk by 3.5% of the gait cycle. External power correlated highly (r>0.82) between the trunk model and the centre of mass. Work correlated moderately high (r=0.77) between the two methods. Work and power asymmetry indexes correlated moderately high (r>0.64). Our findings suggest that accelerometry has the potential to assess functional kinematics and energy-related outcomes in large cohorts.
A non-invasive technique for posture classification suitable to be used in several in-home scenarios is proposed and preliminary validation results are presented. 3D point cloud sequences were acquired using a single time-of-flight sensor working in a privacy preserving modality and they were processed with a low power embedded PC. In order to satisfy different application requirements (e.g. covered distance range, processing speed and discrimination capabilities), a twofold discrimination approach was investigated in which features were hierarchically arranged from coarse to fine by exploiting both topological and volumetric representations. The topological representation encoded the intrinsic topology of the body's shape using a skeleton-based structure, thus guaranteeing invariance to scale, rotations and postural changes and achieving a high level of detail with a moderate computational cost. On the other hand, using the volumetric representation features were described in terms of 3D cylindrical histograms working within a wider range of distances in a faster way and also guaranteeing good invariance properties. The discrimination capabilities were evaluated in four different real-home scenarios related with the fields of ambient assisted living and homecare, namely "dangerous event detection", "anomalous behaviour detection", "activities recognition" and "natural human-ambient interaction". For each mentioned scenario, the discrimination capabilities were evaluated in terms of invariance to viewpoint changes, representation capabilities and classification performance, achieving promising results. The two feature representation approaches exhibited complementary characteristics showing high reliability with classification rates greater than 97%.
This study quantified the accuracy of inertial sensors in 3D anatomical joint angle measurement with respect to an instrumented gimbal. The gimbal rotated about three axes and directly measured the angles in the ISB recommended knee joint coordinate system. Through the use of sensor attachment devices physically fixed to the gimbal, the joint angle estimation error due to sensor attachment (the inaccuracy of the sensor attachment matrix) was essentially eliminated, leaving only error due to the inertial sensors. The angle estimation error (RMSE) corresponding to the sensor was found to be 3.20° in flexion/extension, 3.42° in abduction/adduction and 2.88° in internal/external rotation. Bland-Altman means of maximum absolute value were -1.63° inflexion/extension, 3.22° in abduction/adduction and -2.61° in internal/external rotation. The magnitude of the errors reported in this study imply that even under ideal conditions irreproducible in human gait studies, inertial angle measurement will be subject to errors of a few degrees. Conversely, the reported errors are smaller than those reported previously in human gait studies, which suggest that the sensor attachment is also significant source of error in inertial gait measurement. The proposed apparatus and methodology could be used to quantify the performance of different sensor systems and orientation estimation algorithms, and to verify experimental protocols before human experimentation.
The purpose of this study was to determine the association between isometric muscle strength of the lower limbs and gait joint kinetics in adolescents and young adults with cerebral palsy (CP). Twenty-five participants (11 males) with bilateral spastic CP, aged 14-22 years (mean: 18.9, sd: 2.0 yr) and Gross Motor Function Classification System (GMFCS) level II (n=19) and III (n=6) were tested. Hand held dynamometry was used to measure isometric strength (expressed in Nm/kg) of the hip, knee, and ankle muscles using standardized testing positions and procedures. 3D gait analysis was performed with a VICON system to calculate joint kinetics in the hip, knee and ankle during gait. Ankle peak moments exceeded by far the levels of isometric strength of the plantar flexors, while the knee and hip peak moments were just at or below maximal isometric strength of knee and hip muscles. Isometric muscle strength showed weak to moderate correlations with peak ankle and hip extension moment and power during walking. Despite considerable muscle weakness, joint moment curves were similar to norm values. Results suggest that passive stretch of the muscle-tendon complex of the triceps surae contributes to the ankle moment during walking and that muscle strength assessment may provide additional information to gait kinetics.
Measurement repeatability has important decision-making implications for clinicians and researchers when assessing individuals. The aims of this study were to quantify: (a) the repeatability of direct measurements of standing posture using three dimensional (3D) whole body scanning, and (b) the magnitude of the postural and technical errors involved. Fifty-two asymptomatic adults were scanned twice, 24h apart, using the Vitus Smart 3D whole body scanner. Eleven clinically relevant standing postural measurements were calculated from scan-extracted data. The process was repeated with 10 shop mannequins. Systematic error was expressed as absolute changes in means and as standardised effect sizes, with random (within-subject) error expressed as the typical error. Technical error was calculated as the typical error in the measurement of mannequins; total error as the typical error in the measurement of subjects; and postural error as the square root of the difference between the squared total error and the squared technical error. Most standing postural measurements demonstrated good repeatability, with median (95% CI) systematic and random errors of -0.1° (1.1°) and 2.8° (1.9°), respectively. However, head and neck postures demonstrated poor repeatability due to large random errors brought about by large postural errors. Overall, most of the error was due to postural error rather than technical error. The relatively small technical errors highlight that this 3D measurement process is generally repeatable, while the relatively large postural errors related to the head and neck suggest that these postures probably lack the precision to be clinically useful using this procedure.