Gait & Posture

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.

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.

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.

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.