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Comprehensive care for people with disabling neurological disease—finding the best approach Comprehensive care for people with disabling neurological illnesses is widely acknowledged to require input from many specialisms. The foundation of such multifaceted care should be a detailed assessment of physical and psychosocial function and health needs, ideally by experienced individuals able to work in a transdisciplinary way and possessing excellent communication skills. Such individuals would be capable of both identifying a clinical problem, such as impaired heel strike, and determining the most appropriate treatment, such as stretches from the physiotherapist, botulinum toxin from the physician or orthopaedic release. Clearly clinicians with the wide training and experience for such …

These experiments examine the role of vision and step height in the selection of a simple binary choice of movement pattern by human subjects. The subjects selected a heel strike movement pattern (HS) (as used during level surface locomotion) or a toe strike movement pattern (TS) (as used during stair descent). The functional task involved descending a step of adjustable height followed by level surface walking under vision and nonvision conditions. Triceps surae and tibialis anterior electromyographic (EMG) activity, ankle angle position, and vertical force were examined. As step height was increased, there was an indistinct threshold at which subjects switched from landing with a HS movement pattern to a TS movement pattern. The tibialis anterior and triceps surae precontact EMG burst and subsequent ankle movement for HS and TS trials appear to be part of preprogrammed movement patterns, which are presumably of central origin. The particular mixture of voluntary, stereotypic, and reflex actions for any specified movement is based on the intent or functional outcome desired. The switching to the TS movement pattern as step height increased presumably results in the most efficient and stable movement.

Simultaneous walking and hand clapping were utilized to examine the patterns of coordination between upper and lower limbs. Eighteen normal adult subjects were filmed at high speed under instructions to: (a) walk and clap at a self-determined “preferred” speed, (b) walk as fast as possible while clapping at the preferred speed, (c) walk at the preferred speed while clapping as fast as possible and (d) walk and clap as fast as possible. Temporal data and individual patterns of phase relations were analyzed. Results indicated a disruption of the preferred clap cycle when combine with fast walking. The degree of disruption was a function of the individual coordinative pattern at the preferred rate. It is concluded that: (a) the temporal patterning of the clap cycle can be dictated by the step cycle, (b) heel strike is the point about which the clap cycle is modulated, and (c) subjects can select from various modes of phase linkage.

Modulation of the flexor reflex response during walking in humans following stimulation at 5 points in the step cycle was studied. At heel strike, an extensor response was observed at the ankle and the knee which would allow one to stabilize and plant the ipsilateral foot fast. Later on in the stance, there was a dorsiflexor and an extensor response at the ankle and the knee, respectively, which would result in the removal of the foot from the stimulus without collapsing at the knee. During mid-swing, a flexor reflex response was observed at the ankle and the hip joint. There was a tendency for the normal stride to be longer than the perturbed stride in mid swing and early stance while it was of shorter duration in late stance and early swing.

A category checklist of developmental characteristics for the forward roll, modeled after Roberton's “component” approach, was hypothesized for this study. The categories were used to examine the usefulness of a component approach for describing actions occurring during the forward roll. Age-relatedness of category sequences was also explored. Three components were defined: hand/arm, head/neck, hip/leg. Each component was divided into phases which described the temporal course of actions occurring throughout the forward roll, from initial hand placement to heel strike. Within each component phase were hierarchically arranged steps, ordered from primitive to advanced. The potential usefulness of the components as a developmental checklist was examined using three criteria: (1) the comprehensiveness of the category system for describing observed movement behaviors; (2) the observed ordering of each component sequence in relation to the hypothesized ordering; and (3) the sign of the slopes of the ag...

The use of the musculus tibialis anterior during walking and the type and size of its muscle fibers were determined in 15 young normal subjects (29 +/- 4 years) and in 13 old healthy subjects (70 +/- 3 years). In the average step cycle 16 +/- 6% of the maximal surface EMG was recorded during the swing phase and 44 +/- 15% during 100 msec at the heel strike. Single motor unit recordings showed that low-threshold units fired at 10-15 Hz during the swing and at 20-25 Hz during the heel strike peak. Usually, high-threshold units did not participate in the ordinary step cycle. A significantly higher mean use was found in the old subjects as compared with the young ones presumably due to lower muscle power in relation to body weight. In the young subjects 76 +/- 7% of the muscle fibers were type 1 and 22 +/- 7% were type 2A. In the old subjects 84 +/- 9% were type 1 and 15 +/- 8% were type 2A. In the young subjects the mean cross-sectional area of type 1 fibers was 3950 +/- 950 microns2 and of type 2 fibers was 8070 +/- 1850 microns2. In the old subjects the corresponding numerals were 4050 +/- 890 microns2 and 5700 +/- 1970 microns2, respectively. The significance of physiological variations in use for muscle fiber type composition and size is discussed.

Studies were made of the forces generated at heel stroke in human gait using both force plates having a high resonant frequencies (capable of picking up high frequency components in the contact force) as well as a force transducer inserted into the heel of the shoe of the subjects. The output traces were analyzed for the existence of high frequency impulsive loads during a normal walking cycle. The effect of the complicance of the foot and floor was studied with the force transducers. The results showed that during normal human gait the lower limb is subjected to a high frequency impulsive load at heel strike. The severity of this impulse varied with the individual, the velocity and angle with which the limb aproached the ground and the compliance of the two materials coming in contact at heel strike. The magnitude of this peak force varied from 0.5 to 1.25 times body weight and its frequency components from 10 to 75 Hz.

A mathematical model of gait ground loading is presented. The model allows the ground reactions produced by any particular single- or multiple-footfall pattern to be constructed, given a sufficient variety of other measured ground reactions. An algorithm which uses center of vertical pressure data only to determine the instants of successive heel strikes on a large force plate is then presented. Experiments show the high accuracy of the heel strike algorithm and show that reconstructions of the vertical component of ground reactions are typically within 3% of corresponding measured reactions. The techniques presented allow certain problems associated with small force plates and other problems associated with large force plates to be largely overcome.

Transient vibrations caused by heel strike and travelling vertically through the body have been monitored using accelerometers taped to the skin. A correction for skin movement based on the transmissibility function is described. The average velocity between the foot and the head for the heel-strike transient is 220 m/s. This velocity is greatest in the legs, 610 m/s, and least in the spine, 90 m/s. Shock absorption occurs mainly in the legs and to a lesser degree in the spine.

Greater understanding of human stepping patterns will be gained when different successive portions of the step cycle can be attributed to specific origins. In this study the strength of a known behavior, an operant composed of a colored light as discriminative stimulus and electromyographic activity of the rectus femoris muscle as response, was compared with that of other ongoing behaviors at each of five times during the stance (down) and swing (up) phases. Under computer assistance, while subjects walked on a motorized treadmill a green light discriminated a burst of 100–400 msec within a performance duration of 700 msec, while a red light discriminated muscle silence. Red and green lights were scheduled first in systematic and later in random orders across the 10 consecutive steps of each successive trial. The green light produced large successful bursts in every position after relatively little training, to rule out any powerful competing source of reflexive or other stimulus control. These discriminated bursts were accompanied in some instances by longlasting low amplitude activity, either several hundred msec before heel strike or else prior to the colored light. Control for the first low EMG type might have been reflexive (built in) or acquired through conditioning, but control for the second was acquired and depended upon movement produced stimulation that was associated with each position of the light.

Previous studies have indicated that the shock absorbency of the heel pad is significant in the pathophysiology of pain conditions connected with heel strike. The purpose of this study was to develop a simple clinically usable method for quantification of the heel pad shock absorbency. The results of our efforts was the HPC-device which consists of a fixing device and a transducer. The HPC-device was found suitable in the evaluation of the heel pad force/deformation characteristics. The reproducibility of heel pad deformation was 0.96. Tests of six cadaver heel pads revealed a high correlation between the HPC result and the shock absorbency found by drop tests. In a normal material (200 heel pads), it was found that the shock absorption decreased with age and that men had significantly higher shock absorbency than women. Men also had significantly thicker heel pads than women. However, there was no linear correlation between the thickness of the heel pad and the shock absorbency, although the thinnest heel pads had the lowest shock absorbency. The HPC-device was found clinically usable and will be used in further testing of the significance of heel pad shock absorption for the development of heel strike dependent over-use injuries.

Coming from a country where the majority of people walk in unshod feet and where shoes are an expensive luxury, I would like to offer some unconventional thoughts which might provide a global overview of the problems involved in the design of footwear and foot and ankle orthoses. I was brought up with the traditional concept of the foot being merely a static tripod or a semi-rigid support for superincumbent body weight. The arches of the foot were held to be very important and fie height of the longitudinal arch was correlated with a superior kind of foot. We owe it to Hicks (1961) of Birmingham who taught us to clearly differentiate between a beam, an arch and a truss, and the role of muscles and the plantar aponeurosis in the weight bearing and balancing mechanism of the foot. But the foot can no longer be viewed as a mere weight-bearing device meant only for standing. It has evolved, as the bioengineering team at the University of California (1947) has been telling us over the last two decades, as a dynamic mechanism functioning as an integral part of the locomotor system. The human foot is primarily meant for walking and it is important to understand its behaviour in the walking cycle. The foot is a remarkably mobile mechanism, adapting itself to the contours of the ground as well as responding to the forces transmitted via the suprapedal segments from above. By supinating and pronating, it causes the weight fine to follow a curved pathway leading to an even load distribution on the metatarsal heads. It becomes supple as it is grounded from heel strike to foot flat, and rigid as it prepares itself for heel rise and the final take-off. There is a locking mechanism in the foot, operated

This study analyzed the gait of women exhibiting symptoms of chondromalacia patellae, and compared them with a group of women without chondromalacia symptoms. High speed cinematography was used to film the subjects walking on a level surface and a 15 downhill slope. Flexion of the knee on both surfaces during the single support phase was significantly less for the chondromalacia subjects (P < 0.05). increased external femoral rotation was detected in chondromalacia patellae subjects (P < 0.05) during swing phase on level and sloping surfaces. A radical inward femoral rotation occurred immediately preceding heel strike (P < 0.001). We conclude that significant differences in gait are apparent in females exibiting chondromalacia patellae symptoms as compared with apparently normal female knees.J Orthop Sports Phys Ther 1983;5(3):127-131.

Analytically, the effects of rotation at one joint dominate the normal articulation and the mechanism of lubrication at the other. For a two-region flow model of an idealized knee joint, under the assumptions of small rotations and the short bearing approximation, for negative values of the rotational parameter the load-carrying capacity increases and the load-carrying capacity decreases for positive values of the rotational parameter. These results indicate that during a part of the walking cycle (from heel strike to toe-off) rotation increases with load.

A stress analysis was carried out on below-knee braces of standard design on four patients suffering from drop foot due to poliomyelitis. The maximum stresses were recorded during the stance phase of gait. A comparison was made with stresses analysed in similar braces worn by a normal subject.

The aim of this study was to proof a sensor concept dedicated to overcome severe limitations of laboratory-based research on running footwear. Therefore, the heel part of a commercial running shoe was equipped with five Hall-Effect sensors and the same number of permanent magnets. Due to a specific calibration routine, it was possible to calculate the local deformation of the midsole during heel strike at each of the five positions from the sensor output voltage. The proof of concept was performed by conducting running trials in a laboratory test set-up. The so obtained deformation related variables were correlated to established kinetic and kinematic parameters.

Due to the increase in prescription of insoles to relieve symptoms due to skeletal shocks at heel strike a pilot study was initiated to look at some materials used for this purpose. Five materials were examined (Plastazote, Spenco, Sorbothane, Poron (PPT) and Viscolas) by two methods. The first method used an accelerometer mounted between the teeth of one of the authors (PR) to record skeletal shock. The second method used a force plate to record the shock produced by dropping a ball-bearing onto the insoles from a standard height. The results showed that Plastazote is poor at absorbing shock with Spenco and Sorbothane being quite good. The best insole materials tested were Poron (PPT) and Viscolas with the latter being marginally superior. No account was taken of degradation of the materials in use except that Plastazote worn for 72 hours was also used in the study, this producing the worst results.

The classical researches of Weber and Weber1 on the mechanics of human gait have demonstrated that the movements of man, particularly in walking and running, are amenable to mechanical processing. This is based on the possibility of obtaining accurate knowledge of a particular movement by direct measurement. The results, empirically obtained, constitute the foundation for subsequent studies. One has to deal with a mechanical problem: from the movements carried out by the different parts of the human body the forces necessary to cause those movements have to be deduced. This problem can in principle always be solved if one understands the process of movement and if one knows the magnitude of the mass, the position of the centre of gravity, the magnitude of the moments of inertia of each part of the body and in what way the movements of the different parts of the body are conditioned by articulation and external forces such as friction against the ground. Conversely, difficulties very often oppose the precise solution of the reverse problem, that is to deduce the movements from a knowledge of the forces.

Study of transient force phenomena in the double stance period of normal gait suggests that high temporal resolution is required in concommittant movement analysis. The present study concludes that at least 300 pictures per second are necessary to resolve kinematic transients associated with heel strike.

Shock absorption (SA) is a simple way to reduce the body load and can be used in the prevention and treatment of injuries. The heel pad is the most important shock absorber in the shoe heel complex. The purpose of this study was to investigate whether the SA at heel strike can be increased by heel support in people and shoes with high or low SA. The impact forces at heel strike were measured on an AMTI (R) force platform. Fourteen legs were tested in seven persons (nine with normal and five with low heel pad SA) in gait analysis and in human drop tests. The tests were performed barefooted, and in a soccer and a running shoe (selected by shoe drop test), with and without the distal 2 cm of the heel counter. The heel pad confinement produced by the heel counter (the heel counter effect) increased the SA in both shoe types significantly in both impact situations. The mean increase in SA was 8.8% (range 5.8%-15.5%). The heel counter effect was in all situations significantly higher in persons with low heel pad shock absorbency (LHPSA) than in those with normal heel pads. The barefoot impact peak force per kg body weight was significantly higher (6% mean) on the side with LHPSA. The running shoe provided the significantly greatest SA compared with the soccer shoe. It is concluded that the shock absorbency at heel strike can be increased significantly by heel support, with highest effect in persons with LHPSA, both in shoes with high and low SA.(ABSTRACT TRUNCATED AT 250 WORDS)

The two horizontal orthogonal ground reaction forces, mediolateral (Fx) and antero-posterior (Fy), together with limb segment displacements, were recorded simultaneously during gait from 24 female subjects aged 18–29 years. Recordings were made for each subject barefoot and when wearing each of four different pairs of shoes: soft-soled, rigid-soled, medium- and high-heeled. The results showed a trend for increasing lateral stability with increasing heel height and decreasing ground contact area. This.was reflected in decreasing mean values for defined ground reaction force peaks in the medio-lateral direction at heel strike and at toe off. Limb segments displacements tended to increase with decreasing heel height and increasing shoe-ground contact area, being greatest when subjects were wearing pumps, i.e. flexible-soled, no-heeled shoes.

The new design, compared with conventional legs, aims at providing the amputee with greater stability, better function and proprioception by the elimination of the artificial knee joint. Ground clearance during swing phase is achieved by shortening the effective length of the limb, utilising a self-energising mechanism. Clinical trials have indicated that when patients wore this telescopic limb their gait improved and their confidence increased.

The cyclic impacts induced by heel strike when walking were studied using both a high-resonance-frequency force plate and a low-mass skin-mounted accelerometer. The data were computer analyzed. The results showed that during normal human walking, the locomotor system is subjected to repetitive impact loads at heel strike, lasting about 5 ms and consisting of frequency spectra up to and above 100 Hz. The natural shock-absorbing structures in the musculoskeletal system have viscoelastic time-dependent mechanical behavior, which is relatively ineffective in withstanding sudden impulsive loads. Degenerative joint diseases may thus be seen as a late clinical result of fatigue failure of the natural shock absorbers, submitted to deleterious impacts over a period of time.

The performance of a footswitch which uses conductive rubber modules in foam, sandwiched between two brass shims in the form of an inner sole placed between the foot and the shoe is reported. Contact switching force decreases with module density, whilst position of the conductivity plugs in the footswitch is irrelevant. Comments on the construction of a footswitch using these modules are made, in particular no modification of the conductive rubber is needed and a density throughout greater than 4 modules per square inch leads to threshold switch forces of 30 N and less which is totally acceptable for gait analysis use without fears of contact being made whilst inserting and positioned in the subject's shoe.

Several modern gait analysis techniques, such as Selspot, Vicon etc., provide coordinate data for markers affixed to the body. These data are used for different kinds of kinematic and kinetic locomotion analysis. However, since most variables of interest are depending on stride length and stride duration, it is important to include these basic gait parameters in the analysis. For assessment of the validity of collected data and of the patients ability to carry out stationary gait, it is also useful to have a measure of the degree of stationarity in the data.

Increasing use is being made of implanted joint replacements in the treatment of patients suffering from degenerative and other joint diseases. The success of these is naturally measured in most cases by the patient himself in his expressed satisfaction with the end result in respect of relief from pain and in restoration of function. The clinician also makes an assessment in terms of the degree of activity which the patient can routinely undertake and the degree of abnormality in the restored pattern of use.

Gait characteristics of 19 patients with a unilateral below-knee amputation were studied. The accelerographic and foot placement method used in this study allowed for simultaneous acquisition of data commonly obtained in the experimental laboratory (acceleration) and data easily gathered in the physical therapy clinic (temporal and distance factors). The following results may be of interest to the clinician: 1) measures of cadence, stride length, and velocity were highly related and the magnitude of these measures was below commonly accepted values for normal; 2) the below-knee amputees spent more time in stance phase on their uninvolved lower extremity than on their involved (prosthetic) extemity; 3) the step length from heel strike of the uninvolved lower extremity to heel strike of the involved (prosthetic) lower extremity was greater and accomplished in less time than the opposite step; and 4) smoothness of the gait pattern and any single temporal and distance factor exhibited low statistical relationships.

This study reports an investigation into the effect of shoe mass on the gait patterns of below-knee (BK) amputees. Ten established unilateral BK, patellar-tendon-bearing prosthesis wearers were assessed using a VICON system of gait analysis. Incremental masses of 50g (up to 200g) were added to the subjects' shoes and data captured as they walked along a 15m measurement field. Coefficients of symmetry of various parameters of the swing phase (knee frequency symmetry, swing time symmetry, maximum flexion to heel strike time symmetry) were measured and their correlation was tested with the patient's preferrerd shoe mass and also their own shoe mass, all expressed as a proportion of body mass.The subjects' ‘preferred’ shoe mass (139-318g) showed the greatest symmetry in all the parameters examined (correlations 0.78-0.81 p

Each individual has a characteristic gait pattern, and it is even possible to recognise a person simply from his footsteps. However, these characteristic differences appear to be subtle variations superimposed on a basic pattern and for the purpose of locomotion studies it is the basic pattern that is of interest.

In Chap. 2 the movement of the total centre of gravity of the human body during walking was analysed. This provided a clear insight into the movement of the body as a whole. The external forces which act on the whole human body in the different phases of gait were also established. Some of these forces are independent of the will, e.g. gravity. The magnitude of others can be modified at will, within certain limits, e. g. the ground reaction force and the frictional resistance of the ground. Air resistance can be classed in either of these groups: though no influence can be exerted on air currents, it is possible to change the velocity of the forward movement of the body, on which the magnitude of air resistance mainly depends.

Several investigators have revealed that a relationship exists between articular cartilage deterioration and the mechanical stress that results from transient impulsive forces created in the lower extremity during gait. This study is an investigation of the transmission of impulse waves through the lower extremity and the effect of knee pathology and prosthetic knee replacement on their transmission. An in vitro experiment is performed using human cadaver specimens that are instrumented with accelerometers. The distal end of the tibia is impacted with a vibration shaker to simulate heel strike. The results indicate that the normal knee joint is able to attenuate 59% of the transient peak force applied to it by the tibia. This attenuation capacity is reduced by knee pathology and decreases further with implantation of a knee prosthesis. The results indicate that abnormalities at the knee may increase the risk of degenerative changes at the ankle, hip and in the spine due to increased transient impulsive forces.

Kinematic data were collected on two groups of children with diagnoses of idiopathic toe-walking and mild spastic diplegia. Although both groups lacked a heel strike at initial contact, two distinct gait patterns were found. The toe-walkers displayed a variable pattern of ankle motion with moderate to severe plantarflexion at stance. The cerebral palsy patients showed a repeatable gait pattern with only minimal deviation from normal. The absence of a heel strike in this group is due to the sustained knee flexion at terminal swing and initial contact, which was significantly greater than in the toe-walkers.

Among the movements carried out by the different segments of the human body during walking, none has aroused such controversy as the swinging of the leg. Weber and Weber claimed that this movement was purely that of a pendulum and resulted solely from gravity. The controversy has continued ever since. There are opponents and supporters of the Webers’1 theory. Both have tried to provide the empirical bases to sustain their point of view. But no unequivocal confirmation or refutation of the Webers’ theory has yet been brought forwards. The question thus remains open.

Soft tissue symptoms in the leg due to sporting activity are commonly associated with the force of heel strike. Conventional training shoes compromise between comfort and performance; few models are suitably designed for both considerations. Using a visco-elastic polymer insert the symptoms of heel pain and Achilles tendonitis have been largely or completely abolished in a preliminary study.

Because of the increased popularity of running, interest has focussed on ways of reducing injurious skeletal shocks. This paper examines heel and toe strike running styles and the effect of shock attenuating materials in reducing foot/floor contact forces and skeletal shocks. Using a force plate and an accelerometer, 18volunteers (10 men, 8 women) were studied and the following observations made. Firstly, toe striking reduced the skeletal transients and the rate of rise of foot loading. Secondly, the three materials studied (PPT, Viscolas and Cleron) all reduced the rate of foot loading in heel strike, but only one (PPT) affected the skeletal transient peak height during toe strike. No other significant results were obtained.

Biomechanics is the science which combines principles of engineering, basic laws of physics, and orthopaedic surgery. Biomechanics research enables the surgeon to achieve a greater understanding of the variety of mechanical derangements of the body, to formulate a precise surgical correction of a problem, and to design an effective rehabilitation program.

Simultaneous measurements during normal walking of the transient acceleration on heel strike in the tibia and skull show peaks of ∼ 5 g and 0.5 g respectively when hard heels were worn. Resilient heels halved the amplitudes, while rebound could be avoided by a construction including a viscoelastic polymer insert. The transient is propagated as travelling waves up (and outwards from) the skeleton, its inconspicuous appearance in force plate studies being due to the non-uniform and non-synchronous acceleration of various parts of the body. Implications of these findings are noted, including the potential contribution of heel strike transients to osteoarthritic degeneration. Aggravation of symptoms in sufferers from back troubles may well be due to shear induced by them in para-osteal tissue. Possible physiological roles for the transients, which may account for their existence, are also mentioned.