Stance Phase Duration Research Articles

Ultrasonic motion analysis system—measurement of temporal and spatial gait parameters

The duration of stance and swing phase and step and stride length are important parameters in human gait. In this technical note a low-cost ultrasonic motion analysis system is described that is capable of measuring these temporal and spatial parameters while subjects walk on the floor. By using the propagation delay of sound when transmitted in air, this system is able to record the position of the subjects’ feet. A small ultrasonic receiver is attached to both shoes of the subject while a transmitter is placed stationary on the floor. Four healthy subjects were used to test the device. Subtracting positions of the foot with zero velocity yielded step and stride length. The duration of stance and swing phase was calculated from heel-strike and toe-off. Comparison with data obtained from foot contact switches showed that applying two relative thresholds to the speed graph of the foot could reliably generate heel-strike and toe-off. Although the device is tested on healthy subjects in this study, it promises to be extremely valuable in examining pathological gait. When gait is asymmetrical, walking speed is not constant or when patients do not completely lift their feet, most existing devices will fail to correctly assess the proper gait parameters. Our device does not have this shortcoming and it will accurately demonstrate asymmetries and variations in the patient's gait. As an example, the recording of a left hemiplegic patient is presented in the discussion.

Gait and function in patients with a femoral endoprosthesis after tumor resection: 18 patients evaluated 12 years after surgery.

We performed gait analysis in 18 patients with a femoral endoprosthesis: 12 distal, 3 proximal and 3 total. Follow-up after surgery was mean 12 (0.6-19) years. The gait parameters measured were walking velocity, step length, duration of stance phase and swing phase. Goniometry of the hip, knee and ankle in both legs was determined during free-paced walking. The functional outcome score of the Musculoskeletal Tumor Society (MSTS) and the Ambulation score were also assessed in all patients. The mean free-paced walking velocity was 88% of normal. The step length of the uninvolved leg was longer than that of the involved one. The swing phase of the involved leg was longer than that of the uninvolved leg, and the stance phase of the involved leg was shorter than that of the uninvolved leg. Goniometry showed three abnormal patterns in the involved leg: a stiff knee gait in 10 patients, a flexed knee gait in 6, and an abnormal flexion-extension pattern in the hip in 9. Goniometry of the uninvolved leg was normal. The mean MSTS score was 22 points (72%). This showed a significant positive correlation to the Ambulation score, but no correlation to any of the temporal variables. Our findings indicate that the time of load on the involved leg, whether conscious or not, is reduced. Follow-up studies are needed to evaluate the effects of the asymmetrical gait pattern observed and the abnormal goniometric results on the development of endoprosthesis-related complications.

Gait analysis of spastic walking in patients with cervical compressive myelopathy

To assess neurological status and to evaluate the effect of surgical decompression in patients with cervical myelopathy, we performed computerized gait analysis in 24 patients with cervical compressive myelopathy who showed spastic walking. Gait analysis was repeated during neurological follow-up that averaged 32.4 months. The gait pattern in patients with severe myelopathy was characterized by hyperextension of the knee in the stance phase without plantar flexion of the ankle in the swing phase, significantly reduced walking speed and step length, prolonged stance phase duration and decreased single-stance phase duration, and increased step width. The angle of flexion of the knee joint in the stance phase was significantly correlated with the Japanese Orthopaedic Association (JOA) score. Postoperative neurological improvement was associated with increased walking speed and decreased extension angle of the knee joint (single-stance phase and swing phase). Postoperatively, 12 patients had normalized extension of the knee in stance phase and their walking speed, cadence, stance phase duration, and single-stance phase duration, as well as step length and width, showed nonsignificant differences from these parameters in healthy controls. Our results show that kinesiological gait analysis is clinically useful for the functional assessment of the severity of spastic walking in cervical myelopathy.

Continuous, bilateral Achilles’ tendon vibration is not detrimental to human walk

Sensory feedback from the moving limbs contributes to the regulation of animal and human locomotion. However, the question of the specific role of the various modalities is still open. Further, functional loss of leg afferent fibres due to peripheral neuropathy does not always lead to major alteration in the gait pattern. In order to gain further insight on proprioceptive control of human gait, we applied vibratory tendon stimulation, known to recruit spindle primary afferent fibres, to both triceps surae muscles during normal floor walk. This procedure would disturb organisation and execution of walking, especially if spindles fire continuously and subjects are blindfolded. Vibration induced significant, though minor, changes in duration and length of stance and swing phase, and on speed of walking and kinematics of lower limb segments. No effect was induced on angular displacement of the ankle joint or trunk and head kinematics. This paucity of effects was at variance with the perception of the subjects, who reported illusion of leg stiffness and gait imbalance. These findings would speak for a selective gating of Ia input during locomotion and emphasise the notion that the central nervous system can cope with an unusual continuous input along the Ia fibres from a key muscle like the soleus.

Breakover

The gait characteristics of a horse with an osteochondral fracture of the third carpal bone of the right forelimb are described. Observation at the trot showed a moderate lameness, with the head nodding downward during the left diagonal (left front-right hind) stance phase. Radiographic examination revealed a comminuted fracture of the proximal dorsomedial margin of the third carpal bone.Cinematographic analysis showed that the lame right forelimb had a shorter stance phase duration and slower breakover than the left forelimb (p<0.01). For both diagonals the hind limb preceded the forelimb at impact and at lift off. Compared with the left diagonal, there was a greater temporal dissociation both at impact and lift off between the limbs of the right diagonal (p<0.05) and, consequently, a shorter period of overlap during the right than the left diagonal stance phase (p<0.01). Impact of the hoof with the ground was toe first on the lame right forelimb, flat footed on the left forelimb.

The effects of treadmill inclination and speed on the activity of two hindlimb muscles in the trotting horse.

Electromyographic activity (EMG) was used to determine how hindlimb muscle activation patterns vary with speed and incline in the horse. EMG was recorded using surface electrodes over the gluteus medius and tensor fasciae latae muscles during treadmill locomotion at trot for different combinations of speed (3.5 to 6 m/s) and inclination (0, 3 and 6%). Raw EMG signals were processed to determine stride duration, activity onset and end, and integrated EMG (IEMG). Stride and stance phase duration decreased linearly with increasing speed. Stride duration was not influenced by the slope. Onset and end of muscle activity came significantly earlier in the stride cycle when speed increased and later when inclination changed from 0 to 6%. The relative duration of the burst (percentage of stride duration) increased as running speed increased, but tended to decrease with increasing slope. The IEMG of the muscles increased with increasing speed and slope, the largest increase being observed in the tensorfasciae latae. It is concluded that both increases in speed and inclination lead to an increase in the integrated electromyographic activity and hence to a higher workload of the 2 hindlimb muscles investigated.

Could Different Directions of Infant Stepping Be Controlled by the Same Locomotor Central Pattern Generator?

This study examined the idea of whether the same central pattern generator (CPG) for locomotion can control different directions of walking in humans. Fifty-two infants, aged 2-11 mo, were tested. Infants were supported to walk on a treadmill at a variety of speeds. If forward stepping was elicited, stepping in the other directions (primarily sideways and backward) was attempted. The orientation of the infant on the treadmill belt determined the direction of stepping. In some infants, we also attempted to obtain a smooth transition from one direction to another by gradually changing the orientation of the infant during a stepping sequence. Limb segment motion and surface electromyography from the muscles of the lower limb were recorded. Most infants who showed sustained forward walking also could walk in all other directions. Thirty-three of 34 infants tested could step sideways. The success of eliciting backward stepping was 69%. Most of the infants who did not meet our backward stepping criteria did, however, make stepping movements. The different directions of stepping had similar responses to changes in treadmill speed. The relationship between stance and swing phase durations and cycle duration were the same regardless of the direction of stepping across a range of speeds. Some differences were noted in the muscle activation patterns during different directions of walking. For example, the hamstrings were much more active during the swing phase of backward walking compared with forward walking. The quadriceps was more active in the trailing leg during sideways walking. In some infants, we were able to elicit stepping along a continuum of directions. We found no discrete differences in either the electromyographic patterns or the temporal parameters of stepping as the direction of stepping was gradually changed. The results support the idea that the same locomotor CPG controls different directions of stepping in human infants. The fact that most infants were able to step in all directions, the similarity in the response to speed changes, and the absence of any discrete changes as the direction of stepping was changed gradually are all consistent with this hypothesis.

Early corrective reactions of the leg to perturbations at the torso during walking in humans.

The contribution of afferent feedback to the regulation of locomotion in humans is not well understood. Animal experiments have suggested that loading of the leg during the stance phase may enhance the magnitude of extensor burst activity and delay the onset of swing phase. The aim of the present study was to determine whether transient loading of the leg at the end of stance would enhance extensor-muscle activity and delay the onset of swing in walking humans. To test this hypothesis, we applied loads to the hips of subjects so that the load was applied along the long axis of the leg at the end of stance (down-back unsupported, DBU). This resulted in an unexpectedly complex reaction characterised by rapid co-contraction of antagonist pairs of muscles around the ankle and knee and a prolongation of the stance phase. We speculated that the complexity of the reaction was, in part, due to a disturbance in equilibrium. To address this possibility, two additional perturbation paradigms were tested: (1) subjects held a rail during the loading paradigm (down-back supported, DBS), or (2) subjects received only a posteriorly directed perturbation of the hips, which added no additional load to the leg (backward unsupported, BU). As predicted, the DBS perturbation resulted in an enhancement of the ongoing soleus-muscle activity, and the unexpected tibialis anterior burst that was observed during the DBU paradigm was absent. Allowing the subjects to hold a rail substantially reduced the change in the timing of the step cycle observed in the DBU paradigm. The BU perturbation prolonged the stance phase duration and, as expected, resulted in a burst of activity in tibialis activity. This was usually accompanied by a reduction in the ongoing soleus activity. Two important conclusions are drawn from the present study. First, loading of the leg at the end of stance phase enhances the ongoing extensor-muscle activity. We suggest that afferent feedback responding to the increase load supported by the leg leads to rapid enhancement of the active extensor muscles to compensate for the increased load and prevent collapse of the leg. Interestingly, the duration of the stance phase was only marginally increased when loading was applied without a postural disturbance (DBS). Second, posterior perturbation of the centre of mass at the end of stance phase evokes an "automatic postural response" in tibialis anterior. Of particular interest, this evoked postural response can occur simultaneously with an enhanced activation of soleus. This indicates that the DBU perturbation employed in this study elicited two responses, one to prevent the collapse of the leg and the other to stabilise the centre of mass.

Simulated effects of racetrack material properties on the vertical loading of the equine forelimb

One of the factors cited as contributing to racing injuries of horses is the condition of the racetrack surface. This study examines the possible effects of different dirt racetrack surfaces by using dynamic modelling of the horse and track to quantify the vertical loading of the hoof and coffin joint. Results indicate that as the stiffness of the racetrack material increased from a weak soil to a rock surface (constant soil damping ratio of 15% of critical damping), the maximum track deflection decreased from 5.1 to 1.2 cm; stance phase duration decreased by 60%; energy dissipation decreased by 72%; maximum vertical ground reaction force and coffin joint force increased by 19% and maximum vertical rate of loading increased by 219%. Varying the soil damping ratio from 5 to 30% of critical damping had only small effects on the loading response, changing the above parameters by less than 5% for the medium soil type simulated. These results indicate that the track surface may have a profound effect on the loading conditions of the horse’s limb, with the surface stiffness properties having a greater effect on loading than the surface damping properties. Design of appropriate race track surfaces may therefore be more dependent on selection of soil for structure, rather than soil amendments which have been used primarily to alter damping characteristics.

Limb locomotion — speed distribution analysis as a new method for stance phase detection

The stance phase is used for the determination of many parameters in motion analysis. In this technical note the authors present a new kinematical method for determination of stance phase. From the high-speed video data, the speed distribution of the horizontal motion of the distal limb is calculated. The speed with the maximum occurrence within the motion cycle defines the stance phase, and this speed is used as threshold for beginning and end of the stance phase. In seven horses the results obtained with the presented method were compared to synchronous stance phase determination using a force plate integrated in a hard track. The mean difference between the results was 10.8 ms, equalling 1.44% of mean stance phase duration. As a test, the presented method was applied to a horse trotting on the treadmill, and to a human walking on concrete. This article describes an easy and safe method for stance phase determination in continuous kinematic data and proves the reliability of the method by comparing it to kinetic stance phase detection. This method may be applied in several species and all gaits, on the treadmill and on firm ground.

Locomotor response to exercise in relation to plasma lactate accumulation and heart rate in Andalusian and Anglo-Arabian horses.

To establish the effect of the locomotor pattern on heart rate (HR) and plasma lactate (LA), 28 horses, 18 Andalusian (AN) and 10 Anglo-Arabian (AA), aged 3-4 years, were studied. After a warm-up period, the horses performed a four-step test at 5, 6, 7 and 8 m/s, covering 1000 m at each velocity. HR was monitored, LA was analysed at rest and after each workload, and images were filmed. The locomotor parameters determined were stride duration (SD), frequency (SF) and length (SL), step and bipedal support durations, stance (restraint and propulsion) and swing phase durations, and stride vertical component. The HR and LA were significantly higher in the AN horses from velocities of 5 m/s. Similarly, the stride vertical component was higher in the AN horses at the trot and in the leading forelimbs at the gallop. Conversely, at all the galloping velocities, swing phase duration and stride length were longer in the AA horses. Significant correlations between HR, LA and locomotor pattern were only found in the AN horses. It was concluded that the greater stride vertical component in the AN horses limits SL and the cranial advancement of the hoof, with the result that reaching a longer SL triggers an increase in HR and LA. AA horses reach a balance between SL and SF, improving the efficiency of the gait.

Changes to the gait initiation programme following a running exercise in human subjects

The question addressed by the present study was whether the programme for gait initiation is fully invariant or can be modified by a prior long duration running exercise. Eight subjects performed a series of gait initiation movements on a force platform in three different speed conditions before and after running on a treadmill (3.3 m/s, 0% slope). Following the running exercise, the first step length and velocity were greater and the double stance phase duration was shorter, while the relationships between the temporal parameters of gait initiation and the velocity of the centre of gravity at the end of the first step were not significantly different. During the anticipation phase, the maximal variation of the ankle joints moment remained significantly correlated with the integrated EMG activity of the Tibialis Anterior after the run. However the displacement of the centre of foot pressure, displayed some post-exercise changes, indicating a modification to the postural part of the gait initiation programme. The greater velocities reached after the running exercise could be explained by a recalibration of gravitational force control, while the invariance of time necessary to reach these velocities showed the rigidity of the initiation gait.

Center of gravity dynamic stability in normal and vestibulopathic gait.

The purpose of this study was to examine the three-dimensional whole body center of gravity (CG) kinematics during free and paced gait in healthy subjects (n=16) and individuals with vestibulopathy (n=8). The cycle time, double and single stance phase durations, values and timing of CG forward velocity, and CG vertical displacement were recorded using an 11 segment, 66 degree of freedom whole body model. The free speed gait of the vestibulopathic individuals was remarkable for increased cycle time, increased percentage of time spent in the double stance phase, decreased forward velocity of the CG, and decreased vertical displacement of the CG. However, during paced gait, no statistically significant differences were found between the vestibulopathic and control groups in all measures. In all groups, CG horizontal velocity maxima and minima significantly lagged CG vertical minima and maxima respectively. We conclude that whole body CG control does not result purely from optimization of mechanical potential and kinetic energy exchanges: our temporal offsets in the maxima and minima of the CG horizontal velocity and vertical displacement make this mechanically impossible. Furthermore, individuals with vestibular impairment may self-select a slower walking speed to ease their biomechanic stability challenge despite being able to ambulate faster with 'normal' CG velocities and displacements. Copyright 1998 Elsevier Science B.V.

Effects of Acceleration on Ground Reaction Forces Collected in Healthy Dogs at a Trot

SummaryThe aim of this study was to assess, whether or not, visual grading of changes in subject acceleration during force plate collection within a fixed, measured velocity range was adequate to control acceleration/deceleration. A second question was, whether or not, visual grading of the trials was adequate to prevent significant changes in ground reaction forces within a controlled velocity range. Eight healthy, non-chondrodysplastic dogs, of varying breeds, were used in the study. Each dog was tested in four different protocols. The order in which the dogs completed the different protocols was determined randomly. During all of the protocols, the dogs trotted across the measured testing area within a velocity range of 1.6 to 1.9 m/s. The protocols varied in the amount of acceleration or deceleration allowed in the testing area and the methods of evaluating the acceleration or deceleration. Significant differences in ground reaction force measurements were found, with variations in the acceleration and deceleration. The majority of changes were found in the craniocaudal axis during acceleration and deceleration. Vertical axis measurements were only altered in the rear limbs. Significant differences were not found in any measurement (except the stance phase duration in the rear limb) between the mechanically controlled minimal acceleration/deceleration variation protocol and the visually controlled acceleration/deceleration variation protocol. While visual observation was unable to consistently differentiate acceleration, or deceleration, changes through the testing area, it was able to eliminate enough variation in ground reaction force measurements so that differences were not found between the mechanically controlled minimal acceleration/ deceleration variation protocol nor the visually controlled acceleration/deceleration variation protocol. These results suggest that either method of collection may be acceptable for data collection depending upon the type of study being performed.The effects of acceleration variation were examined in dogs undergoing force plate gait analysis. Significant differences in ground reaction force measurements were found, with variations in the acceleration and deceleration. The majority of changes were found in the craniocaudal axis, during acceleration and deceleration. Visual observation was unable to consistently differentiate variations in acceleration through the testing area.

1〜2歳児の歩行獲得過程における運動力学的変化

The aim of this research is to examine the kinetic and kinematic changes of infant gait by longitudinal observation of infants at the onset of bipedal walking. We are especially interested in the trajectory of the foot force as a kinetic parameter which is important in determining the developmental stage of an infant. Six infants, ranging from 10 months to 2 years and 1 month of age, were examined longitudinally by means of a force plate system and a three-dimensional motion analysis system. Two characteristics of the trajectory of foot force distinguish an infant from an adult during a single stance phase. First, the sagittal track length of the trajectory of the infant, standardized by foot length, is shorter than that of the adult. The length is correlated with the duration of single stance phase. Second, the transverse sway of the trajectory is characteristic of the infant gait. The above results are related to displacement of the joints, that is, transverse displacement of the hip joint, vertical displacement of knee joint, and the pattern of transverse movements of shoulder, hip, and knee joints. The transverse displacement of the hip joint during stance phase is larger in the infant gait than in the adult gait. It decreases with development. Rapid decrease is observed between 10 months and 15 months. The vertical drop of the knee joint is conspicuous at the earlier month of independent walking. This action of the knee joint causes an impact to the force plate. The pattern of transverse movements of shoulder and hip joints differs between infants and adults. The shoulder and hip joints of infants sway together during stance phase. The shoulder and hip joints of adults first begin to move laterally following heel contact. When the load acts on one foot, the adult shoulder joint moves in the opposite direction. The knee joints of infants and adults both move in the opposite direction to the shoulder joints at that time. The sway of each joint causes instability of the center of gravity and changes the trajectory of foot force. The trajectory of foot force and the displacement of joints accordingly express the stability of the center of gravity. They can be added to the series of parameters useful in judging the developmental stage of the infant gait.

The improvement of the gait quality of sound trotting warmblood horses by normal shoeing and its effect on the load on the lower forelimb

This study quantifies the effects of normal shoeing on the gait quality and the load on the lower forelimb in 12 sound Dutch warmblood horses. A modified CODA-3 gait analysis system and a force plate were used to objectively register the quality of the trot and the load on the lower limb. Both kinematic and kinetic variables were studied as a function of shoeing. Important variables for trot quality were considered: the relative stance phase duration, the relative swing phase retraction, the maximal extension of the fetlock joint, and the animation of the trot. All of these variables but the maximal extension of the fetlock joint improved after shoeing. No significant effects of shoeing on the moments of force of the fetlock joint and the coffin joint, as representatives of the load on the lower limb, could be demonstrated. It is concluded that shoeing improves the trot quality of sound Dutch warmblood horses as a result of the increased inertia of the lower limb during the swing phase, due to the increased weight of the hoof. Furthermore, shoeing does not seem to affect the load on the lower limb during the stance phase.

Modification of group I field potentials in the intermediate nucleus of the cat spinal cord after chronic axotomy of an extensor nerve

In walking decerebrate cats the influence of group I afferents from the medial gastrocnemius (MG) and the lateral gastrocnemius/soleus (LGS) muscles on stance phase duration is altered after axotomy of the LGS nerve [Whelan, P.J., Hiebert, G.W. and Pearson, K.G., J. Neurophysiol., 74 (1995) 2782–2787]. We examined whether a site for this plasticity is the connection from group I afferents onto spinal interneurons. Group I field potentials from MG, LGS and plantaris (PL) muscle afferents were recorded in the intermediate nucleus of the L6/L7 segments. Within 5 days following the transection of the LGS nerve in one hind leg, the field potential amplitudes from LGS afferents were decreased, from MG increased and those from PL were unchanged. The changes in the field potentials parallel modifications in the influence of group I afferents from the MG and LGS muscles on stance phase duration during walking.

Hemiplegic gait. Relationships between walking speed and other temporal parameters.

It has been asserted that speed alone is an effective indicator of the degree of gait abnormality. To determine the validity of this assertion, relationships between velocity and 18 other temporal gait parameters were determined in 25 patients with a first hemispheric stroke resulting in hemiplegia or hemiparesis of at least one month duration. Gait characteristics were recorded using footswitchs connected to a portable computerized monitoring device. Velocity was found to be significantly correlated with cadence, mean cycle duration, mean cycle length, hemiplegic limb stance phase duration, nonhemiplegic limb stance phase duration and percent, nonhemiplegic limb swing phase percent, double support phase duration and percent, hemiplegic limb swing/stance phase ratio, nonhemiplegic limb swing/stance phase ratio, and swing phase symmetry ratio but not with the hemiplegic limb stance phase percent, hemiplegic limb swing phase duration and percent, nonhemiplegic limb swing phase duration, stance phase symmetry ratio, and overall asymmetry ratio. Velocity is related to most, but not all, of the other temporal measures of hemiplegic gait. A comprehensive gait evaluation should also include characterization of the degree of asymmetry and descriptions of individual phase durations and proportions (particularly hemiplegic stance and swing percentages).

Training as an influential factor on the locomotor pattern in Andalusian horses.

The physiological and metabolic adaptations to exercise of the Andalusian horse seem to differ slightly from those found in other breeds. The authors studied the locomotor adaptation of 18 Andalusian horses to a training programme in relation to anaerobic energy metabolism, efficacy of the training programme, and changes associated with the onset of fatigue. They also tried to find out if these changes had become diminished by training. Several locomotor variables during trotting and galloping were determined and plasma lactate concentrations were measured before training and after two training periods of different lengths. While trotting after training, an increase in the duration of the restraint phase, a reduction in the propulsion phase and a decrease in the duration and length of step were observed. During galloping, training caused a reduction in stride length but an increase in stride frequency. Significant correlations were obtained between stride duration, frequency and length of step and lactate concentrations. The training might have caused a shift in metabolism from anaerobic to aerobic predominance. This reduction was coupled with a decrease in stride duration, in response to a shorter stance phase duration and an increase in stride frequency. A reduction in the fatigue level was not observed. The study concludes that this training programme was not sufficient for improving the physical capacity of Andalusian horses.

Recovery of Locomotion after Spinal Cord Hemisection: An X-Ray Study of the Cat Hindlimb

Hemisection of the spinal cord in adult cats is a suitable model to study the mechanisms underlying recovery of motor functions. The initial paresis of the hindlimb is followed by a considerable improvement of locomotor functions of the affected hindlimb. Kinematic analyses of treadmill locomotion were performed from 10 days to 8 months after complete hemisections (right side) of the spinal cord at the thoracolumbar level, using X-ray cinematography for precise measurements of the hindlimb joint angles. The footfall pattern and the electromyogram were recorded. Motor control of both proximal and distal hindlimb joints improved substantially during the 1st postoperative month. However, persistent locomotor deficits were still present several months after hemisection. They could be divided into three groups of symptoms: (1) The gait pattern was disturbed with regard to interlimb coordination. The stance-phase duration of the right hindlimb was shortened. (2) The flexor capacity of the affected hindlimb was reduced, resulting in a slow insufficient flexion of the hip, knee, and ankle during the swing phase. (3) The timing of the flexion–extension events was impaired. The onset of the E1-extension was delayed and the amplitude was reduced. Electromyographic patterns of muscle activity during locomotion of the lesioned side hindlimb differed from the contralateral hindlimb, which served as a control. The results indicate that in spite of a good short-term functional improvement there are long-term locomotor deficits present after spinal cord hemisection.