Stance Phase Duration Research Articles

The change of the locomotor pattern caused by the inclination of the substrata in a Japanese macaque

In order to clarify the condition of the change from the horizontal quadrupedal walking to the vertical climbing in a Japanese macaque, we made an experiment on the inclined substrata. The subject was an adult male Japanese macaque. It freely moved on the substrata, a bamboo pole (8cm diameter). The inclination of the substrata was changed from 15 degrees to 65 degrees with each 5 degrees and the number of the steps was eleven. We put the surface extrodes and telemetry transmitters on the subject to record the activity of the triceps brachii and the biceps brachii. The patterns of the electromyography were clearly different between the horizontal quadrupedal walking and the vertical climbing.The palm of the Japanese macaque touched the substrata on the behind side in the vertical climbing. It was found that this type of forelimb use was observed in the inclination of 50 degrees or more. The cycle duration also decreased at the inclination of 50 degrees or more. The relative duration of stance phase of the forelimb decreased at the inclination of 65 degrees and that of the hindlimb increased at the inclination of 55 degrees or more. The electromyography study showed three stages. The first stage was similar to the horizontal quadrupedal walking and it was seen at the inclination of 15 degrees or less. The second stage was the intermediate type and it was observed between the inclination of 20 degrees and 50 degrees. The last stage was similar to the pattern of vertical climbing at the inclination of 55 degrees or more. These results of electromyography were related to the difference in the locomotor function of the forelimb at different degrees of inclination.

Biokinematic effects of collection on the trotting gaits in the elite dressage horse

Trot in hand, working trot, collected trot, passage and piaffe of 6 Grand Prix dressage horses were recorded by high speed film (250 frames/s). Angular patterns and hoof trajectories of the left fore- and hindlimbs were analysed and presented as mean and standard deviation (s.d.) curves. Speed and stride length decreased and fore- and hind stance phase durations increased with collection resulting in no suspension in piaffe. The diagonal advanced placement was positive in all gaits except for piaffe. Most of the changes in forelimb angular patterns were effects of reduction in forelimb pendulation. The horses did not step under themselves more in collected trot, passage and piaffe than in trot in hand. The stifle and hock joints were more flexed at the start of the stance phase in piaffe and passage than in the other gaits. Flexion of the hock joint at the middle of the stance phase was largest in passage and piaffe. In spite of the limited number of horses the present study confirmed earlier observations of conformation and gaits in dressage horses. Hindlimb pendulation, femur and pelvis inclinations and elbow, carpal, stifle and hock joint angles seem to be the most significant angular measurements for dressage performance.

Biomechanical analysis of swing-through gait in paraplegic and non-disabled individuals

The purpose of this study was to determine if the deficit of motor function affects the displacement of the lower limbs and increases the physical strain of upper-body musculature in paraplegic individuals performing swing-through gait. A biomechanical model consisting of four linked rigid bodies was developed to analyze this type of gait. Data were obtained on the spatio-temporal characteristics, kinematics and kinetics from a sample of eight non-disabled and nine paraplegic individuals performing swing-through gait. Net muscle moments acting on the segments and mechanical powers at three joints (shoulder, elbow, hip) were estimated during a complete gait cycle from basic force equations and moments of force acting on a rigid body. Results show that the two groups selected a similar comfortable speed suggesting that the type of gait per se is an important factor in the selection of speed. Paraplegic individuals had a longer crutch stance phase duration than the non-disabled due to inadequate hip muscle activations as confirmed by the moment of force and power analyses. Moreover, a higher moment of force at the shoulder was observed in the paraplegics individuals, mostly during the crutch stance phase. Consequently, the loss of motor function of the lower limbs in paraplegic individuals modifies the biomechanical pattern of swing-through gait compared to non-disabled individuals, and seems to increase the physiological demand on the upper limbs during the stance and swing phases of the gait cycle.

The Ground Reaction Force in the Gait of Intoeing Children

One hundred twenty-four intoeing and 80 age-matched normal children were studied using the Kistler force plate. Intoeing gait was usually caused by increased femoral anteversion (IFA), internal tibial torsion (ITT), or metatarsus adductus (MAD). Thirty-five children showing spontaneous correction and a return to normal gait (COR) were singled out. Our results confirmed that there were variations of the ground reaction force (GRF) in three directions in the different groups, particularly in the vertical and medial-lateral components. Alterations of magnitude of GRF or duration of stance phase was found to be significant compared with normal subjects. On this basis, we suggest that dynamic forces are related to the remodeling of the epiphyseal plate or respond to actions of the plantar flexors, although we could not discern a specific correlation between them.

Electromyograph Analysis of the Popliteus Muscle in Level and Downhill Walking

It has been proposed that the popliteus muscle is a source of lateral knee pain, typically after downhill activities. Electromyography of the popliteus muscle was recorded in 9 normal subjects during level walking, downhill walking, and walking downhill wearing a 40-lb backpack (to simulate hiking). Popliteal muscle intensity during the midstance phase of walking downhill with weights increased significantly over that of level walking (30% versus 13%, respectively) (p < 0.05). There was a nonsignificant trend (p = 0.07) for a similar increase at terminal swing (51% versus 36%). Significantly greater knee flexion was recorded at loading response, midstance, and terminal stance (p < 0.01) during both downhill trials as compared with level walking. Initial contact position showed no differences. Velocities for downhill walking (72.9 m/min) and downhill walking with weights (71.1 m/min) were significantly less than those of level walking (83.9 m/min) (p < 0.01). Stride analysis showed no significant difference in stance phase duration or in initial double-limb support times between level walking and either downhill condition. These data suggest that increased popliteal muscle activity during midstance in downhill walking with weights is in response to weight bearing with an increased load on a flexed knee. Increased Electromyographic activity may be associated with overuse of the popliteus muscle.

Gait analysis of myopathic children in relation to impairment level and energy cost

The electromyographic and kinematic patterns of gait and its energy cost were studied in 12 myopathic patients who were still walking and 12 normal subjects. On the basis of significant gait variables, three distinct levels of impairment were defined in the group of myopathic subjects: early, intermediate and final. These clusterings were predicted with 95.7% accuracy by two gait variables: the stance phase duration and the heel vertical excursion. The gait patterns of each group were compared to the control group. Reduced speed and range of motion, short stride length, small foot-floor clearance, increased energy cost and lateral displacements of centre of gravity were typical and increased with the muscular weakness. The activation of soleus muscle occurred progressively earlier as did the cessation of tibialis anterior activity. In severe disorders, there was increased activity in the muscles acting on the hip and knee. When muscular dystrophy leads to more disability the myopathic patients tended to change from the normal plantigrade gait pattern to an infantile digitigrade-like pattern with a decrease of the tibialis anterior muscle work.

Ground reaction force patterns of Dutch warmblood horses at normal trot.

This study was undertaken to establish limb loading patterns of sound horses at the trot, to provide a data base against which results for lame horses could be compared. Ground reaction force (GRF) data were collected from 20 clinically sound Dutch Warmblood horses. The data from at least 5 stance phases of each limb were averaged after standardisation to the animal's body mass and to the stance phase duration and resulted in 'representative' GRF data. The symmetry in the vertical GRF peak amplitudes, impulses and the stance phase duration comparing left and right limbs exceeded 97%. By averaging the 'representative' GRF of the 20 horses a 'standard' GRF pattern of the Dutch Warmblood horse at the trot was constructed. The GRF patterns at the trot, compared with those at the walk, showed only one vertical force peak in forelimbs and hindlimbs (11.59 N/kg and 10.21 N/kg, respectively). The retardatory and propulsory forces were distributed over the forelimbs and hindlimbs in such a way that the forelimbs contributed more to retardation (peak forces 1.13 and 0.79 N/kg), and the hindlimbs more to propulsion (-0.84 and -1.17 N/kg, respectively).

片側性変形股関節症患者の歩行解析 同一人の術前・術後の比較

We studied 6 unilateral osteoarthritic hip patients before and after total hip replacement, and compared them, using a large floor reaction force plate. The average age of patients was 56.4 years at operation. The mean follow-up was 13.8 months after the last T. H. R.. The “weighing-off” effect ratio, indicating smooth ambulation of the bodies center of gravity, increased (p=0.075) after T. H. R. in comparison with before surgery. The stance phase duration ratio increased (p=0.10), but maximal walking speed did not increase after T. H. R. in comparison with before surgery. This improvement can be quantified, documented, and followed by using a system of gait evaluation.

片麻痺患者の歩行の連続計測 : 短下肢装具の矯正モーメントの影響を中心として

The ankle joint moment in the saggital plane, dorsi and plantar flexion of the ankle joint, flexion and extension of the knee joint, and temporal factors of gait were measured continuously for 10 hemiplegic patients under two conditions: with and without AFO. The ankle joint moment was measured by a capacitive transducer which detected vertical floor reaction forces during the gait. All devices were attached to the subject's body, so that 8 to 20 strides could be measured continuously during 30 seconds. A specially disigned AFO was used in order to decompose the total ankle joint moment into two factors, the moment due to muscle forces and the moment due to the corrective forces generated by the AFO. The data were analyzed with special focus on the corrective moment of the AFO. The maximum dorsi-flexion moment due to the AFO in the early stage of the stance phase was less than 5Nm, and the maximum plantar-flexion moment in the late stage of the stance phase was less than 8Nm. These values were small in comparison with the total ankle joint moment, which ranged up to 70Nm. In regard to the effect of the AFO, the following general tendencies were statistically found. 1. The gait cycle decreased. 2. The single stance phase duration of the affected leg increased. 3. The swing phase duration of the affected leg decreased. 4. The maximum dorsi-flexion angle of the ankle joint during stance phase decreased. 5. The maximum plantar-flexion angle during swing phase of the ankle joint decreased. 6. The maximum dorsi-flexion of the ankle joint occurred in the ealier stage of the stance phase. 7. The maximum extension of the knee joint occurred in the later stage of the stance phase. 8. The maximum dorsi-flexion moment increased. 9. The maximum plantar-flexion moment increased. 10. The maximum dorsi-flexion moment occurred later. 11. The activities of dorsi-flexor muscles and plantar-flexor muscles decreased. However, hemiplegic gait showed extremely large variation depending on the subject. Thus, a case where the ankle joint moment increased with the AFO, a case where the ankle joint moment decreased with the AFO, and cases that showed a change in the knee joint angular pattern are reported and examined in more detail individually.

大型床反力計を用いた片側変形性股関節症患者の歩行解析 特にＴＨＲ前後でのＪＯＡ ｓｃｏｒｅとの関連について

Using a floor reaction force plate system, gait studies were performed on 25 unilateral osteoarthritic hip patients and compared with 5 normal healthy adults. Four parameters of gait analysis, that is, “weight off” effect ratio, deceleration effect ratio, stance phase duration ratio and stance phase impulse ratio, were evaluated by force plate data. The “weight off” effect ratio was shown to be the most reliable parameter and correlated to the JOA score. All parameters, except for the “weight off” effect ratio, showed that there was no statistical significance between the gait of normal adults and that of post-operative patients whose JOA score was over 80 points.

Voluntary bipedal walking of infant chimpanzees

The voluntary bipedal walking of infant chimpanzees was studied by the analysis of foot force and by motion analysis. The infants were trained to locomote on a level platform without any restrictions on the locomotor pattern. The voluntary bipedal walking was compared with the other types of locomotion at the same age and with the trained bipedal walking performed by other chimpanzees, including adult chimpanzees. The characteristics of voluntary bipedal walking in the infant until one year of age were: (1) high-speed walking with short cycle duration; (2) short stance phase duration; (3) small braking component of the preceding leg and large acceleration of the following leg; (4) one downward peak in the vertical component; and (5) a relatively small transverse component. Bipedal walking usually continued for less than one second and ended in quadrupedal locomotion. During walking, the preceding foot touched the floor, heel first, as in the case of older chimpanzees and humans. At this age, bipedal walking was similar to high-speed locomotion. The voluntary bipedal walking of the two-year-old and frour-yearold chimpanzees was characterized as follows: (1) slower speed than during quadrupedal locomotion, (2) relatively long periods and distances; (3) well balanced accelerating and braking components; and (4) a vertical component showing two downward peaks and a trough in between during numerous trials. The last characteristic means that the body center of gravity is higher in the single stance phase, just as in the bipedal walkinbg of the adult chimpanzees and humans. The bipedal walking of infant chimpanzees was discussed in comparison with the walking of humans, including infants.

Stairclimbing kinematics on stairs of differing dimensions.

The purpose of this study was to provide a kinematic description of the task of stair ascent and descent. Fifteen women were divided into short, medium, and tall subject groups. Three testing staircases of different riser and tread dimensions were used. Temporal and cinematographic data were collected simultaneously via switchmats and a high-speed camera, respectively. Measures of stairclimbing gait cycle duration, swing and stance phase durations, cadence, and velocity appeared to be systematically related to subject height. Stance (19% to 64%) and swing (36% to 81%) phase durations varied considerably depending on stair dimensions during stair descent. Less variation was observed in stance (50% to 60%) and swing (40% to 50%) values during tasks of stair ascent. Individuals appeared to adjust to stair dimensions by varying the flexion/extension patterns of the knee rather than those of the ankle or hip. Depending on the staircase climbed, knee flexion angles ranging from 83 degrees to 105 degrees were required. Stair dimensions, therefore, appeared to influence the temporal and angular kinematics of the lower limb during stairclimbing.

Kinematic variability and relationships characterizing the development of walking

The purposes of this study were: (1) to determine the pattern of variability and relationships in joint kinematics characterizing the development of walking and (2) to determine whether controlling for postural stability in new walkers results in less variability. The variability and relationships among hip, knee, and ankle motions were measured during 10 gait cycles of new walkers, supported new walkers, two-year-olds and seven-year-olds. Fourier series were generated for each joint motion and standard deviations were compared across groups. An age-related decline in variability was evident in select portions of the cycle. Stance and swing phase duration correlated with cycle duration for all ages. Postural support did not lessen variability in joint rotations for new walkers. Cross-correlations for hip-knee, knee-ankle, and hip-knee rotations were strong across all groups. These results suggest that a coordinative structure for walking produces strong intralimb coupling early in development, despite variability in select portions of joint motions.

Adaptive control for backward quadrupedal walking. I. Posture and hindlimb kinematics

1. To gain new perspectives on the neural control of different forms of quadruped locomotion, we studied adaptations in posture and hindlimb kinematics for backward (BWD) walking in normal cats. Data from four animals were obtained from high-speed (100 fr/s) ciné film of BWD treadmill walking over a range of slow walking speeds (0.3-0.6 m/s) and forward (FWD) treadmill walking at 0.6 m/s. 2. Postural adaptations during BWD walking included flexion of the lumbar spine, compared to a relatively straight spine during FWD walking. The usual paw-contact sequence for FWD walking [right hindlimb (RH), right forelimb (RF), left hindlimb (LH), left forelimb (LF)] was typically reversed for BWD walking (RH, LF, LH, RF). The hindlimbs alternated consistently with a phase difference averaging 0.5 for both forms of walking, but the phasing of the forelimbs was variable during BWD walking. 3. As BWD walking speed increased from 0.3 to 0.6 m/s, average hindlimb cycle period decreased 21%, stance-phase duration decreased 29%, and stride length increased 38%. Compared to FWD walking at 0.6 m/s, stride length was 30% shorter, whereas cycle period and stance-phase duration were 17% shorter for BWD walking. For both directions, stance occupied 64 +/- 4% (mean +/- SD) of the step cycle. 4. During swing for both forms of walking, the hip, knee, and ankle joints had flexion (F) and extension (E1) phases; however, the F-E1 reversals occurred earlier at the hip and later at the knee for BWD than for FWD walking. At the ankle joint, the ranges of motion during the F and E1 phases were similar for both directions. During BWD walking, however, the knee flexed more and extended less, whereas the hip flexed less and extended more. Thus horizontal displacement of the limb resulted primarily from hip extension and knee flexion during BWD swing, but hip flexion and knee extension during FWD swing. 5. At the knee and ankle joints, there were yield (E2) and extension (E3) phases during stance for both forms of walking; however, yields at the knee and ankle joints were reduced during BWD walking. At the hip, angular motion was unidirectional, as the hip flexed during BWD stance but extended during FWD stance. Knee extension was the prime contributor to horizontal displacement of the body during BWD stance, but hip extension was the prime contributor to horizontal displacement during FWD stance. 6. Our kinematic data revealed two discriminators between BWD and FWD walking.(ABSTRACT TRUNCATED AT 400 WORDS)

A gait training suggestion for lengthening gastrocnemius-soleus muscles: suggestion from the field.

Burns on the posterior lower extremity from the popliteal space to Achilles tendon areas often result in an atypical standing posture and gait pattern. During the acute care hospital stay, the patient frequently assumes a stance position of excessive knee flexion and ankle plantar flexion because of pain splinting or soft tissue shortening, or both (Fig. 1). This burn distribution frequently results in a temporary shortening of the gastrocnemius-soleus muscles. The abnormal stance translates into a familiar gait pattern of absent heel-strike in addition to decreased stride length, weight bearing,1 and duration of stance phase on the involved lower extremity. Furthermore, the pattern may be observed before and after skin grafting is performed. Early intervention is important because a patient is more likely to have optimal results after skin grafting if full active range of motion was attained during the pregrafting phase of burn rehabilitation.1…

Development of chimpanzee locomotion on level surfaces

The objective of this study was to investigate kinesiologically the development of the unique characteristics of the level locomotion of the chimpanzee. The data were obtained semi-longitudinally from six chimpanzees eleven weeks through nineteen years of age. The posture, footfall order, phase duration, speed and foot force (including the hand force) in level locomotion were observed by means of foot contact switches, a 16 mm cine-camera or a video tape recorder and a force plate. The speed or the pattern of locomotion was not particularly controlled. The infants moved freely without any attachments on the body. The age change in locomotion is described. The particular characteristics of the infant chimpanzees compared with those of the adults were: 1) long stance phase duration, 2) wide variety in the difference in the cycle duration between forward movement of the limbs one after another, 3) wide variety in phase duration, speed and foot force, and 4) the forelimbs of the infant just started to stand quadrupedally to carry the larger part of the body weight than the hindlimbs. The dominance of the hindlimbs in locomotor and weight-bearing characteristics becomes clearly fixed at about one year of age. The wide variety of the locomotion pattern will be one of the characteristics of the chimpanzees of all age groups. The human acquisition of bipedal walking is discussed in connection with chimpanzee locomotion.

The technique of jumping a steeplechase fence by competing event-horses

The timing, placement and coordination changes of the limbs of 23 competing event-horses jumping a steeplechase fence were studied using computer-aided analysis of high-speed cinematographic films. All horses appeared to strut with the forelimbs, thereby changing the momentum of forward movement into vertical impulse. The distance of lead and non-lead forelimb placement from the fence was significantly different ( P < 0.05). The average distance between the forelimbs was 0.483 m. The stance phase duration and angle of approach to the ground of left and right limbs ( x = 53.5° ) were not significantly different. Stepwise regression analysis indicated that the distance of the non-lead forelimb was related to the total horizontal distance jumped (standardized regression coefficient = 0.780). The left and right hindlimbs approached the ground at approximately 47.4°, which is significantly different ( P < 0.05) from the approach angle of the forelimbs. The duration of the stance phase did not differ significantly ( P < 0.05) between the left and right hindlimbs nor between hindlimbs and forelimbs. The placement distance of the left and right hindlimbs from the fence was not significantly different, but the distance between the hindlimbs ( x = 0.093 m ) did differ significantly ( P < 0.05) from that of the forelimbs. It is suggested that the synchronous and symmetrical action of the hindlimbs at takeoff allows these limbs to coordinate their movement in the air phase.