Lower Extremity Joint Moments Research Articles

Using induced accelerations to understand knee stability during gait of individuals with muscle weakness

The purpose of this case series was to quantify the effectiveness of different compensatory strategies used by individuals with muscle weakness to produce knee extension during the stance phase gait. Subjects were three males with less than anti-gravity strength in the quadriceps femoris and a variable pattern of weakness elsewhere in the lower extremity. They walked independently at a self-selected speed without assistive devices. Gait analysis of the pelvis and bilateral lower extremity segments was performed with a six-camera, two force platform motion capture system. Joint angles and net internal moments were computed from the motion data. Induced acceleration analysis was performed to quantify the relative ability of each lower extremity joint moment and gravity to produce knee angular acceleration. Results showed that a variety of adaptive strategies both within and across limbs can control knee position during gait. One subject generated knee extension almost exclusively via the hip extensor moment. Another relied less on the hip extensor moment (39%) and more on the ankle plantar flexor moment (61%) to create knee extension. The third subject used the ipsilateral hip extensor moment (24%) and the contralateral ankle plantar flexor moment (67%) to assist knee extension. The strategy selected by each subject likely was influenced by both their total pattern of impairments and the effectiveness of the available compensations. This case series demonstrates how an induced acceleration analysis can augment a traditional gait analysis to expand and enhance our understanding of compensatory movement control strategies.

22.26 Postural instability in the frontal plane induced by lateral perturbations during treadmill walking

The purpose of this investigation was to determine the effect of unexpected forward perturbations (FP) during gait on lower extremity joint mechanics and muscle Electromyographic (EMG) patterns in healthy adults. The muscles surrounding the hip were found to be most important in maintaining control of the trunk and preventing collapse in response to the FP. Distinct lower extremity joint moment and power patterns were observed in response to the FP but an overall positive moment of support (Ms) was maintained. Therefore, reactive balance control was a synchronized effort of the lower extremity joints to prevent collapse during the FP.

Hip and knee frontal plane moments in persons with unilateral, trans-tibial amputation

Persons with unilateral, lower-extremity amputation are at risk of developing osteoarthritis in their intact limb. Among persons without amputation, knee osteoarthritis disease severity has been linked to elevated frontal plane knee moments. Therefore, the purpose of this study was to examine knee and hip frontal plane moments in persons with unilateral, trans-tibial amputation. We hypothesized that knee and hip internal abduction moments are greater in the intact limb compared to the prosthetic side. Three-dimensional gait mechanics were measured bilaterally from 10 persons with unilateral, trans-tibial amputation during walking to calculate lower-extremity joint moments. The intact limb knee and hip peak internal abduction moments were 46% and 39% greater, respectively, than on the prosthetic side. The intact side knee and hip peak internal abduction moments were 17% and 6% greater, respectively, than normal. Larger moments suggest joint loading is of higher magnitude on the intact side, which may be predisposed to premature joint degeneration, particularly knee osteoarthritis.

Lower Extremity Joint Moments of Collegiate Soccer Players Differ Between Genders During a Forward Jump

Lower Extremity Joint Moments of Collegiate Soccer Players Differ Between Genders During a Forward Jump

Lower Extremity Joint Moments of Collegiate Soccer Players Differ Between Genders During a Forward Jump

Lower Extremity Joint Moments of Collegiate Soccer Players Differ Between Genders During a Forward Jump

ドロップ着地における関節モーメントによる回転安定性の姿勢制御

In drop landing studies, control of rotary stability based on the net effect of the three joint moments has not been previously investigated. Ashby & Heegaard(2002) quantified rotary stability in a standing long jump study by using the moment about the center of mass by ground reaction force (MCM). The purpose of the present study was to investigate rotary stability by MCM and the lower extremity joint moments, as well as the effects of the joint moments on rotary stability. Ten healthy male sublects(age;22.9±0.99yr, body mass;mass 68.2±7.00kg, and height;174.5±3.57cm)participated.A fbrce platform(Kistler type 9287BA&9281CA, Kistler Instnlments, Switzerland)was used to measure ground reaction fbrces(GRF)at 1kHz. Also, two high speed cameras(FASTCAM, Photron, Japan)were used to record human motions at 0.25kHz. Each subject performed stiff and soft drop landings from a platfbrm (0.48m). In stiff landing, as much as possible, the subjects did not flex their joints. On the other hand, in soft landing the subjects used joint flexions to attenuate impact. Joint moments were calculated using an inverse dynamic analysis. In addition, MCM was calculated by vector product of the position vector from the whole body center of mass to the center of pressure and GRF. The MCM in backward direction was larger in stiff landing than in soft landing. In addition, when the hip joint moment increased, the knee joint moment decreased. On the contrary, when the hip joint moment decreased, the knee joint moment increased. Thus, these findings indicate that the coordination of knee flexion joint moment and hip extensor joint moment is an important factor for controlling rotary stability during drop landings.

달랑베르(D`Alembert)의 운동방정식을 이용한 수직점프시 하지관절의 모멘트 계산

달랑베르(D`Alembert)의 운동방정식을 이용한 수직점프시 하지관절의 모멘트 계산

PARKINSON??S DISEASE AFFECTS LOWER EXTREMITY JOINT MOMENTS DURING GAIT

The kinematics of gait in patients with Parkinson's disease (PD) has received considerable attention. However, little information is known about lower extremity joint kinetics during locomotion in individuals with PD. PURPOSE To compare lower extremity joint moments in optimally medicated patients with PD to gait velocity-matched older adults during gait. METHODS Sixteen patients with PD (PDP) (mean ± SD, age: 64.6 ± 12.0 yrs; height: 175.7 ± 7.2 cm; mass: 84.6 ± 12.4 kg) and 21 elderly adults (ELD) (age: 80 ± 6 yrs.; height: 162.3 ± 9.9 cm; mass: 65.7 ± 11.8 kg) performed multiple walking trials at a self selected pace. Kinematic and kinetic data were obtained using a motion analysis system time synchronized to two force plates. Video and GRF recordings were combined with anthropometric data to perform an inverse dynamics analysis. The peak plantarflexor moment (PFM) at the ankle and peak extensor moments at the knee (KEM) and hip (HEM) during the stance phase were extracted and normalized to body mass. We compared the peak moment data in the ELD group (average of left and right legs) against the most (MAS) and less (LAS) affected sides of the PDP group using a 1X3 ANOVA. Post hoc testing was performed when appropriate. RESULTS Gait velocity for the PDP and ELD groups both averaged 1.07 m/s. The peak PFM at the ankle in the LAS of the PDP group was significantly greater than that in the ELD group (p = 0.022). At the knee, the peak KEM for the PDP group (LAS and MAS) was significantly greater than that in the ELD group (p < 0.001).In addition, the peak KEM in the LAS was significantly greater than that in the MAS in the PDP group (p = 0.002). No significant differences were observed in the peak HEM. CONCLUSIONS The larger KEM in the PDP group may be a response to the comparatively larger knee flexion moment of the contralateral limb that is in late stance. Increased extensor moments in the LAS are likely an attempt to compensate for the MAS. Future studies are warranted to evaluate individual joint moment contribution to gait performance in PD Supported by NIH grant #RO-1AT00612-01

계단 오르기 동작시 계단 높이에 따른 하지 관절 모멘트의 변화 분석

nEun, S-D. The effect of the stair heights on lower extremity joint moment in stair-ascent activity. Korean Journal of Sport Biomechanics, Vol. 13, No. 1, pp. 121-138. The purpose of this study was to investigate the effect of the stair heights on lower extremity joint moment in stair-ascent activity. Data were collected by 3-D cinematography, force platform. six normal males were participated in this experiment. All subjects performed a stair-ascent in four different heights of stairs (10, 14, 18, 22cm) having a 5 step staircase. The moment of lower extremity joint was analyzed during stance phase. The results were as follows: First, the second increase of plantar flexion moment of ankle joint in the `forward continuance` phase was not occurred for stair A and B. But it occurred for stair C and D. And the maximum plantar flexion moment increased as the stair height become higher. Second, it was shown that the maximum inversion moment of the ankle joint was the smallest at stair B and it increased significantly at stair C. Third, maximum extension moment appeared in the `pull-up` phase. And it increased as the stair height become higher. Fourth, it was shown that the maximum abduction moment of the knee joint was the smallest at stair C and it increased significantly at stair C. Fifth, maximum extension moment of hip joint increased significantly at stair C. Sixth, remarkable value of adduction moment occurred at hip joints and maximum adduction moment increased at stair D.

Changes in gait when anticipating slippery floors.

Falls precipitated by slipping are listed among the leading causes of injuries. The biomechanical analysis of such events is a necessary component of the slips/falls prevention research. One of the challenges of biomechanical studies is reproducing the unexpected nature of real-life slipping accidents. Thus, the goal of this study was to quantify changes in gait biomechanics when subjects anticipate slippery environments. Foot ground reaction forces and body dynamics of 16 subjects were recorded during level walking and descending ramps of varying frictional properties and inclination. Gait biomechanics were compared among three types of dry trials: (1) baseline (subjects knew the floor was dry); (2) anticipation (subjects were uncertain of the contaminant condition, dry, water, soap or oil); and (3) recovery trials recorded after a contaminated trial (subjects again knew the floor was dry). Subjects were asked to walk as naturally as possible throughout testing. Anticipation trials produced peak required coefficient of friction (RCOF(peak)) values that were on average 16-33% significantly lower than those collected during baseline trials, thus reducing slip potential. During recovery trials, RCOF(peak) values did not return to baseline characteristics (5-12% lower). Postural and temporal gait adaptations, which affected ground reaction forces, were used to achieve RCOF(peak) reductions. Statistically significant gait adaptations included reductions in stance duration (SD) and loading speed on the supporting foot, shorter normalized stride length (NSL), reduced foot-ramp angle and slower angular foot velocity at heel contact. As a result of these adaptations, anticipation of slippery surfaces led to significant changes in lower extremity joint moments, a reflection of overall muscle reactions. Thus, this study suggests that significant gait changes are made when there is a potential risk of slipping even though subjects were asked to walk as naturally as possible. Insights are also gained into the adaptations that are used to reduce the potential of slips/falls.

Lower extremity corrective reactions to slip events

A significant number of injuries in the workplace is attributed to slips and falls. Biomechanical responses to actual slip events determine whether the outcome of a slip will be recovery or a fall. The goal of this study was to examine lower extremity joint moments and postural adjustments for experimental evidence of corrective strategies evoked during slipping in an attempt to prevent falling. Sixteen subjects walked onto a possibly oily vinyl tile floor, while ground reaction forces and body motion were recorded at 350 Hz. The onset of corrective reactions by the body in an attempt to recover from slips became evident at about 25% of stance and continued until about 45% into stance, i.e. on average between 190 and 350 ms after heel contact. These reactions included increased flexion moment at the knee and extensor activity at the hip. The ankle, on the other hand, acted as a passive joint (no net moment) during fall trials. Joint kinematics showed increased knee flexion and forward rotation of the shank in an attempt to bring the foot back towards the body. Once again, the ankle kinematics appeared to play a less dominant role (compared to the knee) in recovery attempts. This study indicates that humans generate corrective reactions to slips that are different than previously reported responses to standing perturbations translating the supporting surface.

Effect of age on lower extremity joint moment contributions to gait speed.

We investigated the relationship of hip, knee and ankle function to gait speed in healthy elderly subjects. We hypothesized that the hip extension moment would make a significantly smaller contribution to propulsion power in the elderly than in healthy young subjects even when the elders were ambulating at speeds comparable to those of the young subjects. We analyzed the free speed gait of 16 young and 14 elderly subjects, and the fast gait of the elder subjects. In elderly subjects free speed gait linear power transfer from the leg to the upper body due to the hip and knee moments was decreased compared with young subjects walking at their normal gait speed. However, when asked to walk fast, elders significantly increase knee and hip moment contributions to hip linear power to levels comparable to those of young subjects at a similar speed. These results refute our hypothesis and support our earlier findings indicating that kinematic alterations at the hip are a cause of reduced gait speed in the elderly.

Whole-Body Momentum during Gait: A Preliminary Study of Non-Fallers and Frequent Fallers

The importance of momentum in compensating for elderly individuals’ strength deficits to achieve activities of daily living, such as rising from a chair has been demonstrated in earlier studies. Here we present a case-control study of three healthy “non-fallers” and two “frequent fallers.” All 5 elders were community-living and were tested in the gait laboratory. A four-camera Selspot system was used to obtain whole-body momentum from an 11-segment kinematic model. Ground reaction forces and kinematics were used to calculate lower extremity joint moments. With the exception of the whole-body’s angular momentum about the vertical axis, linear and angular momenta during gait were minimum during mid-single limb support and maximum near heel contact. Whole-body momentum values for individuals with a history of falls were similar to those measured in non-fallers. However, subjects with a history of falls had between 17 and 37% smaller maximum ankle and knee torque values than the subjects without a history of falls during ambulation, A comprehensive description of whole-body linear and angular momenta during steady-state gait in older individuals is presented. While whole-body momentum characteristics and magnitude were similar between fallers and non-fallers. the consequences of the lesser torque values in the fallers’ knees and ankles to generate and control this momentum warrant further investigation.

Lower Extremity Joint Moments during Uphill Cycling

Lower extremity joint moments were investigated in three cycling conditions: level seated, uphill seated and uphill standing. Based on a previous study (Caldwell, Li, McCole, &amp; Hagberg, 1998), it was hypothesized that joint moments in the uphill standing condition would be altered in both magnitude and pattern. Eight national caliber cyclists were filmed while riding their own bicycles mounted to a computerized ergometer. Applied forces were measured with an instrumented pedal, and inverse dynamics were used to calculate joint moments. In the uphill seated condition the joint moments were similar in profile to the level seated but with a modest increase in magnitude. In the uphill standing condition the peak ankle plantarflexor moment was much larger and occurred later in the downstroke than in the seated conditions. The extensor knee moment that marked the first portion of the down-stroke for the seated trials was extended much further into the downstroke while standing, and the subsequent knee flexor moment period was of lower magnitude and shorter duration. These moment changes in the standing condition can be explained by a combination of more forward hip and knee positions, increased magnitude of pedal force, and an altered pedal force vector direction. The data support the notion of an altered contribution of both muscular and non-muscular sources to the applied pedal force. Muscle length estimates and muscle activity data from an earlier study (Li &amp; Caldwell, 1996) support the unique roles of mono-articular muscles for energy generation and bi-articular muscles for balancing of adjacent joint moments in the control of pedal force vector direction.

Relative contributions of the lower extremity joint moments to forward progression and support during gait

Abstract A method, which was found to be accurate within 0.54 m/s 2 , was developed to estimate the relative contributions of the net joint moments to forward progression and support in the gait of five normal subjects. Forward progression was produced primarily by the ankle plantar flexors with a significant assist from the knee extensors. Support was produced largely by the plantar flexors during single limb support and by a combination of ankle plantar flexors, knee extensors and hip extensors during double limb support.

An Alternative Model of the Lower Extremity during Locomotion

An alternative to the Iterative Newton-Euler or linked segment model was developed to compute lower extremity joint moments using the mechanics of the double pendulum. The double pendulum model equations were applied to both the swing and stance phases of locomotion. Both the Iterative Newton-Euler and double pendulum models computed virtually identical joint moment data over the entire stride cycle. The double pendulum equations, however, also included terms for other mechanical factors acting on limb segments, namely hip acceleration and segment angular velocities and accelerations Thus, the exact manners in which the lower extremity segments interacted with each other could be quantified throughout the gait cycle. The linear acceleration of the hip and the angular acceleration of the thigh played comparable roles to muscular actions during both swing and stance.

Relative contributions of the lower extremity joint moments to forward progression and support during gait

Relative contributions of the lower extremity joint moments to forward progression and support during gait

On the assumption of bilateral lower extremity joint moment symmetry during the sit-to-stand task

This study examined the validity of the assumption of bilateral lower extremity joint moment symmetry during the sit-to-stand motion for a group of young ( n = 7) and a group of elderly ( n = 7) female subjects. Two force plates and a motion analysis system were used to determine peak joint moments at the ankles, knees, and hips following liftoff from a chair. Statistically, bilateral asymmetries in peak joint moments were found at the knee joint in the young group [a right to left difference of 0.43 %BW × BH (body weight × body height)] and at the hip joint in both subject groups (differences of 0.20 %BW × BH and 1.09 %BW × BH for the young and elderly subjects, respectively). Subsequent data analysis, using an algorithm that assumed bilateral ground reaction force (GRF) symmetry, was performed to determine whether the bilateral differences were a result of kinematic or GRF asymmetry. It was concluded from these results that both the kinematic and GRF data account for the bilateral asymmetry. The results of the subsequent analysis also showed that the method which assumed bilateral GRF symmetry underestimated the peak joint moments at the ankles, knees, and hips, with the greatest difference between methods being 0.10 %BW × BH for the ankle joint. The results of this study suggest that the assumption of bilateral symmetry of lower extremity joint moments during the sit-to-stand is not valid. However, the biomechanical significance of the errors associated with assuming symmetry must also be taken into account. Studies involving the sit-to-stand task should consider the effects of asymmetry on the interpretation and application of their results.

On the assumption of bilateral lower extremity joint moment symmetry during the sit-to-stand task

On the assumption of bilateral lower extremity joint moment symmetry during the sit-to-stand task

Bilateral performance symmetry during drop landing

The assumption that lower extremity function is bilaterally symmetrical is prevalent throughout the biomechanics literature. The unilateral development of many overuse and acute injuries may suggest that this assumption is inaccurate. Analyses of bilateral function report conflicting results and may be partially attributable to the types of movement activities utilized and to research methodology. The purpose of this study was to evaluate the concurrent bilateral performance of the lower extremities during an apparently symmetrical movement task. Concurrent left/right side vertical ground reaction forces (VGRF) and lower extremity joint moments (JM) were obtained for 10 subjects performing 25 voluntary hanging drop landings (60 cm) on each of 3 consecutive days. Bilateral variability (BV) and systematic bilateral asymmetry (BA) were calculated for each trial. Bilateral variability was less for VGRF variables (12.8%) than JM variables (25.3%). Bilateral asymmetry was identified more often among VGRF variables (52.5%) than JM variables (16.7%). The magnitude of identified BA was greater than either the group BV (25%) or BA (110%) and indicates that bilateral differences are biomechanically meaningful.