Biomedical subjects

B M Nigg

Publications and source records attributed to B M Nigg.

At least 55 records · Page 3Linked to original sources

PubMed1997

Tibiocalcaneal motion during running, measured with external and bone markers.

OBJECTIVE: The purpose of this study was to compare tibiocalcaneal motion during running based on skeletal markers with tibiocalcaneal motion based on external markers. DESIGN. IN VIVO: measurements of external and skeletal tibiocalcaneal kinematics. BACKGROUND: External (shoe, skin) markers are typically used to determine rearfoot kinematics. However, it is not known if such markers are able to provide a good representation of the skeletal (tibiocalcaneal) kinematics. METHODS: Bone pins were inserted into the tibia and calcaneus of five subjects. The 3-D motion of markers attached to bone pins as well as of external markers attached to the shank and shoe were determined during the stance phase of five running trials. Intersegmental motion was expressed in terms of Cardan angles (plantarflexion/dorsiflexion, abduction/adduction, inversion/eversion). RESULTS: It was found that the skeletal inversion/eversion, abduction/adduction, and plantarflexion/dorsiflexion motions were similar across the subjects. The shape of the tibiocalcaneal rotation curves based on external markers were similar to those based on bone markers. However, the rotations were generally overestimated when using external markers, e.g. the average maximal eversion motion calculated from external markers was 16.0 degrees whereas the skeletal maximal eversion motion was only 8.6 degrees. These discrepancies were mainly due to the relative movement between shoe markers and underlying calcaneus. CONCLUSIONS: External markers are only gross indicators of the skeletal tibiocalcaneal motion. The rotations derived from external shoe and shank markers typically overestimate the skeletal tibiocalcaneal kinematics. RELEVANCE: Quantitative results determined from external markers have to be used with caution. For tibiocalcaneal rotations, external markers may be used to show trends, but absolute values cannot be trusted.

Journal Article↗

PubMed1997

Assessment of the mechanical properties of area-elastic sport surfaces with video analysis.

Mechanical properties of a surface are assumed to be of importance with respect to injuries, comfort, and performance in sport. For a better understanding of the factors that do influence the etiology of injuries as well as comfort, a method was developed to compare mechanical characteristics of wooden area-elastic indoor surfaces. The method was based on video analysis of markers mounted on the surface during tests using human subjects performing movements. The method provided information concerning deflection, area-elasticity, and vibration. With the proposed methodology it was possible to detect differences with respect to these variables in differently built wooden sport surfaces. The accuracy of the analysis was greater than 0.1 mm. The results show that it was possible to use the proposed methodology in the assessment of the area-elastic wooden sport surfaces. This information may be at help in understanding the relation between surface characteristics and surface-related injuries, comfort, and possible fatigue.

Elasticity↗

PubMed1996

A method for inverse dynamic analysis using accelerometry.

A method was developed to calculate total resultant force and moment on a body segment, in three dimensions, from accelerometer data. The method was applied for an analysis of intersegmental loading at the hip joint during the single support phase of working and running, using four triaxial accelerometers mounted on the upper body. Results were compared to a conventional analysis using simultaneously recorded kinematics and ground reaction forces. The loading patterns obtained by both methods were similar, but the accelerometry method systematically underestimated the intersegmental force and moment at the hip by about 20%. This could be explained by the inertial and gravitational forces originating from the swing leg which were neglected in the analysis. In addition, the accelerometry analysis was not not reliable during the impact phase of running, when the upper body and accelerometers did not behave as a rigid body. For applications where these limitations are acceptable, the accelerometry method has the advantage that it does not require a gait laboratory environment and can be used for field studies with a completely body-mounted recording system. The method does not require differentiation or integration, and therefore provided the possibility of real-time inverse dynamics analysis.

Acceleration↗

PubMed1996

The clinical biomechanics award paper 1995 Lower extremity joint loading during impact in running.

OBJECTIVE: The main purpose of this study was to estimate lower extremity joint impact loading in running and the influences of muscles on this loading. DESIGN: A 2D simulation model that included skeletal motion, muscles, and soft-tissue movement was developed in this study. BACKGROUND: Our understanding of joint impact loading has been mainly based on measurable external loading variables. Furthermore, changes in muscular forces have often been neglected, assuming that muscular activation cannot react during the period of impact, which ignores passive muscle properties. METHODS: Kinematics and ground reaction forces were collected for each of five subjects performing heel-toe running. Kinematic and inverse dynamics analyses provided the initial conditions for the simulation models. The motion of each subject was simulated for 50 ms following heelstrike. RESULTS: Motion of body segments following heelstrike reduced the rate of joint impact loading, sometimes substantially, in comparison to the ground reaction force. In addition, substantial changes in muscular forces were sometimes observed that further reduced the rates of joint loading. CONCLUSIONS: The rates of joint impact loading are reduced in comparison to the ground reaction force during normal heel-toe running. Changes in muscular forces may have a relevant effect on joint impact loading and should not be neglected in future studies. RELEVANCE: Repetitive external impact loading has resulted in degeneration of articular cartilage in animal models. However, runners, as a group, do not have a high incidence of osteoarthritis. The present study suggests that there are mechanisms available to the runner that can substantially reduce the rate of joint impact loading relative to the rate of external loading. These mechanisms may be sufficient to prevent overloading and degeneration of the joints.

Journal Article↗

PubMed1996

Influence of ankle ligaments on tibial rotation: an in vitro study.

The purpose of this study was to clarify the role of the ankle ligaments in controlling the tibial rotation for different foot positions. A 6 degrees of freedom device was constructed for in vitro simulation of this movement transfer during the support phase of gait. Tibia rotation angle was measured for different foot positions and vertical loads, while the ligament integrity was modified. Data were collected from eight legs of four different cadavers. The results showed that vertical loading is unimportant to influence tibial rotation, while the lateral ankle ligaments have significant influence, especially during eversion. It was concluded that chronic partial or total lateral ankle instability may contribute to knee and foot injuries through abnormal tibial rotation.

Aged↗

PubMed1996

The effect of an ankle orthosis on ankle range of motion and performance.

Ankle joint orthoses are used for rehabilitation and/or prevention of ankle sprains. The purpose of this study was to determine the effect of the Malleoloc ankle joint orthosis on active and passive range of motion reduction and on a jumping and a figure-eight running test. Twelve subjects with a history of inversion ankle sprain and documented increased anterior translation in a drawer test participated in the study. Active and passive range of motion for inversion was determined with and without the orthosis and pre- and post-exercise. Additionally, performance tests for figure-eight running and jumping were administered. The results showed that the tested orthosis 1) restricted the active range of motion and passive inversion substantially, 2) reduced the other movement degrees of freedom only minimally, 3) provided the same movement restriction before and after exercise, and 4) did not affect performance. The Malleoloc ankle joint orthoses can, therefore, restrict ankle joint motion without affecting performance negatively.

Adult↗

PubMed1995

Direct dynamics simulation of the impact phase in heel-toe running.

The influence of muscle activation, position and velocities of body segments at touchdown and surface properties on impact forces during heel-toe running was investigated using a direct dynamics simulation technique. The runner was represented by a two-dimensional four- (rigid body) segment musculo-skeletal model. Incorporated into the muscle model were activation dynamics, force-length and force-velocity characteristics of seven major muscle groups of the lower extremities: mm. glutei, hamstrings, m. rectus femoris, mm. vasti, m. gastrocnemius, m. soleus and m. tibialis anterior. The vertical force-deformation characteristics of heel, shoe and ground were modeled by a non-linear visco-elastic element. The maximum of a typical simulated impact force was 1.6 times body weight. The influence of muscle activation was examined by generating muscle stimulation combinations which produce the same (experimentally determined) resultant joint moments at heelstrike. Simulated impact peak forces with these different combinations of muscle stimulation levels varied less than 10%. Without this restriction on initial joint moments, muscle activation had potentially a much larger effect on impact force. Impact peak force was to a great extent influenced by plantar flexion (85 N per degree of change in foot angle) and vertical velocity of the heel (212 N per 0.1 m s-1 change in velocity) at touchdown. Initial knee flexion (68 N per degree of change in leg angle) also played a role in the absorption of impact. Increased surface stiffness resulted in higher impact peak forces (60 N mm-1 decrease in deformation).(ABSTRACT TRUNCATED AT 250 WORDS)

Ankle Joint↗

PubMed1995

Correlation between physical activity and the gait characteristics and ankle joint flexibility of the elderly.

The correlation between the type, duration and intensity of physical activity on the gait characteristics and the range of active ankle joint motion of the elderly were investigated in this study. Three-dimensional (3D) kinetic and kinematic assessments were performed on the normal walking patterns of 59 healthy elderly male and female subjects (aged 60-79 years). Gait analysis was performed using a high-speed video-based (3D) motion analysis system with synchronized ground-reaction force measurements. The maximal active range of motion (RoM) of the ankle joint complex of each subject was determined using an external six-degree-of-freedom flexibility assessment device. Physical activity levels were classified based on energy expenditure requirements. In general the results suggest that habitual level of physical activity did not have a significant effect on the kinetic or kinematic variables during walking, or the maximal ankle joint range of motion. Differences in ankle joint RoM and gait variables were found based on gender. No distinct benefit with respect to ankle joint range of motion or gait characteristics was provided with participation in higher-energy intensive physical activities in comparison to physical activities requiring low to moderate energy expenditures. It is speculated that the benefits of physical activity may be more pronounced in activities which demand rapid muscular strength and control movements such as recovering from a fall or obstacle avoidance. RELEVANCE: Participation in low-energy intensity activities provides the same benefits to ankle joint flexibility and locomotion, without the added risk of injury associated with high-energy intensity sports. This finding has important implications with respect to physical activity programmes for the elderly with an objective to maintain or improve independent mobility.

Journal Article↗

PubMed1995

Influence of sensory input on plantar pressure distribution.

The sensory feedback control system plays a central role in human locomotion. However, few studies have been published discussing the influence of sensory input at the plantar surface of the foot on the kinematics and kinetics of locomotion. The purpose of this study was to examine the effect of changes in sensory input at the plantar surface of the foot on the pressure distribution measured at the plantar surface of the foot. Three pairs of specially made socks with sand at the plantar surface of the foot and one pair of normal socks were used to simulate different sensory inputs. Pressure distribution at the plantar surface of the foot was measured using an emed system for 10 subjects for each of the four sensory input conditions during walking and running on a treadmill. The results showed significant and substantial changes in pressure in selected areas for changes in sensory input. The pressure increased in the midfoot area and decreased in the toe area with increasing sensory inputs. These results are similar to results of a previous study where similar changes were found in a comparison between comfortable and uncomfortable shoes. RELEVANCE: Pressure distribution is increasingly used in clinical assessments. However, the factors influencing the pressure distribution pattern are only partially understood. One factor may be the sensory input into the foot. It is important to understand this influence in order to provide appropriate interpretation of the pressure distribution data.

Journal Article↗

PubMed1995

Reliability and validity of active, passive and dynamic range of motion tests.

The purposes of this project were to determine (a) the reliability of ROM and POM assessment methods for tests where an ankle joint brace was used and (b) the relationship between active and passive ROM and POM inversion measurements. The range of motion of the ankle joint complex for inversion was quantified using a range of motion apparatus. The inversion path of motion for the foot and the shoe was quantified using a high speed video system. The results of this study indicated: (a) Comprehensive functional tests of ankle joint braces using ROM and POM measurements showed maximal group differences of less than 1 degree between days for ROM (rAROM = 0.96 and rPROM = 0.93) and less than 1.5 degrees for POM measurements (rPOM = 0.88). (b) PROM measurements showed a consistent "creep" effect of about 2 degrees with increasing trial number during the first ten trials which must be taken into consideration for the design of the appropriate test protocol. (c) The correlation coefficient between AROM and POM was 0.37 and 0.44 between PROM and POM, suggesting that AROM and PROM measurements do not predict inversion during actual movement.

Adult↗

PubMed1995

In vitro kinematics of the axially loaded ankle complex in response to dorsiflexion and plantarflexion.

The rotational movements of the tibia and calcaneus that occur with dorsiflexion-plantarflexion and axial loading were studied in cadaver foot-leg specimens using an unconstrained testing apparatus. Independent of the foot flexion position, significant internal rotation of the tibia and eversion of the calcaneus were noted after the ankle complex was axially loaded. Independent of loading, 10 degrees of dorsiflexion resulted in 0.1 degrees of eversion and 2.1 degrees of internal rotation of the tibia. Conversely, 10 degrees of plantarflexion resulted in 1.6 degrees of inversion and 1.3 degrees of external rotation of the tibia. The induced rotational movements of the tibia and the calcaneus differed significantly between the specimens. These results suggest that the foot "axes" did not change by axially loading the ankle complex and they support previous reports that the ankle complex uses different axes for dorsiflexion and plantarflexion.

Aged↗

PubMed1995

Influence of ligament transection on tibial and calcaneal rotation with loading and dorsi-plantarflexion.

The purpose of this study was to quantify the effect of sequential ligament transection (anterior talofibular, calcaneofibular, posterior talofibular, deltoid, and subtalar interosseous ligaments) on the rotational movement of the tibia and the calcaneus as associated with axial loading and dorsi-plantarflexing the foot. Eight cadaver foot-leg specimens were investigated using a unconstrained testing apparatus. As the ankle complex was axially loaded, almost the same internal rotation of the tibia and the same calcaneus eversion was found with and without the various degrees of lateral and medial ligament release; additional sectioning of the subtalar interosseous ligament tremendously increased the resulting tibial and calcaneal rotation. While tibial and calcaneal rotation from foot dorsi-plantarflexing did not alter significantly with transection of the lateral ligaments, almost no tibial and calcaneal rotation occurred after additional sectioning of the deltoid and subtalar interosseous ligament. These results indicate that, after release of the lateral ligaments, the foot becomes partially mechanically disconnected from the tibia by additional transection of the medial ligaments and even further disconnected after transection of the subtalar interosseous ligament.

Aged↗

PubMed1995

Influence of arthrodeses on kinematics of the axially loaded ankle complex during dorsiflexion/plantarflexion.

The purpose of this study was to quantify the effect of selective arthrodesis (stabilization) of the ankle, subtalar, and talonavicular joints on the rotational movement of the tibia and the calcaneus occurring with dorsiflexion/plantarflexion. Six cadaver foot-leg specimens were investigated using an unconstrained testing apparatus. Simulated ankle joint arthrodesis caused a large increase in tibial rotation and calcaneal eversion-inversion. Subtalar and talonavicular stabilization did not cause as large a rotation.

Aged↗

PubMed1995

Influence of heel height on ankle joint moments in running.

Clinically, heel lifting or heel wedging in running shoes has been proposed as a prevention and treatment of Achilles tendinitis. It has been speculated that heel lifting decreases the Achilles tendon forces. The purpose of this study was to determine the effect of heel height on resultant ankle flexion moments during running. It was assumed that plantarflexion moments at the ankle joint would indicate Achilles tendon loading. Each of the five subjects performed five running trials (4.6 m.s-1) for each of the five shoes, differing only in heel height (2.1-3.3 cm). Resultant plantar-/dorsiflexion moments were calculated using a standard three-dimensional inverse dynamics analysis. The results showed that, typically, a small initial dorsiflexion moment took place changing into a larger plantarflexion moment before 20% of stance phase. The magnitude and time of occurrence of the initial dorsiflexion moment were significantly affected by heel height changes, but the maximum plantarflexion moment and its time of occurrence were not significantly affected. The results did not support the speculation that a heel lift generally decreases the Achilles tendon loading during running. However, single subject analyses indicated that for two subjects the plantarflexion moments decreased with increasing heel height.

Achilles Tendon↗

PubMed1995

Energy aspects for elastic and viscous shoe soles and playing surfaces.

The purpose of this project was to determine the effect of changes in stiffness and viscosity of the foot ground interface on the work performed during locomotion. The estimation of the work during locomotion was derived from a mathematical two segment model, representing the foot and the rest of the body. The typical passive elements between the foot and the rest of the body were replaced by a strategic formulation of how a resultant force, F, representing the net effect of all the muscles between the foot and the rest of the body, has to evolve over time in a running situation. The calculations were performed under the assumption that the force F is selected so that the mechanical work performed by F is minimal. The estimations of the work required during a step cycle is generally higher for softer than for harder springs and for low damping compared with high damping. The model calculations demonstrate that specific combinations of material properties may be advantageous or disadvantageous from an energy point of view.

Algorithms↗

PubMed1995

A kinematic comparison of overground and treadmill running.

Treadmills are often used in research projects to simulate overground locomotion, assuming that locomotion is similar on a treadmill and overground. The purpose of this investigation was to determine whether a treadmill could be used to simulate overground locomotion. Twenty-two subjects ran on four different surfaces: overground and three treadmills that differed in size and power. The kinematics of the right leg and foot were studied using two high-speed Locam cameras (lateral and posterior view). The subjects ran in two different shoes at four different speeds (3.0-6.0 m.s-1). The differences in the kinematics between treadmill and overground running could be divided into systematic and subject dependent components. Subjects systematically planted their feet in a flatter position on the treadmill than overground. Most of the lower extremity kinematic variables, however, showed inconsistent trends for individual subjects, depending on the individual subject's running style, running speed, and shoe/treadmill situation. The differences were substantial. It is not yet understood how the human locomotor system adapts to a particular treadmill running situation. However, it is concluded that individual assessment of running kinematics on a treadmill for shoe or shoe orthotic assessment may possibly lead to inadequate conclusions about overground running.

Adaptation, Physiological↗

PubMed1994

In vivo determination of the anatomical axes of the ankle joint complex: an optimization approach.

This study investigates the feasibility of a subject-specific three-dimensional model of the ankle joint complex for kinematic and dynamic analysis of movement. The ankle joint complex was modelled as a three-segment system, connected by two ideal hinge joints: the talocrural and the subtalar joint. A mathematical formulation was developed to express the three-dimensional translation and rotation between the foot and shank segments as a function of the two joint angles, and 12 model parameters describing the locations of the joint axes. An optimization method was used to fit the model parameters to three-dimensional kinematic data of foot and shank markers, obtained during test movements throughout the entire physiological range of motion of the ankle joint. The movement of the talus segment, which cannot be measured non-invasively, is not necessary for the analysis. This optimization method was used to determine the position and orientation of the joint axes in 14 normal subjects. After optimization, the discrepancy between the best fitting model and actual marker kinematics was between 1 and 3 mm for all subjects. The predicted inclination of the subtalar joint axis from the horizontal plane was 37.4 +/- 2.7 degrees, and the medial deviation was 18.0 +/- 16.2 degrees. The lateral side of the talucrural axis was directed slightly posteriorly (6.8 +/- 8.1 degrees), and inclined downward by 7.0 +/- 5.4 degrees. These results are similar to previously reported typical results from anatomical, in vitro studies. Reproducibility was evaluated by repeated testing of one subject, which resulted in variations of about one-fifth of the standard deviation within the group, the inclination of the subtalar joint axis was significantly correlated to the arch height and a radiographic 'tarsal index'. It is concluded that this optimization method provides the opportunity to incorporate inter-individual anatomical differences into kinematic and dynamic analysis of the ankle joint complex. This allows a more functional interpretation of kinematic data, and more realistic estimates of internal forces.

Algorithms↗

PubMed1994

[Movement transfer between foot and calf in vitro].

The mechanical coupling of leg and foot which may be related to the aetiology of knee injuries is still not well understood. The goal of this study was to determine in vitro the movement transfer from calcaneal eversion-inversion to tibial rotation and vice versa occurring in the ankle joint complex. A lower leg holding and loading device with 6 degrees of freedom was used for investigation of 14 fresh-frozen, foot-leg specimens. Movement transfer between calcaneus and tibia was not the same for different input modes and different from calcaneus to tibia compared to movement transfer from tibia to calcaneus. Vertical loading of the tibia and foot flexion position had a major influence on this transfer of movement. The results implicate that excessive pronation, in running for instance, is only critical for high knee loading when coupled with a high movement transfer in the ankle joint complex.

Ankle Joint↗