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Biomedical subjects

B M Nigg

Publications and source records attributed to B M Nigg.

At least 73 records · Page 4Linked to original sources
PubMed1994

Foot movement and tendon excursion: an in vitro study.

The purpose of this study was to determine tendon excursions resulting from selected foot movement and to derive moment arms with respect to the eversion-inversion and flexion-extension axes of the foot. A lower leg-holding device with 6 degrees of freedom was used for the in vitro investigation of 15 fresh foot-leg specimens. Although high variation among the subjects existed, there was a pronounced uniformity of tendon excursion throughout a given foot eversion-inversion or flexion-extension range of motion. With reference to the tibialis posterior (1.00), average invertor moment arms with respect to the foot eversion-inversion axis were found to be as follows: flexor digitorum longus, 0.75; flexor hallucis longus, 0.62; tibialis anterior, 0.59; soleus, 0.24; extensor hallucis longus, 0.22; extensor digitorum longus, -0.26; peroneus longus, -0.82; and peroneus brevis, -0.85. A trend toward decreasing evertor/invertor moment arms was observed during the ranges of foot eversion, as well as when the foot was in flexion. Flexor and extensor moment arms were found to be substantially dependent on foot flexion-extension angle. Increasing flexor moment arms were observed when rotating the foot throughout the range from extension to flexion. The obtained results may have significant implications in foot surgery, muscle function analysis, and general considerations of foot function.

Aged↗
PubMed1993

Effects of arch height of the foot on angular motion of the lower extremities in running.

It has been suggested that a relationship exists between the height of the medial longitudinal arch of the foot and athletic injuries to the lower extremities. However, the functional significance of arch height in relation to injury is not well understood. The purpose of this study was to determine the influence of arch height on kinematic variables of the lower extremities that have been associated with the incidence of injury in running in an attempt to gain some insight into a functional relationship between arch height and injury. The three-dimensional kinematics of the lower extremities were measured during running for 30 subjects using high-speed video cameras. A joint coordinate system was used to calculate the three-dimensional orientation of the ankle joint complex for a single stance phase. Simple, linear regression analyses showed that arch height does not influence either maximal eversion movement or maximal internal leg rotation during running stance. However, assuming that knee pain in running can result from the transfer of foot eversion to internal rotation of the tibia, a functional relationship between arch height and injury may exist in that the transfer of foot eversion to internal leg rotation was found to increase significantly with increasing arch height. A substantial (27%), yet incomplete, amount of the variation in the transfer of movement between subjects was explained by arch height, indicating that there must be factors other than arch height that influence the kinematic coupling at the ankle joint complex. Additionally, the transfer of movement is only one factor of many associated with the etiology of knee pain in running.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Orthopedic and biomechanical concepts of sports shoe construction].

Based on anatomical, orthopaedic and epidemiological considerations two sets of concepts relevant for sport shoe construction have been proposed and discussed, one for the reduction of excessive load and one for the improvement of performance. The concepts for excessive load reduction are cushioning, support and guidance. These can be achieved by altering the material properties or the construction of the shoe. The concepts for improving performance are, first, that energy should be returned at the right location, at the right time, with the right frequency, and second, that reduction of loss of energy is more important than return of energy.

Athletic Injuries↗
PubMed1993

Application of the joint coordinate system to three-dimensional joint attitude and movement representation: a standardization proposal.

The selection of an appropriate and/or standardized method for representing 3-D joint attitude and motion is a topic of popular debate in the field of biomechanics. The joint coordinate system (JCS) is one method that has seen considerable use in the literature. The JCS consists of an axis fixed in the proximal segment, an axis fixed in the distal segment, and a "floating" axis. There has not been general agreement in the literature on how to select the body fixed axes of the JCS. The purpose of this paper is to propose a single definition of the body fixed axes of the JCS. The two most commonly used sets of body fixed axes are compared and the differences between them quantified. These differences are shown to be relevant in terms of practical applications of the JCS. Argumentation is provided to support a proposal for a standardized selection of body fixed axes of the JCS consisting of the axis ê1 embedded in the proximal segment and chosen to represent flexion-extension, the "floating" axis ê2 chosen to represent ad-abduction, and the axis ê3 embedded in the distal segment and chosen to represent axial rotation of that segment. The algorithms for the JCS are then documented using generalized terminology.

Algorithms↗
PubMed1993

Differences in ankle joint complex range of motion as a function of age.

The purpose of this study was to determine whether gender- and age-related differences in ankle joint complex (AJC) range of motion (ROM) exist in children (range 9-13 years), adolescents (14-16 years), and young adults (17-20 years), and to compare these data with those published for older subjects (21-79 years) using the same protocol. A total of 120 subjects (58 males and 62 females) ranging in age from 9 to 20 years were tested for AJC ROM using a specifically designed 6 degrees of freedom fixture. All measurements were made with respect to a laboratory coordinate system, and represented assessment of active AJC ROM. Angular displacements for plantarflexion, dorsiflexion, inversion, eversion, abduction, and adduction were digitally recorded and compared. AJC ROMs of females aged 9 to 20 years were generally greater than those for males about all three orthogonal axes. Within each gender, there was a consistent trend for AJC ROM to decrease from a maximum at 14 to 16 or 17 to 20 years to a minimum after age 60 years. The average decrement was greater for females than for males. This study provided evidence to support the contention that age-related and gender differences in AJC ROM do exist. The possibility of minimizing the decline in AJC ROM with age requires further investigation.

Adolescent↗
PubMed1993

[Pronation from the viewpoint of the transfer of movement between the calcaneus and the tibia].

Excessive foot eversion and abnormal tibial rotation have been associated with knee injuries. Why and whether or not overpronation in athletes leads to overuse injuries at the knee joint, however, is still not understood. It could be that this is related to the mechanical coupling at the ankle joint complex. The purpose of this study was to quantify the movement transferred from calcaneal eversion-inversion into tibial rotation, and vice-versa from tibial rotation into calcaneal eversion-inversion. Fourteen foot-leg specimens were used for investigation. A holding device with six degrees of freedom was constructed which allowed to rotate the calcaneus and to determine the resulting tibial rotation, and vice-versa. The movement transfer between calcaneus and tibia varied substantially, and it was not the same for both input modes. In the case of applied internal tibial rotation no calcaneal eversion was found. Apparently, the movement transfer depends from the individual mechanical coupling at the ankle joint complex. Excessive calcaneal eversion does only result in excessive rotational loading of the knee joint when coupled with a high movement transfer at the ankle joint complex. Finally, the results imply that, during gait, pronation results from ground reaction forces acting on the calcaneus, since internal tibial rotation is not transferred into calcaneal eversion.

Biomechanical Phenomena↗
PubMed1992

Mechanical analysis of the landing phase in heel-toe running.

Results of mechanical analyses of running may be helpful in the search for the etiology of running injuries. In this study a mechanical analysis was made of the landing phase of three trained heel-toe runners, running at their preferred speed and style. The body was modeled as a system of seven linked rigid segments, and the positions of markers defining these segments were monitored using 200 Hz video analysis. Information about the ground reaction force vector was collected using a force plate. Segment kinematics were combined with ground reaction force data for calculation of the net intersegmental forces and moments. The vertical component of the ground reaction force vector Fz was found to reach a first peak approximately 25 ms after touch-down. This peak occurs because, in the support leg, the vertical acceleration of the knee joint is not reduced relative to that of the ankle joint by rotation of the lower leg, so that the support leg segments collide with the floor. Rotation of the support upper leg, however, reduces the vertical acceleration of the hip joint relative to that of the knee joint, and thereby plays an important role in limiting the vertical forces during the first 40 ms. Between 40 and 100 ms after touch-down, the vertical forces are mainly limited by rotation of the support lower leg. At the instant that Fz reaches its first peak, net moments about ankle, knee and hip joints of the support leg are virtually zero. The net moment about the knee joint changed from -100 Nm (flexion) at touch-down to +200 Nm (extension) 50 ms after touch-down. These changes are too rapid to be explained by variations in the muscle activation levels and were ascribed to spring-like behavior of pre-activated knee flexor and knee extensor muscles. These results imply that the runners investigated had no opportunity to control the rotations of body segments during the first part of the contact phase, other than by selecting a certain geometry of the body and muscular (co-)activation levels prior to touch-down.

Acceleration↗
PubMed1992

Footprint parameters as a measure of arch height.

The human foot has frequently been categorized into arch height groups based upon analysis of footprint parameters. This study investigates the relationship between directly measured arch height and many of the footprint parameters that have been assumed to represent arch height. A total of 115 male subjects were measured and footprint parameters were calculated from digitized outlines. Correlation and regression analyses were used to determine the relationship between footprint measures and arch height. It may be concluded from the results that footprint parameters proposed in the literature (arch angle, footprint index, and arch index) and two further parameters suggested in this study (arch length index and truncated arch index) are invalid as a basis for prediction or categorization of arch height. The categorization of the human foot according to the footprint measures evaluated in this paper represent no more than indices and angles of the plantar surface of the foot itself.

Adult↗
PubMed1992

Effects of arch height of the foot on ground reaction forces in running.

There is a suggested link between running injuries and arch type of the foot. However, a distinct cause and effect relationship has not been established. Feet may be functionally categorized on the basis of arch height. The purpose of this study was to compare selected ground reaction force variables in running for different arch heights. Static height of the medial longitudinal arch was measured using a caliper, arch flattening during running was determined by video analysis, and ground reaction forces during running were recorded from a KISTLER force plate. Thirty-four subjects were divided into three arch height and three arch flattening groups, and single-factor analyses of variance were conducted to compare the groups. Arch height and arch flattening were not found to be significantly related. However, the initial medial force peak in the low arch group occurred significantly later than in the normal and high arch groups, and the anterior force peak in the low flattening group was lower compared with the medium and high flattening groups (P < 0.05). Both arch measurements were ineffective in accounting for the observed variability in the ground reaction forces in running. Specifically, the impact forces did not differ for the different arch height and arch lowering groups.

Adult↗
PubMed1992

Biomechanical and orthopedic concepts in sport shoe construction.

Two sets of concepts for sport shoe construction are discussed, based on anatomical, orthopedic, and epidemiological considerations: one for the prevention of excessive load and related injuries, and one for the improvement of performance. The proposed concepts for prevention of excessive load and related injuries in the foot and the lower extremities are cushioning, support, and guidance. The goals outlined in the concepts can be achieved by altering the material properties or the construction of the shoe. It is suggested that the concept "cushioning" is not well understood yet and needs further research. The discussed concepts for improving performance are first, that energy should be returned at the right location, at the right time, with the right frequency, and second, that loss of energy should be minimized. Reduction of energy loss is an important concept for performance. The concept "return of energy" seems inappropriate for sport shoes.

Athletic Injuries↗
PubMed1991

Calculation of vertical ground reaction force estimates during running from positional data.

The purpose of this study was to calculate, as a function of time, segmental contributions to the vertical ground reaction force Fz from positional data for the landing phase in running. In order to evaluate the accuracy of the method, time histories of the sum of the segmental contributions were compared to Fz(t) measured directly by a force plate. The human body was modeled as a system of seven rigid segments. During running the positions of markers defining these segments were monitored using a video analysis system operating at 200 Hz. Special care was taken to minimize marker movement relative to the mass centers of segments, and low-pass cutoff frequencies of 50 Hz (markers defining leg segments) and 15-20 Hz (markers defining upper body) were used in filtering the position time histories so as to ensure that high signal frequencies were preserved. The magnitude of the high-frequency peak in Fz, also known as 'impact force peak', was estimated with errors less than 10%, while the time of occurrence of the peak was estimated with errors less than 5 ms. It would appear that the positional data were sufficiently accurate to be used for calculation of intersegmental forces and moments during the landing phase in running. Analysis of the segmental contributions to Fz(t) revealed that the first peak in Fz has its origin in the contribution of support leg segments, while its magnitude is determined primarily by the contribution of the rest of the body. These contributions could be varied independently by changing running style. It follows that if the possible relationship between 'impact force peaks' and injuries is to be investigated, or if the effects of running shoe and surface construction on these force peaks are to be evaluated, the calculation of segmental contributions to Fz(t) is a more suitable approach than measuring only Fz(t).

Acceleration↗
PubMed1990

On the potential of various approaches in load analysis to reduce the frequency of sports injuries.

The purpose of this paper is to discuss various approaches used in load analysis with special consideration of whether there is some evidence that these approaches have actually contributed to a reduction of sport injuries and whether these approaches have the theoretical potential to reduce the frequency of injuries at all. Two possible approaches are compared. The 'cause-effect approach' uses the estimation of internal stress. It is proposed that a comparison of the internal stress with the critical stress limits for an anatomical structure of interest may not help to reduce the frequency of injuries for two reasons. Firstly, the estimation of the critical stress limits and the internal stress may have significant errors which inhibit possible conclusions. Secondly, the information provided by the comparison of internal stress and critical stress limits was implicitly available in the injury frequencies and no new knowledge has been added. It is proposed that stresses estimated from model calculations can successfully be used to reduce the frequency of injuries if they are compared (comparison technique) with stresses estimated for comparable situations (e.g. shoes with and without orthotics). The 'empirical approach' is based on the assumption that the knowledge of the mechanisms of an injury is not a prerequisite for the reduction of the frequency of injuries. The approach establishes statistical correlations between factors related to injuries on one side and specific injuries or groups of injuries on the other side. This approach has frequently been used in the development of sport shoes. It is speculated that studies using an empirical approach have the potential to actually reduce the frequency of injuries. The conclusive evidence that biomechanical research in load analysis has in fact contributed to a reduction of the frequency of injuries is still missing for both discussed approaches.

Athletic Injuries↗
PubMed1990

A technique for normalizing centre of pressure paths.

Centre of pressure paths may be expected to provide useful information in the analysis of gait. In this paper, a technique for normalizing and averaging centre of pressure paths is presented. It utilizes force data obtained from force platform measurements together with information about the placement of the foot on the force platform. This placement is described by specifying the location of the 'centre' and 'midline' of the foot which are defined for a footprint. The coordinate system associated with a footprint is defined and centre of pressure locations are determined in relation to this system. A comparison of the centre of pressure paths obtained using this method and the method proposed by Cavanagh [J. Biomechanics 11, 487-491 (1978)] shows significant differences. It is concluded that the selection of an appropriate technique to obtain centre of pressure paths is important.

Biomechanical Phenomena↗
PubMed1990

Three-dimensional measurement of rearfoot motion during running.

Excessive ranges of motion during running have been speculated to be connected to injuries to the lower extremities. Movement of the foot and lower leg has commonly been studied with two-dimensional techniques. However, differences in the alignment of the longitudinal axis of the foot with the camera axis will produce measurement errors for projected angles of the lower extremities. A three-dimensional approach would not have this limitation. The purpose of this study is to present a three-dimensional model for calculation of angles between lower leg and foot, lower leg and ground, and foot and ground, and to compare results from treadmill running derived from this model with results derived from a two-dimensional model for different alignment angles between foot axis and camera axis. A two camera Selspot system was used to obtain three-dimensional information on motion of the studied segments. It was found that several two-dimensional variables measured from a posterior view are very sensitive to the alignment angle between the foot and the camera axis. Some variables change as much as 1 degrees for every 2 degrees of change of the alignment angle. The large influence of rotations other than the measured one in two-dimensional measurements makes advisable the use of a three-dimensional model when studying motion between foot and lower leg during running.

Biomechanical Phenomena↗
PubMed1990

Elongation and forces of ankle ligaments in a physiological range of motion.

The purposes of this study were: (1) to measure the distances between the insertion sites of selected ankle ligament fibers, (2) to measure the force-elongation characteristics of isolated bone-ligament-bone preparations, and (3) to relate the force measurements to angular positions of the ankle. The findings can be used to discuss clinically the correlation between possible ligament injuries and associated foot movement. Three fresh cadaveric ankles were dissected to expose the anterior talofibular ligament, the calcaneofibular ligament, and the superficial deltoid ligament. The ankles were first mounted on a fixture, and insertion to insertion distances of the ligament fibers were measured for selected positions of the ankle/subtalar joint. Bone-ligament-bone preparations were then removed, returned to their anatomical length and uniaxial force-extension testing was performed. The forces in each ligament were recorded for distances corresponding to those measured in situ for various ankle positions. These results allowed: (1) estimation of the forces in these three ligaments in various ankle positions, (2) identification of positions where ligaments were carrying no force, and (3) identification of positions where they carry large forces. The clinical analysis reveals that the anterior talofibular ligament is sensitive to excessive plantarflexion or dorsiflexion, the calcaneofibular ligament is sensitive to excessive inversion or eversion as well as dorsiflexion or plantarflexion, and that the deltoid ligament appears to be sensitive to plantarflexion, external rotation, and eversion. The fact that all three ligaments tested demonstrated different ranges of tension supports the view that there are optimal positions for testing ankle ligament integrity.

Adult↗
PubMed1990

The validity and relevance of tests used for the assessment of sports surfaces.

Inappropriate cushioning and/or tractional characteristics of sports surfaces are assumed to increase surface-related injuries in various sports activities. Various tests assessing cushioning and frictional properties are currently in use to evaluate sports surfaces with respect to their potential to reduce the number of surface-related injuries. A critical review of the currently used test procedures showed that most of them are not relevant. The main shortcomings are 1) errors in the measured test results by not correcting for inertia terms due to moving test foot or surface sample, 2) use of inadequate material test procedures where the test procedure influences significantly the test result, and 3) use of material test procedures where the used materials or the applied forces are not representative of the actual situation during sport activities. It is suggested that appropriate test batteries should include 1) test procedures that determine the material properties (stress-strain relation and traction coefficients) relevant for the surface-shoe interaction and 2) subject tests that describe the adaptation of the athlete to the surface-shoe-athlete situation.

Athletic Injuries↗
PubMed1989

Asymmetries in ground reaction force patterns in normal human gait.

The purpose of this study was to propose a measure of symmetry/asymmetry for normal human gait and to quantify symmetries/asymmetries of normal human gait for selected gait variables using a force platform. Sixty-two subjects performed ten gait trials each, stepping on the force platform five times with each leg. From these gait trials a symmetry index was calculated for 34 gait variables. The upper and lower limits of normal gait were calculated such that 95% of all symmetry indices obtained from this subject population fell within these limits. Upper and lower limits were found to vary from +/- 4% to over +/- 13,000%. Extremely high percentages were found for variables which had absolute magnitudes close to zero and/or variables which occurred at distinctly different instants during the gait cycle. The results of these variables need to be interpreted with caution.

Adult↗