Tibiocalcaneal kinematics of barefoot versus shod running

Barefoot running kinematics has been described to vary considerably from shod running. However, previous investigations were typically based on externally mounted shoe and/or skin markers, which have been shown to overestimate skeletal movements. Thus, the purpose of this study was to compare calcaneal and tibial movements of barefoot versus shod running using skeletal markers. Intracortical bone pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The subjects ran barefoot, with a normal shoe, with three shoe soles and two orthotic modifications. The three-dimensional tibiocalcaneal rotations were determined using a joint coordinate system approach. Test variables were defined for eversion and tibial rotation. The results showed that the differences in bone movements between barefoot and shod running were small and unsystematic (mean effects being less than 2 degrees ) compared with the differences between the subjects (up to 10 degrees ). However, differences may occur during midstance when extreme shoe modifications (i.e. posterior orthosis) are used. It is concluded that calcaneal and tibial movement patterns do not differ substantially between barefoot and shod running, and that the effects of these interventions are subject specific. The result of this in vivo study contrasts with previous investigations using skin and shoe mounted markers and suggests that these discrepancies may be the result of the overestimation with externally mounted markers.

Control of digits via C3-C4 propriospinal neurones in cats; recovery after lesions

C3-C4 propriospinal neurones (C3-C4 PNs) transmit the command for forelimb target-reaching in cats, while the command for food-taking is mediated by interneurones in the forelimb segments. The ability of the C3-C4 PNs to control digits has now been reinvestigated with combined lesions in dorsal C5 (transecting the cortico- and rubrospinal tracts) and ventral C2 (transecting reticulospinal tracts) leaving the C3-C4 PNs in sole control of the forelimb. Components of food-taking like flexion in the proximal interphalangeal joints were found in half of the cats. Supination and terminal flexion of the metacarpophalangeal joints by which normal cats bring the morsel of food to the mouth were lacking in all cats.

Recovery of food-taking in cats after lesions of the corticospinal (complete) and rubrospinal (complete and incomplete) tracts

The food-taking movement by which a cat grasps a morsel of food and brings it to the mouth is governed by interneurones in the forelimb segments (C6-Th1) and is normally controlled by the cortico- and rubrospinal tracts. It disappears reversibly when these tracts are transected in C5. The reappearance after some time is at least in part due to a reticulospinal take-over of the command. We have compared the recovery after total transection of both tracts with that after lesions giving subtotal transection of the rubrospinal tract but total transection of the corticospinal tract. With 4-6% of the rubrospinal fibres left, the recovery of food-taking was clearly faster than after total transection.

Movement coupling at the ankle during the stance phase of running

The purpose of this study was to quantify movement coupling at the ankle during the stance phase of running using bone-mounted markers. Intracortical bone pins with reflective marker triads were inserted under standard local anaesthesia into the calcaneus and the tibia of five healthy male subjects. The three-dimensional rotations were determined using a joint coordinate system approach. Movement coupling was observed in all test subjects and occurred in phases with considerable individual differences. Between the shoe and the calcaneus coupling increased after midstance which suggested that the test shoes provided more coupling for inversion than for eversion. Movement coupling between calcaneus and tibia was higher in the first phase (from heel strike to midstance) compared with the second phase (from midstance to take-off). This finding is in contrast to previous in-vitro studies but may be explained by the higher vertical loads of the present in-vivo study. Thus, movement coupling measured at the bone level changed throughout the stance phase of running and was found to be far more complex than a simple mitered joint or universal joint model.

Effects of foot orthoses on skeletal motion during running

OBJECTIVE

To quantify the effects of medial foot orthoses on skeletal movements of the calcaneus and tibia during the stance phase in running.

DESIGN

Kinematic effects of medial foot orthoses (anterior, posterior, no support) were tested using skeletal (and shoe) markers at the calcaneus and tibia.

BACKGROUND

Previous studies using shoe and skin markers concluded that medially placed orthoses control/reduce foot eversion and tibial rotation. However, it is currently unknown if such orthoses also affect skeletal motion at the lower extremities.

METHODS

Intracortical Hofman pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The three-dimensional tibiocalcaneal rotations were determined using a joint coordinate system approach. Eversion (skeletal and shoe) and tibial rotation were calculated to study the foot orthoses effects.

RESULTS

Orthotic effects on eversion and tibial rotations were found to be small and unsystematic over all subjects. Differences between the subjects were significantly larger (p<0.01; up to 10 degrees ) than between the orthotic conditions (1-4 degrees ). Significant orthotic effects across subjects were found only for total internal tibial rotation; p<0.05).

CONCLUSIONS

This in vivo study showed that medially placed foot orthoses did not change tibiocalcaneal movement patterns substantially during the stance phase of running.

RELEVANCE

Orthoses may have only small kinematic effects on the calcaneus and tibia (measured with bone pins) as well as on the shoes (measured with shoe markers) during running of normal subjects. Present results showed that orthotic effects were subject specific and unsystematic across conditions. It is speculated that orthotic effects during the stance phase of running may be mechanical as well as proprioceptive.

An in vitro comparison of bone deformation measured with surface and staple mounted strain gauges

Chicken tibiae were chosen as a model for human second metatarsals. Local surface bone deformation in a 4-point bending configuration was measured in vitro by both strain gauge instrumented staples and strain gauges bonded to the bone's cortical surface. A series of staple bridge dimensions (0.5, 0.6, 0.8 and 1.0 mm) was compared to test for staple influence on bone characteristics and greatest measurement validity and reliability. Thicker staple inhibition of bone deformation was the greatest but differences to thinner staples were not statistically significant (p > 0.05). All staples except 0.5 mm had maximum deviations from linearity less than 1%. The 1.0 mm staple had an R2 value of 0.992 +/- 0.006 plotted against the 4-point bending input force and 0.994 +/- 0.002 plotted against the surface strain gauge signal. The mean intraclass correlation coefficients (ICC) calculated with four input forces (30, 60, 90 and 120 N) and for loading and unloading conditions for the 0.5, 0.6, 0.8 and 1.0 mm staples were 0.75, 0.83, 0.87 and 0.92, respectively. Finally, the differences in slope of the staple strain gauge signal plotted against surface strain gauge signal between input force loading and unloading conditions (0.32), and between input compression and tension conditions (0.79) was least for the 1.0 mm staple which also resulted in the lowest standard deviations. These results suggested the appropriateness of the 1.0 mm staple for in vivo application.

A new method for estimating the axis of rotation and the center of rotation

A new method is presented for estimating the parameters of two different models of a joint. The two models are: (1) A rotational joint with a fixed axis of rotation, also referred to as a hinge joint and (2) a ball and socket model, corresponding to a spherical joint. Given the motion of a set of markers, it is shown how the parameters can be estimated, utilizing the whole data set. The parameters are estimated from motion data by minimizing two objective functions. The method does not assume a rigid body motion, but only that each marker rotates around the same fixed axis of rotation or center of rotation. Simulation results indicate that in situations where the rigid body assumption is valid and when measurement noise is present, the proposed method is inferior to methods that utilize the rigid body assumption. However, when there are large skin movement artefacts, simulation results show the proposed method to be more robust.

Assortative mating and female clutch investment in black grouse

Variation in female behaviour has only recently received attention in studies of sexual selection. It has been suggested that females may invest differentially in their offspring in relation to the quality of their mate. This may lead to females that mate with high-quality and/or attractive males laying larger clutches. Females may also differ in their ability to choose between males. For example, females in good physical condition may make better choices. If physical condition and clutch size are positively correlated, this hypothesis could also produce a relationship between male attractiveness and female clutch size. We found, in lekking black grouse, Tetrao tetrix, that females mated to the highest ranked males laid the largest clutches. Furthermore we found, regardless of female age, a positive relationship between a measure of female condition and male rank but not between female condition and her clutch size. In addition, females in good condition visited a larger number of different male territories, and old females produced the largest clutches. Our results suggest two mechanisms to explain our findings. First, females in good physical condition tend to mate with the top males, suggesting an assortative mating pattern. Second, females mating with the highest ranked males lay larger clutches as a consequence of their choice. In general, our result calls for caution in evaluating studies that look at the consequences of mate choice. It may be that differences in female quality produce effects that may be wrongly interpreted as male quality effects. (c) 1998 The Association for the Study of Animal Behaviour.

Food-taking in the cat investigated with transection of the rubro- and corticospinal tracts

In cats with the distal paw shaved food-taking from a horizontally or vertically placed tube was recorded with a video camera, supplementary results were obtained with a high frequency video system. Measurements were made of the dorsal contour of the digits to investigate angular movement in the proximal interphalangeal (PIP) joint and withdrawal of the paw before and after complete transection of the rubro- and corticospinal tracts just rostral to the forelimb segments. In the preoperative state PIP flexion occurs before withdrawal of the paw in the large majority of cats. Postsurgically the main part of PIP flexion is made during withdrawal of the paw. It is suggested that PIP flexion before withdrawal allows for accurate manipulative placement of the digits on the target which depends on the rubro- and corticospinal tracts, while PIP flexion during withdrawal, which may favour speed at the expense of accuracy, can be made without the rubro-and corticospinal tracts.

Mechanical load and primary guinea pig osteoarthrosis

Hartley guinea pigs spontaneously develop knee osteoarthrosis. The reproducible course, the changes first appearing at the central medial condyle and then progressing peripherally and laterally, makes this animal a suitable model for intervention studies. We studied the effect of load, and randomized 9-month-old male animals into 4 groups: immediate killing, mid-femoral 30 degrees-valgus osteotomy, sham operation or below-knee amputation. After 3 months, the proximal tibia was step-sectioned and examined stereologically by light microscopy. Local load-redistribution from the medial to the lateral condyle (osteotomy) reduced cartilage fibrillation by 22% medially and increased it 27% laterally. Subchondral bone thickness decreased by 36% in the medial condyle. In contrast, general load-redistribution (amputation) did not affect the progress of fibrillation, despite pronounced bone atrophy. Cartilage thickness, however, did not change; calcified cartilage thickness remained remarkably constant, and it was always higher on the lateral side. Therefore tide-mark advancement does not appear to be an important mechanism in early guinea pig osteoarthrosis. Thus, when the natural course of guinea pig osteoarthrosis is interfered with surgically, in the early phase, changes in bone are more conspicuous than those in cartilage, which further indicates that mechanical load and stiffness gradients are important pathogenetic mechanisms.

Role of claws and pads in taking and holding food in cats

In order to investigate the role of claws and pads in taking food the planter surface of the distal forelimb paw was recorded with a conventional video camera. The claws were involved in the great majority of trials. The morsel of food may be taken by piercing with one claw (rarely two) either alone or by pressure against a digital pad; support by pressure from another claw was also common, while pressure between two claws was used more rarely. Another technique was pressure between claws (without piercing) and digital pads. The morsel was also taken without participation of claws by pressure between digital pads and the central pad and more rarely between two digital pads.

Control of claw movements in cats

In cats with the distal paw shaved and the claws painted with nail varnish, claw movements were recorded during the approach to a morsel of food with a conventional video camera; supplementary results were obtained with a high frequency video system. The claws can be protruded in two directions, either ventrally or more dorsalwards. Measurements of the outer contour of the paw suggest that these two modes are not due to differences in angular movements in the proximal interphalangeal joints; it is suggested that they depend on some (so far unknown) function in the distal interphalangeal joints. Differential movements of the claws of the different digits suggest some degree of individual control of the digits.

Effect of spinal cord lesions on forelimb target-reaching and on visually guided switching of target-reaching in the cat

Cats were trained to reach to an illuminated tube placed horizontally at shoulder level and retrieve food with the forepaw. The trajectory of an infrared light emitting diode, taped to the wrist dorsum, was recorded with a SELSPOT-like recording system. Movement paths and velocity profiles were compared before and after lesions: (1) in dorsal C5, transecting cortico- and rubrospinal pathways to the forelimb segments so that the cats could only use the C3-C4 propriospinal neurones (PNs) to command reaching, (2) in the ventral part of the lateral funicle in C5, transecting the axons of C3-C4 PNs so that the cats had to use circuitry in the forelimb segments to command reaching. Comparison of trajectories and velocity profiles before and after lesion 1 did not reveal any major qualitative change. After lesion 2, the last third of the movement was fragmented with separate lifting and protraction. Switching of target-reaching occurred when illumination was shifted to another tube during the ongoing movement. The switching latency measured from the time of illumination shift to the earliest change in movement trajectory had a minimal value of 50-60 ms. Short latencies were present after lesion 1 as well as lesion 2 which suggest that fast switching mediated by the C3-C4 PNs and the interneuronal system in the forelimb segments is controlled in parallel by the brain. In order to test a hypothesis that fast switching depends on the tectospinal and tecto-reticulospinal pathways (the tecto-reticulo-spinal system) a ventral lesion was made in C2 aiming at interrupting these pathways. Large ventral C2 lesions tended to block conduction in the more dorsally located rubrospinal (less in corticospinal) axons probably due to compression during surgery. When conduction in the rubrospinal tract was completely interrupted by a ventral C2 lesion which also completely transected the axons of the tecto-reticulo-spinal system, then there was a prolongation of the switching latency with 10-20 ms. After a similar large ventral lesion with remaining conduction in the rubrospinal tract the switching latencies were unchanged. It is postulated that fast visually governed switching does not depend on the tecto-reticulo-spinal system alone but on more dorsally located pathways, presumably the rubrospinal tract, either acting alone or together with the tecto-reticulo-spinal system. It is further postulated that the delayed switching after interruption of conduction both in the rubrospinal tract and the tecto-reticulo-spinal system depends on the corticospinal tract. Visual control of rubrospinal and of corticospinal neurones is considered. It is postulated that target-reaching normally depends on signals in the cortico- and rubrospinal tracts and mechanisms for co-ordination of activity in them as required during switching is discussed in view of the findings now reported.

Fluctuating asymmetry and copulation success in lekking black grouse

In lekking black grouse, Tetrao tetrixmales at the centre of the leks obtain more copulations than males at the edges. We found that males with territories at the edge of the lek obtained fewer matings and also have the most asymmetric tarsi. However, when considering the tail ornament (the lyre) no correlation between asymmetry and mating success was found. Although females are unlikely to select males on the basis of tarsus symmetry, asymmetry in this trait may reflect male condition. We suggest that males in poor condition, as reflected by higher levels of fluctuating asymmetry in the tarsi, do not achieve central positions on the lek arena. This would account for the lower success of males with higher levels of fluctuating tarsus asymmetry.

Effect of skin movement on the analysis of skeletal knee joint motion during running

It is not known how well skin markers represent the skeletal knee joint motion during running. Hence the purpose of this investigation was to compare the skin marker derived tibiofemoral motion with the skeletal tibiofemoral motion during running. In addition to skin markers attached to the shank and thigh, triads of reflective markers were attached to bone pins inserted into the tibia and femur. Three-dimensional kinematics of the stance phase of five running trials were recorded for three subjects using high-speed cine cameras (200 Hz). The knee motion was expressed in terms of Cardan angles calculated from both the external and skeletal markers. Good agreement was present between the skin and bone marker based knee flexion/extension. For abduction/adduction and internal/external knee rotation, the difference between skeletal and external motion was large compared to the amplitude of these motions. Average errors relative to the range of motion during running stance were 21% for flexion/extension, 63% for internal/external rotation, and 70% for abduction/adduction. The errors were highly subject dependent preventing the realization of a successful correction algorithm. It was concluded that knee rotations other than flexion/extension may be affected with substantial errors when using skin markers.

An experimental in vivo method for analysis of local deformation on tibia, with simultaneous measures of ground reaction forces, lower extremity muscle activity and joint motion

This paper presents the pilot procedures of a new in vivo experimental method for measures of local bone deformation on tibia. The tibia transducer consists of a strain gauge mounted on a surgical staple, and was designed to measure local bone deformation. Pilot measurements were undertaken during two standardized conditions of forefoot and heel landing in seven healthy volunteers. Implantation of two tibia force transducers on tibia were performed under local anaesthesia. The local peak tibia deformation occurred at 20-42 ms (median) after ground contact, and was up to eight times higher during stance phase loading compared with standing still on one leg. Ground reaction forces, muscle activation patterns and kinematics were registered simultaneously, and were used to validate that the observed local deformation on tibia occurred under controlled and clinically relevant conditions. The new method may be used for investigating local deformation within various bone structures of the lower extremity. There are further methodological issues to address before major clinical interpretations may be concluded. In order to verify that the strain gauge transducer system was valid, a controlled displacement of the staple shanks was performed with a micrometer, and showed a linear relationship between applied deformation and strain gauge response (r = 0.97-0.99). In addition, a linear relationship was found between externally applied static forces and strain gauge response in a four-point bending cadaver system (r = 0.96-0.98).

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.

Early-onset myopathy with tubular aggregates

We report a 14-year-old girl with early onset of slowly progressive muscular weakness and atrophy. There was no family history of neuromuscular disease. A persistent increase of serum creatine kinase was found. Muscle biopsy specimens showed type 1 fiber predominance and tubular aggregates in almost every fiber. The clinical findings and pathology suggest that the disease represents one variant in a group of rare myopathies with different patterns of inheritance, characterized by slowly progressive muscle weakness and tubular aggregates.

Three-dimensional tongue surface shapes of English consonants and vowels

This paper presents three-dimensional tongue surfaces reconstructed from multiple coronal cross-sectional slices of the tongue. Surfaces were reconstructed for sustained vocalizations of the American English sounds [symbol: see text]. Electropalatography (EPG) data were also collected for the sounds to compare tongue surface shapes with tongue-palate contact patterns. The study was interested also in whether 3-D surface shapes of the tongue were different for consonants and vowels. Previous research and speculation had found that there were differences in production, acoustics, and linguistic usage between the two groups. The present study found that four classes of tongue shape were adequate to categorize all the sounds measured. These classes were front raising, complete groove, back raising, and two-point displacement. The first and third classes have been documented before in the midsagittal plane [cf. R. Harshman, P. Ladefoged, and L. Goldstein, J. Acoust. Soc. Am. 62, 693-707 (1976)]. The first three classes contained both vowels and consonants, the last only consonants. Electropalatographic patterns of the sounds indicated three categories of tongue-palate contact: bilateral, cross-sectional, and combination of the two. Vowels used only the first pattern, consonants used all three. The EPG data provided an observable distinction in contact pattern between consonants and vowels. The ultrasound tongue surface data did not. The conclusion was that the tongue actually has a limited repertoire of shapes and positions them against the palate in different ways for consonants versus vowels to create narrow channels, divert airflow, and produce sound.