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C Tardieu

Publications and source records attributed to C Tardieu.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Morphogenesis of the femoral diaphysis in humans: significance of function and evolution].

The obliquity of the femoral diaphysis, measured by the bicondylar angle, permits the adducted position of the knee in humans. The presence of a high femoral bicondylar angle has been a hallmark of hominid bipedality, but its pattern of development has not been documented. We have observed radiographic and skeletal data on the development of this angle. The two samples exhibit a pattern of a bicondylar angle of 0 degrees at birth and then a steady average increase in the angle through infancy and into the juvenile years. These data establish a high degree of potential for plasticity in the development of this angle and the direct association of a bipedal locomotion with the developmental emergence of a human femoral bicondylar angle. We show that the obliquity angle, which occasionally appears in some non-human primates, is not homologous to the human condition. As this angle is an epigenetic functional feature in modern humans, we suggest that it developed following a change in infantile locomotor behaviour of the early australopithecines and was not the result of a genomic change.

Adolescent↗
PubMed1993

New method of three-dimensional analysis of bipedal locomotion for the study of displacements of the body and body-parts centers of mass in man and non-human primates: evolutionary framework.

The current biomechanical interpretation of the chimpanzee's bipedal walking argues that larger lateral and vertical displacements of the body center of mass occur in the chimpanzee's "side-to-side" gait than in the human striding gait. The evolutionary hypothesis underlying this study is the following: during the evolution of human bipedalism one of the necessary changes could have been the progressive reduction of these displacements of the body center of mass. In order to quantitatively test this hypothesis, it is necessary to obtain simultaneously the trajectories of the centers of mass of the whole body and of the different body parts. To solve this problem, a new method of three-dimensional analysis of walking, associated with a volumetric modelling of the body, has been developed based on finite-element modeling. An orthogonal synchrophotographic device yielding four synchronous pictures of the walking subject allows a qualitative analysis of the photographic sequences together with the results of their quantitative analysis. This method was applied to an adult man, a 3-year-old girl and a 9-year-old male chimpanzee. Our results suggest that the trajectory of the body center of mass of the human is distinguished from that of the chimpanzee not by a lower movement amplitude but by the synchronization of the transverse and vertical displacements into two periodic curves in phase with one another. The non-human primate uses its repertoire of arboreal movements in its bipedal terrestrial gait, provisionally referred to as a "rope-walker" gait. We show that the interpretation of a "side-to-side" gait is not applicable to the chimpanzee. We argue that similarly this interpretation and the initial hypothesis presuppose a basic symmetric structure of the gait, in relation to the sagittal plane of progression, similar to the human one. This lateral symmetry of the right and left displacements of the center of gravity, in phase with the right and left single supports of walking, is probably a very derived feature of the human gait. We suggest that low lateral and vertical displacements of the body center of mass are not indicative of a progressive bipedal gait and we discuss the new evolutionary implications of our results.

Adult↗
PubMed1989

Toe-walking in children with cerebral palsy: contributions of contracture and excessive contraction of triceps surae muscle.

The study was designed to provide a quantitative analysis of toe-walking in children with cerebral palsy (CP). The total internal moment developed about the ankle joint during locomotion and the passive component of this internal moment were measured. The contributions of the active and passive components were expressed as the ratio (R) between the passive moment and the total internal moment. Measurements were compared for 13 children with CP and 5 healthy children. For the data analysis, the children with CP, exhibiting apparently similar toe-walking, were divided into two groups: 1) Group CPI and 2) Group CPII. Group CPI was characterized by a small ratio R value, which indicated the presence of excessive contractions of the triceps surae muscle during locomotion. In Group CPII, the ratio R value was abnormally high, which indicated that a contracture (ie, structural change of the muscle or the tendon) was entirely or at least partly responsible for toe-walking. Each group requires a different therapeutic strategy.

Adolescent↗
PubMed1989

[Is surgery of the tendons of the knee flexor muscles justified in cerebral palsy?].

The lengths of the tendons and muscle belly connective tissue envelopes of the knee flexor muscles of 6 healthy and 11 children with cerebral palsy were measured. The restricted passive knee extension was found to be associated with abnormally short tendons in all cases of contracture. This correlation provided an experimental support for the surgical lengthening of the tendon.

Biomechanical Phenomena↗
PubMed1988

For how long must the soleus muscle be stretched each day to prevent contracture?

The extent to which treatment of passive muscle contracture could be minimised without loss of efficiency was studied. Soleus muscle contracture was measured by the difference between the ankle angles at which minimal and maximal resistance occurred during slow dorsiflexion of the ankle. This examination was done twice, at the beginning and end of a seven-month observation period. During the observation period, also, the ankle angles were measured throughout a 24-hour period in the ordinary life of the child. The number of hours per 24-hour period during which the soleus muscle was stretched above a minimal threshold length was calculated. The major finding was that there was no progressive contracture when the soleus was stretched for at least six hours a day (the same time as in non-handicapped children). On the other hand, there was progressive contracture when the stretching time was as short as two hours. Two of the cases examined illustrated the possible causes of success or failure of night splints. These results provide new guidelines for the continuous treatment of children with cerebral palsy.

Adolescent↗
PubMed1987

Cerebral palsy. Mechanical evaluation and conservative correction of limb joint contractures.

Studies in animals and in children with cerebral palsy (CP) allow precise evaluation of the physiologic and pathophysiologic adaptations in muscle and tendon. In the individual child with CP, clinical evaluation must be much more precise than a routine examination in order to clearly define the nature of the contractures and select the correct therapeutic program.

Adaptation, Biological↗
PubMed1985

Tendon adaptation to different long term stresses and collagen reticulation in soleus muscle.

Leg immobilization with or without soleus muscle denervation was studied in young rabbits. Muscle and tendon were maintained in extension, i.e., in the most lengthened position. Length measurements performed on sarcomeres, muscle fibers and tendon-plus-muscle complexes suggest the following progression in tendon growth rates: normal less than denervated-extended less than innervated-extended. Collagen reticulation was studied as a function of fiber location along these tendons by measuring hydrothermal isometric tension (HIT). Large variations were observed depending on fiber location, and significant modifications were induced by immobilization in extension. The results are discussed in relation to stress as a possible factor controlling collagen maturation in connective tissues.

Adaptation, Physiological↗
PubMed1985

[Close interdependence between passive and active soleus muscle torques in man: approach to the coregulation of the number of sarcomeres and length of the connective tissue].

Soleus muscle has, to as great an extent as possible, been functionally isolated in man. A device previously described permitted measurement of the soleus torque as a function of the tibia-calcaneum angle, and not as a function of tibia-foot angle. This latter angle cannot be correctly related to soleus length, since the arch of the foot can not be considered as rigid throughout the experiment. Ankle movements were performed on a horizontal plane by successive increments of 5 degrees from full extension (plantar flexion) up to full flexion (dorsiflexion). Passive torques were measured for every angle. At the same angles, the total torques were recorded while the subject exerted a voluntary constant contraction which corresponded to 45% of the maximum integrated electromyographical activity of soleus muscle. The active torque-angle curve was obtained by subtracting, for the same angle, the passive from the total torques. It must be stressed that, when the muscle is maximally shortened, little or no torque was measured. For the angle corresponding to the top of the sub-maximal active curve (integrated electromyographic activity 45% of the maximum), the passive torque was about 1.75 Nm and showed no significant interindividual variations. This result contrasted with the marked interindividual shifts which affect both passive and active curves. This interdependence of passive and active curves in human soleus muscle is compatible with the results of a previous study in the cat showing the concomitant adaptations of sarcomere number and connective tissue length.

Calcaneus↗
PubMed1984

Can vibration-induced illusions be used as a muscle perception test for normal and cerebral-palsied children?

Since poor control of muscle contractions in cerebral palsy may be due partly to defective processing of data originating from muscle, the need arose for a test as uncontaminated as possible by other afferent effects. For 18 normal children, vibration of the brachial biceps tendon always gave the illusion of elbow extension; when the triceps was vibrated the opposite illusion occurred. For 22 cerebral-palsied children the vibration test was successful for 26 elbows and failed for 18. These failures might provide a future explanation for certain therapeutic failures.

Adolescent↗
PubMed1983

Tendon adaptation to bone shortening.

The ability of tendon to adapt its length to imposed conditions was tested in rat soleus. Shortening of one tibia left tendon insertions intact, but reduced the distance between them. Tendon lengths were found to decrease after a short period of recovery (1 or 2 months) whether surgery was performed in young or adult animals. Comparison of tibia and tendon length correlation in control rats of different ages and in experimental animals showed that adaptation was more complete in young rats than in adult rats. A long period of recovery seemed to improve adaptation only in young rats. Hydrothermal isometric tension measurements indicated that collagen remodeling occurred during tendon adaptation to bone length, with the process being more marked at the muscle-tendon junction.

Adaptation, Physiological↗
PubMed1982

Effects of muscle length on an increased stretch reflex in children with cerebral palsy.

No inhibitory influence of length on the increased stretch reflex was found in the internal gastrocnemius muscle of 19 cerebral palsied children. A facilitory influence of length was found in at least five patients in which quantitative data were obtained. These results were compared with previous data on a facilitory influence in the hamstrings and inhibitory influence in quadriceps muscles.

Cerebral Palsy↗
PubMed1982

Muscle hypoextensibility in children with cerebral palsy: II. Therapeutic implications.

Twenty-nine children with cerebral palsy and triceps surae hypoextensibility were divided into 2 groups. In group I trophic regulation of the muscle was defective and in group II it was normal. Torque values were plotted against tibiocalcanean angles before and after treatment, which consisted of muscle lengthening by successive plaster casting or of surgical elongation of the tendon or the aponeurosis. In group I, casting had no effect, but surgery increased passive dorsiflexion and gave definite clinical improvement without modifying the range of passive muscle stretch. In group II, with normal muscle adaptation, plaster casts were successful when tolerated. Children in this group required braces after surgery to prevent rapid recurrence of hypoextensibility. Both casting and surgery increased the passive muscle stretch. There was a displacement of the starting point of the passive and active curves in both groups. This is an unavoidable side-effect which makes walking on tiptoes impossible after casting or surgery.

Achilles Tendon↗
PubMed1982

Muscle hypoextensibility in children with cerebral palsy: I. Clinical and experimental observations.

Extensibility of the triceps surae was compared in 12 normal children and in 21 children with cerebral palsy (CP). The latter group represented selected subjects who showed hypoextensibility in ischemia-tested noncontracting muscle, which is considered an indication of change in the physical properties of muscle. The difference between the 2 groups is illustrated by curves plotting torque of the noncontracting muscle against tibiocalcanean angles. Two measurements were found to be especially representative: 1) the angle related to a very slight torque and 2) the angle corresponding to a strong, standardized torque. In children with CP and with muscle hypoextensibility, both angles had abnormally high values and the difference between the 2 measurements was abnormally small. These findings indicate an insufficient range of passive muscle stretch, reflected by excessive steepness of the torque-angle curve. In normal children, maximal muscle contraction produces full plantar flexion; in some children with CP, contraction fails to produce any force in full plantar flexion. Instead, force is generated only at a smaller tibiocalcanean angle when the muscle reaches a sufficient length. These cases represent hypoextensibility with abnormally short muscle and abnormally long tendon. Data obtained by instrumental measurements can be reproduced with sufficient accuracy by appropriate clinical technique as described in this paper, and applied clinically, as described subsequently.

Adolescent↗
PubMed1982

Adaptation of connective tissue length to immobilization in the lengthened and shortened positions in cat soleus muscle.

1. The aim of this study was to investigate length adaptation of connective tissue in adult cat soleus muscle immobilized in the lengthened position for 28 days (group I) or in the shortened position for 14 (group II) or 28 days (group II). 2. The method, combining passive tension-length curves of the whole muscle with measurement of the length of the contractile part of isolated fibres, enabled separate determination of length of the very slightly compliant tendinous part, and of the highly compliant parallel elastic component (PEC) mainly constituted of belly connective tissue. 3. PEC length was found to increase in group I and to shorten in group II and III, showing that it adapted to the length imposed on the muscle. 4. Tendinous part lengths did not change significantly in any of the three groups compared to the controls. 5. Comparison of the respective adaptations of PEC and contractile tissue lengths showed that PEC adaptation was insufficient in groups II and III.

Adaptation, Physiological↗
PubMed1981

Effects on torque angle curve of differences between the recorded tibia-calcaneal angle and the true anatomical angle.

The present study gives the results of a comparison of the recorded and true tibia-calcaneal angles in 17 normal subjects and in 14 patients with abnormally hypoextensible non contracting triceps. 1. For a minimal passive torque, the difference between true and recorded angles varied considerably from one individual to another. The mean and ranges for the two groups were respectively: -8 degrees (+7 degrees, -21 degrees) and -7 degrees (+5 degrees, -20 degrees). 2. When the passive torque increased as a result of slow passive lengthening of the muscle, the true curve was steeper than the recorded one, owing to differences between the two angle measurements. For each of the two groups the differences in means and ranges were respectively: 6 degrees (0 degrees, +13.5 degrees) and 8 degrees (3 degrees, 12 degrees). 3. Subjects made isometric voluntary contractions of the triceps surae at fixed angles which corresponded to step by step muscle lengthening. The resulting true curve was much steeper than the recorded curve. The differences in means and ranges were: 7 degrees (1.5 degrees, +15 degrees) in children of the two groups and respectively 3 degrees (0 degrees, +9 degrees) and 12 degrees (10 degrees, 14 degrees) in adults of the two groups. The present results show that this methodology was the only reliable way of correctly obtaining passive and active torque-angle curves, measuring differences between subjects, appreciating the effects of treatments and these by ascertaining whether or not trophic muscle regulation was defective.

Adult↗
PubMed1979

Trophic muscle regulation in children with congenital cerebral lesions.

A decrease in sarcomere number and hypoextensibility of ankle extensors was observed in certain children with congenital cerebral lesions. This phenomenon was reproducible and reversible in normal animals, i.e. trophic regulation adapted the muscle to the imposed length. The form of the torque-ankle angle curve was studied in 30 children. Its modification after treatment was considered as a sign of muscle adaptation. This adaptation was present in one group of 14 children. The steepness of the curve increased or diminished depending on the initial disorder and the treatment administered. In another group, treatment failed to modify the shape of the curve. In certain cases trophic regulation of the muscle appeared to be absent.

Adolescent↗
PubMed1979

Decrease of muscle extensibility and reduction of sarcomere number in soleus muscle following a local injection of tetanus toxin.

Slow soleus muscle in guinea pig developed within 4--6 days after local injection of a sublethal dose of tetanus toxin and 2--4 days after the first signs of local tetanus, a myostatic contracture characterized by a change in the passive tension--lengthening curve associated with a considerable decrease of the sarcomere number. It was demonstrated by clinical and EMG investigations that the soleus did have a tetanic spasm at least within the 2--4 day period of observation. When local tetanus was confined to slow soleus by functional suppression of rapid gastrocnemius and ankle flexor muscles, the decrease of the sarcomere number still persisted. This decrease failed to occur after section of the nerve supplying the soleus when associated with an injection of the tetanus toxin, and was much greater than when the soleus was passively shortened for the same period of time by plaster cast.

Animals↗