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Biomedical subjects

E Stüssi

Publications and source records attributed to E Stüssi.

At least 55 records · Page 3Linked to original sources
PubMed1992

Heel movement within a court shoe.

Lateral movements of the leg and foot were filmed from behind to evaluate court shoes. Inversion/eversion may be an indicator of potential injuries, but estimates of actual inversion/eversion have typically been measured as the angular displacement of marker pairs on the lower leg and on the shoe. The purpose of this study was to measure the shoe movement versus the heel movement inside the shoe in order to determine the appropriateness of using shoe markers to represent the heel position. Two windows were cut into the heel counter of the shoe to show the heel position in addition to shoe position. The subjects were filmed from behind during a lateral side-stepping movement. The difference between the shoe and heel position was [corrected] statistically significant. The average maximum change in heel inversion inside the shoe was 13.3 +/- 3.8 degrees, compared with 30.7 +/- 6.2 degrees for the shoe. In addition, the maximum change in heel inversion in a barefoot movement was 10.1 +/- 3.1 degrees. The results suggest that for a lateral movement shoe markers do not accurately represent the position of the heel, and heel movement inside a shoe is similar to a barefoot movement. Skin markers on the heel as observed through windows in the shoe give a better indication of the actual position of the calcaneus than do markers placed directly on the shoe.

Adult↗
PubMed1992

[Biomechanical considerations of the load on the ankle joint].

The biomechanical approach to the characteristics of load on the ankle joint and the surrounding structures allows a better understanding of the cause and effect of externally acting forces in human movement (walking, running, jumping). This detailed understanding of the mechanics involved (not only in the functional anatomical sense) makes preventive measures possible that can reduce the risk of distortion at the ankle. With the same mechanical models, clinically applicable methods allow biomechanically monitored rehabilitation. The case studies reported here illustrate that therapeutic success can be measured objectively, leading to improvement in therapy and in the ability to make decisions in the clinical environment.

Achilles Tendon↗
PubMed1992

The movement of the heel within a running shoe.

Most running shoe investigations have used the same standard procedure for the evaluation of the shoes: the runners are filmed from behind and a film analysis is carried out digitizing markers at the heel counter of the shoe and on the lower leg. The angular displacement of these markers relative to the horizontal or the vertical is assumed to be an indicator for various sports injuries. The goal of this investigation was to measure the movement of the heel counter as well as the movement of the heel inside the shoe. First, the influence of the size of different heel counter windows was controlled and found negligible for the test conditions of this study. Second, 15 subjects performed the following procedure: running (a) barefoot, (b) with shoes with windows, and (c) without windows. Overall, the heel was found to move similarly but not identically to the heel counter. The maximum change of pronation was (a) 13.7 +/- 3.7 degrees, barefoot; (b) 14.1 +/- 3.8 degrees for the shoe with windows and 12.1 +/- 3.7 degrees for the heel inside these shoes; and 14.9 +/- 4.2 degrees for the shoes with no windows. To achieve a general impression of a shoe in the sense of a qualitative description, the previous method without heel counter windows still seems adequate. However, for a detailed analysis of quantitative nature, it is important to use the method with heel counter windows.

Adult↗
PubMed1991

The effects of shoes on the torsion and rearfoot motion in running.

Excessive pronation is accepted as a good indicator for various running injuries. The least amount of pronation takes place when running barefoot. The latest investigations show that this is connected to a large torsional movement between forefoot and rearfoot which can be influenced by the shoe sole construction. The shoes which are in use among runners in track and field are basically of two types, running shoes (in general torsionally stiff) and spikes (torsionally flexible). The possibly varying effect of these shoes on the shoe/foot motion in running is not known. The purpose of this investigation was therefore to show whether the pronation angle and the torsion angle differ when running barefoot, with spikes, and with running shoes (forefoot touchdown, N = 9 left and right). A film analysis provided the angular movements of the lower leg, rearfoot, and forefoot as well as pronation and torsion in the frontal plane. The results show that at touchdown the torsional movements with both shoe types are quite different from those of running barefoot. With shoes, the torsion angle is reduced back to zero--with running shoes more than with spikes--and the pronation angle is increased beyond the barefoot values (P less than 0.01). In order to reduce the risk of injury, both shoe types should be improved--the running shoes with respect to torsion and the spikes with respect to pronation.

Achilles Tendon↗
PubMed1989

[Biomechanics in sports].

Sports are often practised nowadays in balance for a non challenging profession or as means to counteract stressful life style. This desirable and reasonable development calls however for a critical assessment of biomechanical factors contributing to stress and admissible load of the human locomotor system. Considerate training renders excessive strain of the skeleton, cartilage and vertebral column virtually impossible. In view of the time required for adaptive processes this statement has to be combined with an appeal for appropriate training to those seeking compensation in physical exercise. Especially young people and middle-aged persons experiencing so called midlife-crisis tend to practise unbalanced and excessive sportive activity.

Adaptation, Physiological↗
PubMed1989

[Torsion --a new concept in construction of sports shoes. Motion excursion of the foot in athletic stress--anatomical and biomechanical observations and their effects on construction of sports shoes].

In recent years several construction elements resulted in an increasing stiffening of the sport shoe so that the foot was partly forced to make its own movements inside the shoe. A new sport shoe concept is presented basing on the results of anatomic and biomechanical studies, its innovative feature being decoupling of the foot movement between the calcaneal part of the foot and the metatarsus (= torsion). The foot is given an opportunity to transmit its freedom of movement in the longitudinal axis of the foot to the shoe without the shoe acting as a lever, this goal being achieved by a limited liberation of the metatarsal pronation/supination and a controlled uncoupling of the metatarsus from the calcaneal part of the foot.

Ankle Joint↗
PubMed1988

Phase velocity measurement of flexural waves in human tibia.

A method is proposed to measure the phase velocities of the first mode of flexural waves in the human tibia. Keeping in mind the dispersive nature of flexural waves in beam-like bodies, a two point measurement method was developed which enables the calculation of the phase difference of the propagating wave between two observation points for a selected frequency range. The method for dispersion analysis was tested with synthetic and observed signals for a cylinder. This was done by comparison of observed radial acceleration on the surface of a PVC-cylinder with computed synthetic signals consisting only of first mode flexural waves. An in vivo study was performed with 43 subjects. The phase velocity measurements in human tibia show a good correlation with the bone mineral content estimated by means of the Cameron-Sorenson technique (Cameron and Sorenson, 1963). The bone mineral loss is reflected by decreasing phase velocities. This indicates that phase velocity measurements of flexural waves can be used for an estimation of bone mineral content in vivo.

Biomechanical Phenomena↗
PubMed1988

[Running injuries and running shoe construction: demonstration of possible correlations].

Previous investigations about the running shoe design demonstrated a relationship between the geometry of the shoe sole, the ground reaction forces and the foot movements during impact. Thus, the question arised in which way this relationship would influence the internal forces. The purpose of this investigation was to model the impact situation and to simulate different sole geometries in order to calculate the internal forces and the pronation velocity. The results show that the geometry has a small effect upon the joint forces, but a very high effect on the pronation velocity. As a consequence, the joint forces changed only by 10% or less, but the load of the structures which are stressed by pronation is increased up to 200%. Thus, the control of the initial pronation is much more important in current running shoe design than the shock-absorption.

Ankle Injuries↗
PubMed1986

The effect of propranolol on whole-body microvibrations during examination stress.

Whole-body microvibrations (MV) in three dimensions were measured in 51 volunteers, all medical students, 26 without and 25 with beta-receptor blockade (propranolol), immediately before a practical physiology examination and during the ensuing vacation. Propranolol impeded the increase in MV values in all three axes, significantly those in the z axis (vertical), the differences in MV values between the two measurements being minimal in the beta-receptor blocked group. On the other hand, propranolol enhanced MV in the x axis (anteroposterior) and the y axis (transverse), the y axis difference being significant only in females. Propranolol obviously relieves examination stress: the majority of candidates (52%) felt "quieter" in the examination with than in other similar situations without beta-receptor blockade. Propranolol was, however, without effect on the examination results. The rectified impulse in the z axis when related to body weight (Jz) correlates linearly with the calculated cardiac output. Propranolol, however, reduced cardiac output more than Jz, pointing to a Jz component non-sensitive to beta-receptor blockade. The part played by muscle tonus, mainly reflected in the y axis, thus remains unknown. The large and slow oscillations in the x and y axes, observed particularly in beta-receptor blocked females, might be attributed to diminution in standing ability.

Adult↗
PubMed1981

[Measurement of tibial torsion-Comparison of various methods was computerised axial tomography (author's transl)].

The success of an operative correction taking for an example tibial realigment, depends largely on the accuracy and precision of preoperative measurements of tibial torsion. Several methods which are reported in the literature are discussed and compared with a computer-aided tomographic method (CT method). Some diagnostic indications for the CT method, in the case of tibial and femoral torsion measurements are described.

Ankle Joint↗
PubMed1980

Tibial torsion calculated by computerised tomography and compared to other methods of measurement.

A new method for the measurement of tibial torsion using computerised transverse tomography is presented. Its accuracy is equal to that of cadaveric skeletal measurement. This method may be used in patients with unilateral post-traumatic torsional deformities, especially when these are combined with genu varum or valgum. The study of torsional aberrations in connection with congenital abnormalities of the foot is of further interest.

Bone Diseases↗
PubMedDate not supplied

[Torsion movement of the foot in landing after a jump].

The risk of injury during landing after a jump is considered high, because large moments can force the foot into a distortion. The goals of this investigation were to measure the foot-movements during landing and to check the hypothesis, whether with changes at the shoe sole the rearfoot can be brought into a vertical and therefore stable position during the landing movement. The results show, that during landing the foot twists between forefoot and rearfoot. This movement is referred to as torsion and is described in detail in the anatomical literature. With grooves in the shoe sole the torsion with shoes comes closer to the barefoot values. The rearfoot is stabilized by 5-10 degrees and the risk of injury is decreased.

Ankle Injuries↗
PubMedDate not supplied

[Mechanics of joint stress].

The calculation of the possible load on human joints is of great importance in orthopedics. The magnitude of the force transmitted in the joints during the process of movement, whether in everyday life or in athletics, plays a decisive role. Especially at moments of impact, as in sports, high accelerations are transmitted through the human body. Bones and tissue (muscles, tendons and ligaments) react quite differently in this phase, and their reactions have a large influence on the magnitude and course of the forces working within the body, particularly in the joints. In previously developed methods of load-determination on joints during dynamic movements, these reactions were not considered. In the following paper, however, we will introduce a physical model that takes the various materials of the body's constitution into account. By introducing "wobbling mass", which, elastically damped, is coupled to the bony parts of the body, we can simulate the reaction of the body tissues, and a realistic calculation of the forces and moments transported through the body can be reached. The temporal sequence of these magnitudes for the knee and hip joints will be illustrated using an exemplary selected movement and interpreted using simplified joint structures. The main features of the method of calculation, using simple examples from statics, will be shown in Part One of this paper.

Biomechanical Phenomena↗