The significance of the triceps surae muscle action as a determinant in the biomechanical genesis of ski fall injuries

In an epidemiologic study of 700 ski fall injuries YOUNG /1/ established a classification of the different fall modes involved. In more than 60 % of all falls that lead to an injury he found a forward bending motion of the body which is frequently coupled with a twisting of the body around the lower extremity. This clearly shows the importance of the forward motion component of the skier’s body in ski fall traumatology. The type of injury and its location depend on the action of the ski binding system. If the binding does not release in a ski fall, the fraction of injuries in the lower extremity amounts to nearly 100 %. If the binding does release, however, the injuries ocurring in this cas…

Effects of a 21 days space flight on the mechanical performance and the EMG power spectrum of the leg muscles

The influence of lateral release on patello-femoral joint loading in knee arthroplasty

Eight fresh, cadaveric knees have been fitted with four different total knee cemented prostheses. Loading forces at the bone implant fixation interface of the patella component have been measured in a knee joint testing rig by four miniaturized force transducers, before and after a lateral release of the patellar retinaculum. The lateral release resulted in a significant local force reduction in the lateral and/or proximal quadrant of the patella resection plane depending on the knee flexion angle, quadriceps tensile force direction, and the patellar prosthesis design.

The effect of cement fixation on initial micromotion of the femoral component in condylar knee replacement

Four fresh, cadaveric specimens were fitted with total knee replacements and mounted on a knee joint loading and measuring rig. Femoral component micromotion in the sagittal plane was measured with a transducer during flexion and extension of the specimen. Various condylar designs were used without and with cement. Movement followed a characteristic curve pattern and was less with cement fixation particularly for bone of low trabecular strength as determined by bone sample tests for stiffness. Cement fixation appears to be superior to cementless fixation.

The deltoid muscle: an electromyographical analysis of its activity in arm abduction in various body postures

We have carried out an electromyographical examination of the activity of five different regions of the deltoid muscle during abduction/adduction in various body postures with different biomechanical actions of arm gravity. The results show that the deltoid action is highly differentiated in its different regions and is not restricted only to the generation of an abducting moment in the shoulder joint. There is obviously a biomechanical contribution, mainly by its spinal and clavicular regions, to the stabilization of the glenohumeral joint and to the control of the selected plane of abduction.

Rechnerunterstützte Auswertung elektromyographischer und goniometrischer Meßsignale mit statistischen Signalanalyseverfahren

Messung der Pfannenwanderung bei zementfreien Hüftimplantaten

PURPOSE Migration measurements of acetabular components using a special computer aided method (EBRA = abbreviation for the German term "Ein-Bild-Rontgenanalyse") were performed to evaluate early results of the implants and predict aseptic loosening. METHODS Standard ap-radiographs of the pelvis were marked, specific points were digitised. Simulating the spatial situation the programme computes longitudinal and vertical migration of the cup. 74 acetabular components in 71 patients could be studied by migration measurements. RESULTS 14 patients showed migration of more than 1 mm, which is the confidence limit of this method. Each of these patients showed diverse reasons for the migration, i.e…

Biomechanical Diagnosis and Rehabilitation Control of Pes Equinus Patiens by Computerized Motion Analysis

If a foot is fixed in plantar flexion such as to inhibit a dorsal flexion beyond a rectangular position with reference to the lower leg the resulting syndrome is called pes equinus. These patients exhibit a characteristic gait with stance phases on tiptoe that may amount to a severe handicap for them. The pes equinus is a most common deformity found in patients with a hemiplegic or diplegic disorder in the region of the foot and the lower leg with typical structural changes in the ankle joint and the calf muscles. The therapy of the pes equinus depends on its etiology and its severity. A less severe pes equinus deformity can be treated by physical therapy and other conservative measures. Mo…

Ein rechnerunterstütztes elektromechanisches Meßsystem zur Untersuchung der Flexions- und Extensionskraft im oberen Sprunggelenk

Die Aktivität der Rückenstreckmuskulatur beim aufrechten Stehen und beim Sitzen mit standidentischer Rumpfhaltung - eine elektromyographische Studie

Problem: There is a controversial discussion about the loading of the spine by the force of the extending muscles of the back in upright sitting with the back curved as in upright standing. Experimental studies investigating this issue are still lacking. Methods: In the study presented in this paper we measured in 30 subjects the activity of the extending back muscles both in a natural upright standing posture and in sitting with identical posture of the back as recommended in some back training programs. To this end we recorded the electromyographical surface activity of the back muscles at four levels of the spine in both postures. The EMG activities were intraindividually normalized with…

Ensemble Averaging and Multiple Statistical Testing of EMG Activities of Cyclically Repeated Body Motions. A Tool for Muscle Function Analysis in Experimental and Clinical Orthopaedics. Ensemblemittelung und multiple statistische Analyse von EMG-Aktivitäten zyklisch wiederholter Körperbewegungen. Ein Instrument der Muskelfunktionsanalyse in der experimentellen und klinischen Orthopädie

Coupled with suitable computerized signal recording and processing methods surface electromyography can be a powerful tool for the analysis of muscle activity in specific body movements. It can be used for this purpose in experimental and in clinical diagnostic orthopaedics as well as in physiotherapy. We describe in this paper a motion analysis system comprising this feature. It has been employed for the diagnosis of the basic angular kinematics and muscle function in human gait and other cyclically repeatable movements of the human locomotive system. Changes in the temporal characteristics of the movements and the muscle activity due to changed physical or experimental conditions can be s…

Experimentelle Untersuchungen zur Reproduzierbarkeit von Ensemble-gemittelten elektromyographischen Ganganalysedaten im Bereich der experimentellen und klinischen Orthopädie / Experimental Investigation on the Reproducibility of Ensemble Averaged Electromyographic Gait Analysis Data in Experimental and Clinical Orthopaedics

With suitable application and signal processing methods, surface electromyography is a comparatively simple instrument for investigating the temporal pattern of the muscular activity of a walking subject. The influence of changes both in the external experimental conditions (e.g. orthopedic shoe design) and in the human locomotor system (due to disease or therapy) on the individual muscular gait characteristics can be documented in this way. The usefulness of this kind of investigation is basically limited by the reproducibility of the gait analytical findings of the subject, who is examined at different times with unchanged bodily state and under identical experimental conditions unchanged…

Gait analysis in idiopathic scoliosis before and after surgery: a comparison of the pre- and postoperative muscle activation pattern

In a prospective experimental study the level gait activity scores of the iliocostalis lumborum, glutaeus medius, tensor fasciae latae, vastus lateralis and peronaeus longus muscles of both body sides were examined by computerized electromyography in 23 patients with idiopathic scoliosis before and after CD instrumentation. The pre- and postoperative findings were examined as to asymmetric patterns in muscle requisition during gait and the respective changes induced by the spinal correction. These results were compared with the corresponding results obtained in healthy subjects in two independent sessions with identical experimental conditions. A muscle activity asymmetry coefficient was de…