In vivo registration of Achilles tendon forces in XXXX . I. Methodological development.

@entity1 @entity717 @entity924 @entity1538
Mechanical behavior of muscle and its control is largely unknown under normal movement conditions. The present report deals with the methodological development to record directly in vivo forces from the @entity1 @entity924 ( @entity924 ) when the subjects perform normal movements ranging from slow walking to maximal sprinting and jumping. The development began with animal experiments, which dealt with the transducer design, surgical operation procedures, and duration of implantation. The first @entity1 experiment utilized an E form transducer implanted around the @entity924 under local anesthesia. The transducer was kept in situ for 7 days, and on the 8th day recordings were made on @entity1538 movements and during slow walking. Further development led to final selection of a "buckle"-type transducer, and the measurements can be made immediately after operation and they usually last 2-3 h. The @entity924 transducer can be calibrated by placing the subject in a prone position on to a calibration table. His operated foot was placed in a special shoe, the axis of which coincided with that of the ankle joint. A pulley system with known weights was used to dorsiflex the foot. Taking into consideration the geometrical arrangement of the @entity924 transducer, @entity717 , and the pulley system, the exact values of @entity924 forces could be calculated. The actual measurements incorporate the use of EMG recordings of the leg extensor muscles and various external force measurements, such as long force platform or oscillating ergometers. The transducer is removed immediately after the measurements and the subjects recover.
