[Experimental studies on the biomechanical reaction of collagenous fibres during impulse mechanical strain working conditions (author's transl)].

A wide spectrum of stress-strain factors of varying directions and magnitudes are acting on collagenous fibres. Bundles of parallel collagen fibres in tendons and ligaments are mainly subject to tension forces. Single twitches and unfused tetanus of muscles fibres are giving rise to impulse strains on tendon fibres. Tendon reflexes are causing contractions of the muscle and sudden extensions of the corresponding collagenous fibres. In vitro studies were performed on tendon fibres. Tendon reflexes are causing contractions of the muscle and sudden extensions of the corresponding collagenous fibers. In vitro studies were performed on tendon fibre bundles. Systematic impulse extensions were applied as input functions. The force resp. stress impulses were recorded as output functions. When linear extensions with superimposed impulse strains were applied, the force-elongation curve showed a stepwise increase of the force impulse initially. Under consecutive isometric conditions an impulse relaxation curve arises. After partial deloading and subsequently isometric conditions an impulse force recovery function emerges. The output force impulses are dependent on the frequency of the input strain impulses. The effects are called frequency dependent force impulse relaxation and recovery. The findings are briefly discussed in correlation with functional anatomy and muscle physiology.