Postural activation of the human medial gastrocnemius muscle: are the muscle units spatially localised?
نویسندگان
چکیده
منابع مشابه
Damage to different motor units from active lengthening of the medial gastrocnemius muscle of the cat.
Slow-twitch motor units in the medial gastrocnemius muscle of the anesthetized cat were found to have an average optimum length for active tension that was 0.8 +/- 0.5 (SE) mm longer than the whole muscle optimum. For fast-twitch units (time to peak < 50 ms), the average optimum was 1.3 +/- 0.3 mm shorter than the whole muscle optimum. After the muscle had been subjected to 10 stretches while m...
متن کاملRegional variability of stretch reflex amplitude in the cat medial gastrocnemius muscle during a postural task.
The relationship between local fibre stretch velocity (mechanical input) and the corresponding local reflex electromyographic (EMG) amplitude (a measure of the neural output) was assessed to determine the contribution of muscle spindle feedback in postural control. We hypothesized that traditionally measured input variables (e.g., the velocity of an external movement or whole muscle velocity) m...
متن کاملActive muscle stiffness in the human medial gastrocnemius muscle in vivo.
The aims of this study were to 1) directly assess active muscle stiffness according to actual length changes in muscle fibers (fascicles) during short range stretching; and 2) compare actual measured active muscle and tendon stiffness using ultrasonography with the stiffness of active (i.e., muscle) and passive (i.e., tendon) parts in series elastic component of plantar flexors using the alpha ...
متن کاملTwitch force and action potentials of single motor units in medial gastrocnemius muscle of the rat.
On the basis of a sag test in unfused tetanus we classified fast and slow motor units (MUs) in medial gastrocnemius muscle of the rat. The following parameters of motor units were investigated: single twitch force, duration of the action potentials, maximum-minimum amplitude time (M-MAT), action potentials amplitude and their latencies after stimulus (to the onset of potentials) and the diamete...
متن کاملPassive mechanical properties of human gastrocnemius muscle-tendon units
Background The passive mechanical properties of skeletal muscletendon units are important because they determine the amount of motion available at joints. Human gastrocnemius muscle-tendon units are of particular interest because this muscle is prone to develop contractures, may have a role in lower limb overuse injuries, and is a common site of muscle tears. This workshop provides an introduct...
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ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 2011
ISSN: 0022-3751
DOI: 10.1113/jphysiol.2010.201806