Motor unit control and force fluctuation during fatigue
نویسندگان
چکیده
منابع مشابه
Motor unit control and force fluctuation during fatigue.
During isometric contractions, the fluctuation of the force output of muscles increases as the muscle fatigues, and the contraction is sustained to exhaustion. We analyzed motor unit firing data from the vastus lateralis muscle to investigate which motor unit control parameters were associated with the increased force fluctuation. Subjects performed a sequence of isometric constant-force contra...
متن کاملChanges in motor unit action potentials during the fatigue test.
The studies were performed on medial gastrocnemius motor units of the rat. Changes in amplitude, duration and latency of motor unit action potentials were monitored in the course of fatigue test in the three types of motor unites: FF (fast twitch, fatigable), FR (fast twitch, resistant), and S (slow twitch, resistant) motor unit. In a majority of the motor units the amplitude of action potentia...
متن کاملMotor unit control properties in constant-force isometric contractions.
1. The purpose of this study was 1) to characterize the decrease observed in mean firing rates of motor units in the first 8-15 s of isometric constant-force contractions and 2) to investigate possible mechanisms that could account for the ability to maintain force output in the presence of decreasing motor unit firing rates. 2. The decrease in mean firing rates was characterized by investigati...
متن کاملControl of motor unit firing during step-like increases in voluntary force
In most skeletal muscles, force is generated by a combination of motor unit (MU) recruitment and increases in the firing rate of previously active MUs. Two contrasting patterns of firing rate organization have been reported. In the first pattern, the earliest recruited MUs reach the highest firing rates as force is increased, and later recruited MUs fire at lower rates. When firing rate of mult...
متن کاملExperimental pain has a greater effect on single motor unit discharge during force-control than position-control tasks.
OBJECTIVE When matching target force during pain, single motor unit (SMU) discharge is modified in a manner thought to redistribute load in painful tissue. This adaptation might not be appropriate when maintaining joint posture against an external load. We compared changes in SMU discharge rate of knee extensor muscles in a force-control and a position-control task during pain. METHODS Thirte...
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ژورنال
عنوان ژورنال: Journal of Applied Physiology
سال: 2009
ISSN: 8750-7587,1522-1601
DOI: 10.1152/japplphysiol.00035.2009