recruitment pattern
The orderly activation and firing pattern of motor units during voluntary muscle contraction assessed by EMG.
Full Definition
The recruitment pattern describes how motor units are activated during voluntary muscle contraction, following the size principle where smaller motor units are recruited before larger ones. Normal recruitment shows a gradual increase in motor unit firing frequency before additional units are activated. Pathologic patterns include reduced recruitment (fewer motor units firing at higher frequencies) in neurogenic conditions, and early recruitment (many small motor units firing rapidly) in myopathic disorders. Assessment of recruitment provides crucial information for distinguishing neurogenic from myopathic processes.
Usage
Usage note: Describe as normal, reduced (neurogenic), or early (myopathic) with supporting details.
In Context
- "Reduced recruitment pattern with high-frequency firing suggested neurogenic etiology." — EMG interpretation
- "Early recruitment of low-amplitude motor units was consistent with a myopathic process." — Needle electromyography