Intramuscular Coordination
Intramuscular coordination: refers to the coordinated recruitment of motor units within a single muscle. This concept is used to explain increases in maximal strength and power; however, the coordinated and sequential recruitment of motor units is also essential to strength endurance and smooth coordinated motion. For example, it is hypothesized that the "shaking" noted during a novice exercisers attempt at an activity like the stability ball crunch may be due to relatively poor intramuscular coordination. Rather than smooth, sequential firing of rectus abdominis motor units, groups of motor units turn on and off in an uncoordinated manner.