Muscle activity during 3-D movements at complex ´joints´: changing synergism

Neuromotor control strategies, as estimated from EMG activity in multiple muscles, are considered for a variety of types of movement tasks. It is seen that the same muscles may be synergistic for certain tasks and yet antagonistic for others. Furthermore, such changes can routinely occur even within the same task. Reasons for such changing synergism can usually be traced to mechanical factors not always immediately evident that are related to holding posture, movement dynamics, or joint stability. Causal relationships between osteoarthritic conditions and muscle strategies are also suggested.<>