This term refers to the concept that muscles may be acting concentrically, eccentrically, & isometrically all at the same time, at different joints, and/or in different planes of motion. JH asked me to give an example of where this occurs in the human body, and the answer is everywhere. If you are going to buy into the concepts put forth in my blog, you have to re-examine the idea of agonists, antagonists, synergists, and stabilizers. In function, all muscle are synergists. I am not an expert in this area, and if you need more info, Gary Gray goes in depth on the concept in one of his functional video digests. If you really want to dive into this stuff, apply for next year's GAIN APPRENTORSHIP and learn hands on. Dr. Dan Cipriani, biomechanics professor at San Diego State will go over the theory, while Vern & Steve put it into practice.
Ay Dios Mio, here come the rotten tomatoes again, but here is an example:
The gastrocnemius at late mid stance: Proximally is isometrically contracting to prevent hyperextension at the knee, distally eccentrically decelerating dorsiflexion at the ankle, while concentrically inverting the calcaneus.