hello in this video i'm going to talk about motor control theories um so first we'll talk about what is a theory um theories are used in all fields of science uh they help us understand phenomena and explain why those phenomena exist or behave the way that they do stephen hawking wrote that a good theory should accurately describe a large class of observations and make definite predictions about the results of future observations so that applies widely in all areas of science and that looks different depending on what area you're studying in behavioral sciences theories focus on explaining human behavior and motor control is a behavioral science so that's where we focus here um so motor control theories explain why people perform skills the way they do they identify variables that account for differences in performance you know from one individual to another or one trial to another they explain why specific capabilities are possible and they explain why an intervention is effective like an injury rehabilitation interventions like physical therapy for example um so from a practical standpoint theories are important because they give us a foundation to develop skill instruction programs so how do we help athletes learn a new skill um they help us understand practice environments and how we can facilitate better performance through you know adjusting how we're practicing they help us develop rehabilitation programs that are more effective so it's really helpful if you're working in any area of motor control to have a solid foundation and understand theory in our area so motor control theories describe and explain how the nervous system coordinates movement to perform motor skills in different environmental contexts so there are different ways to to theorize a motor control here we are not really focusing on the neural level uh theories of the control process here we're looking more at behavioral theories so there are you can look at both but i would argue that the neural level theories are more physiological um more physiological neuroscience type theories and here in motor control we're focusing on behavioral theories um so these are laws and principles that govern coordinated human motor behavior and well in future videos i'll go through very specific motor control theories but here i first just want to introduce two specific issues that are addressed by behavioral motor control theories so the first is the issue of coordination and the second is the issue of degrees of freedom so coordination is motor so motor control theories include explanations of how we control coordination so we define that in motor control as the patterning of head body and limb movements relative to the patterning of environmental objects and events so importantly when we look at coordination and motor control we look at the a specific time point during skill performance and the relationship between the movements of the different limbs and segments so like we've talked in past videos about angle angle diagrams that's an example of how we might look at coordination but importantly we also have to consider the environmental context so like imagining imagine you're walking down a path now there might be the normal coordination of a normal walking gait pattern but the environmental context is going to make a really big difference like let's say you have to step over something so that would be an environmental constraint that caused you to coordinate that movement differently to be able to execute the movement accurately or maybe you need to duck because there's a branch in the way so when considering coordination we also have to consider the environmental context and the goal of the action and how that's affected by the environment all right the second issue is degrees of freedom problem so degrees of freedom that's a term that's used in lots of different areas of science depending on what it is that you're looking at and this is not a problem that is isolated just to the area of motor control so the degrees of freedom are the number of independent components of a system and the number of ways each component can vary so let's say for example i'm looking at joints and i'm looking at the number of degrees of freedom of each joint if i looked at the shoulder joint if i just looked at the glenohumeral joint we would say that it has six degrees of freedom because it can move in both directions in the sagittal plane in both directions in the frontal plane and in both directions in the horizontal plane and then everything in between so if we're looking at a joint and the degrees of freedom of a joint the maximum number of degrees of freedom it can have is six meaning that it can move it has full movement in all three planes of motion um and then that would include everything that occurs in between uh then if we look at the elbow then we would say it has four degrees of motion or degrees of freedom because we can do flexion and extension and pronation and supination so collectively if we're looking at simply the glenohumeral joint and the elbow complex then collectively we would have 10 degrees of freedom okay and so we can look from joint to joint through the whole body and count up the degrees of freedom based on the the planes of motion of each joint but we can also define the degrees of freedom based on how many motor units are recruited how many muscles are activated um the movement of the joint so there are so many different ways that we could count and describe degrees of freedom so the the point is that there are so many different variables and ways that we can create movement really that could add up to the same ultimate goal the same movement so maybe i'm reaching for a target or i'm reaching to get something on a shelf well i can organize my limb in a thousand different ways and i can activate motor units and muscles in a thousand different ways to be able to achieve that same end goal of reaching that target and achieving the same goal of the movement so different movements to achieve the same action goal essentially and that's the degrees of freedom problem is that if we have so many variables and so many independent components that we can change and and that we can use differently to achieve the same goal then how do we decide the correct strategy like how do we constrain the system to be able to produce the specific result that we're looking for um and so that's a classic problem in motor control that different theories seek to explain or to describe how we answer that question okay thank you so much for watching and i'll see you in the next video