Motor Control Final Exam 2023

How do we modify COM? - Answer- by lowering the body (torque) What is postural control? - Answer- - permanent re-establishment of balance - COM within BOS - increase PC w/ reduced distance b/w COM and ground - stances influence What strategies can we employ to offset perturbations (anxiety) to the system? - Answer- - use mental imagery by setting a routine - have preparation and practice What muscles are excited in the ankle and hip strategy? - Answer- - Ankle strategy: paraspinal, hamstrings, gastrocnemius - Hip Strategy: abdominals, quadriceps What is Reflexive theory? - Answer- self input= motor output What is Hierarchical theory? - Answer- low areas of brain(reflexive)- brain stem (subconscious PC)- high areas of brain (voluntary movement) What is Motor Program theory? - Answer- relative, adaptive, motor programs/memory control actions with commonalities What is Dynamical Systems theory? - Answer- self organization of movement to coordinate DOF w/ consideration of environment and body of the individual How is feedback used during closed loop movement? - Answer- feedback is received intra-trial and it detects errors and update memory and perceptual trace to continue and terminate movement not needed How is feedback provided to an open loop system? - Answer- it does not provide feedback however the control center provides all the information for effectors to carry out movement What is feedforward? - Answer- anticipatory use of sensory information to prepare for movement How does spinal reflexes work? - Answer- - Stimulate AMN (agonist) - Inhibit AMN (antagonist) via reciprocal inhibition ( Extrafusal fibers and intrafusal fibers stretch are detected via alpha and gamma coactivation) Stretch Reflex: How does platform tilting/backward movement influence EMG? - Answer- - Backward movement of platform: EMG shows from trial 1-4, there is a reduced amount of time muscle stretch reflex activates (stretch reflex increases) - Tilting of platform: EMG shows stretch reflex decreases b/c it's not needed due to the tilting of the platform - Stretch reflex is adaptive when its needed and when its not needed What is Hoffman Reflex (H-Reflex)? - Answer- - electrically induced monosynaptic reflex. - stimulate IA sensory (afferent) fibers from muscle spindles which excites AMN and promote muscle activation - produces H-wave at low stimulus strength and increases as magnitude increases then declines so at very high magnitude, only H-wave disappears (only M-wave present) What is the Flexor Withdrawal reflex? - Answer- - spinal reflex in which the limb is quickly withdrawn from painful stimulus, usually by simultaneous contraction of all flexor muscles in the limb - activation of pain receptors is sent to the spinal cord via Group III afferents What is Crossed-extension reflex? - Answer- - contraction of extensor muscles in limb opposite of the one that is withdrawn - a branch of the Group III afferent from the flexion withdrawal reflex innervates an excitatory interneuron that sends its axons across the midline into the contralateral spinal cord. There, it excites the alpha motor neuron that innervate the extensor muscles of the opposite body part Bernstein's motor learning stages - Answer- stage 1: freezing of the limbs stage 2: releasing the limbs stage 3: exploiting the environment Gentile's 2 Stage Model of Learning - Answer- Stage 1: getting the idea of the movement (learner gains an understanding of the basic coordination pattern that must be organized to accomplish the motor skill; learner distinguishes the regulatory or relevant information to the motor skill and non regulatory conditions or non relevant/distractions to the motor skill) Stage 2: fixation and diversification (Fixation is closed skill and goal is consistency; diversification is open sills and goal is adaptable to changing environment) Fitts and Posner's Learning Stages - Answer- - Cognitive stage: gathering information, large gains, inconsistent performance - Associative Stage: putting actions together, small gains, disjointed performance, conscious effort - Autonomous Stage: much time and practice, performance seems unconscious, automatic, and smooth How do you measure learning? - Answer- - measure performance over time - consistency (stability) over time - less effort - less attention - persistence - adaptability How is motor learning research typically designed? - Answer- acquisition phase (practice/ blocks and trials), retention phase (game day), and transition phase (test learning in varying environment) identical elements theory - Answer- the amount and direction of transfer depend on the number of identical elements between the motor skills ( disc golf vs golf) Transfer-appropriate processing theory - Answer- similar cognitive processing equals high likelihood of transfer (handball vs soccer) cocktail party problem - Answer- - the process of tracking one conversation in the face of the distraction of other conversations - people have a hard time concentrating when other things are going on inattentional blindness - Answer- - w/o attention, we can't cue ourselves to detect change Stroop test - Answer- people have a tough time at switching task Multitasking from perspective of attention - Answer- - information processing task 1 + information processing task 2= very hard to accomplish (if task 2 does not rely on information processing, it is easier to accomplish) - performance depends on competition for attention resources within and between multiple sources ( 2 tasks share/compete for common resources which exceeds the sources, performing multiple tasks at the same time is difficult) What is external focus and why is it preferred in motor skill acquisition? - Answer- - when the person's attention is mainly on the environment which is best for performance because it increases automatic nature for the skill - ex: the basket during free throws - distal is good for the skilled - proximal is good for the unskilled What is internal focus of attention and what population is it good for? - Answer- - when the person's attention is within hims