Motor Skills and Motor Games PDF

Motor Skills and Motor Games Sensory components of motor control Professor: PhD. Juan Pablo Rey Lopez [email protected] Catholic University of Murcia (UCAM) Number of credits: 4.5 ECTS. Timing unit: Firs...

Motor Skills and Motor Games Sensory components of motor control Professor: PhD. Juan Pablo Rey Lopez [email protected] Catholic University of Murcia (UCAM) Number of credits: 4.5 ECTS. Timing unit: First semester 2024/25  Introduction “When you reach a glass of water to drink or catch a ball,… touch, proprioceptive and visual systems come into play. Understanding of the anatomical and physiological basis help us to understand how they influence the control of movement”  In the study of human sensory physiology, there are three main senses involved*: 1. Proprioception and motor control 2. Touch and motor control 3. Vision and motor control * Despite other senses are also important (auditory information is relevant is sports or to keep balance)  1. Proprioception - 1.1 Historical background - 1.2 The kinesthetic sensors - 1.3 The senses of force - 1.4 Proprioception in the elderly - 1.5 Proprioceptive training and ankle sprains  1.1 Propioception- Historical background Aristotle firmly believed that there were only five senses: sight, hearing, smell, taste, and touch. “We are sensible of the most minute changes of muscular exertion, by which we know the position of the body and limbs” Bell C. On the nervous circle which connects the voluntary muscles with the brain. Philos Trans R Soc 116: 163–173, 1826. German physiologists talked about the “Muskelsinn.” What was meant here was not a sensation originating in the muscles themselves, but in the brain (sensation of innervation). Sherrington rejected these ideas, largely based on the observation that in the absence of motor commands, when our limbs lie relaxed, we still know where they are, even if we are not looking at them. Sherrington C. The muscular sense. In: Textbook of Physiology, edited by Schaefer EA. Edinburgh, UK: Pentland, 1900, p. 1002– 1025. Charles Scott Sherrington. Nobel Prize in Medicine- 1934  So there were two schools of thought, one claiming that the muscle sense had an entirely central origin, and the other believing that a peripheral signal was principally responsible.  Proprioception is the sense of position and movement of body and limbs in the space. It also includes and the sense of muscle force Any tissue imbued with mechanical sensors that exhibits a change in shape or tension as a consequence of passive or self-generated motor actions may serve as a source of proprioceptive information. By this definition, proprioceptors include afferents that innervate skeletal muscle and tendons, joint ligaments, connective tissues surrounding muscles, and skin  1.2 The kinesthetic sensors During limb movement and changes in position, the tissues around the relevant joints will be deformed, including skin, muscles, tendons, fascia, joint capsules, and ligaments. All these tissues are innervated by mechanically sensitive receptors: Muscle spindles play the major role in kinesthesia The intrafusal fibers include the large nuclear bag 1 and bag 2 fibers together with the smaller nuclear chain fibers. Ends of the bag fibers extend beyond the capsule while chain fibers lie within the limits of the capsule. Large, group Ia afferent fibers terminate as primary endings, making spiral terminations around the nucleated portions of all three intrafusal fiber types. Smaller, group II afferent fibers terminate as secondary endings, lying to one side of the primary endings and supplying bag 2 and chain fibers. Gamma dynamic fusimotor fibers innervate bag 1 fibers, while gamma static fusimotor fibers innervate bag 2 and chain fibers. Some lines of evidence of why muscle spindles are the dominant mechanoreceptor for proprioception? Joint replacement surgery Muscle vibration  Joint replacement surgery In patients who have had a total hip replacement involving removal of all capsular and ligamentous components, both position and movement sense remained intact. Grigg P, Finerman GA, Riley LH. Joint-position sense after total hip replacement. J Bone Joint Surg Am 55: 1016 –1025, 1973.  Muscle vibration Vibration of the tendon of biceps or triceps brachii produced an illusion of movement and of changed position at the elbow in a direction that would elongate the vibrated muscle. Vibration over the elbow joint produced no illusion. Microneurography has revealed that the primary endings of spindles are largely responsible for the illusion and that the vibration frequency for an optimal response in human muscles is around 80 Hz (muscle relaxed). Skin afferents play a significant role in kinesthesia, and they are likely to contribute to movement sensation at most joints. However, their contribution to position sense at the more proximal joints is likely to be less important than the input from muscle spindles. Perhaps a special case should be made for skin receptors in signaling facial expressions, since facial muscles are believed not to contain any muscle spindles Electrical stimulation of peripheral nerves (ulnar nerve) also stimulates the spindles and lead to illusory movements  Golgi tendons organs contributes to proprioception including the senses of force and heaviness 1.3 The senses of force Comparison of perceived forces generated by self stimulation compared with stimulation by an external source. Subjects were instructed to reproduce a target force, applied to the left index finger by a torque motor, either directly by voluntary pressing with the right index finger (red) or indirectly by controlling the output of a torque motor with a remote joystick (blue). Interpretation of the overestimation of force due to self-stimulation The overestimation of force is presumably due to the partial suppression of the afferent activity associated with self-stimulation. In everyday activities, such sensory suppression would allow us to focus attention on external stimuli and be less distracted by the sensations arising from our own movements. This overestimation only occurs at low forces (Walsh LD, Taylor JL, Gandevia SC. Overestimation of force during matching of externally generated forces. J Physiol 589: 547–557, 2011). Overestimation of force due to fatigue Under control conditions subjects are quite accurate at matching forces, producing matching errors of 5% maximum voluntary contraction (MVC) or less between the two sides. However, when one arm is exercised to fatigue, the level of force generated in the fatigued muscle is usually overestimated. The overestimation was considered to arise from efferent signals of similar magnitudes being sent to the muscles of the two arms, the unfatigued muscle responding with a higher force for a given level of activation Isometric force matching before and after fatigue. A: the subject is seated with their forearms in the vertical position, strapped to paddles locked at 90°. The torque generated by elbow flexor muscles is recorded by strain gauges, and the output of the reference arm is displayed on a computer screen visible to the subject. The subject is required to match its torque level with their other arm (output not visible). B: the control error (red, right hand ordinate) is close to zero. Then the subject was required to carry out a series of fatiguing eccentric contractions that led to a 40% drop in MVC torque (blue, left hand ordinate). The fall in torque led to an overestimation of 14% by the unexercised arm of the torque generated by the fatigued reference arm. Over the subsequent 100 h, the matching errors gradually fell to a residual 4% while torque recovered to control levels.  1.4 Proprioception in the elderly The losses of muscle fibers and motoneurons that are a part of sarcopenia could include intrafusal fibers and fusimotor neurons. Kim et al. showed that in aged rats the number of the sensory endings in each spindle was about normal, but most primary endings had lost their typical annulospiral configuration. Elderly human subjects may have a reduced sense of movement as a result of a degraded dynamic sensitivity of spindle primary endings. Kim GH, Suzuki S, Kanda K. Age-related physiological and morphological changes of muscle spindles in rats. J Physiol 582: 525–538, 2007. 1.5 Proprioception and ankle sprains Proprioceptive training involves exercises that challenge the ability of the targeted joint to detect and react to afferent input regarding joint position. Examples of proprioceptive exercises include balancing on a wobble board, throwing and catching or dribbling a ball whilst in single leg stance, or balancing with eyes closed.  May proprioceptive training reduce the incidence and recurrence rates of ankle sprains in the sporting population? At 3 years, the RR of diabetes in the lifestyle group vs placebo group is approximately? a. 2.0 b. 0.7 c. 0.5  The student must read The effectiveness of proprioceptive training in preventing ankle sprains in sporting populations: A systematic review and meta-analysis Gabriella Sophie Schiftan, Lauren Ashleigh Ross, Andrew John Hahne Do you think that proprioceptive training is effective to prevent ankle sprains? Do you think that ankle sprains history may influence the effect of proprioceptive training? Discuss the NTT in people with history versus non-history of ankle sprains.  The student must read Bracing superior to neuromuscular training for the prevention of self-reported recurrent ankle sprains: a three- arm randomised controlled trial. Janssen et al. 2014 Do you think bracing is superior to proprioceptive training to prevent ankle sprains?