DATA ANALYSISSensorimotor Systems KIN 460 – Motor Control Lab Section 2 Lab 7: Postural Control Introduction Balance is both a biomechanical and neurological problem. If your center of mass is within your base of support, you remain in balance. But because you have multiple segments and joints, your nervous system must constantly make corrections to keep you in balance. Three sensory modalities make important contributions to the neurological control of posture: visual input, somatosensory input and vestibular input. Purpose To describe biomechanical instability and to test how perturbations or removal of each of three sensory modalities affect balance. Protocol Time the duration you can keep your balance while holding a ping-pong ball on a spoon between your teeth and without dropping the ball. Maximal time is 30 seconds. Perform the following 3 balance trials (take the average of 2-3 trials for each condition for each person in your group, discard obviously incorrect trials): 1) normal standing 2) perturbed somatosensory input (standing on a foam pad) 3) perturbed vestibular input (spin in circles 10 times) Perform each trial with 4 different conditions: 1) full base of support (2 feet) with visual input (eyes open) 2) partial base of support (1 foot) with visual input 3) full base of support without visual input (eyes closed) 4) partial base of support without visual input That means that there’s a total of 3x4 = 12 balance conditions Perform each trial with a full base of support (using both feet, closely together) and a partial base of support (using a single foot). For each trial: - your arms should be folded across your chest, with hands touching opposite shoulders - take off your shoes - if you hop, step, raise a foot (full base of support), or have a foot sway outside a radius within elbows reach (i.e. circle around your body with a diameter the length of the distance between your elbows when arms are held straight out to your sides) from your body (partial base of support) you’ve lost balance and the timer stops.Sensorimotor Systems KIN 460 – Motor Control Lab Section 2 DATA ANALYSIS 1. Graph your groups postural data (the time you kept balance in the 4 conditions) as a clustered column graph with the means of your group results. Follow along with your instructor to find out how to do this. 2. Graph the Moodle data using a single X-Y smooth line scatterplot without markers. Make a scatterplot of one of the conditions, then add the remaining conditions to the existing scatterplots. The x-axis is mediolateral center of pressure (m) and y-axis is anteroposterior center of pressure (m). X-axis range is 0.25 to 0.33 m and y-axis range is 0.15 to 0.24 m. Include a legend. Keep the horizontal and vertical grid lines (for once!). NO TITLE. Indicate the experiment in the figure caption. LAB REPORT 1. Rank the following conditions from most stable to least and briefly state how the center of pressure would be different between each condition that is compared a. Eyes open vs closed b. Normal vs perturbed somatosensory vs perturbed vestibular c. Full vs partial base of support 2. Why would removing visual input affect your balance? What information does the visual system provide that can be used to control balance? 3. Why would perturbing somatosensory input affect your balance? What information does the somatosensory system provide that can be used to control balance? 4. Why would perturbing vestibular input affect your balance? What information does the vestibular system provide that can be used to control balance? 5. Why would reducing the size of the base of support reduce our ability to maintain balance? WHAT YOU ARE TURNING IN • 2 graphs • Include a brief answer to each of the questions above – these should be presented in bullet