1 Chapter 20 Motor Performance in Adults © Gallahue, D.L., & Ozmun, J.C.. Understanding Motor Development. McGraw-Hill

2 Key Concept An Adult’s Motor Performance Depends on the Interaction of a Wide Variety of Variables, Some of Which Can Be Manipulated With Ease While Others Are Resistant to Change

3 Factors Affecting Adult Motor Performance State of individual physiological systems (musculoskeletal system, CNS, sensory systems, circulatory/respiratory systems) Specific environmental conditions (light, temperature, contact surface, etc.) Specific task demands (speed, accuracy, strength, endurance, flexibility etc.)

4 Reaction Time (Figure 20.1) Reaction time (RT): the time delay from the initial stimulus to start of the initial movement response RT’s Fractionated components - Reception time (travel time from external stimuli to sensory receptors) -Integration time (travel time from sensory receptors to motor cortex)

5 Reaction Time (cont.) -Motor overflow time (travel time from motor cortex to first electrical activity in the muscles -Motor time: (travel time from first electrical activity to actual initiation of movement)

6 Variations in RT Changes under different conditions -Using multiple response choices -Using varying sensory system -Changing stimulus intensities Age influences -Peaks in early to mid-20’s -Regresses gradually with age -Practice & familiarity minimizes age differences -“Speed-accuracy trade-off”

7 Aging, Physical Activity and RT Men (active older men have RT like non-active young men) Women (stronger older women have better RT than weaker older women) Physical activity (for many reasons positively affects RT in older adults)

8 Mechanisms of Balance and Postural Control Postural muscle response synergies (the timing & sequence of muscle activation) Sensory systems (use of visual, auditory, prospective cues) Adaptive systems (modifications based on sensory input & motor output) Muscular strength (ankles, knees, hip) Joint flexibility (range of motion) Body morphology (biomechanical influences of ht, wt, leg & foot length, center of mass)

9 Aging, Balance and Postural Control Balance recovery decrements -Slower muscle activation -Additional muscle group activation -Sequence reversal in muscle group activation -Simultaneous agonist/antagonist muscle group activation Visual & vestibular decrements

10 Improving Balance and Postural Control Make environmental changes (surface area, lighting) Increase physical activity (improve leg strength, increase joint flexibility, use multiple sensory approach)

11 Falls (Table 20.1) Falls occur in 30% >65 years old 20-30% suffer moderate to severe injuries (hip fractures & head traumas) Increase in fear & depression Why do they occur? (physiological factors, environmental factors, task requirement factors)

12 Aging and Gait Changes Swing phase changes Support phase changes Period of double support changes Stride length changes Toe-floor clearance changes Speed changes Possible pathological changes

13 Aging and Activities of Daily Living Perform some tasks segmentally Make environmental modifications (ht of objects, assistive devices, garments, lighting) Increase community awareness & support (crosswalks, benches, public restrooms)

14 Aging and Physical Activity Learning new skills (table 20.2) -Emphasize active rather than passive learning -Focus on procedures not just concepts -Provide for extended practice time Growing old isn’t for sissies -Competition can be good -Master athletes (table 20.3)

15 Concluding Concept A Physically Active Lifestyle Throughout Adulthood Can Contribute Significantly to the Slowing and Lessening of Decrements in Motor Performance