The Effect of Age and Physical Activity Level on Motor Skill Learning during both Expected and Unexpected Events

年齡與身體活動量對動作學習在預期不預期情境下之影響

顏竹伶(Chu-Ling Yen) ； Richard Shields

《物理治療》 42卷4期 (2017/12) Pp. 330-331

https://doi.org/10.6215/FJPT.2017.74.O09

摘要

Background and Purpose: The aging process is associated with a reduced capacity to learn new motor skills. Physical activity level has recently emerged as a powerful factor influencing motor skill acquisition and retention. However, none of the previous studies examined if regular physical activity would modulate the capacity to learn to respond to unexpected events at a time prior to the volitional reaction time (transcortical reflex timeframe). Therefore, the purpose of this study was to determine whether age and physical activity level would influence (1) the ability to learn to respond within the transcortical reflex timeframe following unexpected events, and (2) the muscle strategies used to respond to unexpected events that occur before the volitional reaction time. Methods: Twenty less active young, 17 active young, 16 less active old, and 14 active old healthy adults tracked a target using the left wrist before and after motor training over one week (Day 1 pre, Day 1 post, Day 7). Unexpected stretches were imposed to the wrist extensor muscles by releasing the resistance of the device. Surface electromyography (EMG) was recorded from the left wrist extensor and flexor muscles. User rates, the slopes of best-fit lines through wrist displacement during the period before the volitional reaction time, were calculated to measure learning. Repeated measures analysis of variances (ANOVA) were used to compare differences across time points, groups, and physical activity levels. Results: During unexpected events, the less active old group demonstrated poorer motor performance than the active old group. However, motor performance did not differ between the less active young and active young groups. Moreover, four groups showed similar motor acquisition skill with about 20–30 percent decrease in user rates on Day1post as well as similar retention capacity on Day 7. Furthermore, for each age group, the less active and active groups used similar feedforward and feedback strategies to respond to unexpected events during motor learning. Conclusion: This study supported the value of an active lifestyle with age, but also the capacity for less active people to benefit from practice in both expected and unexpected events. Clinical Relevance: These findings assist in designing novel rehabilitation interventions for people with aging or neurological diseases.