Based on inflow explanations, the predictions related to EMG activity during imagery of a dumbbell and manipulandum curl were that EMG activity: (a) increases, relative to baseline, in both the biceps and triceps of the active arm; (b) is localized to muscles used in executing the real movement; and (c) mirrors the pattern of activity observed during the real movement. Based on literature which suggests that EMG activity during imagery may be due to expectancy effects, it was also hypothesized that EMG activity would be greater during imagery for those who were aware of the predictions of inflow explanations than for those who were unaware of those predictions. Undergraduate students (N = 60) completed a series of real and imagined dumbbell and manipulandum curls. For both movements, biceps and triceps EMG activity was measured in both the passive and active arms during baseline, imagery, and real movement conditions. No EMG differences were found between those who were aware or unaware of the predictions derived from inflow explanations. For both curls, average EMG biceps and triceps activity was significantly greater in the active arm during imagery than during baseline. Pattern analysis showed that the EMG activation patterns for biceps and triceps did not mirror the triphasic EMG pattern observed during the real movement. Results did not support the mirroring hypothesis (e.g., the psychoneuro-muscular theory), as the pattern of increased activation during imagery did not reflect that observed during the real movement.
The authors are with the Dept. of Exercise Science and Physical Education at Arizona State University, Tempe, AZ 85287-0404.