The effect of combining motor imagery and electrical stimulation on improving performance in a force tracking task.

PURPOSE: This study aimed to investigate whether combining motor imagery (MI) and peripheral electrical stimulation (ES) enhances motor performance more effectively than MI alone, as literature on this is lacking.

METHODS

Participants executed a wrist flexion tracking task with performance measured by error areas pre-practice, immediately post-practice (Post1), and 20 min post-practice (Post2). ES was applied at two intensities: above the motor threshold (ES-MT) and below the motor threshold but above the sensory threshold (ES-ST). In Experiment 1, 29 healthy participants were assigned to six conditions (MI + ES-MT, MI + ES-ST, MI alone, ES-MT, ES-ST, and control), completing 150 practice trials to evaluate the MI + ES effects. Experiment 2 involved 52 healthy participants across four conditions (MI + ES-ST, MI alone, motor execution, and control), extending task difficulty and reducing trials to 100 for an equivalent practice duration, further investigating MI + ES-ST.

RESULTS

In Experiment 1, a significant interaction between practice and condition was found (p = 0.019). Post-hoc analysis revealed that while all practice groups showed reduced error from Pre to Post1 and Post2, only the MI and MI + ES-ST groups demonstrated significant improvements from Post1 to Post2 (all p < 0.05). In Experiment 2, a significant interaction was also found (p < 0.001). The MI + ES-ST condition showed a significant decrease in error from Post1 to Post2, an effect not significant in the MI condition.

CONCLUSION

The combination of MI and ES-ST may have a slight positive effect on motor performance.