The Effect of Action Observation and Motor Imagery Combinations on Upper Limb Kinematics and EMG during Dart Throwing

Recent research has begun to employ interventions that combine action observation and motor imagery (AOMI) with positive results. However, little is known about the underpinning facilitative effect on performance. Participants (n=50) were randomly allocated to one of five training groups: action observation (AO), motor imagery (MI), simultaneous action observation and motor imagery (S-AOMI), alternate action observation and motor imagery (A-AOMI) and control. The task involved dart-throwing at a concentric circle dartboard at pre- and post-test. Interventions were conducted 3 times per week for 6 weeks. Data were collected from performance outcomes and mean muscle activation of the upper and forearm muscles. Angular velocity and peak angular velocity measurements of the elbow were also collected from the throwing arm. Results showed performance of the A-AOMI group improved to a significantly greater degree than the AO (p = 0.04), MI (p = 0.04), and control group (p = 0.02), and the S-AOMI group improved to a greater degree than the control group (p = 0.02). Mean muscle activation of the triceps brachii significantly reduced in the S-AOMI and A-AOMI (p < 0.01) groups and participants in the AO (p= 0.04), A-AOMI and S-AOMI (p < 0.01) groups significantly reduced activation in the bicep brachii from pre to post-test. Peak angular velocity significant decreased from pre- to post-test in both A-AOMI and S-AOMI (p < 0.01) groups. The results reaffirm the benefits of AOMI for facilitating skill learning and provide an insight how these interventions produce favourable changes in EMG and movement kinematics.