Combining an Internal Attentional Focus With Mirror Motor Observation Enhances Mechanical Output During Isokinetic Leg-Extension Exercise

When carrying out a motor task, the direction of the performer's attentional focus can affect mechanical output and muscle activation. Cortical excitability increases with the observation of motor skills. However, it is unknown if this effect can be additive to that resulting from an internal attentional focus during resistance exercise. A crossover-study design was employed to examine the acute effects of combining mirror self-motor observation (MO) and internally focused verbal instructions on mechanical output and muscle activation during isokinetic concentric knee-extension exercise. Ten participants were tested in 2 different conditions: verbal alone and verbal + MO-mirror. The combination of verbal + MO-mirror attenuated the decrease in torque output in response to 6 sets of 10 isokinetic contractions (P = .043). Interestingly, this effect was paired by a lower-level antagonist/agonist coactivation with the verbal + MO-mirror condition (P = .031). No other differences between conditions were noted. Taken together, these results suggest that the combination of both cueing modalities elicits a more effective contraction strategy during knee-extension exercise. Ultimately, this provides preliminary evidence of better motor performance and heightened fatigue resistance in response to isokinetic exercise.