Award Date

August 2019

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Kinesiology and Nutrition Sciences

First Committee Member

Gabriele Wulf

Second Committee Member

Rebecca Lewthwaite

Third Committee Member

Brach Poston

Fourth Committee Member

Jing Nong Liang

Fifth Committee Member

Szu-Ping Lee

Sixth Committee Member

Joel Snyder

Number of Pages



According to the OPTIMAL (Optimizing Performance Through Intrinsic Motivation and Attention of Learning) theory of motor learning, enhanced expectancies (EE), autonomy support (AS), and external focus (EF) augment the coupling of a person’s actions to intended movement goals. This goal-action coupling is postulated to boost a person’s focus on goal-related aspects of the motor task while reducing the person’s self-related thoughts, resulting in enhanced performance of skilled movements as well as in improving the acquisition outcomes for the learning of motor skills. The three studies in this compilation report were aimed at providing empirical evidence for the motor performance benefits of the combinatory implementation of the three key motivational (i.e., EE and AS) and attentional (i.e., EF) factors of the OPTIMAL theory. In addition, a preliminary investigation of the neuromechanistic influence of such an implementation on the human motor system was carried out.

Using a between-participants design, the first study employed a maximal-effort countermovement jump task to examine the additive effects of the consecutive (or serial) implementation of EE, AS, and EF on motor performance. Results indicated that optimized group participants produced greater relative jump heights than control group participants. The second study used a within-participants design involving a clinical-applied balance test to determine the immediate effects of implementing EE, AS, and EF simultaneously (in parallel) on motor performance. The results showed that participants experienced greater postural stability in terms of making fewer balance errors and producing lower center-of-pressure velocity in the optimized condition than the control condition. Finally, a simple visuomotor task involving the rhythmic production of force via isometric finger abduction was used in the third study with a between-participants design. The neurophysiological and behavioral effects of a simultaneous implementation of EE, AS, and EF in relation to motor performance were examined using a novel TMS-force experimental protocol. The corticospinal excitability of all participants remained stable throughout the experiment. Additionally, the force-accuracy performance of participants in the optimized group was similar to that of participants in the control group.


Autonomy support; Enhanced expectancies; External focus; OPTIMAL theory; Optimized conditions; Performance of motor skills


Kinesiology | Medicine and Health Sciences | Social and Behavioral Sciences

File Format


Degree Grantor

University of Nevada, Las Vegas




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