The authors examined several issues related to the motor learning benefits resulting from giving learners choices. In 2 experiments, participants practiced a novel task, throwing a lasso. In Experiment 1, giving learners a choice ostensibly irrelevant to performance (color of mat under target) resulted in enhanced learning relative to a control group. The choice group also reported more positive affect. Experiment 2 compared the effectiveness of task-irrelevant (mat color) versus task-relevant (video demonstrations of the skill) choices. In both choice groups, each participant was yoked to a participant in the other group, and each received the same mat color or saw the video demonstration, respectively, as chosen by their counterpart in the other group. In the control group, participants were yoked to their respective counterparts in each of the choice groups. On a retention test, the 2 choice groups did not differ from each other, but both outperformed the control group. The affective and learning effects seen when learners are given choices, and the fact that task-relevant and task-irrelevant choices resulted in similar learning benefits, are consistent with a content-neutral mechanism for the effects of choice on learning, as described in the OPTIMAL theory of motor learning (Wulf & Lewthwaite, 2016 ).

A patellar-tendon-bearing (PTB) bar is a common design feature used in the socket of trans-tibial prostheses to place load on the pressure-tolerant tissue. As the patellar tendon in the residual limb is subjected to the perpendicular compressive force not commonly experienced in normal tendons, it is possible for tendon degeneration to occur over time. The purpose of this study was to compare patellar tendon morphology and neovascularity between the residual and intact limbs in trans-tibial amputees and healthy controls. Fifteen unilateral trans-tibial amputees who utilized a prosthesis with a PTB feature and 15 age- and sex- matched controls participated. Sonography was performed at the proximal, mid-, and distal portions of each patellar tendon. One-way ANOVAs were conducted to compare thickness and collagen fiber organization and a chi-square analysis was used to compare the presence of neovascularity between the three tendon groups. Compared to healthy controls, both tendons in the amputees exhibited increased thickness at the mid- and distal portions and a higher degree of collagen fiber disorganization. Furthermore, neovascularity was more common in the tendon of the residual limb. Our results suggest that the use of a prosthesis with a PTB feature contributes to morphological changes in bilateral patellar tendons.