Objective: The main objective of this study was to investigate the effect of a self-regulated dual task on muscle endurance within a single rehabilitation session in patients recovering from an elbow fracture. Design: This is a cross-sectional study of individuals recovering from elbow fractures (N = 20). Muscle endurance was tested using elastic bands at Borg’s CR10 intensity 3—during four conditions: single-task and dual-task for elbow flexion and extension. Results: The cognitive condition significantly influenced muscle endurance (P < 0.001), while the type of elbow exercise (flexion or extension) did not show significant differences (P = 0.592). The perceived difficulty of the tasks showed a significant interaction effect (P = 0.032). The dual-task condition showed an average increase of about 15 repetitions. A moderate negative correlation was found between the differences in repetitions and the perceived difficulty of the flexion exercise (r = 0.677, P = 0.001). Conclusions: Dual-task with self-regulation enhances muscle endurance among patients recovering from an elbow fracture. However, the improvements seem to depend on the perceived difficulty of the cognitive task. Future randomized controlled trials are required to understand the therapeutic implications of dual-tasking.