Background: Attention focus on either one's own body movements (internal focus) or the effect of one's movements (external focus) has been shown to play a significant role in motor control. Particularly, an external focus has emerged as the most beneficial in terms of both performance and rehabilitation. However, there remains uncertainty about whether an external focus is preferable in all contexts. Aim: The aim of this study was to investigate whether internal and external attention focus affect motor control of the lower extremity during a bilateral leg extension and flexion task among uninjured individuals and individuals with anterior cruciate ligament reconstruction. Method: The participants consisted of 12 uninjured individuals and five individuals with anterior cruciate ligament reconstruction (ACLR) aged between 21 and 38 years. All participants performed a supine leg press movement on a sliding board with different focus instructions that were either neutral, externally on separate bars under each foot, internally on the feet, or internally on the knees. The movements were captured by a 3D camera system. The outcome variables were the difference in the position of the bars in the sagittal plane and the smoothness of the movement. The outcome variables were statistically compared between focus instructions for the control group and between the control group and the ACLR group for each focus. Results: In the analysis for the control group, some significant differences between different focuses were found, where internal distal focus on the feet yielded the best results. The results did not show any significant differences between the control and ACLR groups in any of the chosen variables. Conclusion: In the control group only, a few significant differences were observed when comparing the focuses against each other. The study's results indicate that the different attention focuses implemented did not have a significant difference in performance between the groups. This may suggest that a larger sample size or more studies are needed to confidently determine which focus is advantageous for improved smoothness and symmetry in a similar test.