Reliability of Brain Activity During a Supine Bilateral Leg Press and Association With Concurrent 3D Knee Joint Biomechanics

Previous neuroimaging studies have established a foundation of knowledge regarding the supraspinal control of lower extremity movements. However, the relationship between subtle differences in lower extremity kinematics and concurrent brain activity during motor tasks is mainly unknown. Additionally, there is limited information regarding the consistency of brain activation measures during a lower extremity motor task. The current study evaluated the within-session reliability of knee joint kinematics and brain activation during a supine bilateral leg press task using functional magnetic resonance imaging in 67 adolescent female athletes. Knee joint kinematics, including the number of leg press repetitions (cycles), as well as sagittal and frontal ranges of motion and their standard deviations, were analysed with concurrent blood-oxygen-level-dependent signals to explore the relationship between these biomechanical variables and brain activation. The results showed good reliability for knee joint kinematics and moderate reliability for brain activation in sensorimotor regions (precentral and postcentral gyri, supplementary motor cortex, brainstem, and anterior cerebellum lobules). Greater knee sagittal range of motion correlated with increased activation in motor planning and sensory integration regions, such as the dorsal striatum and lateral occipital cortex. These findings establish the supine bilateral leg press task as a reliable paradigm for investigating lower extremity motor control, providing insights into the neural mechanisms underlying movement variability. Additionally, brain regions exhibiting reliable activation could serve as valuable regions of interest for future investigations, enhancing the statistical power and reproducibility of research findings.