MOVEMENT-RELATED CORTICAL POTENTIALS DURING MOTOR PLANNING IN REACTIVE SIDECUTS: VALIDATING A MOBILE EEG, FREE-FALL PARADIGM

The ability to plan and execute motor actions is fundamental for humans to interact with the environment. However, our understanding predominantly derives from simplified laboratory paradigms involving self-paced or highly predictable movements. Although more ecologically valid motor tasks, such as sidecutting maneuvers, are extensively studied in sports biomechanics contexts, the underlying cortical processes have not been sufficiently investigated. This study established and validated an experimental approach for recording movement-related cortical potentials during reactive sidecutting.
Twenty-one female athletes (22.6 ± 2.1 years) performed 140 reactive sidecutting maneuvers initiated by dropping from a 30 cm platform. During free-fall, participants received directional cues. 64-channel EEG was recorded until initial ground contact (IC), including the free-fall period. Data processing included filtering, automated channel rejection, artifact subspace reconstruction, and independent component analysis. Movement-related cortical potentials (MRCP) at C3/C4 and lateralized readiness potentials (LRP) were analyzed using cluster-based permutation testing.
Group-averaged MRCP (Figure 1) exhibit contralateral lateralization, with contralateral electrodes showing negativity until ~250 ms pre-IC followed by positivity until IC. This biphasic pattern is consistent with MRCP from controlled laboratory studies. LRP analysis reveals significant lateralization in two temporal clusters: 820-214 ms and 90 ms pre-IC (p < .05).


This proof-of-concept study demonstrates the validity of EEG recordings of motor planning processes during highly dynamic movements including free-fall. The observed primary motor cortex lateralization validates the methodological approach and reveals that motor preparation during naturalistic, whole-body maneuvers exhibits temporal dynamics similar to classical motor preparation paradigms, despite substantial differences in movement complexity and ecological validity.