Stroke is one of the most common neurological disorders where the evaluation of functional connection between the motor cortex and muscle is essential. This corticomuscular control is usually determined by measuring coherence in the simultaneously recorded electroencephalography (EEG) - electromyography (EMG) activities. In this work, an attempt has been made to estimate the EEG-EMG coherence using Magnitude Squared Coherence function. For this purpose, the simultaneous EEG-EMG activities of ten healthy subjects during standing, level walking, stair descending, stair descending, ramp descending, and ramp ascending are considered. The EEG signals associated with the motor cortex region and EMG signal of Tibialis Anterior (TA) are subjected to magnitude squared coherence function. In addition, the interaction of conventional frequency bands of EEG, namely, alpha (8-12 Hz) and beta (14-30 Hz) spectral components with EMG signals are also analysed. The results show that there exists notable coherence between the electrical activities of brain and muscular system during various activities. In addition, the frequency band interactions are also found to be distinct for different activities. Therefore, it seems that the analysis could be extended for the evolution of corticomuscular functions in patients with stroke.