Even the simplest volitional movements must be precisely coordinated with anticipatory postural adjustments. Little is currently known about the neural networks that coordinate these adjustments in healthy adults. We measured brain activity prior to movement during a bimanual load-lifting task, designed to elicit anticipatory adjustments in a restricted and well-defined set of musculature in the arm. Electroencephalography and magnetoencephalography brain measurements were obtained from eleven participants while they performed a bimanual load-lifting task that required precise inter-limb coordination. Anticipatory biceps brachii inhibition in the loaded arm was associated with a robust desynchronization of the beta rhythm. Beamforming analyses localized beta band responses to the parietal lobules, pre- and post-central gyri, middle and medial frontal gyri, basal ganglia and thalamus. The current study shows that premovement brain activity in a bimanual load-lifting task can be imaged with magnetoencephalography. Future experiments will partition out brain activity associated with anticipatory postural adjustments and volitional movements. The experimental paradigm will also be useful in the study of motor function in patients with developmental or degenerative disorders.