An accompanying peak was observed at 22 Hz over C3 ( Fig 2 ) after termination ( M = 2.71 μV, SD = 1.35) over the last contraction second ( M = 2.01 μV, SD = 1.17) with marginal significance t (19) = 1.98, p = .06, d z = .44, which likely represents a harmonic component of the upper alpha enhancement [ 44 ].
In the confirmation analysis with alternative EEG referencing schemes ( S2 Annex ) the Surface Laplacian corroborated the currently observed effects, namely, an interaction between phase and hand-block F (2, 38) = 3.29, p = .048, η p 2 = .15, while the average reference showed the same patterns, albeit the aforementioned interaction did not reach statistical significance F (2, 38) = 2.43, p = .101, η p 2 = .11.