Spectral analysis of the electromyograph of the erector spinae muscle before and after a dynamic manual load-lifting test. A.C. Cardozo, M. Gonçalves and A.C.F. Gauglitz. Brazilian Journal of Medical and Biological Research, 37 (7): 1081, 2004.
Figure 1. M.A. ISOSTATION 2000 device. A, Isometric contractions and initial position in the 1-min test; B, final position in the 1-min test.