The Effect of Burst-Duty-Cycle Parameters of Medium-Frequency Alternating Current on Maximum Electrically Induced Torque of the Quadriceps Femoris, Discomfort, and Tolerated Current Amplitude in Professional Soccer Players. - ELOIN LIEBANO, RICHARD; WASZCZUK, JR., SILAS; BARBOSA CORRÒA, JULIANA (Journal of Orthopaedic & Sports Physical Therapy, 2013)