title: Myoeletric Activity of the Quadriceps During Leg Press Exercise Performed With Differing Techniques.
abstract: Machado, W, Paz, G, Mendes, L, Maia, M, Winchester, JB, Lima, V, Willardson, JM, and Miranda, H. Myoeletric activity of the quadriceps during leg press exercise performed with differing techniques. J Strength Cond Res 31(2): 422-429, 2017-The quadriceps muscle supplies the motive force for dynamic knee extension. During this action, the vastus medialis oblique (VMO) and vastus lateralis (VL) co-contract to stabilize the patella as it tracks within the patellofemoral groove. The purpose of this study was to analyze surface electromyographic (SEMG) responses for the VL, VMO, rectus femoris (RF), and biceps femoris (BF), as well as the VMO:VL ratio during an open-kinetic chain 45° angled leg press (LP45). The traditional LP45 technique was compared with 2 alternative LP45 exercise techniques that used a physioball and elastic band, respectively. Thirteen female college students performed 3 protocols in random order: TRAD-1 LP45 set performed using the traditional exercise technique, PBALL-1 LP45 set performed with a physioball held between the knee joints, and PEB-1 LP45 set performed with an elastic band proximal to the knee joints. Ten repetitions at 70% of a 10 repetition maximum load were performed in each protocol, and the SEMG data were recorded for the VMO, VL, RF, and BF muscles. Significant increases in VMO activity were noted during PBALL vs. PEB (p = 0.001) and TRAD (p = 0.002). Higher VMO activity was noted during TRAD vs. PEB (p = 0.001). Greater VL activity was noted during PBALL vs. TRAD (p = 0.0001) and PEB (p = 0.0001). The PBALL condition elicited a greater VMO:VL ratio during the concentric phase vs. the PEB (p = 0.001) and TRAD (p = 0.001) protocols. Greater RF activity was observed during PEB vs. TRAD (p = 0.001) and PBALL (p = 0.001). Therefore, practitioners should consider placing a physioball between the knees during the LP45 exercise as an alternative technique when greater overall quadriceps activity is desired for clinical rehabilitation or a muscle strengthening program.
authors.affiliation: 1School of Physical Education and Sports, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil;2Lato Sensu Postgraduate Program in Strength Training, School of Physical Education and Sports, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil;3Laboratory of Biodynamic of Exercise, Health and Performance, Castelo Branco University, Rio de Janeiro, Brazil;4School of Physical Therapy, University of the Incarnate Word, San Antonio, Texas; and5Department of Health and Human Performance, Rocky Mountain College, Billings, Montana.
authors.forename: Wallace
authors.initials: W
authors.lastname: Machado
authors.forename: Gabriel
authors.initials: G
authors.lastname: Paz
authors.forename: Leonardo
authors.initials: L
authors.lastname: Mendes
authors.forename: Marianna
authors.initials: M
authors.lastname: Maia
authors.forename: Jason B
authors.initials: JB
authors.lastname: Winchester
authors.forename: Vicente
authors.initials: V
authors.lastname: Lima
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Willardson
authors.forename: Humberto
authors.initials: H
authors.lastname: Miranda
mesh_terms: D000328:Adult; D004576:Electromyography; D015444:Exercise; D005260:Female; D006801:Humans; D007700:Kinetics; D007717:Knee / Q000502:physiology; D007866:Leg / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology; D055815:Young Adult