Isolated Activation Ratio of the Quadriceps Femoris Muscle on Different Support Surfaces During Squat Exercise

스쿼트 운동 시 지지면 변화에 따른 넙다리네갈래근의 독립활성비율

  • Kim, Yong-Hun (Department of Physical Therapy, Masan University) ;
  • Kim, Byeong-Jo (Department of Physical Therapy, Dongeui University) ;
  • Park, Du-Jin (Department of Physical Therapy, Kaya University)
  • 김용훈 (마산대학교 물리치료학과) ;
  • 김병조 (동의대학교 물리치료학과) ;
  • 박두진 (가야대학교 물리치료과)
  • Received : 2018.01.29
  • Accepted : 2018.02.23
  • Published : 2018.04.30


Purpose: The aim of this study was to investigate the isolated activation ratio of the quadriceps femoris muscle on different support surfaces during squat exercise. Methods: Twenty participants (10 males and 10 females) voluntarily agreed to participate in the research after receiving an explanation about the purpose and process of the study. Each participant performed squat exercises on three different support surfaces (a flat surface, a form roller, and an unstable surface). Muscle activities of the rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) were measured by electromyography. The isolated activation ratio of the quadriceps femoris muscle was calculated using the %isolation formula. Results: For the squat exercise, the %isolation value of the VM was significantly higher on the unstable surface than on the flat surface and form roller. In contrast, the %isolation values for the RF for the squat exercise were significantly higher on the flat surface and form roller than on the unstable surface. There was no significant differences in the %isolation values of the VL on the three different surfaces. Conclusion: The findings indicate that squat exercise on different surfaces results in differential activation of the quadriceps femoris muscle, which suggests that squat exercise on a multi-directional unstable surface could increase the isolated activation ratio of the VM.


Supported by : National Research Foundation of Korea (NRF)


  1. Arlotta M, Lovasco G, McLean L. Selective recruitment of the lower fibers of the trapezius muscle. Journal of Electromyography and Kinesiology. 2011;21(3): 403-410.
  2. Begalle RL, Distefano LJ, Blackburn T, et al. Quadriceps and hamstrings coactivation during common therapeutic exercises. Journal of Athletic Training. 2012;47(4):396-405.
  3. Cannell LJ, Taunton JE, Clement DB, et al. A randomised clinical trial of the efficacy of drop squats or leg extension/leg curl exercises to treat clinically diagnosed jumper's knee in athletes: pilot study. British Journal of Sports Medicine. 2001;35(1):60-64.
  4. Chae WS, Jeong HK, Jang JI. Effect of different heel plates on muscle activities during the squat. Korean Society of Sport Biomechanics. 2007;17(2):113-121.
  5. Clark DR, Lambert MI, Hunter AM. Muscle activation in the loaded free barbell squat: a brief review. Journal of Strength and Conditioning Research. 2012;26(4):1169-1178.
  6. Cook JL, Khan K, Maffuli N, et al. Overuse tendinosis, not tendinitis part 2: applying the new approach to patellar tendinopathy. The Physician and Sportsmedicine. 2000;28(6):31-46.
  7. Cram JR, Kasman GS, Holtz J. Introduction to surface electromyography, Gaithersburg. Aspen. 1998.
  8. Crossley K, Cowan SM, Bennell KL, et al. Patellar taping: is clinical success supported by scientific evidence? Manual Therapy. 2000;5(3):142-150.
  9. Escamilla RF, Fleisig GS, Zheng N, et al. Effects of technique variations on knee biomechanics during the squat and leg press. Medicine and Science in Sports and Exercise. 2001;33(9):1552-1566.
  10. Hubbard JK, Sampson HW, Elledge JR. Prevalence and morphology of the vastus medialis oblique muscle in human cadavers. The Anatomical Record. 1997;249(1):135-142.<135::AID-AR16>3.0.CO;2-Q
  11. Hyong IH. Effects of squats accompanied by hip joint adduction on the selective activity of the vastus medialis oblique. Journal of Physical Therapy Science. 2015;27(6):1979-1981.
  12. Hyong IH, Kang JH. Activities of the vastus lateralis and vastus medialis oblique muscles during squats on different surfaces. Journal of Physical Therapy Science. 2013;25(8):915-917.
  13. Irish SE, Millward AJ, Wride J, et al. The effect of closed-kinetic chain exercises and open-kinetic chain exercise on the muscle activity of vastus medialis oblique and vastus lateralis. Journal of Strength and Conditioning Research. 2010;24(5):1256-1262.
  14. Jaberzadeh S, Yeo D, Zoghi M. The effect of altering knee position and squat depth on VMO : VL EMG ratio during squat exercises. Physiotherapy Research International. 2016;21(3):164-173.
  15. Kim HH, Song CH. Effects of knee and foot position on EMG activity and ratio of the vastus medialis oblique and vastus lateralis during squat exercise. Journal of Muscle and Joint Health. 2010;17(2):140-150.
  16. Koh EK, Lee KH, Jung DY. The effect of isometric hip adduction and abduction on the muscles activities of the vastus medialis oblique and vastus lateralis during leg squat exercise. Korean Journal of Sport Biomechanies. 2011;21(3):361-368.
  17. Kushion D, Rheaume J, Kopchitz K, et al. EMG activation of the vastus oblique and vastus lateralis during four rehabilitative exercise. The Open Rehabilitation Journal. 2012;5:1-7.
  18. Lutz GE, Palmitier RA, An KN, et al. Comparison of tibiofemoral joint forces during open-kinetic-chain and closed-kinetic-chain exercises. The Journal of Bone and Joint Surgery. American Volume. 1993;75(5):732-739.
  19. Marchetti PH, Jarbas da Silva J, Jon Schoenfeld B, et al. Muscle activation differs between three different knee joint-angle positions during a maximal isometric back squat exercise. Joural of Sports Medicine. 2016. Epub.
  20. Marcus RL, Yoshida Y, Meier W, et al. An eccentrically biased rehabilitation program early after TKA surgery. Arthritis. 2011. Epub.
  21. Nakajima M, Kawamura K, Takeda I. Electromyographic analysis of a modified maneuver for quadriceps femoris muscle setting with co-contraction of the hamstrings. Journal of Orthopaedic Research. 2003;21(3):559-564.
  22. Park DJ, Kim JH, Lee HO. Effectiveness of modified quadriceps femoris muscle setting exercise for the elderly in early rehabilitation after total knee arthroplasty. Journal of Physcial Therapy Science. 2012;24(1):27-30.
  23. Park SY, Yoo WG. Activation of the serratus anterior and upper trapezius in a population with winged and tipped scapulae during push-up-plus and diagonal shoulder-elevation. Journal of Back and Musculoskeletal Rehabilitation. 2015;28(1):7-12.
  24. Powers CM. Patellar kinematics, part I: the influence of vastus muscle activity in subjects with and without patellofemoral pain. Physical Therapy. 2000;80(10):956-964.
  25. Prilutsky BI. Coordination of two- and one-joint muscles: functional consequences and implications for motor control. Motor Control. 2000;4(1):1-44.
  26. Shelton GL, Thigpen LK. Rehabilitation of patellofemoral dysfunction: a review of literature. The Journal of Orthopaedic and Sports Physical Therapy. 1991;14(6):243-249.
  27. Souza DR, Gross MT. Comparison of vastus medialis obliquus: vastus lateralis muscle integrated electromyographic ratios between healthy subjects and patients with patellofemoral pain. Physical Therapy. 1991;71(4):310-320.
  28. Tang SF, Chen CK, Hsu R, et al. Vastus medialis obliquus and vastus lateralis activity in open and closed kinetic chain exercises in patients with patellofemoral pain syndrome: an electromyographic study. Archives of Physical Medicine and Rehabilitation. 2001;82(10):1441-1445.
  29. Yoo WG, Yi CH, Lee HJ. Effects of a combined posture of the lower extremity on activity of the vastus medialis oblique muscle and vastus lateralis muscle during static squat exercise. Korean Research Society of Physical Therapy. 2004;11(3):1-9.