Comparison of Knee Muscle Strength and Ankle Dorsiflexion Range of Motion Between Standing Workers With and Without Patellofemoral Pain Syndrome

  • Weon, Young-soo (Department of Physical Therapy, The Graduate School, Yonsei University) ;
  • Ahn, Sun-hee (Kinetic Ergocise Based on Movement Analysis Laboratory) ;
  • Kim, Jun-hee (Kinetic Ergocise Based on Movement Analysis Laboratory) ;
  • Gwak, Gyeon-tae (Department of Physical Therapy, The Graduate School, Yonsei University) ;
  • Kwon, Oh-yun (Kinetic Ergocise Based on Movement Analysis Laboratory)
  • Received : 2020.10.13
  • Accepted : 2020.10.28
  • Published : 2020.11.20


Background: Prolonged standing during work causes a lower extremity pain and disorders. Patellofemoral pain syndrome (PFPS) is one of the common diagnoses of the knee pain. Although the etiology of PFPS is not completely understood, it is considered to be multifactorial. Objects: The purpose of this study was to investigate difference in strength of knee muscles, quadriceps:hamstring muscles strength ratio (Q:H ratio), asymmetry ratio of knee muscles strength and dorsiflexion range of motion (ROM) between standing workers with and without PFPS. Methods: Twenty-eight standing workers with PFPS and 26 age-, height-, and weight-matched standing workers without PFPS participated in this study. A tension sensor measured knee muscle strength, and motion sensor measured dorsiflexion ROM. The asymmetry ratio of knee muscles was calculated by a specific formula using the knee muscles strength of the dominant side and the sound side. An independent t-test was used to identify significant differences in the strength, ROM, Q:H ratio, and asymmetry ratio between the PFPS and normal groups. Results: The standing worker with PFPS have significantly lower dorsiflexion ROM (p < 0.000) and higher asymmetry ratio of the hamstring muscles strength (p < 0.000) compare to the standing worker without PFPS. No significant differences were seen in the strength of quadriceps muscle and hamstring muscles, Q:H ratio, and asymmetry ratio of quadriceps muscle strength. Conclusion: There was a significant difference in the asymmetry ratio of the isometric hamstring muscle strength. This finding suggests that the asymmetry ratio of isometric hamstring muscle strength may be more important than measuring only the hamstring muscle strength of the PFPS side. Furthermore, the results of this study showed a significant difference in dorsiflexion ROM between the standing industrial workers with and without PFPS. Dorsiflexion ROM and isometric hamstring muscle strength should be considered when evaluating the subjects with PFPS.


  1. Halim I, Omar AR. A review on health effects associated with prolonged standing in the industrial workplaces. Int J Res Rev Appl Sci 2011;8(1):14-21.
  2. Reid CR, McCauley Bush P, Karwowski W, Durrani SK. Occupational postural activity and lower extremity discomfort: a review. Int J Ind Ergon 2010;40(3):247-56.
  3. Jaffar N, Abdul-Tharim A, Mohd-Kamar I, Lop N. A literature review of ergonomics risk factors in construction industry. Proced Eng 2011;20:89-97.
  4. Daneshmandi H, Saki F, Shahheidari S, Khoori A. Lower extremity malalignment and its linear relation with Q angle in female athletes. Proced-Soc Behav Sci 2011;15:3349-54.
  5. Shultz SJ, Nguyen AD, Levine BJ. The relationship between lower extremity alignment characteristics and anterior knee joint laxity. Sports Health 2009;1(1):54-60.
  6. Krijnen RM, de Boer EM, Ader HJ, Bruynzeel DP. Venous insufficiency in male workers with a standing profession. Part 1: epidemiology. Dermatology 1997;194(2):111-20.
  7. Tuchsen F, Hannerz H, Burr H, Krause N. Prolonged standing at work and hospitalisation due to varicose veins: a 12 year prospective study of the Danish population. Occup Environ Med 2005;62(12):847-50.
  8. Esculier JF, Roy JS, Bouyer LJ. Psychometric evidence of selfreported questionnaires for patellofemoral pain syndrome: a systematic review. Disabil Rehabil 2013;35(26):2181-90.
  9. D'hondt NE, Struijs PA, Kerkhoffs GM, Verheul C, Lysens R, Aufdemkampe G, et al. Orthotic devices for treating patellofemoral pain syndrome. Cochrane Database Syst Rev 2002;(2):CD002267.
  10. Dye SF. The pathophysiology of patellofemoral pain: a tissue homeostasis perspective. Clin Orthop Relat Res 2005;(436):100-10.
  11. Lankhorst NE, Bierma-Zeinstra SM, van Middelkoop M. Risk factors for patellofemoral pain syndrome: a systematic review. J Orthop Sports Phys Ther 2012;42(2):81-94.
  12. Csintalan RP, Schulz MM, Woo J, McMahon PJ, Lee TQ. Gender differences in patellofemoral joint biomechanics. Clin Orthop Relat Res 2002;(402):260-9.
  13. Goodfellow J, Hungerford DS, Woods C. Patello-femoral joint mechanics and pathology. 2. Chondromalacia patellae. J Bone Joint Surg Br 1976;58(3):291-9.
  14. Lee TQ, Yang BY, Sandusky MD, McMahon PJ. The effects of tibial rotation on the patellofemoral joint: assessment of the changes in in situ strain in the peripatellar retinaculum and the patellofemoral contact pressures and areas. J Rehabil Res Dev 2001;38(5):463-9.
  15. Kumar D, Manal KT, Rudolph KS. Knee joint loading during gait in healthy controls and individuals with knee osteoarthritis. Osteoarthritis Cartilage 2013;21(2):298-305.
  16. Pandy MG, Andriacchi TP. Muscle and joint function in human locomotion. Annu Rev Biomed Eng 2010;12:401-33.
  17. Kaya D, Citaker S, Kerimoglu U, Atay OA, Nyland J, Callaghan M, et al. Women with patellofemoral pain syndrome have quadriceps femoris volume and strength deficiency. Knee Surg Sports Traumatol Arthrosc 2011;19(2):242-7.
  18. Dvir Z, Halperin N, Shklar A, Robinson D. Quadriceps function and patellofemoral pain syndrome. Part I: pain provocation during concentric and eccentric isokinetic activity. Isokinet Exerc Sci 1991;1(1):26-30.
  19. Werner S. An evaluation of knee extensor and knee flexor torques and EMGs in patients with patellofemoral pain syndrome in comparison with matched controls. Knee Surg Sports Traumatol Arthrosc 1995;3(2):89-94.
  20. Brown CA, Carragee C, Sox-Harris A, Merchant AC, Mcadams TR. Prevalence of abnormal patellofemoral congruence in elite American football players and association with quadriceps isokinetic testing. J Knee Surg 2014;27(1):47-52.
  21. Benetti MC, Marchese T. Management of common musculoskeletal disorders. J Nurse-Midwifery 1996;41(2):173-87.
  22. Leardini A, Stagni R, O'Connor JJ. Mobility of the subtalar joint in the intact ankle complex. J Biomech 2001;34(6):805-9.
  23. Piva SR, Goodnite EA, Childs JD. Strength around the hip and flexibility of soft tissues in individuals with and without patellofemoral pain syndrome. J Orthop Sports Phys Ther 2005;35(12):793-801.
  24. Farrar JT, Young JP Jr, LaMoreaux L, Werth JL, Poole RM. Clinical importance of changes in chronic pain intensity measured on an 11-point numerical pain rating scale. Pain 2001;94(2):149-58.
  25. Reider B. The orthopaedic physical examination. Philadelphia: Elsevier Saunders; 2005.
  26. Hyde TE, Gengenbach MS. Conservative management of sports injuries. Sudbury: Jones and Bartlett; 2007.
  27. Mizner RL, Chmielewski TL, Toepke JJ, Tofte KB. Comparison of 2-dimensional measurement techniques for predicting knee angle and moment during a drop vertical jump. Clin J Sport Med 2012;22(3):221-7.
  28. Kim HA, Hwang UJ, Jung SH, Ahn SH, Kim JH, Kwon OY. Comparison of shoulder strength in males with and without myofascial trigger points in the upper trapezius. Clin Biomech (Bristol, Avon) 2017;49:134-8.
  29. Moraes GF, Faria CD, Teixeira-Salmela LF. Scapular muscle recruitment patterns and isokinetic strength ratios of the shoulder rotator muscles in individuals with and without impingement syndrome. J Shoulder Elbow Surg 2008;17(1 Suppl):48S-53S.
  30. Warner JJ, Micheli LJ, Arslanian LE, Kennedy J, Kennedy R. Patterns of flexibility, laxity, and strength in normal shoulders and shoulders with instability and impingement. Am J Sports Med 1990;18(4):366-75.
  31. Hurd WJ, Morrey BF, Kaufman KR. The effects of anthropometric scaling parameters on normalized muscle strength in uninjured baseball pitchers. J Sport Rehabil 2011;20(3):311-20.
  32. Rabin A, Kozol Z. Measures of range of motion and strength among healthy women with differing quality of lower extremity movement during the lateral step-down test. J Orthop Sports Phys Ther 2010;40(12):792-800.
  33. Arndt A, Westblad P, Winson I, Hashimoto T, Lundberg A. Ankle and subtalar kinematics measured with intracortical pins during the stance phase of walking. Foot Ankle Int 2004;25(5):357-64.
  34. Stergiou N, Bates BT, James SL. Asynchrony between subtalar and knee joint function during running. Med Sci Sports Exerc 1999;31(11):1645-55.
  35. Molgaard C, Rathleff MS, Simonsen O. Patellofemoral pain syndrome and its association with hip, ankle, and foot function in 16- to 18-year-old high school students: a single-blind casecontrol study. J Am Podiatr Med Assoc 2011;101(3):215-22.
  36. Powers CM, Perry J, Hsu A, Hislop HJ. Are patellofemoral pain and quadriceps femoris muscle torque associated with locomotor function? Phys Ther 1997;77(10):1063-75; discussion 1075-8.
  37. Callaghan MJ, Oldham JA. Quadriceps atrophy: to what extent does it exist in patellofemoral pain syndrome? Br J Sports Med 2004;38(3):295-9.
  38. Duvigneaud N, Bernard E, Stevens V, Witvrouw E, Van Tiggelen D. Isokinetic assessment of patellofemoral pain syndrome: a prospective study in female recruits. Isokinet Exerc Sci 2008;16(4):213-9.
  39. Boling MC, Padua DA, Marshall SW, Guskiewicz K, Pyne S, Beutler A. A prospective investigation of biomechanical risk factors for patellofemoral pain syndrome: the Joint Undertaking to Monitor and Prevent ACL Injury (JUMP-ACL) cohort. Am J Sports Med 2009;37(11):2108-16.
  40. Willson JD, Davis IS. Lower extremity strength and mechanics during jumping in women with patellofemoral pain. J Sport Rehabil 2009;18(1):76-90.
  41. Rathleff CR, Baird WN, Olesen JL, Roos EM, Rasmussen S, Rathleff MS. Hip and knee strength is not affected in 12-16 year old adolescents with patellofemoral pain--a cross-sectional population-based study. PLoS One 2013;8(11):e79153.
  42. Besier TF, Fredericson M, Gold GE, Beaupre GS, Delp SL. Knee muscle forces during walking and running in patellofemoral pain patients and pain-free controls. J Biomech 2009;42(7):898-905.
  43. Aagaard P, Simonsen EB, Trolle M, Bangsbo J, Klausen K. Isokinetic hamstring/quadriceps strength ratio: influence from joint angular velocity, gravity correction and contraction mode. Acta Physiol Scand 1995;154(4):421-7.
  44. Li RC, Maffulli N, Hsu YC, Chan KM. Isokinetic strength of the quadriceps and hamstrings and functional ability of anterior cruciate deficient knees in recreational athletes. Br J Sports Med 1996;30(2):161-4.
  45. Aagaard P, Simonsen EB, Beyer N, Larsson B, Magnusson P, Kjaer M. Isokinetic muscle strength and capacity for muscular knee joint stabilization in elite sailors. Int J Sports Med 1997;18(7):521-5.
  46. Lund-Hanssen H, Gannon J, Engebretsen L, Holen K, Hammer S. Isokinetic muscle performance in healthy female handball players and players with a unilateral anterior cruciate ligament reconstruction. Scand J Med Sci Sports 1996;6(3):172-5.
  47. Aagaard P, Simonsen EB, Magnusson SP, Larsson B, Dyhre-Poulsen P. A new concept for isokinetic hamstring: quadriceps muscle strength ratio. Am J Sports Med 1998;26(2):231-7.
  48. Jenkins ND, Hawkey MJ, Costa PB, Fiddler RE, Thompson BJ, Ryan ED, et al. Functional hamstrings: quadriceps ratios in elite women's soccer players. J Sports Sci 2013;31(6):612-7.
  49. Werner S. Anterior knee pain: an update of physical therapy. Knee Surg Sports Traumatol Arthrosc 2014;22(10):2286-94.
  50. Westing SH, Seger JY, Karlson E, Ekblom B. Eccentric and concentric torque-velocity characteristics of the quadriceps femoris in man. Eur J Appl Physiol Occup Physiol 1988;58(1-2):100-4.