What is the quadriceps muscle?

The quadriceps muscle is a group of four muscles (rectus femoris, vastus medialis, vastus lateralis and vastus intermedius) [1]. All four muscles attach into the patella (kneecap) through a common quadriceps tendon and attaches to the tibia (shin) via the patella ligament [1]. The rectus femoris muscle originates from the pelvic bone while the other three muscles originate from surfaces of the femur [1].


What does the quadriceps muscle do?

The anatomy of the quadriceps muscle acts to bend the hip joint and straighten the knee joint [1]. Additional to creating movement at these joints, the quadriceps muscle also functions to stabilise the knee joint during movement [2]. Joint stability during movement is compromised with weak quadriceps muscles, increasing the risk of damage to knee joint structures [2,3]. The quadriceps muscle also acts to absorb load and stresses applied to the knee joint [4]. Hence, weakness in the quadriceps muscles could result in abnormal loading and subsequent structural damage to joint structures, including menisci, ligaments, cartilage and bone [4,5].


Is quadriceps muscle strength related to knee pain?

Although knee pain may result from multiple factors including both biological and/or psychosocial, studies suggest that quadriceps muscle weakness can contribute to worsening knee pain [5]. Contrarily, greater quadriceps muscle strength has been shown to prevent further damage to knee joint structures [5,6]. It is also alluded to in research that a certain amount of quadriceps muscle strength is necessary to protect the knee from adverse loading [5]. Therefore, quadriceps muscle strength is shown to be strongly associated with knee pain and disability [7]. Interestingly, both the strength of the muscle contraction as well as the mass of the muscle contributes to the overall strength of the quadriceps muscle [8,9].  


Is quadriceps muscle strength related to knee injuries?

A common finding in research is that reduced quadriceps muscle strength is a common clinical finding and risk factor among individuals with or at risk of knee osteoarthritis [8]. Additionally, the progression of knee osteoarthritic changes has been associated with quadriceps muscle strength [5,6]. Weakness in the quadriceps muscle is also a risk factor for non-contact anterior cruciate ligament injuries as well as patellofemoral pain syndrome [9,10].


How can physiotherapy help?

1. Exercise therapy

Physiotherapists can provide a range of appropriate exercises specific to an individual’s condition and movement [11]. Though as stated previously, quadriceps muscle strengthening is crucial in the management of knee pain, it is by far not the only therapy required to ensure healthy knee joints. Research studies have demonstrated strong evidence to show that physiotherapy management based on exercise is effective in reducing knee pain and improving function [12]. Concurrently, individual adherence to these exercises is needed to optimise long-term improvements [11,12].

2. Manual therapy

Physiotherapists may also provide manual therapy in adjunct with an exercise-based management for knee pain. Manual therapy may include but not exclusive to soft tissue releases, mobilisation, dry needling and dry cupping. Studies have shown that manual therapy in addition with exercise is effective in relieving knee pain and physical disability in individuals recovering from an acute knee injury as well as individuals with more chronic conditions such as knee rheumatoid arthritis and knee osteoarthritis [12].


3. Motor control and plyometric training

Physiotherapists can also provide a range of exercises focused on motor control and plyometrics. It is well documented that athletes participating in sports involving high impact and agility have a higher incidence of knee injury and pain [6,13]. Studies have demonstrated a decreased incidence of knee injury in athletes that have participated in training programs focused on motor control and plyometrics [13].


Take home message

Although knee pain may result from multiple factors including both biological and/or psychosocial, studies suggest that quadriceps muscle weakness is associated with worsening knee pain [5]. Physiotherapy can provide a range of therapy modalities including exercises, manual therapy, education and advice, which have proven to be effective in reducing knee pain and functional disability [6,11,12].


If you have any questions regarding knee pain or think you may benefit from physiotherapy, please give us a call at (02) 8411 2050. At Thornleigh Performance Physiotherapy, we can give you an accurate diagnosis and treatment, to help you get back in action as soon as possible. We are conveniently located near Beecroft, Cherrybrook, Hornsby, Normanhurst, Pennant Hills, Waitara, Wahroonga, Westleigh, West Pennant Hills, and West Pymble.


  1. Kary JM. Diagnosis and management of quadriceps strain and contusions. Curr Rev Musculoskelet Med. 2010;3:26-31. doi:10.1007/s12178-010-9064-5.

  2. Segal NA, Glass NA. Is Quadriceps Muscle Weakness a Risk Factor for Incident or Progressive Knee Osteoarthritis? Phys Spotsmed. 2011;39:44-50. doi:10.3810/psm.2011.11.1938.

  3.  Winby CR, Lloyd DG, Besier TF, Kirk TB. Muscle and external load contribution to knee joint contact loads during normal gait. J Bio- mech. 2009;42:2294–2300. doi:10.1016/j.jbiomech.2009.06.019.

  4.  Herzog W, Longino D, Clark A. The role of muscles in joint adaptation and degeneration. Langenbecks Arch Surg. 2003;388:305–315. doi:10.1007/s00423-003-0402-6.

  5.  Glass NA, Torner JC, Frey Law LA, et al. The relationship between quadriceps muscle weakness and worsening of knee pain in the MOST cohort: a 5-year longitudinal study. Osteoarthr Cartil. 2013;21:1154-1159. doi:10.1016/j.joca.2013.05.016.’

  6. Thomas KS, Muir KR, Doherty M, Jones AC, O'Reilly SC, Bassey EJ. Home based exercise programme for knee pain and knee osteoarthritis: randomised controlled trial. BMJ. 2002;325:752. doi:10.1136/bmj.325.7367.752.

  7. O’Reilly SC, Jones A, Muir KR, Doherty M. Quadriceps weakness in knee osteoarthritis: the effect on pain and disability. Ann Rheum Dis. 1998;57:588-594. doi: 10.1136/ard.57.10.588.

  8. Petterson SC, Barrance P, Buchanan T, Binder-Macleod S, Snyder-Mackler L. Mechanisms underlying quadriceps weakness in knee osteoarthritis. Med Sci Sports Exerc. 2008;40:422-427. doi:10.1249/MSS.0b013e31815ef285.

  9. Bodor M. Quadriceps protects the anterior cruciate ligament. J Orthop Res. 2001;19:629-633. doi:10.1016/S0736-0266(01)00050-X.

  10. Moller BN, Jurik AG, Tidemand-Dal C, Krebs B, Aaris K. The quadriceps function in patellofemoral disorders. A radiographic and electromyographic study. Arch Orthop Trauma Surg. 1987;106:195-198. https://www.ncbi.nlm.nih.gov/pubmed/3606363. Accessed June 24, 2019.

  11. Thomas KS, Muir KR, Doherty M, Jones AC, O’Reilly SC, Bassey EJ. Home based exercise programme for knee pain and knee osteoarthritis: randomised controlled trial. BMJ. 2002;325:752. doi:10.1136/bmj.325.7367.752.

  12. Page CJ, Hinman RS, Bennell KL. Physiotherapy management of knee osteoarthritis. Int J Rheum Dis. 2011;14:145-151. doi:10.1111/j.1756-185X.2011.01612.x.

  13. Hewett TE, Lindenfeld TN, Riccobene JV, Noyes FR. The effect of neuro muscular training on incidence of knee injury in female athletes. A prospective study. Am J Sports Med. 1999;27:699-706. doi:10.1177/03635465990270060301