If you have ever battled with ITB pain, you know it can be one of the most frustrating injuries to manage. Despite the high prevalence of ITB pain in runners, the true nature of the ITB has been poorly understood for many years. Previously, it was thought to be a passive “strut” like structure that was static and did not change. However, we now know the ITB should be viewed as a biological spring as it stores and releases energy during the gait cycle. To better understand how the ITB can cause pain in running, it is important to fully understand its anatomy. In this post, I will continue to explore the iliotibial band’s anatomy, its energy storage capacity, and how it is loaded by the hip muscles during running. If you missed our last post on ITB pain, go back and check it out to gain an overview of the condition and how to progress back from it.
ITB Anatomy
The ITB is dense connective tissue that originates at the lateral hip and travels down the outside of the leg to the knee. Its origins start at the Tensor Fascia Latae (TFL) and the Glutes Maximus (GMax). 100% of the TFL muscle fibers turns into the anterior portion of ITB while around 40-70% of the GMax muscle fibers becomes the posterior portion of the ITB.
These fibers turn into the dense, avascular sheath with the thickness of construction paper that is primarily made up of type 1 collagen. The ITB then stretches down the entire lateral aspect of the thigh until it inserts at the outside of the knee. Specifically, it inserts into Gerdy’s Tubercle on the anterolateral aspect of the tibia, while also attaching along the lateral femoral epicondyle and the lateral patellar retinaculum.
ITB Elastic Energy During Running
The ITB is no longer considered a passive structure as there has been more research showing its energy storage capability. A study back in 2015 by Eng et al. showed that the ITB stores around 1 J of elastic strain with running around 13:30 mile pace and up to 7 J with running at 5:23 mile pace.
This is a significant amount of energy storage when compared to the primary spring used in running, the Achilles tendon (AT). The AT stores around 45 J during high speed running which means the ITB stores around 14% as much as the AT. Forget super shoes that can improve energy storage and release by 3-4%, the ITB provides over 3x the capacity.
To store and release this energy, the ITB works in two specific functions. Initially, the anterior portion of the ITB becomes loaded during the early swing phase of gait. As the hip extends back along with knee flexion, the ITB becomes stretched which “loads” the spring to allow it to recoil forward aiding into hip flexion. Then as the leg moves into terminal swing, the posterior fibers of the ITB become stretched with hip flexion and knee extension. This stretch again, “loads” the ITB spring to help with hip extension during the stance phase of gait. Overall, this helps to reduce the workload of the hip flexors and extensors by about 5% during each phase.
ITB as Stabilizer
Beyond its energy return capacity, the ITB also plays a key function in hip stabilization and knee rotation in running. During mid stance of gait, the hip muscles like the glute medius (Gmed), TFL, piriformis and GMax work together to keep the hips level while the force of gravity causes the opposite hip to drop. The ITB acts as a passive stabilizer during this process to further help control the medial collapse of the hip.
Further, the ITB helps to manage knee internal rotation during the stance phase of gait due to its insertion into lateral femur and tibia. However, if internal rotation becomes excessive, this can cause increased compression across the highly innervated fat pad. Potentially, one reason why ITB pain can occur but we will explore the exact cause further in the next post.
The IT band is dense connective tissue that plays a key role in running gait. Due to origin points from the TFL and GMax to its insertion along the lateral aspect of the knee, it has multiple functions. The primary function is to store and release energy during the gait cycle to help improve running efficiency. The secondary role to help aid in hip and knee stabilization during the stance phase of gait. With this better understanding of the anatomy and biomechanics of the ITB, our next post will review the true cause of ITB pain and how to diagnose it.
Ready to get back to running and overcome your ITB pain? Schedule an appointment today if you live in the CSRA on our booking page!
Disclaimer: This information is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or health-related goals.
References
Abubakar, A., Anwar, M., Sameen, H., Saher, U., Abid, H., Rafi, S., Ali, I., Fatima, W., Zubair, A., & Rafique, H. (2024). Prevalence and association of iliotibial band tightness with daily sitting hours and type of sitting surface among tailors of Sahiwal, Pakistan. Journal of Health and Rehabilitation Research, 4(3), 1–6.
Buckthorpe, M., Stride, M., & Della Villa, F. (2019). Assessing and treating gluteus maximus weakness – A clinical commentary. International Journal of Sports Physical Therapy, 14(4), 655–669. https://doi.org/10.26603/ijspt20190655
Charles, D., & Rodgers, C. (2020). A literature review and clinical commentary on the development of iliotibial band syndrome in runners. International Journal of Sports Physical Therapy, 15(3), 460–470. https://doi.org/10.26603/ijspt20200460
Ebaugh, D., Gard, K., Maschi, R., & Milner, C. (2016, February 20). Anatomy and biomechanics of running injury: From cadaver dissection to practical interventions [Presentation]. APTA Combined Sections Meeting, Anaheim, CA, United States.
Eng, C. M., Arnold, A. S., Lieberman, D. E., & Biewener, A. A. (2015). The capacity of the human iliotibial band to store elastic energy during running. Journal of Biomechanics, 48(12), 3341–3348. https://doi.org/10.1016/j.jbiomech.2015.06.017
Kashyap, R., Goyal, M., Bhowmik, S., Nagpal, A., Chhaya, Bathla, M., Saha, J., & Goyal, K. (2026). Development and content validation of a novel Iliotibial Band Friction Syndrome Index questionnaire: A cross-sectional study. Journal of Clinical and Diagnostic Research, 20(7), YC06–YC09. https://doi.org/10.7860/JCDR/2026/87821.23695
Lenhart, R., Thelen, D., & Heiderscheit, B. (2014). Hip muscle loads during running at various step rates. Journal of Orthopaedic & Sports Physical Therapy, 44(10), 766–774. https://doi.org/10.2519/jospt.2014.5575
Nielsen, R. Ø., Sørensen, H., Parner, E. T., Lind, M., Nohr, E. A., & Rasmussen, S. (2014). Excessive progression in weekly running distance and risk of running-related injuries: An association which varies according to type of injury. Journal of Orthopaedic & Sports Physical Therapy, 44(10), 739–747. https://doi.org/10.2519/jospt.2014.5164
