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The braking effect: An important concept for the possible cause of knee pain in runners.


One of the common issues faced by runners is knee pain. It can vary in severity and location, but one common and overlooked is known as the "braking effect." The braking effect is a biomechanical fault in running mechanics which was discovered several years ago, however, seems to rarely be mentioned in recent time when knee pain (in runners) is discussed. It refers to the phenomenon where the body's forward momentum is impeded by biomechanical factors during the running stride, leading to increased impact forces and potential discomfort.

Understanding the Braking Effect:

The braking effect in running can be described as the inefficiency caused by certain biomechanical movements that lead to a reduction in the overall forward momentum of a runner. During a typical running stride, the runner swings a leg forward and before the foot strikes the ground, the same leg’s gluteal muscles contract to prepare the lower extremity for shock absorption and stabilization. Furthermore, before the foot strikes the ground, the leg begins its backward movement (the transition between the running-gait’s swing phase and push-off phase is this particular phase) where the initial strike of the foot occurs near or slightly forward to their line of gravity.

Certain factors can interrupt this smooth process, such as over-striding, inadequate stride length, and poor running form. These factors collectively contribute to the braking effect by effectively slowing down the runner's forward motion during each stride. From my experience, a tired runner often swings their leg out in front and neglects to pull it back, causing the foot to strike the ground too far in front of their line of gravity.

Linking the Braking Effect to Knee Pain:

The braking effect can have a significant impact on the knees, potentially leading to pain and discomfort among runners. When the body experiences increased braking forces, the knees are subjected to higher impact loads than they would experience in a more efficient running gait. Over time, these repetitive impacts can contribute to the development of various knee-related issues, such as patellofemoral pain syndrome and/or iliotibial band syndrome.

The braking effect can also disrupt the natural kinematic chain of movements, causing muscle imbalances and altered joint mechanics. This can lead to improper distribution of forces across the knee joint, resulting in excessive stress on certain structures and contributing to pain. Additionally, the repeated microtrauma caused by the braking effect can inflame tissues and exacerbate knee pain.

Mitigating the Effects of the Braking Effect:

Addressing the braking effect (if occurring) is crucial for preventing and managing knee pain among runners. It is important to implement the following to minimize its impact:

Proper Running Form and Biomechanical Analysis: Educating runners about maintaining proper running form can help reduce the braking effect. Shortening stride length and increasing cadence is an example of a possible strategy which could be utilized to promote a more efficient running gait and reduce the braking effect. Runners can benefit from professional biomechanical analysis to identify any gait abnormalities contributing to the braking effect. Customized interventions, such as orthotics or shoe adjustments, can also be recommended based on these analyses.

Strength and Conditioning: Incorporating strength and conditioning exercises can reinforce the knee through improved muscular recruitment and dynamic control. Strengthening the quadriceps, hamstrings, and hip abductor muscles, as well as learning to properly recruit them, can contribute to better shock absorption and improved running mechanics.

Gradual Progression: Proper training progression is essential to allow the body to adapt to increased loads. Sudden increases in mileage or intensity should be avoided to prevent overloading the knee joint and exacerbating the braking effect. Generally speaking, it is advisable to modify one variable at a time (such as speed or distance) to properly assess how one’s body adapts to the change.


The braking effect is a concept that exemplifies how certain biomechanical factors can contribute to knee pain in runners. By understanding and addressing this phenomenon, runners can take proactive measures to minimize the braking effect's impact and reduce the risk of knee pain and related injuries. Emphasizing proper running form, incorporating strength training, and seeking professional guidance for biomechanical analysis are important steps toward maintaining healthy knees while enjoying the benefits of running.


Hamill, J., & Gruber, A. H. (2007). "Mechanical basis of overground and treadmill running." Medicine & Science in Sports & Exercise, 39(5), 1905-1911.

Willson, J. D., & Davis, I. S. (2014). "Lower extremity mechanics of females with and without patellofemoral pain across activities with progressively greater task demands." Clinical Biomechanics, 29(5), 683-691.

Chappell, J. D., Creighton, R. A., Giuliani, C., & Yu, B. (2007). "Shoe-surface friction influences movement strategies during a sidestep cutting task." Journal of Science and Medicine in Sport, 10(5), 297-304.

Esculier, J. F., Dubois, B., Dionne, C. E., Leblond, J., & Roy, J. S. (2015). "A consensus definition and rating scale for minimalist shoes." Journal of Foot and Ankle Research, 8(1), 42.

Heiderscheit, B. C., Chumanov, E. S., & Michalski, M. P. (2011). "Effects of step rate manipulation on joint mechanics during running." Medicine & Science in Sports & Exercise, 43(2), 296-302.

At John Lathrop Physical Therapy, we don’t have a “treatment protocol” for each diagnosis.Instead, we appreciate and take in to account that each patient presents with different dysfunctions that are likely contributing to the etiology of their medical diagnosis.

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