It is no secret that distance running places a significant demand on the body’s musculoskeletal system. The cyclic impact (ground reaction) forces inherent to running continuously load the lower extremity and spine with every step. Due to this constant, repetitive stress, overuse injuries are common and can likely be attributed to less than optimal biomechanics.
Although the running cycle is complex, we discuss three of the most well known and researched components (foot strike, trunk position, step rate / stride length). Additionally, we will provide a few examples of how altering your running biomechanics may help decrease pain and improve performance.
Foot Strike
The manner in which the foot initially contacts the ground has been classified into three popular subgroups: forefoot, midfoot, and heel strike. A majority of distance runners likely fall into the heel strike category, however, elite performers are less likely to heel strike.
Elite runners who heel strike do so with their foot directly under their body while non-elite runners tend to heel strike out in front of their body – this blocks forward momentum which results in a massive increase in ground reaction forces and an increased likelihood of injury. It does not mean that these runners need to change to a different foot strike, they may just need to address biomechanical issues to improve how they are heel striking.
As a note, research struggles to clearly identify any economical or performance benefit in distance runners when it comes to midfoot or forefoot striking. As speed increases, most runners do, however, tend to naturally shift toward a midfoot or forefoot running pattern.
My recommendation: When necessary, intentionally changing footstrike may be an option to reduce stress on various tissues. For example, heel striking increases impact forces at the knee compared to midfoot striking. Thus, people with chronic knee could pain try a midfoot strike.
Conversely, midfoot and forefoot striking is associated with a greater load on the Achilles tendon, so people with chronic Achilles or calf pain may be advised to use a heel strike. Although changing to a rearfoot strike pattern may reduce the likelihood of Achilles related issues, foot and hip biomechanics are most likely the culprit of the Achilles pain.
Forward Trunk Lean
Running methods like ‘ChiRunning’ and POSE method promote a forward lean of the trunk while running. The biomechanical reasoning behind a forward lean is that it better incorporates the power of the posterior chain.
Research on this topic is mixed. A recent study concluded that runners who implemented a forward trunk lean as well as an increased step rate (see below) reduced their risk of knee injury. On the other hand, another study concluded that using the POSE method of running for three months actually worsened the triathlete’s running economy compared to their habitual running form.
Due to the mixed results of research thus far, ChiRunning and POSE method should be trialed with caution. Unfortunately, none of these studies account for biomechanics issues, such as mobility and stability throughout each participant’s body, which makes it challenging to draw conclusions. Any restriction in posterior chain mobility may result in an inability to successfully implement a forward lean.
As a note, it is essential that runners do not fall into the habit of overly tightening their core when trialing these ChiRunning and POSE running methods as this can actually block the ability of the torso to counter rotate relative to the hips thereby shutting down the efficiency and activation of the core and glutes.
My Recommendation: If you are a runner suffering from knee pain, you may want to consider an increased forward trunk lean complemented with an increased step rate. To implement this technique, subtly lean forward bending at the ankles, forming a straight line from ankles to shoulders. Research shows that about 14 degrees of forward lean can be enough to decrease impact at the knee.
Spatiotemporal (Step Rate and Stride Length)
Running speed is a function of step rate and stride length. Step rate is measured in steps per minute and stride length is measured in distance from toe off to foot strike. By increasing one or the other (or both), running velocity increases directly.
A decreased step rate (fewer steps per minute) is associated with a greater likelihood of shin and knee injury while an increased step rate coincides with decreased stride length, decreasing the likelihood of running injury. Modifying these two running characteristics is a direct strategy to reduce the likelihood of running injury.
My recommendation: If you are injured, consider modifying your running form by changing your step rate and stride length. A subtle 5-10% increase in your step rate has been shown to reduce ground reaction and joint forces during running. iPhone and Android apps like AudioStep, Running Cadence Tracker, and RunCadence, can aid in helping you adjust your step rate.
No Right Way To Run
It is important to remember that no one running style or body type wins all races, even at the most elite levels. All runners have individual physical, biomechanical, emotional, and physiological strengths and weaknesses. Thus, a change that works for one runner, may not work for another. It is most important to find and develop your own style of running. Your goal should be to optimize your body’s abilities and address your biomechanical related issues so you can run at your best and without pain.
Be aware that changing running biomechanics may cause an unexpected injury, so don’t change too many things too quickly or too intensely! If you cannot seem to solve your running aches and pains with these quick biomechanical changes, there is likely an underlying problem that needs to be addressed with an in-depth biomechanical examination by your physical therapist.
References:
Kasmer, M. E., Xue-Cheng, L., Roberts, K. G., & Valadao, J. M. (2013). Foot-Strike Pattern and Performance in a Marathon. International Journal Of Sports Physiology & Performance, 8(3), 286.
Warr, B. J., Fellin, R. E., Sauer, S. G., Goss, D. L., Frykman, P. N., & Seay, J. F. (2015). Characterization of Foot-Strike Patterns: Lack of an Association With Injuries or Performance in Soldiers. Military Medicine, 180(7), 830-834. doi:10.7205/MILMED-D-14-00220.
Dallam GM, Wilber RL, Jadelis K, Fletcher G, Romanov N. Effect of a global alteration of running technique on kinematics and economy. J Sports Sci. 2005;23(7):757-64.
Teng HL, Powers CM. Sagittal plane trunk posture influences patellofemoral joint stress during running. J Orthop Sports Phys Ther. 2014;44(10):785-92.
Luedke LE, Heiderscheit BC, Williams DS, Rauh MJ. Influence of Step Rate on Shin Injury and Anterior Knee Pain in High School Runners. Med Sci Sports Exerc. 2016;48(7):1244-50.