We have simplified the literature investigating running to bring you the Runner’s Prehab Checklist. For the new and experienced recreational runners, this is a reference guide with biomechanical information to check and optimize your movement system for running. Be sure to add these exercises to your training routine to protect your body in helping you run!
Runner’s Prehab Checklist
Running is one of the most popular forms of exercise in the world. However, up to 50% of all runners may sustain an injury that will impact their training or running performance. Long distance running imposes highly repetitive forces, which can be up to 8x the body weight of the runner.
“A marathon runner takes an average of 25,000 steps during a race1.” You can only imagine how much total load is imparted on the body! “Often, it is the number of repetitions that is responsible for the development of an injury. Four of the most common clinical entities are anterior knee pain, iliotibial-band syndrome, Achilles tendinopathy, and plantar-fasciitis1.”
It has been reported that the knee is the most common location for an injury2. This may be due to the fact that the knee eccentrically absorbs more than 40% of the energy associated with ground contact. Running has been shown to increase the external force on the knee 5x the force of that generated while walking1!
The position of the trunk and pelvis in relation to your center of mass has a huge impact on the direction of force directed at the knee. “For example, excessive movement of the COM over the stance limb during an activity such as landing from a jump on one foot could move the resultant ground reaction force vector lateral to the knee joint center, thereby creating a valgus moment at the knee3.” An example of this includes leaning your trunk over the leg in contact with the ground in an attempt to keep your balance.
Hip adduction promotes dynamic knee valgus, “which would be expected to strain the soft tissue restraints that limit knee valgus such as MCL and ACL3. Without even taking trunk and pelvis position into account, “the peak valgus moment is two and a half times greater during running that it is during walking1.”
Theoretically, repetitive stress to structures in poor kinematic positions may increase the risk of sports-related injury. It is important to train the body to move in an optimal strategy and limit poor movement patterns such as excessive dynamic knee valgus. Practicing landing and working on these faulty mechanics is a great drill to add to your running training program. It has been shown that using the hip extensors to absorb external forces from the ground can reduce the knee valgus moment in women post-op ACL reconstruction4. Hip strength or motor control? The debate continues, but likely it is a combination of both that should be considered in a runner’s training program. Be sure to have the sound on to learn MORE!
3 Core Exercises For Runners
Lets face it, there are a TON of exercises for the core. A lot of them would likely help with trunk and pelvis stability, but these three have specific implications for runners. Runners should perform core exercises that also target hip abduction and external rotation to help resist dynamic knee valgus.
“There is a tendency for the hip to collapse into adduction and internal rotation as the hip flexes during weight bearing. This triplanar motion is most commonly observed during the weight acceptance phase of high-demand activities such as running or landing from a jump. As a single joint muscle, the gluteus maximus is best suited to provide 3-dimensional stability of the hip, as this muscle resists hip flexion, adduction, and internal rotation3.”
Here are three core exercises that target the gluteus maximus in a prone position.
- Hip extension
- Donkey kicks
- Fire Hydrants
According to Kang et al. 2013, EMG amplitude of the gluteus maximus (GM) was highest when the hip was in 30˚ abduction, and another study by Kwon and Lee in 2013 found GM EMG amplitude to be the highest when the knee was flexed to 90˚. Try bunching these three exercises back-to-back and doing multiple sets for time to build endurance! Once these exercises get easy, you can progress to upright standing exercises targeting the glutes.
Calf Strengthening For Runners
In addition to glute and core strength, the gastrocnemius-soleus (GS) complex also has an important role during running. “Peak forces in the Achilles tendon can be estimated; these forces range from 6-8x body weight, with the greatest forces generated during mid-stance of running.1” Also, the literature suggests 90% of the force at the ankle in running is efficiently absorbed and transferred by the Achilles tendon via elastic potential energy.
The musculotendinous unit of the GS and Achilles tendon are responsible for shock absorption and force generation. That means running demands eccentric and concentric muscle action from this unit. Also, we know training increases the tensile and maximum static strength of the tendon. Exercise increases collagen synthesis, the number and size of the fibrils, and the concentration of metabolic enzymes1.”
We want to train this unit in that exact way. This is a great drill for runners as it focuses on calf strength with the hip and knee in an extended position that also incorporates a single leg stability component. Be sure to add this exercise to your training regiment to improve your single leg strength, balance, and control.
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According to an article by Powers 2010, “The external moments (force couples) created by the resultant ground reaction force (from the ground) are resisted internally by muscles and noncontractile tissues such as ligaments and the joint capsule.” This is referred to shock absorption, which happens over a period of time once the foot makes contact with the ground.
Active shock absorption happens during eccentric muscle contraction such as the hip and knee bending after it contacts the ground. Leg stiffness is inversely related to active shock absorption. However, leg stiffness is directly related to loading rate. So, the less the hip and knee bend at initial contact through stance, the faster passive structures including the hip and knee joints are compressed.
A study by Teng and Powers in 2015, concluded increasing trunk lean and hip flexion during running can decrease the energy absorbed at the knee. Here is a bounding exercise to promote active shock absorption with hip flexion. We want to maximize use of the gluteus maximus and active shock absorption by allowing the hip to flex during landing. The best cues to use are land softly and stay quiet! The less sound you make, likely the more active shock absorption you are doing!
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Stay tuned for part two coming in the near future, hope you enjoyed!
- Van Gent RN, Siem D, van Middelkoop M, van Os AG, Bierma-Zeinstra SMA, Koes BW. Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. Br J Sports Med. 2007;41(8):469–80; discussion 480.
- Powers CM. The Influence of Abnormal Hip Mechanics on Knee Injury: A Biomechanical Perspective. J Orthop Sport Phys Ther. 2010;40(2):42–51.
- Tsai L-C, Powers CM. Increased Hip and Knee Flexion During Landing Decreases Tibiofemoral Compressive Forces in Women Who Have Undergone Anterior Cruciate Ligament Reconstruction. Am J Sports Med. 2013;41(2):423–429.
- Kang S-Y, Jeon H-S, Kwon O, Cynn H, Choi B. Activation of the gluteus maximus and hamstring muscles during prone hip extension with knee flexion in three hip abduction positions. Man Ther. 2013;18(4):303–307.
- Kwon Y-J, Lee H-O. How different knee flexion angles influence the hip extensor in the prone position. J Phys Ther Sci. 2013;25(10):1295–7.