Running remains one of the world’s most popular forms of exercise, arguably due to its accessibility. All you need is a good pair of running shoes and the determination to step outside and put one foot in front of the other. Data from Strava reveals 82 million runs were recorded in 2016, which would only account for a fraction of the total number. Participation in running has had several booms since the late 50’s aided by outstanding athletic achievement such as Sir Roger Bannister breaking the 4min mile. Literature such as the bestselling book Aerobics, by Dr. Kenneth Cooper and The Complete Book of Running by Jim Fixx. More recently Born to run by Christopher McDougall prompted a surplus in people taking up or returning to the sport. Along with running being one of the most popular sports in the UK, it also has one of the highest injury rates according to several studies. Injury incidence has been shown to be as high as 80% over the course of a year, often resulting in soft tissue or bony stress injuries which then means time away from the sport. A significant proportion of these injuries can be attributed to training errors. Commonly known as doing “too much too soon”. An effective rehab program should not only aid recovery, but focus on helping to prevent injury by improving resilience to load.
Load and over training
The load we place on our body or more specifically the lower limb from running is between 2.5-3 times our bodyweight. The average male weighs approximately 80kg x2.5 (Load)=200kg. Times that by 500 steps per km that equals 100,000 of load per leg per km. Naturally our bodies are designed to withstand these kinds of loads but the problems start when the force exerted on the body is greater than the body’s ability to deal with it. Under-loading leads to loss of muscle mass and therefore weakness, reduced nerve function and stiffness within the joint. All of this can have a negative impact on how our body moves. Optimal loading has multiple benefits; increase in muscle mass leading to increased force production, load capacity and improved muscle contraction. Other benefits include improved tendon and ligament load capacity, joint health and increased bone dentist (Dye at el 2005). Over training puts excessive load on the body and this can lead to acute or chronic injury.
Causes of over loading
Training errors commonly consist of sudden changes to the training load beyond the body’s capacity to deal with it, this can be sudden increases in distance, duration or speed. A study by Fields, Karl B et al 2010 suggested excessive mileage or sudden changes in routine were associated with injury prevalence of up to 72%. Increase training volumes of greater than 30% were associated with higher injury rate. Some studies have even gone further, showing an increase in training volume was associated with patella femoral pain, patella tendinopathy and iliotibial band syndrome (ITBS). Increased speed was associated with greater rates of Achilles tendinopathy and calf injury.
Biomechanics and load
Biomechanics has been a hotly debated topic in running and there are still varying opinions of ideal running posture, foot strike and cadence. Running with sub-optimal biomechanics can lead to unnecessary stress being placed on the joints and soft tissue often leading to injury. These inefficient biomechanics can be attributed to lack of training, weakness, immobility or even previous injury. There is still a lot of debate regarding running biomechanics but we simply do not have the data to support it. To make things easier The UK Athletic Association has developed the following recommendation for the idea posture to maximize running efficiency.
Cadence
Increasing step rate (cadence) while maintaining a constant speed. Increased Cadence has been shown to reduce stride length and in turn reduce the force on the hip knee and ankle joint by 14%, reducing load on the body and improving running biomechanics (Willy et al 2012). Other benefits of gait retraining include injury prevention, improved propulsion and running economy.
Strength and load management
If we think about the forces acting on our body as previously mentioned, then it stands to reason that we need strengthen our body, not only to resist these forces, but to overcome them and propel ourselves forward when we run. Snyder et al 2009, Willy et al 2011 and Wouter et al 2012 demonstrated that strength and control included in training programs helped to reduce load on the body. However, strength alone does not appear to significantly improve biomechanics. Lauersen et al 2013 found that strength and control training reduced risk of acute injuries by 1/3 and overuse injuries to 1/2. Building muscle strength and endurance leads to reduced cardiovascular demand and a more energy efficient run technique. A systematic review by Blagrove et al. (2018) found strength training improved running economy by between 2-8% and time trial performance by between 2-5%.
Exercises to help avoid injury:
1. Running high knees Increase cadence to around 160-180 steps per min, complete for 30-60sec x3
2. Single leg gluteal bridge to develop hip strength, complete 10reps x3 on each leg
3. Single leg dip focus of strength and coordination needed for running, complete 10reps x3, start with a 1/4 squat and increase to and full squat as your strength and control improves.
Conclusion
Correct load management is essential to reducing unnecessary joint and soft tissue stress resulting in injury. The best way to do this is to plan your training a head of time so you can monitor your training load. Increasing cadence reduces peak force on the hip knee and ankle joint and improve running biomechanics. As a result, injury rate is reduced and propulsion and running economy are improved. Greater muscle strength allows us to effectively manage the load placed of the body during running and has been show to significantly reduced the risk of injury and improved economy.
References
Fields, K. B et al 2010
Prevention of running injuries.
Current Sports Medicine Reports:
https://journals.lww.com/acsm-csmr/Fulltext/2010/05000/Prevention_of_Running_Injuries.14.aspx#R34-14
Schubert, A. G., et al (2014).
Influence of Stride Frequency and Length on Running Mechanics: A Systematic Review. Sports Health, 6(3), 210–217. https://doi.org/10.1177/1941738113508544
Wouters, Isaac & Almonroeder, Thomas & Dejarlais, Bryan & Laack, Andrew & Willson, John & Kernozek, Thomas. (2012). Effects of a movement training program on hip and knee joint frontal plane running mechanics. International journal of sports physical therapy. 7. 637-46.
Blagrove R.C et al 2018
Effects of Strength Training on the Physiological Determinants of Middle- and Long-Distance Running Performance: A Systematic Review
Sports medine, Volume 48, Issue 5, pp 1117–1149
Lauersen, J et al (2013).
The effectiveness of exercise interventions to prevent sports injuries: A systematic review and meta-analysis of randomised controlled trials. British journal of sports medicine. 48. 10.1136/bjsports-