How To Run Economically
Be it a novice runner just getting into the sport, or someone who has been running for years, there is always room for improvement. Having the most efficient running form may help you minimize any potential injuries, or improve your time at the given distance you are running towards.Figure-1 shows how many different factors that can influence a runner’s efficiency or economy. How much you run or train, the environment you run in, your body shape (known as anthropometry), internal physiological factors, and biomechanics all influence how you run, and if you are efficient.
Looking at the biomechanical aspect, two key factors come into play – mechanical factors, and ground reaction forces. Ground reaction forces are forces exerted by the body against the ground, and vice versa (think of Newton’s third law of physics – with every action, there is an equal and opposite reaction). With different activities, different levels of ground reaction forces occur. For running, the reaction force of your body against the ground is approximately 2-3x your body weight. Times that by 1000’s of steps per run and the fact that you land on only one leg when you are running, and you can see why running related injuries occur fairly frequently.
Due to this increased demand and forces coming into the body, the need for the body to absorb the force is subsequently increased (if you absorb the forces well, you don’t get injured). But how does the body absorb force? From the ground up – the muscles, tendons, ligaments, bones, and joints all need to take in the forces, and distribute them. Force transfers happen from the foot, to the calf and shin, to the knee, to the hamstring and quadriceps muscles, to the hip joint, and to the lower torso. This is why injuries can occur anywhere along that chain – any weak link will be exposed, and over time, a repetitive strain injury can occur (ranging from a muscle strain, ligament sprain, or if not dealt with adequately, shin splints or stress fractures in the shin or hip).Proper mechanics usually starts with the foot. To minimize forces, the foot lands on the outside of the foot (known as supination) then rolls on the ground, turning inwards (known as pronation). Having over pronation or supination can cause injuries as well, which is why people are fitted and wear different types of shoes or have shoe orthotics (either over the counter or custom created). Figure-2 gives a good picture representation of what supination, and pronation looks like for the right foot. It’s in the extremes of pronation and supination where issues occur, your foot does need some of these motions to absorb the ground reaction forces entering the body.
Not only does an individual have their foot turn in or out, but different landing patterns can affect forces as well. Figure-3 showcases three styles of running landing patterns – forefoot (a), midfoot (b), or rearfoot (c). 90% of runners are rearfoot strikers, but the more elite runners adopt a midfoot or forefoot strike. Why is that and how do you do it?
When looking at ground reaction forces again, switching from a rearfoot (c) to forefoot (a) pattern decreases forces entering the body by 50%. If you minimize forces entering the body, this may minimize injury risk. However, this does take training to convert your landing pattern, and if your shoe isn’t durable for the amount of running you do per week, you can have an increased risk of certain injuries (like stress fractures in the long bones of your foot, since you are now directly landing on them).
How do you develop a midfoot pattern? You need to increase your number of steps/strides taken per minute (known as cadence). If you try to stretch out too far with each step, you will naturally land on your heel. Watch tape of an elite runner – they look like they are prancing, and will more often than not land on their midfoot due to their shorter stride. Doing so helps push them forward as they are driving the ground backwards (think of a sprinter in the starting blocks – they are pushing backwards against the block, propelling them forward). If you land on your heel, it’s like putting on the brakes with every step.
However, there is some caveats to this improvement in economy. You would think that the fastest marathon runner has a midfoot or forefoot striking pattern, but Dennis Kimetto (who holds the current world record for a marathon with a 2:02:57 time) was shown to have a rearfoot striking pattern. And studies have shown that even if you start as a midfoot striker, with fatigue you will slowly fall back into a rearfoot pattern. So just like with any recommendations, there are some limitations, but the science is sound, and any change may lead to an improvement in time.
Overall, there is a lot of factors that come into play in a runner becoming better and more efficient. We just briefly discussed a couple of biomechanical factors that can come into play. The takeaways are to strive to become a midfoot striker (takes practice and more steps per minute), having shorter strides, and having a moderate level of foot pronation (but not too much). Strive to be as efficient as you can be, look at other factors not discussed (like training, environment, etc), and seek out a health care provider for advice on shoe wear, training tips, or if any injuries come up along the way.
And in the end, just get out there and run. You’re only racing against yourself, and you are doing more than the people who are watching on the sidelines.