RUN (rŭn) - to go steadily by springing steps so that both feet leave the ground for an instant in each step
Competitive running, be it against yourself or against others, is essentially about getting from A to B in as short a time as possible. Looking at the definition above, logic suggests there are two ways you can cover a specified distance in less time:
Move your legs faster, i.e. increase step frequency
Travel further with each step, i.e. increase step length.
At this point, shorter runners will probably be looking at option 1 and thinking, “Yep, that’s where I can shine!” whilst the taller of you will smile at option 2 in the thought that being lanky does have its advantages! And yet, in reality, research suggests that the secret of covering more ground in less time boils down to an ability to excel in both options.
Step vs. stride
Before we continue, I feel it may be useful to point out a little clarification regarding terminology. Though in practice you will see the words “step” and “stride” used interchangeably (e.g. stride frequency and stride length), technically speaking they are different.
A stride incorporates two steps, the left and the right. Stride length is therefore actually double the step length (assuming the left step is more or less the same as the right step). In other words, stride length is the distance covered between initial contact (IC) of one foot and the consecutive IC of that same foot. Step length, on the other hand, is the distance covered between IC of one foot and IC of the opposite foot, i.e. half.
By the same reasoning, you will take twice as many steps per minute as strides, so stride frequency will be half that of step frequency. It’s not a biggie as in literature you will commonly see the two words used interchangeably, but next time you do see Usain Bolt being quoted as running the 100m in 41 strides with a stride length (SL) of 2.44m and a stride frequency (SF) of 256spm, you will now know the “strides” they refer to are actually “steps”.
Step frequency
“Move your legs faster” sounds an obvious way of increasing speed but it is in fact a skill that requires not only increased aerobic capacity but also progressive neuromuscular training and more often than not modifications to your running form.
The speed your legs move is measured in number of steps per minute (spm), often referred to as cadence. The average recreational runner has a cadence of about 150-170spm, with variance due to factors such as individual height, level of general fitness, hip strength, running form, speed, etc.
As we saw in the article Heel Striking, Overstriding and Cadence, research shows that elite runners at race pace also vary in their cadence, but they are always in excess of 180spm. Though this does not mean you should directly go out and try running in excess of 180spm, being aware of your current cadence and experimenting with runs at a 5% increase may well be worth considering.
To determine your own cadence, simply count the number of times your left foot hits the ground whilst running for 30 seconds. Let’s imagine yours turned out to be 40. Double that to get the total for 60 seconds (80); then double it again to get the total for both feet (160). Your cadence (for that particular running speed) is therefore 160spm. For more information on such, see the aforementioned article.
Step length
When one suggests increasing step length, the immediate thought is to try and reach further in front of you. After all, that is what you would do if you were walking. The problem with doing this when running is two fold.
Firstly, landing your foot way out in front of your body (centre of mass) can in effect act as a brake with every step you take, especially if you are landing on a locked knee and heel. This is where all the fuss about heel striking stems from, even though the issue is not that you are landing on your heel but the fact you are jamming your leg out in front of you and decelerating each step.
Given that we are looking at ways to help you run faster, this is obviously not a great idea.
The second problem is to do with injury. Though the exact mechanism is as yet unknown, there does seem to be a correlation with the above and picking up lower limb injury. It may be something to with efficiency of load absorption and transference, and is very likely dependent on the individual, but if you are over striding and suffering from injury it may well be an area to address.
So, if reaching out in front of you is not the best way to increase step length, how about increasing the distance your leg travels behind you before leaving the ground? How far your leg gets behind you is a product of hip extension, which we looked at in the article, The Importance of Hip Extension.
Though inflexibility in the hip flexors (front of the hip) is often blamed for limiting hip extension in running, in actual fact the maximum angle of 10-12o is not that hard to achieve, so it could be argued that for most runners, limited hip extension is not an issue. Greg Lehman, a specialist in Running Injury/Biomechanics, has a detailed look in his article here.
In practice, elite athletes do not have greater hip extension. Their incredible step length comes from the ground they manage to cover whilst both feet are off the floor, also known as flight time. This is a product of the power they manage to generate pre-take off, bearing in mind we are talking about forward propulsion and not vertical propulsion.
In future articles we shall take a look at where this power comes from and what we can do to increase it, but for now we will turn our attention to how elite runners use both step length and step frequency to win races!
A study of step length and step frequency
In his excellent article Understanding Stride Rate and Stride Length, coach Steve Magness considers a study done by Enomoto et al. in 2008 which included a look at the stride (step) length and stride (step) frequency of the 3 medallists in the 10,000m at the 2007 World Championships of Athletics. The runners were Kenenisa Bekele (1st), Sileshi Sihine (2nd) and Martin Mathathi (3rd).
In summary, analysis of the 10,000m race revealed the following:
For the first 9km of the 10k race (approximately 23 laps of 25), all three athletes ran at more or less the same speed. However, the step frequency and step stride used by each of them to maintain that speed did vary:
Bekele, out of the three athletes, had the lowest step frequency (190spm) but the longest step length (despite being 7-11cm shorter than the other two athletes!)
Sihine’s had a higher step frequency than Bekele but a lower step length.
Mathathi had the highest step frequency of all three runners, but the shortest stride length.
During the final km, all three athletes managed to increase their speed, but using different modifications to their step frequency and length:
Bekele went from having the lowest stride frequency (190spm) to having the highest at 216spm, and did not lose hardly any step length whatsoever. The resulting increase in speed won him the race.
Sihine managed to increase his moderate step frequency, and in the last lap also managed to significantly increase his step length. The overall increase in speed was enough to bring him 2nd place.
Mathathi managed to increase his shorter step length but in doing so lost some of his high step frequency. As a result his speed stayed more or less the same and for that reason he came in 3rd.
Points to take away from the study
As Magness points out, the most important thing to take away from this study is that all three medallists sustained and increased their speed using distinct, individual methods. At Runners Connect we cannot stress enough how important it is to recognise that all runners are individuals with unique strengths and weaknesses, physical and mental attributes, physiological response to exercise, etc.
The elites succeed by developing a running form that suits their unique characteristics, and so should we. Make a note of what works for others and how they got they got there, by all means try it yourself, but never expect a one-size-fits all solution based on the success of another runner/s.
For mere mortals like ourselves, the study serves as a reminder of the relevance of both step rate and step length in maintaining and increasing speed.
Being aware of our performance for each may open the door to pin pointing where we should be directing our efforts. If we discover that our step length is low, that could be a sign that we need to do more strength/power work. If we notice our step frequency (cadence) is low, maybe some cadence/neuromuscular work are called for.
Bekele excels in being able to sustain an impressive stride length, but when the moment comes he can also increase his step rate by some 16spm. The implications for running coaches could be many.
In a future article we will look at greater detail on how to improve both step frequency and step length. We will see that in fact the two are very related. For many runners, increasing step rate is in itself one way to develop the power that is needed for increased step length.
As always, changes to running form including step length and step frequency are typically best addressed via ancillary exercise and drills.
Trying to continuously modify either whilst running is never a good idea as any changes you do achieve will remain the isolated product of conscious effort, as opposed to learning, practicing, drilling and being cued outside of your normal runs, so that the modifications take place unconsciously whilst running, which is how it needs to be.
And as always, the goal is to gradually optimize your unique step length and step frequency, not imitate someone else’s. And do not expect any magic formulas. If you make a sufficient effort at doing the hill work, interval training and strength conditioning (including plyometric exercise) that are recommended for so many aspects of running performance, both your step length and step frequency will naturally develop. Stretching those hip flexors may be less work, but when has less work ever paid off?
Do you have any experience of working on your step (or stride!) length or frequency? As always we are keen to hear about any experiences you care to share. There is so much we can learn from each other, so do please feel free to leave comments!
Happy running!
Matt Phillips is a Run Conditioning Coach, Video Gait Analyst & Sports Massage Therapist with over 20 years experience working within the Health & Fitness Industry. Follow Matt on Twitter
References
1. Magness, S.: Understanding Stride Rate and Stride Length
http://www.thebodymechanic.ca/2012/09/08/running-in-the-backseat-a-rationale-for-improving-hip-extension-in-runners/
http://www.scienceofrunning.com/2010/11/speed-stride-length-x-stride-frequency.html
2. Enomoto et al. Biomechanical analysis of the Medalists in the 10,000 metres at the 2007 World Championships in Athletics, New Studies in Athletics (2008)
3. Lehman, G.: Running in the Backseat: A rationale for improving hip extension in runners
http://www.thebodymechanic.ca/2012/09/08/running-in-the-backseat-a-rationale-for-improving-hip-extension-in-runners/