How to run faster without injuring oneself and without needing to spend more time training to do it? I think most runners would like to know the answer to that. There's much advice out there, especially through social media, and sorting the wheat from the chaff can be difficult, so I have done some proper research to save you the bother, so you can spend your time usefully, i.e. training, doing what will make you faster.
Background
This article actually started as a bit of research to determine whether children, especially Under 11s should be running adult Parkrun frequently. That question turned out to be difficult to answer but I will and soon! However, during the process of gaining the understanding to be able to address that "Juniors Question", I found myself learning much more about running mechanics that is applicable to adults and would perhaps benefit our Club members, if I could write about it clearly. NB - my previous article "The Need for Speed" complements this one.
Some simple physics
The late great physicist, Stephen Hawking, wrote in a "Brief History of Time" that every equation you include in a book halves the readership. So I am about to halve the readership!
Running speed (velocity) is related to only two factors : cadence (or step/stride frequency, f) and stride length (L) :
v = f x L
Then, the only additional factors that impact your Parkrun, or marathon, or ultra, times is how long you can maintain that velocity for.
Fundamentals of endurance training
England Athletics call their training framework for Under 11s FUNdamentals because the emphasis is that the kids have fun and so are motivated to participate fully and return for the next session. I write this as this should also be our feeling. If we don't enjoy our running training and want to come back for the next session, why are we doing it? There's loads of other things we could be doing. So think about what you enjoy when your running, because your mindset is critical to getting the best out of your running training. NB Don't get me wrong, there's days when we just don't feel "at it", but we go along anyway, sometimes with great results, sometimes not. The latter may be because we shouldn't be doing the session, due to illness or over-training. listen ro your body and note how it feels (this is an important attribute for your training).
I am not going to go into along explanation about what endurance running should comprise. We all know that "time on feet" is important, as steady (not fast) running (in Heart rate zones 1 or 2, for those who understand such things) will be general fitness and result in adaptations in our bodies that help our muscles function better when running, e.g. capillarisation. A general rule of think is this should actually comprise most of our training time, about 80%. It does vary depending on what you are training for and when is that race. The remaining running training time, as opposed to training time in the gym or classes, such as yoga, should be done at about your race pace, generally in the form of about 20 minutes to 40 minutes tempo runs, again dependent on what your training for, below race pace (say HR zone 3) and interval sessions, comprising intense efforts (HR zones 4 and 5) with recoveries, at and above your race pace. I will post some information on Heart Rate Zones from triathlete and coach, Mike Trees, from his "Run.nrg" instagram posts, and how to find out your race pace, again courtesy of Mike.
Running cadence
How fast we can "turn our legs over" is limited by our Central Nervous System, about 4Hz, but I won't explain why, as endurance runners do not run anywhere near their limit, except perhaps in the final 30m of a race! Typically endurance runners' cadence is about 75% of this limit, so 3Hz, or 180 steps per minute. So what does determine the cadence for endurance runners and should 180spm be a target?
As endurance events imply the need to keep going for a while, certainly compared to sprint events, efficiency is the key factor. We want to spend the least energy to get us round our event, whatever the distance. Energy delivery to our muscles, etc. is determined primarily by our heart rate, so we want the lowest heart rate for a given speed. We naturally adopt a cadence that tries to achieve this. It's equally true for cyclists with their cycling cadence.
In fact, most (but not all) of endurance runners, including experienced ones, actually have a cadence slightly lower (~5 steps per minute) than the optimum, the body perhaps being overly conservative (Ref 1), not by much, about 2-3%. So, as a first step in improving your race performance, you could try training at a slightly higher cadence. In theory, you should get some free gain!
NB a stride is complete when the right leg does a complete cycle so is twice a step. Step frequency is 2x stride frequency (ahh, another 50% readership lost!).
An additional benefit is that, for a given race time, a higher cadence might reduce your risk of injury (Ref 2), due to lower forces being involved, due to shorter stride length.
The issue of 180 SPM, as a target, is that it is not necessarily the optimum for all runners. Research (3) has shown that stride length correlates negatively with leg length and body mass, so taller and heavier runners will have a lower cadence than shorter and lighter runners.
So try running at a slightly higher cadence than you usually would, but do this in training, it's not something to try out first on race day.
Stride length
In all forms of running, this is the generally the greatest determiner of speed and so race times.
Research (4) on whether body dimensions influence stride length for endurance runners, as per cadence, found little evidence for that, so stride length is an outcome of running technique and training, not build.
This graph from the early work by Cavanagh and Kram is consistent with other research done later with more data points, e.g. Weyand, 2000 (Ref 5).
So how do we increase stride length? Now the answer is simple but counter-intuitive! The tendency would be to extend the leg further out in front of you, but this would actually have the opposite effect. Landing the foot in front of you causes greater braking forces to be overcome, so slowing you down. For those interested as to why, see the really good explanation in Force 2 (Ref 6).
To have a longer stride requires us to think about what a stride is. When we run we spend some time on the ground and some time in the air. The combination lead to stride frequency. So if we want to travel further each step we need to increase how far we travel in the air (hopefully our foot is stationary on the ground!).
Now we could turn our running technique into bounds but what happens is that to do that we would spend more time on the ground, so reducing our stride frequency. What we need to do is two things: 1) we need to spend more time in the air at the expense of time on the ground and 2) we need to generate more force so we "fly" through the air further each step. This is why running technique is so important, as this is not trivial.
"More force in shorter ground contact time" is not a good cue to runners, but "light feet", "quick feet" or "quiet feet" are, as they imply shorter contact time, as a longer foot contact tends to be louder. A great session to help develop this would be one of Bob's downhill running sessions at Tinglesfield, as he focuses on quiet feet, and the downward force is increased due to the extra energy we gain from the gravitational potential energy of going downhill.
With greater force into the ground and shorter contact time will maintain stride frequency, but increases the distance travelled per stride, and so increases your speed. One thing to consider here, is that we are increasing the force into the ground and travelling further in the air. This requires a greater range of movement from the hips predominantly. This is why drills, such as high knees, butt kicks and lunges, are important. If you look at runners running at different speeds you can see this quite clearly : jogging along we hardly get our heel as high as our knee but as we speed up the foot gets higher. Watch Mo Farah, or any other great endurance athletes, at speed. There's good reason why the foot gets higher - it's to reduce the effort (energy) in getting our trailing leg back in front of us. Bringing the knee through higher aids this as well.
Running with a faster longer stride also means that there is more force to absorb on landing. Typically, we absorb 2-3x bodyweight force when running. This energy has to go somewhere. Ideally we want to absorb it in a way we can get it back into our running, the so-called "stretch reflex". If we don't get it back our body has to absorb it elsewhere and this can lead to tipping of the hips, extra upper body rotation, being too bouncy. All of these will lead to injury eventually. So how do we get it back?
The Achilles is the thickest and strongest tendon in the body for good reason. Each Achilles has to manage both contractions and stretching every we time we move, and generally with all our bodyweight. An interesting aspect of tendons compared to muscles is how fast they can react. As an example here's a fun activity for you to try! I would like you to click your fingers to make a loud snap. Now take away your thumb, can you still make a loud snap? No - because your muscles don’t act fast enough. But with the thumb, you can preload the muscle-tendon unit and it’s the tendons that determine how fast your finger moves to make the snap as you click your fingers.
So tendons are critically important to running technique. As we go faster, guess what, they become more important. We all know about and fear tearing our Achilles tendon. We definitely don't want to do that, so we need to strengthen it through calf, especially soleus muscle strengthening exercises, e.g. calf raises, standing on one foot's toes for a few minutes is a great isometric. Other useful tendon exercises are plyometrics, e.g jumps, especially off an object onto the floor. If considering that, start very low and easy.
One important aspect of tendons to consider is how much energy they can absorb. Let's consider elastic bands which are a good analogy. Obviously, a thicker band can absorb more energy, hence why we strengthen our Achilles. But also a longer band can absorb more energy than a shorter band of the same thickness, so stretching our Achilles, mainly through exercises that dorsiflex the ankle, are great.
NB most of the exercises mentioned above will aid the body more than just for the aspects highlighted, i.e. stronger calf muscles will aid our ability to run uphills and on uneven surfaces.
Putting it all together
Now you will recognise that adopting this strategy will make you faster, but also probably tire quicker, so we need to mitigate that issue with some speed sessions, such as tempo and intervals to enable the body to develop the strength (muscles and tendons) and fitness, as measured by cardio vascular measures, such as "VO2 max" - see Ref 7 for a really good explanation on that. That way we will be able to maintain our increased capability to run at speed.
Running with good technique will reduce risk of injury and enable you to run more efficiently and so faster generally. It's worth recognising that any changes to technique, even improvements, take a little while to bed in, so it's worth including some strides into your runs; near the end is better than the beginning (I'll let you work out for yourselves why!). Strides are run at less than race pace, so they feel "easy" and the focus is purely on technique.
Summary
run with a slightly higher cadence (5spm more) in training
run downhill with "quiet feet"
do speed sessions
do exercises to strengthen and lengthen your Achilles
remember to have fun doing it
I hope this helps
Dorian
References
Cornelis J de Ruiter 1 , Peter W L Verdijk, Wout Werker, Menno J Zuidema, Arnold de Haan, "Stride frequency in relation to oxygen consumption in experienced and novice runners", from : Eur J Sport Sci. 2014;14(3):251-8.
Amy G. Schubert, PT, DPT, Jenny Kempf, MPT, CSCS, and Bryan C. Heiderscheit, PT, PhD, "Influence of Stride Frequency and Length on Running Mechanics: A Systematic Review", from American Orthopaedic Society for Sports Medicine's "Sports Health: A Multidisciplinary Approach" Volume 6 Issue 3
B.T. Van Oeveren, C.J. De Ruiter, M.J.M. Hoozemans, P.J. Beek & J.H. Van Dieën "Inter-individual differences in stride frequencies during running obtained from wearable data" from Journal of Sports Sciences ,Volume 37, 2019 - Issue 17
Peter Cavanagh (Washington Uni) & Rodger Kram (Colorado Uni), “Stride length in distance running: velocity, body dimensions, and added mass effects”, from Medicine and Science in Sports and Exercise · September 1989
Peter G. Weyand, Deborah B. Sternlight, Matthew J. Bellizzi, and Seth Wright, "Faster top running speeds are achieved with greater ground forces not more rapid leg movements" from Journal of Applied Physiology, Vol. 89, No. 5
Dan Cleather & Jon Goodwin, "The Biomechanics of Sprinting : Force 2", KMA Press 14/4/23
Jack Daniels, "Daniels' Running Formula", Edition 2, Human Kinetics 2005