Blog By Dr John Cronin

Two passions of mine are getting athletes faster and wearable resistance. In this article I combine both to discuss how we can train step frequency to improve speed in runners and sprinters.

Determinants of Speed

So you want to get faster getting from A to B, whether it be a 100 m, 1000 m or 10,000 m. Well it is simple – mechanically speaking, as all you need to do is increase your step frequency or your step length as these are the two primary mechanical determinants of speed for getting between the start and finish faster (see Figure 1). If you can increase your step length by a cm or two or more, and maintain your frequency then you’ll get to the finish quicker. Conversely, if you get your feet down more often to apply force against the ground and maintain step length, that finish line will appear quicker. If you can do both then you are going to be a real winner and smash your PBs.

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Figure 1: Primary mechanical determinants of speed are step length and step frequency


Some of you might be saying – “tell me something new.” Others of you, will be asking give me the low down on how I can improve these two determinants of speed. Those of you who want to get the maximum out of your time may be saying, “what should I do to get the best bang for buck? What should I concentrate on?” So let’s talk about how we do this with smart training, rather than smart shoes!

Before I answer the above questions lets back up the bus and let’s have a look at the interaction of these two components. As you can see from the diagram below, increasing speed requires both an increase in step frequency and step length, and your maximal speed will be an optimization of both these qualities. However, what you have most likely seen in the graph also is that as we increase our velocity, step length begins plateauing and step frequency becomes more important. This is confirmed by researchers (1) that have shown high correlations between maximal 100 m speed and step frequency (r = 0.897), whereas step length would seem less important (r = 0.363).

Figure 2: Interaction of step length and step frequency for increases in running velocity

Wearable Resistance and Step Frequency

So where is all this leading. Well I want to discuss one way in which you can increase step frequency. This is not to say I don’t think step length is important, but I will address this another day. Also I am the first to acknowledge that there are a number of ways to increase step frequency, from technical cueing to specific strength and power drills/training. However, one of the easiest ways (smart training) to improve step frequency is to use a pair of wearable resistance (WR) calf sleeves or shorts and run. It’s as simple as that. 

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Figure 3: Wearable resistance loaded runner


So How Does It Work? 

Well what has been shown again and again in the research is that as soon as we attach loads as little as 1-2% of body mass to the thigh or the calf, we see a small but significant reduction in swing velocity of the legs and therefore step frequency, without noticeable changes in step length. So in short, limb loading provides a step frequency overload.

Some of you may be asking, “how is a reduction in step frequency a good thing?” Well you need to remember WR is movement specific strength training. If you are wearing the shorts the muscles across the hip are working harder, and if you are wearing the calf sleeves the muscles across the hip and knees will be overloaded. So when you are running limb loaded, you are strengthening the musculature specific to running. The trick then is to try and match or equal previous lap or distance paces, loaded. Then at some stage run unloaded, and I am pretty sure you will smash your previous PBs, and the likely reason for this improvement is an increase in step frequency via increased strength at the hips and knees depending on what garment you are wearing.

 Give it a go, experience it for yourself!


(1) Morin et al. (2012). Mechanical determinants of 100-m sprint running performance. European Journal of Applied Physiology. 112, pages3921–3930


“The LILA® EXOGEN® product has made me a stronger and a more balanced Triathlete. It directly helped me improve my PB by 30 minutes which directly helped me go sub 10 hours and win IRONMAN® AsiaPAC!”

Todd Gilmore
IRONMAN® 70.3 Asia Pacific Age Group Champion
IRONMAN® Certified Triathlon Coach



Two passions of mine are getting athletes faster and wearable resistance. In this article I combine both to discuss how we can train step frequency to improve speed in runners and sprinters.

johncronin strengthandconditioning athleticperformance wearableresistance speed faster runners sprint

Dr. John Cronin is recognized internationally as one of the world’s leading sports scientists. He is a Professor of Strength and Conditioning at Auckland University of Technology’s Sports Performance Research Institute New Zealand. As our Head of Research, Dr. Cronin oversees all EXOGEN® wearable resistance research globally.

The Sports Performance Research Institute New Zealand (SPRINZ) is New Zealand’s number one rated sports research institute with a growing global reputation. SPRINZ is a group of dynamic and innovative researchers producing applied research in improving human health, sports performance and long-term athletic development.