by Dr. John Cronin


So you want to get faster getting from A to B, whether it be a 100 m, 1000 m or 10,000 m. 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 determinants of speed or getting between the start and finish faster.  Just to spell it out, 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 (Personal Best).


Well, the smarties amongst you are probably saying – “tell me something new.”  Others will be asking to give the low down on how they can improve these two determinants of speed.  The time poor amongst you will 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 just smart shoes!


Before I answer the above questions let’s 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 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 researchers1 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).

So where is all this leading?  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 put a pair of wearable resistance (WR) shorts or calf sleeves on and run.  It is simple as that.

So how does it work?  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 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 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 unload and I am pretty sure you will smash your previous PBs, and the likely reason for this improvement is an increase in step frequency.

1 Morin et al. 2012. Mechanical determinants of 100-m sprint running performance


“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



Dr. John Cronin is recognised 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.