Guest Post by Lindsey Scherf, Lumo Run sponsored athlete and member of our product team.
Let me start my intro with a brief mention of what cadence is and some of the terminology that is used when talking about it. Cadence is the number of steps you take per minute while running. The term step is sometimes confused with or used interchangeably with the term stride. A stride is considered 2 steps or the number of times the same foot (counting just the right foot) strikes the ground—so 90 strides per minute = 180 steps per minute.
I began my research on cadence with hopes of discovering magical cadence numbers that maximize running performances at various speeds, distances, or percentages of maximum effort for racing. However, I ended up through my exploration of the utility of cadence, discovering that altering your self selected cadence may ultimately play an even greater role in enhancing your recovery from hard running days.
How fast we run is a combination of stride length and stride frequency. I discovered elite runners seem to go against logical assumptions regarding their self selected cadence when running at race pace. For example one might assume that taller runners would have longer strides and slower cadences at race speeds, however this is not what studies have found. A case study by Enomoto et al. (2008) examined the cadences and stride lengths of the top 3 finishing men at the 2007 World Championship 10,000 meter finals. The study found that until the final lap of the race the race’s winner, who was the shortest, had the lowest cadence and longest stride length. Then going into the final lap this same runner picked up his cadence the most significantly while maintaining his stride length. The 2nd place runner slightly increased his cadence and significantly increased his stride length. And the 3rd place runner slightly decreased his cadence while significantly increasing his stride length. Not a finding that enables you to make precise assumptions around cadence numbers that may universally optimize racing results for all runner.
I next sought to explore the correlation between cadence and injury and found the body of research suggests that there is no correlation between wildly different cadences at various speeds and injury rates. However there is a lower end number of roughly 167 that you want to train yourself to stay above to stay above to avoid a heightened vulnerability to injury which was found in recent study by Heiderscheit et al. (2016). So once you are above 167, whether you are running at 170 or 185, there seems to be no difference in your susceptibility to injury.
So now let’s move on to what I found most intriguing from my analysis of the cadence research. If a runner is running at a constant speed with a lower cadence that the runner needs to generate more muscular power to have a longer stride to keep pace. If that same runner were to shorten their stride and quicken their cadence, the runner would be relying less on generating muscle power and calling more on their neuromuscular system to activate a quicker cadence for maintaining pace. The body of research and my knowledge of physiology leads me to suggest that on a day when your muscles are feeling sore you might benefit from letting your over taxed muscle fibers recover by running with a quicker cadence and reduced stride length combo that allows you to maintain pace with reduced muscle power output.
On the flip side if your muscles aren’t feeling sore but you’re feeling “sluggish”, such as the day after you marathon training long run, you likely have impaired low frequency neuromuscular function. The tiredness you feel in the absence of muscle soreness is likely due to low frequency neuromuscular fatigue. There is also something known as high frequency muscular fatigue but this is something that is unlikely to be a significant source of fatigue in a distance runs that exceed 10 minutes in duration. Furthermore high frequency neuromuscular fatigue is typically something you fully recover in a matter of minutes.
Low frequency fatigue seems to occur when then there is a prolonged reduction in the release of extracellular calcium ions. Studies show that low frequency neuromuscular fatigue inducing levels of extracellular calcium ions seems to be highly correlated with being in a state of glycogen depletion. After a very long glycogen depleting bout of exercise, like racing a marathon, it can take a runner a week or more on a high carbohydrate diet to fully replenish their depleted muscle glycogen stores. While a well trained runner can replenish their glycogen stores fully after a moderate intensity 6 mile run in a window of 4-6 hours given adequate amounts of carbohydrate intake occur post exercise. Given this information, I’d like to suggest that as a runner you may benefit from paying attention to the source of your fatigue to discern which system is causing your fatigue; muscular? Or low frequency neuromuscular?
Are you feeling sore in your muscles after doing hill repeats the day before?—Possible training prescription: quicken your cadence. Are you feeling sluggish from your long run but your muscles don’t feel sore?—Possible training prescription: eat carbs and let your body self select a comfortable at or above 167 and keep the run short. Are you feeling both sore in your muscles and sluggish?—Consider taking an off day, get some extra sleep and eat well; your body likely needs to heal and doing anything more than a short easy run might set back the progression of your fitness because your body is telling you it’s tired from both high intensity and long duration stimuli.
I decided to test out hypothesis. So I hit the trail intentionally increasing my self selected cadence on my post hard workout and post weight lifting days. On my post workout recovery run days I typically run with a self selected cadence of 173-176 steps per minute which I was able to identify by running in my Lumo Run capris.
I needed to find a helpful (and non irritating) way to help me up my cadence. I found running to a metronome sound rather unpleasant so I discovered a nifty app called “Spring” which alters the cadence beat of music I actually like (it’s essentially pandora to the cadence of my choice). On my recovery run days I preset my cadence music to be a beat between 180-190 steps per minute without altering my running effort on my easy days. Low and behold I found that I felt subjectively better during my recovery run days (feeling best at a cadence of 184-187). And I also felt itching to do my next hard workout earlier than I used to before this cadence upping intervention. This was an anecdotal study of one, but I felt the positive effects strongly and I thinks it’s something other runners may want to give some serious consideration to testing out in their training regimens.
If you want to attempt upping your cadence on your recovery run days I would suggest starting with an increase of 5 steps per minute and see how you feel and repeat this 3 times. If you’re continuing to have good results, try increasing another 5 steps per minute and pay attention to how your body feels, because change, even good change, can increase your susceptibility to injury while your body adapts to the new stimuli.
- Enomoto, Y., Kadono, H., Suzuki, Y., Chiba, T., Koyama, K., Biomechanical analysis of the medalists in the 10,000 metres at the 2007 World Championships in Athletics. New Studies In Athletics. No. 3 pp 61-66.
- Heiderscheit, B., Luedke, L., Rauh, M., Williams D., Influence of Step Rate on Shin Injury and Anterior Knee Pain in High School Runners, Med Sci Sports Exer, Jan 26, 2016.