Run Cadence vs. Velocity. n = 1
There are many discussions on this forum in which "optimal run cadence" is brought up, and by and large, the recommendation is that most of us should shoot for the low 90s but are in the upper 80s.
A point I've tried to make many times is that the cadence varies with velocity for everyone, so quoting your cadence is fairly closely related to where you are in your own velocity curve. It's self evident that run velocity = (run cadence) * (distance per stride). What's not known by most people (including me) is how much of the velocity increase comes from cadence vs distance per stride.
Thus, I decided to analyze some of my own recent data. I grabbed all my runs on which I had used my footpod in the year 2012. This amounted to around 16 runs, most in the 45-75 minute range. (I leave my shoes with the footpod at the gym, so if I run outside from home, I don't have the footpod.) Most of the runs were on an indoor track, but a few were outside. They had all kinds of runs: strides, VO2 intervals, threshold intervals, and steadier runs.
Below is the result:
After looking at it, it's immediately obvious there are two ranges, and they correspond roughly to running (red, 12 min/mi and faster) and walking (blue, 15 min/mi and slower). I chopped out the transition area (5-6 minute miles) and left that in green. I found it absolutely remarkable how linear the data look in those two zones, so I did simple fits to them and came up with the following:
- Run: Cadence = 68.1 + 2.60 V
- Walk: Cadence = 23.1 + 10.8 V
Considering a factor of two in velocity in each range (2-4 mph walking and 6-12 mph running), you get the following:
- Run cadence increases by factor of 1.186 (99.3 vs 83.7) while distance per stride increases by a factor of 1.68 (10.6 ft vs 6.3 ft)
- Walk cadence increases by factor of 1.483 (66.3 vs 44.7) while stride distance increases by factor of 1.348 (5.3 vs 3.9 ft)
So, now I can say with confidence that I am a 90-92 cadence runner in the MP to TP range (92.1 at 6:30 miles).
With this post I am NOT saying you shouldn't try to increase your cadence. I did that a few years ago, from mid 80s at threshold to now 92, along with changing my stride. Yes, I got faster, but the curve has shifted, because 85 cadence is now about 9:15 miles and I was certainly faster than that when I started.
I would be very curious to know if anyone else has looked at data like this or thought about it much. I am afraid I didn't do a lit search because I thought it was more fun and self-instructive to spend the time on my own data first. :-)
But anyway...with this here... what are your thoughts? My conclusion remains similar to what I thought before: if you're going to talk about cadence, you should do it in relationship to what pace you are running. Probably MP-TP pace is a narrow enough range for most people (and the cadence is variable enough) that this is the lesson...quote your cadence in that range... because that's what's race-relevant for triathletes and it's also a way to minimize this unnecessary variable of stride length from the equation.
Comments
In all seriousness, that does match my expectations, as I know my cadence is higher when I'm at TP - 5k pace, and I even notice myself changing going from EP to MP, albeit slightly. It does reinforce two things in my head
1) the notion that 'the best runners' have the same cadence whether running easy or hard may be more related to how compressed their zones are (Vdot of just 61 has an EP of 7:15, MP of 6:07, and it gets more compressed from there). This is likely very bad advice for most of us who have a much bigger delta in their zones.
2) in your example above, the majority of the difference does come from stride length change (68% vs.19%), which does make sense.
Thanks, now I'm going to waste a bunch of time in excel tonight... :-)
For the record, 1.68 x 1.19 = 2.00. But I'm not sure how one goes about saying "X% of your speed increase comes from stride length"...
I was thinking about pace compression as I was jogging along at about EP+30 during a warmup, and trying to run at 90rpm. For me, it's so awkward, it's almost comical. My HR goes up by 5-10 beats just to keep that cadence up at such a short stride. Can't be the right thing to do...
Great observational science. I have no data other than my own counting of steps on the treadmill, which i often do on the days I use the TM for intercal runs. E.g., today, i was at 89-90 while warming up at about8:30/ mile. Then during 6:53 intervals, I was at 94-5.
Is there any lesson here for racing? During an IM, we are going slower, but I dont think that means we can let cadence drop. During my last IM, i made a conscious effort to keep my cadence at 90-92, despite 9:30-45 miles. And, going up hills in races,despite the drop in speed, should also be done with no drop in cadence IMO.
So, if the natural tendancy during triathlons, when run speed is decoupled from usual training RPE at the same pace, would be to run at too slow a cadence for best efficiency, then maybe there needs to be attention paid to keeping cadence high even at slow speeds in training. Which of course requires a shorter stride.
Yeah - this is one of those things where comparing the elites to amateurs is potentially not a great comparison; similar to our arguments on ROI as it relates to time in training.
The fastest guys can't be the benchmark for someone with a vDot of 45...that just isn't realistic.
I wonder if there is a way to calculate height (or leg length) with a vDot to yield 'ideal/optimal' cadence? I wouldn't be the one to try to come up with that...but it might be doable given the comments here...what do you think?
I woke up in the middle of the night with a thought about this - let's see if it makes sense in the light of day. I see Ironman success resulting from accretion of a lot of details which must all mesh together - training, nutrition, recovery, race day strategy & pacing, all focused on being able to run well after 7-10 hours of swimming/biking on race day.
The observational data talked about here implies that our natural tendancy would be to run with a "slower" cadence on race day, as we are going slower than almost all of our training paces. Using myself as an example (racing VDOT of 46 last fall), I'd like to present an argument for concerted effort to race the IM marathon at a cadence in the low 90s. My example would by useful for many people, whose VDOT fall in the range of 43-50, which probably includes many faster women, and the majority of the AG men here at EN.
Last fall, I developed severe Plantar fasciitis six weeks before IM AZ, and after not running for a week, started running again solely on flat ground, and never faster than my LRP, which had slowed to about 9:15 as a result of the injury. Since I wanted to run the race @ about 9:15-9:30, and since trying to run at even that slow a pace I would get pain in my foot, I started to take shorter strides. To keep my pace up, I had to increase my cadence. Long story short, on race day I managed to run 4:14 (10 minutes sloer than my previous effort there), with short quick little steps the whole way.
So this got me to thinking in my sleep last night, how much time could one improve, if he simply increased his cadence during the IM marathon by 5%. This would be the same as increasing from 87 to 92. Stride length stays the same, just quicker turnover. Well, at my pace of 9:30, this would be 30 seconds a mile, or an improvement of 13 minutes for the marathon - a pretty big deal, IMO.
It almost seems like free speed. Like Rich, I've spent a lot of time looking at runners on race day. I notice that many of them are "plodding" - running with a slow cadence, as we would expect if their pace is slower than what they train at normally. Simply by increasing the cadence from 87 to 92, it looks like one could improve his chances of meeting his time goals.
There are a couple of things which could help one prepare for this. First, every time one does a brick, the first 10-20 minutes should vbe spent paying attention to cadence - either counting steps or using a meter of some sort - and working to get that over 90. Second, reducing the weight at the end of the lever arm by racing on lighter shoes would also help. Personally, I race in 4 oz Wave Universe from Mizuno, but even dropping down from 12 oz to 8 oz would be a 30% reduction in the weight one has tro move forward wi180 times a minute.
One more middle of the night thought: Many coaches will say, "To go faster, increase your stride length." Well, of course that's true at "high" (5K, 10K) speeds, when one's cadence is presumably max'd out.. But if the correlation described above of slower speed = slower cadence at usual training paces, and our IM marathon is done SLOWER than normal training pace, AND (most important here), THE ENERGY COST OF INCREASING STRIDE LENGTH IS GREATER THAN THE ENERGY COST OF INCREASING CADENCE, then it seems like the best thing for race preparation and performance is to have a race day cadence similar to what one would use in a 5 or 10 K race.
Thus our coach notes that his run cadence is always 92-3, irrespective of speed.
Now, to amplify the idea in CAPS above. Though I have no physiologic data to prove this, it should be obvious. Running is simply a series of connected hops. Try this: hop and down ten times. Then swing your leg back and forth ten times. Which makes you more tired? Also, the data above demonstrate this, as well as the received wisdom quoted above: want to run faster? Increase your cadence; it's a lot easier than trying to increase your stride length.
Now, read that last sentance again. On race day, in an IM marathon, we are running slow. Our natural tendancy will be to run at a slow cadence. If we want to run faster on those "tired legs", and keep it up for 4 hours or more, we should focus FIRST on getting the cadence up to a racing rate of 92-95, and THEN on increasing stride length - just the opposite of what a runner is usally told.
And, like I said, try lighter shoes - it makes increasing cadence that much easier.
stride length: comes from muscle force (more force to stabilize against ground reaction force, but let's not get too technical!) in the quads, glutes (min/med/max), and hamstrings, along with TFL, hip flexors, and abdominals
cadence: comes mostly from stretch reflex, hip flexors, and abdominals
What's the biggest impact here? With tired legs, asking for 3.5+ hours of more muscle force after biking 112 seems like a dangerous place to go, where working on cadence, relying on stretch reflex (from good leg swing) and the hip flexors (which are almost entirely slow twitch and designed to go all day), seems to be the smart money.
The other day, I watched the broadcast of the 2008 IMLP, where Cait Snow ran down Hillary Biscay and Kim Loeffler. Her cadence was easily 5-10 bpm higher than each, and she made passing them look easy. She made up almost 1 minute per mile on Hillary...
That pretty much nails my perspective on it.
I haven't been using my foot pod but I think I'll make a point of it because I'm curious to see how my data shakes out when plotted like William.
I agree from just an intuitive/experiential point of view with what I think is Al's point, i.e., that if there's one thing to focus on when you're really beat and considering "the shuffle" or how to cope with that otherwise, it seems like keeping the frequency ought to be the far more effective way of keeping moving at a good pace. I wish I had something more substantial to add!
The pace compression mentioned earlier goes a long way in explaining why some better runners think their cadence is constant. I bet it wouldn't be if they really plotted it out.
Cadence is constant in well trained efficient distant runners ( ie. Ryan Hall, Ethiopians, etc.). Cadence is constant but not always the same between runners (ie. Marinda Carfrea - longer stride v Chrissie Wellington - shorter stride length) I believe that most "endurance"/distance runners would tell you that efficent speed/running is more a function of stride length not cadence....you wanna run faster take longer strides...the problem is that most people don't have the range of motion (necessitating higher cadence lest we fall) and/or "increase stride" by reaching out in front (and braking) rather than elongating the push off and stride behind the body.
Maybe so, but when was the last time Ryan Hall ran a 9:00 mile? If he did, would his cadence still be the same? doubtful...
Okay..yes... Well I must apologize that I was speaking generally and did not read through the entire thread.
However; I'm not sure I agree with the comments regarding the relative "cost" of Stride Length and Cadence....( I would say that Hillarys cadence is a consequence of her stride lenght not the other way around...see Mirinda v Chrissie)
as a thought consider (in your mind)..that from a standing start take two giant steps by simply lifting one leg partially extending one foot Rearward as far as you can...falling forward (little energy expended here) and landing and rolling over your front foot and extending that back wards (ie. no reaching out with your front leg)...gravity is doing much of the work. Mark were you finish
now go back to the same spot and cover the distance using twice as many steps..ie. short unnatural choppy strides...aren't you using more energy? and having a tendency to move vertically?...seems to me yes.
So...to Al's point...if you keep stride length the same and increase cadence you will go faster...that is straight forward...just as if you increased stride lenght and kept cadence the same...my fundemental point is that ...stride lenght is the more running economical way to get there.
This, of course, may be Bass Ackwards...but it is how I have always thought of it...and I'm not being argumentative...just offering an alternative thought line. (and I actually believe there is no correct answer here...the idea is to optimize both relative to each other for each individuals build and natural tendencies...again Mirinda v. Chrissie )
Exactly Joel...except I'm not convinced it is a function of force...it is effortless..or perhaps more correctly...force directed rearward..think of swimming...do you move your arms faster to swim faster? and the stroke is most effective..and less energy wasting when directed rearward..its almost effortless
.....I think what I am trying to say is that in execution...people tend to increase cadence by becoming choppy..ie. applying force vertically and that that is a greater strain than leg extension...
I know/fear I'm not being clear in what I'm trying to convey....but also agree with you that when people "lengthen" their stride ...they tend to reach out in front...also bad.
Also...I think there is an interesting discussion in the book IronWar...about Entropy in running...and how Entropy decreases as we tire and try to control the fluid nature of our stride...part of that is what I'm trying to capture....
By the way; this is an interesting discussion. Thanks.
Trying to be crystal clear at the risk of being repetitive ... I am speaking ONLY about how to race an IM marathon. I've been in the middle of a couple thousand people doing just this at least 20 times. And my observation is the average Joes who are trying to run 4-4:30 for the IM marathon are much more often than not "shuffling" or "plodding", with a slow cadence (probably in the mid 80s). Without risking the added energy cost of lengthening their stride, most of them could shave 10-20 minutes off their run split simply by turning the feet over at about 92-3 times a minute.
During training, shorter tris, stand alone running races ... sure, longer strides = faster times. But that strategy won't work in an IM for most of us. Those who try it are probably going to end up with cramps, asking the lower extremity muscles to work past their capacity 8 hours into the day.
This article on competitor.com talks about running (not in tri, but stand alone):
running.competitor.com/2012/03/trai...akes_48731
Al - I understand your point now...but believe this applies.....Certainly both Stride Length and Cadence are important...and increasing cadence if your typical cadence is too low helps tremendously....but I still stick to my point that the most economical way to get faster is by improving form,flexibility and stride lenght.
Maybe this helps (borrowed from....http://www.corerunning.com/stride_length.html)- Assuming you had a stride length of 2 meters (approx. 6 feet) and your 5k time was 14 minutes you'd take 2500 steps to complete the race.
If we keep your cadence constant but increase your stride by merely 1 cm (less than half an inch) your time would improve to 13:55.8.
All other things remaining constant, the result is that you could shave 21 seconds off your 5k time with a 2% greater stride length. For a 2 meter stride length that is a 4 cm (or 1.57 inches) increase.
I know most of us aren't running 14 minute 5km's but regardless of your speed the point is an increase in stride length will increase your performance and make you a faster runner.
How to Improve Stride Length
It might seem almost paradoxical but the first thing I teach my runners is to improve their stride rate (cadence) and not worry about their stride length.
Why? Because most recreational runners have too low a cadence. Many are below 170.
The cadence range of 170 - 180 covers all speeds from easy runs to racing. For speed workouts you may get over 180.
It's important to keep in mind that you should work on your cadence during your easier runs. Everyone's cadence naturally goes up when doing speed work but the key is to make your normal running cadence fall in that magic range.
Once the cadence is established you should then worry about stride length. To improve it, you need to add technique drills, plyometrics and speedwork into your program.
I don't mean to single you out with this, but since you're the one bringing it up... :-)
There's this popular misconception recently that there is a way to increase your stride length with low/minimal increase with muscle force. Popularized by Pose and Chi method advocates, they suggest that running can become 'like riding on a unicycle', where all you do is lean further forward, and magically, a longer stride happens without additional effort. This is flat wrong.
Running is a series of one-legged hops. Want to hop further, need to hit the ground harder. Period. The best runners in the world hit the ground with tremendous force (3x Body Weight) in order to travel at top speed. Even recreational runners trained to run with the Pose method hit the ground with 1.3x body weight. Bottom line, if you want a longer stride length, it has little-to-nothing to do with your flexibility or how far back your leg can swing (remember, you've already started to lift it off the ground just a little behind your center of mass). It has everything to do with how hard you hit the ground (and for how short a time, but that's for another discussion).
Hitting the ground hard has consequences. Every foot strike means your entire kinetic chain needs to absorb that impact, hopefully in a springy-like fashion if you've got good strength and technique, and release it. This requires significant force production from your glutes, your hamstrings, and to a lesser extent, your quads.
Increasing your cadence, on the other hand, requires increased involvement of the hamstrings at lift-off (the more your knee bends, the quicker your forward swing, and therefore cadence), involvement of the abs, and hip flexors (though mostly in an elastic return-type function, less in a force-generating type function).
So, I'll ask, which of those sounds more appealing after a 112 mile bike, staring down the barrel of a marathon? Elastic return, you can use all day. It usually feels effortless. Hitting the ground harder, well, it catches up to most people.
Now, having said all that, there is a good reason why most people feel some sort of 'effortless speed' when they adopt a Chi-style of running. If you run with a cadence in the 70's, you're probably landing with your foot way out in front of you, causing some braking, and then you have to do a lot of work mid-stance to re-accelerate the leg. By increasing your cadence and adding some forward lean, you remove that braking and re-acceleration, which feels like 'free speed'. I assure you, the game of free speed has a finite runway.
If the cadence is below 90, I think runners should strive to increase it and will achieve better results. HOWEVER, I do not think the way to do this is just to "make your legs go faster." If you work at running with good form (leaning forward, letting gravity pull you, landing on your midfoot, and not letting your feet get ahead of you center of gravity), your cadence will just get faster and should fall into this zone. If you are leaning forward and your cadence is too slow, you will just fall on your face. I worked on this over several months one summer by doing about half of my runs in 5-fingers and I've been a better runner ever since.
Now I do most of my runs with a foot pod to make sure my cadence stays in that zone and it invariably does whether I am doing speed work or at the end of a 50 mile trail run.
MIke - okay...I'm enjoying this conversation and I hope noone is taking this other than good natured interested discussion...
Understand that I do not disagree with the increased cadence side of the argument completely...I just believe...that in the context of running a distance race...the most energy efficient method to increase speed is to become more flexible and form proper..so you that you naturally increase your stride length.
Perhaps I am biased because I have horrible hip/flexiblity and know that my stride is not efficient...that I need to become more fluid and lenghten my stride...
There are many parralels to efficient swimming stroke here....think Front Quadrant running (ie. mass in front of the food strike)...foot kick (up to the back) is like the catch...getting your hand/foot in postiion to push off...and when you get it right...the force/energy is directed efficiently backward propelling you forward (and less up the leg or into the shoulders)...most people when they think about increasing cadence...do the same thing they do when they think about swimming faster....throw the arms/legs out in front more faster...(in the water hand pushing downward inefficiently braking/energy wasted..alot of force directed at the shoulders...)...in running throwing the foot out in front of the center line...again braking and putting more jolting force into the leg/knee/hips...etc.....
Thats just my experienc/thinking....I will end time in front of the court with this closing pleas for mercy.
Cheers...and lets all get faster!
After you've got proper form and stability, increases in run speed don't come from additional flexibility in order to 'lengthen your stride'. Stride length (as measured by distance from foot strike to foot strike) has much more to do with how far you travel in the air than how far back you can push your foot. In fact, the fastest runners typically have the shortest ground contact time (meaning very high impact forces over a very short time, creating an impulse to the ground). It's a misnomer to think of stride length as related to how flexible your hips are (as long as you have average flexibility, if you're overly tight in the flexors, it can limit your ability to achieve full extension).
Definitely enjoying the discussion, and hope to continue to evolve the thought process. Cadence doesn't come for free, either, and for some, it's hard to be efficient at higher cadence (ie. higher HR at the same speed with a higher cadence). Not sure if this is something that should be a goal in IM build training (ie. run some of your long runs focusing on keeping cadence up, knowing that it's part of the strategy for the race).
This is a great topic guys and very timely as my footpod arrived last Friday. I've been running w/ a metronome since late 2005 and have gradually increased it to my current 184. BPM.
I don't have much data yet but did note that when I paced a loop of a hilly marathon course last week, my avg cadence was only 89. Was expecting higher but then I averaged 7:51/mi which is about my Z1 pace of 7:54/mi. I haven't done any hard runs yet but am anxious to see what happens w/ an increase in speed. Hoping I am in 92 range in Z2/MP pace range. Will keep you posted if any unusual results occur.
And to expound on Al's observation about plodding in IM and improving time w/ increased cadence, my 1st two IM's were done prior to my cadence work and I ran both of them at 4:14 on the nose. After I worked on my run cadence, my next IM run was 3:43 off pretty much same training/fitness/execution and I've since been able to get under 3:40 wearing my metronome during the race (aggravating my fellow racers I'm sure!). Hoping to break 3:35 w/ some EN execution and running w/ a footpod set to alarm if my run cadence drops too low!
Keep on discussing this. Fascinating topic Jenks! Thx.
After IMLP I decided to work on my run form. Worked primarily on foot strike and cadence on the Treadmill. I then entered the OS in January. Currently in Week 10. I have gone from a VDOT of 44 to 49. A little more fit, a lot more efficient I feel. One of the benefits of running on a TM, IMO, is you can really focus on cadence at x pace for an extended period of time. I find that a higher cadence also gives me a better chance of landing mid strike and less heal strike. I do feel there is some diminishing returns at some point where the higher cadence is starting to burn more energy than a slightly slower cadence longer stride. Not real sure yet where that point is but suspect its somewhere in the high 90s..
Not an expert in run form, but One things for sure is that working on running form is pretty important for staying injury free and getting faster.
@Joel...YEP!
Makes people speed up or slow down! LOL