A Runner’s Arm swing affects your cadence and heart rate

The other day I was riding my bike through the park and I noticed there were a lot of runners running with poor form.  The easiest thing to notice when passing by quickly on the bike is how people hold and swing their arms.  It appeared to me that they were working unnecessarily hard.  I began to wonder how something as simple as arm swing could affect someone’s pace, run cadence, and heart rate.  I suspected that with running with your arms low, at waist level would decrease run cadence due to making larger arm swings.  The larger arm swings would require more energy, thus raising their heart rate.  Those two things would decrease the pace they could sustain at any given heart rate.  I decided to test this out on our treadmill.  I set the treadmill at 9 MPH and a 1% incline to simulate out door running.  Below is the video of the test and screen shots of the data within the video.  If you don’t have time to watch this short video, the findings are below the video:

  1. 9 MPH at 1% grade with arms at correct height (about chest level at a 90 degree bend at the elbow) = 150 BPM and a cadence of 180-185
  2. 9 MPH at 1% grade with arms at waist = 155-156 BPM and a cadence of 165-170
  3. I could sustain the same HR of 155-156 BPM with the correct arm bend and swing at 9.2 MPH.  That is about 10 seconds per faster per mile.


  Correct run form (and arm position) from my triathlon days back in 2015.

This arm bend angle is too big. Running with an arm bend a this angle will decrease cadence, increase heart rate, and slow you down.



How to Quantitatively Recognize Increased Fitness

Here at Progressive Endurance, I am all about measuring fitness gains and adjusting training zones accordingly for each athlete to get the most out of each individual.  If you were to read any number of fitness articles on testing zones, they will say to retest every 6 to 8 weeks.  I typically do 8 week cycles because it allows for two 4 week cycles of 3 weeks of building and 1 recovery week.  However, there are times when I would retest an athlete sooner than 8 week cycle based on some key numbers that every athlete should monitor if they use Training Peaks as the workout journal/data base.

Before you trust any numbers that auto populate in Training Peaks after a workout, you must be sure to have your threshold pace, HR, or power set correctly.  To do so, go to your settings and put the correct numbers in the box

The 2 numbers/terms that you need to monitor when looking at when your zones need to be changed for the run and the bike are you TSS and IF.

TSS – Training Stress Score.  This directly related your threshold that you have set in Training Peaks.  This number tells you how difficult a workout was on your body.  If your threshold is set correctly, it is impossible to score over 100 TSS in one hour.  Riding or running at threshold for one hour is 100 TSS.  Riding or running at 90% of threshold for one hour comes out to 80 TSS.  80% of threshold for one hour give 64 TSS.  50% of threshold for one hour only gives you 25 TSS.  As you can see, the percentage of threshold and the amount of TSS is not linear, its exponential either.

IF – Intensity factor.  This is essentially the percentage of threshold that you held for all, or part of the workout depending on how much of the workout you are looking at.

So now that we got the basic understanding of TSS and IF out of the way, I want to use a workout of an athlete I’m coaching this year, Kira Williams.  This was a run test that was prescribed 8 weeks after the last test.  But, for the sake of the discussion, let’s pretend that this was just a normal track workout with no static rest.

So the first thing I want you to see is the bottom middle of the picture.  Kira ran the entire workout (warm up, main set, and cool down) at 102% of threshold.  That alone doesn’t mean anything since the length of the workout is under an hour.  I suppose someone could manage to go 2% over threshold for almost 52 minutes… but I bet it would be close to impossible.  At this point, an eye brow has risen and more digging is needed to determine if her pace zones need adjusting.

The most obvious thing is the right above the IF (also located in big font at the top center of the picture) is the TSS.  Remember how i said someone can not score more than 100 TSS in an hour if the threshold is set up correctly.  Well, it is also impossible to score 100 TSS in less than an hour if your threshold is set up correctly.  Kira managed to hit 100 TSS in just 52 minutes.  I would bet if she continued to keep running, even at a comfortable pace for 8 more minutes, that number would be between 110 and 115 TSS.

At this point, as a coach, I know this athlete has made fitness gains and if we are only 3 to 4 weeks into the 8 week cycle, I would consider retesting early.  I don’t do this often, because most of the time zones don’t change that quickly.  However, I have done it before.

**Swim TSS is a little trickier to recognize increased fitness because of how Training Peaks measures time in the pool swimming.  In short, it doesn’t count the time resting on the wall in your total swim time.  So you could 60 minutes of swimming with lots of rest after each distance you swam over threshold and it would populate as 60 minutes of workout time in TrainingPeaks instead of the 90 minutes (or however long it took you) to get that 60 minutes of actual swimming.




Why Cadence Matters for Triathletes

Over the 4 years I have been coaching, it has surprised me how many triathletes find their preferred cadence in the 70’s and 80’s. Some people are able to adapt quickly to the suggestion of cadence in the 90’s, others have tried and made progress much slower, while others seemed to ignore the advice. Cadence seems like such an insignificant thing to focus on when there are so many other “more important” things to look at with cycling data, such as watts, heart rate, variable index, intensity factor, etc. Just like not all calories (energy) in our food are created equally, the watts (energy) we create while riding the bike are not created equally. For example, you can push 1000 watts in a 53:11 gearing as low cadence and high force pedals. Or, you can create 1000 watts at your 39:28 gearing spinning extremely fast with low force on the pedals

This is where a tool known as Quadrant Analysis comes in extremely handy. Unless I am mistaken, TrainingPeaks used to have this on their on-line software up until a couple years ago when the whole software got a face lift. I haven’t been able to find it on there anymore, so if someone reading this knows where it is buried in the program, please let me know.

When cycling there are basically 2 variables that control the wattage that shows up on your cycling computer. Those variables are force (in Newtons) and velocity/ (cadence). Depending on how much force, relative to your functional threshold power (FTP), and how fast you are spinning those pedals in around in a circle will determine which quadrant that second of power will fall in.

Quadrant #1 – High cadence and high force: Think of this on the extreme end of sprinting your brains out. Your force will be maximal effort and your cadence will be high because you are likely running out of gears to shift into. However, this could include suprathreshold efforts to bridge a gap, pass another triathlete within the time alloted by either USAT or IronMan.

Quadrant #2 – Low cadence and high force: A watt usually falls into this quadrant when climbing a really steep hill and you don’t have an easier gear to get into. Most commonly probably found in MTB races and cyclocross, but some triathletes that pedal at a chronically low cadence no matter their effort will fall into the quadrant as well.

Quadrant #3 – Low cadence and low force – watts created in this quadrant typically occur during recovery rides or social rides. These can also occur when soft pedaling down a hill or in a group when the group isn’t attacking

Quadrant #4- low force and high cadence – watts created in this quadrant typically occur during accelerations when done correctly. Just like when a car accelerates, the RPMs go high and then gears shift. Cycling accelerations should be the same, bringing the cadences up over 100 or 110 RPM before shifting gears.

So what does all this fancy stuff mean for the triathlete? Remember how I said earlier that not all watts are created equally and used the example of how to produce 1000 watts? Well, the reason is because of the type of muscle fibers recruited to create any amount of power. People are born with slow twitch (type 1) and fast twitch (type 2) muscles. Fast twitch muscles are recruited more the second quadrant (high force, low cadence) and more slow twitch muscles are recruited in the fourth quadrant (low force, high cadence). This is extremely important to the triathlete out there trying to race well. The more fast twitch muscles that are recruited to create the same wattage, the more glycogen that is burned in comparison of fat to fuel the muscles. This saves you valuable energy for the run (along with maintaining a smooth power output, or variable index, over the duration of the bike course). Reducing the amount of glycogen burned on the bike allows you to use more on the run. The average person can only store about 2000 calories of glycogen in their muscles. In comparison, even the leanest athletes can store over 10,000 calories in fat.

Now, I’m not saying that you should 100% of the time use low force and high cadence for your triathlon training. What I am saying is to be mindful of how much time you spend mashing gears, or pushing harder than you need to complete a pass. These small efforts in a triathlon race can really wreak havoc later in the race, especially if it is a longer race such as a 70.3 or 140.6.

Below are quadrant analsys from both an athlete that paced well in their Ironman race and another that didn’t from the book “Training and Racing with a Power Meter” by Hunter Allen Andrew Coogan.

Notice how the majority of the dots are in quadrants 3 and 4. this means the athlete is burning more fat than glycogen and set themselves up for a good run off the bike

Notice how the dots are scattered all over the place with a fair amount of them in quadrant 2 – low cadence and high force. This athlete burned a lot of glycogen and probably didnt run well off the bike