Cadence
Stride length is a bit tricky because everyone has different leg lengths, run style, weight, speed and body composition. So to create a ‘rule’ that generally applies for stride length to all runners, people talk about cadence. Cadence is how many steps you take per minute (both feet).
Cadence is great because no matter your speed, it should be about the same. Remember that these are general guidelines and the best thing to do is listen to your body. I personally find that my cadence is a bit lower (longer strides) when I’m running slow versus when I’m doing a speed workout or racing. But I’m also not a professional runner, so I may not be the best example. Keep in mind that we are all approaching perfect form and that as your body, muscles and speed changes your stride will change as well. Do what works for you now and continue to play with these mechanics as you improve.
‘Perfect’ Cadence
The general number for cadence right now is 180 steps per minute. Like anything, there is debate around this, but for beginners, it's a good target to work towards. If that's hard to visualize or apply, I like to think of it as three steps in a second, which may seem awfully fast. Remember this is a target to work towards. If you try to force or over analyze this target (or any other aspect of run form), you will probably throw off your natural stride and feel awkward. So use these as guides to work towards while still feeling natural. It takes time to gently change your run form, which is great because you want to adapt as your weight, muscles and speed adjust.
Consistent Cadence
The nice thing about cadence is that it shouldn't be based on speed. As you go faster your stride length will increase, but the general principle of three steps per second should stay the same. And as you slow down, your stride length will shorten and your three steps per second will stay the same.
Stability
Another aspect to consider, which I think supports this higher cadence (more steps per minute/shorter stride length) is thinking about how the length of your stride relates to your stability. Here is an easy way to understand this relationship:
Short Length
Standing with your feet next to each other, think about how stable you are.
If someone pushed you right now, could you stay still or would you fall over/have to move your feet to remain upright?
For most people, you would have to move to stay upright, which implies that there is a more stable stance.
Long Length
Standing, take a giant step forward and plant your feet.
If someone pushed you right now, could you stay still or would you fall over/have to move your feet to remain upright?
Like before, for most people, you would have to move to stay upright, which implies that there is a more stable stance.
For stride length, there is a balance between too long and too short. This balance will give you the most natural stability. This is what you want to find. Part of the reason we want to find that balance is that your stability comes from your core/secondary muscles (Abs, glutes, back and inner thighs). Unfortunately, these muscles, relative to your primary muscles, are not as strong. If you choose a stride that is less stable, then you will make your secondary muscles work harder to maintain stability. If you make them work harder, they will use more energy (which is a precious resource) and fatigue faster.
Think about going up stairs. If you decide to take two steps at a time, you probably wobble more and fatigue faster. That's fine if you’re just going one flight, but if you’re climbing the CN Tower in Toronto (147 flights of stairs and yes, there actually is a race for this), you may want to reduce the stress you’re putting on the stabilizing muscles and just take one step at a time.
Theoretically, one could argue that you could just build up your secondary muscles so they could last longer, which is true, but you’d still be running inefficiently. As far as I'm aware, there is no research that specifies the perfect ratio of primary to secondary muscles for running, so this is where you have to collect data and listen to your body. If at the end of a run, your secondary muscles were the limiting factor then you have the opportunity to adapt. You can find targeted exercises to build up those muscles or you can assess your run form to figure out if there is a way you can run that would give you more natural stability and therefore take pressure off the secondary muscles.
Exercises
Stability for Long and Short Strides
Required Material: none
Duration: 30-180 secs per aspect, 180-240 secs per stage
Stage 1
Engage your core (Back, glutes, abs and inner thighs).
Walk around with long strides.
Notice these things:
How do you feel? Do you feel more or less stable?
Repeat this exercise for the following:
While taking very short strides half foot to a foot per step.
Compare how all of these feel and collect data.
Stage 2 - Try this while jogging slowly. Find the balance that works.
Stage 3 - Go for a jog and throughout the run try doing 30 seconds short, 30 seconds long and then play with the balance.
Cadence of 180 steps per minute
Required Material: none
Duration: 30 secs per aspect
Stage 1
Standing, perform the following
Engage your core (Back, glutes, abs and inner thighs).
Standing in the same spot, try to take three steps per second on the spot, I like to count the steps out loud.
Notice these things:
How do you feel about this pace? Does it seem fast or slow?
Do you feel like this is faster or slower than your regular cadence?
Repeat this exercise for the following:
Lean from your ankles and slowly move forward half foot length with each step still maintaining the three steps per second.
Lean from your ankles more and increase your forward movement while still maintaining the three steps per second.
Compare how all of these feel and collect data.