Performance perspective of stride length

What it stride length, what does the evidence say, how can you apply this understanding & recommendations about collecting and analysing data.

What is stride length?

Stride length is defined as the distance between successive ground contacts of the same foot. When running speed is kept constant, stride length and stride frequency are inversely related. This means if you increase one, the other will decrease, so a longer stride length produces a slower stride frequency.

How can I calculate stride length?

To measure stride length all you need to know is how many strides per minute an individual takes and the running speed. The easiest way to determine the number of strides per minute is to count the number of strides per 15 seconds and extrapolate to a minute. I have put together a spreadsheet that will do this extrapolation, as well as calculate the stride length and stride time for you (stride length calculation.xlsx).

Stride length from a performance perspective

Trained runners develop an economical stride length by fine-tuning their running technique to minimise how much oxygen they consume during running - a process known as ‘self-optimisation’. There have been a few studies that have identified differences in running technique between more/less economical runners or trained/untrained runners or runners improving their own running economy (see Moore, 2016 for a full review). On top of this, trained runners are closer to their mathematically derived optimal than untrained runners, which further supports the theory that runners self-optimise.

Small changes to stride length (3% shorter) do not affect performance, but larger changes (6-7%) do. Changing stride length also alters numerous other aspects of an individual’s running technique, in particular the loads going through the knee and ankle. This is one of the reasons why it is often targeted by clinicians during running gait retraining interventions. However, these alterations can also influence running performance, therefore considerations of both perspectives – injury and performance – is needed.

But, how can coaches, clinicians and athletes determine if their stride length is optimal? Whilst many places outside academia may not have access to equipment to measure oxygen consumption, evidence shows that heart rate can be used as a surrogate measure to determine optimal stride length.

How can I determine an optimal stride length?

Start by measuring the individual’s heart rate whilst they are running normally. It is best to take an average (mean) over a minute or two, noting heart rate every 20 or 30 seconds. Then, using a metronome, you can manipulate an individual’s stride length and frequency. This is best done on a treadmill at a constant running speed. It is important that an individual has reached a ‘steady-state’ when you take the heart rate readings, for trained runners this usually takes 4 minutes. When using the metronome instruct an individual to strike the ground in time with the metronome beats.

The table below outlines what and when to record data during 3 conditions. Repeat the steps for other stride length manipulations (e.g. 10% & 12%).

Try to use at least five different stride lengths, including the individual’s normal stride length. Once you have the heart rate and stride length data you can enter the data into the spreadsheet I’ve devised that will determine the economical stride length and fit a line to examine the relationship (stride length heart rate relationship.xlsx).