Getting stuck on a performance plateau is a common feeling for runners, where we find it difficult to nudge our running pace on to the next level. NURVV Run has tools that allow the runner to take a closer look at their performance factors and begin to understand which aspects of their technique may need development to allow them to move on to the next level.
At NURVV we are keen that our runners are aware of a very important relationship:
Speed = Cadence * Step Length.
This relationship provides the link between a runner’s most important performance metric (speed) and the two primary factors / technique metrics contributing to speed (cadence and step length). To understand how to generate and maintain speed (or pace) over the course of a run a runner must understand how well they are maintaining their cadence and step length profiles.
Speed: the distance covered per unit time, eg 15 km/h
Pace: the time taken to cover a given distance, eg 04: 00 min/km
Pace = 60 / Speed
Cadence: the step rate, how many steps the runner takes per minute, eg 175 spm
Step Length: the distance over ground covered per step, eg 1.30 m
A runner’s pace will vary over the duration of a run, either deliberately due to race or pacing strategy or as a consequence of fatigue or environmental factors such as wind, gradient, and surface. As a runner fatigues, it can become difficult to hold the preferred pace and speed may drop. This drop in speed will be a direct result of a decrease in cadence and/or step length. The way that a runner’s technique changes over the course of a run is individual to them – fatigue affects all runners differently depending on factors such as their experience and conditioning. For example, local muscle fatigue may reduce the leg’s ability to generate a forceful ground contact with each step and this will lead to a reduction in step length. Similarly, central fatigue may decrease the neural drive to exercise muscles, particularly fast-twitch fibers, and lead to a decrease in the speed of contraction and therefore cadence.
A “breakdown” in form / technique will impact on a runner’s pace but may also increase injury risk. If the runner can appreciate where in the run their technique starts to degrade and also which factors begin to degrade sooner or most rapidly then all of this information can help the runner refine their training plan in terms of good distances to run on a single occasion and also in terms of focussing their training on developing strength or leg turnover.
For many runners, a slight increase (5-10%) in their cadence over their self-selected preferred cadence helps them improve their running economy and can reduce the amount of loading the body joints experience. By accessing Cadence Profile the runner can examine where in long runs their cadence starts to drop and then manage their run distances to avoid this decline.
Reading This Graph: Cadence (in steps per minute) is shown on the vertical axis and time (split km or miles) is shown on the bottom axis. The thick pink line is the continuous trace of cadence. The values above the split number represent the average cadence value for that split. If the run is longer than 6 splits then swipe right to see later splits.
Step Length Profile
The middle / long distance runner needs to find a compromise between generating a good step length to help them run with pace but also make sure that their step length isn’t exaggerated to the point of “overstriding”, which will decrease their running economy and may increase the chances of lower limb injuries. Step Length Profile allows the runner to inspect how this metric varies with fatigue, surfaces, and elevation. The runner will get a better grasp of their current unfatigued step length and be able to analyze how this changes due to fatigue, either dropping as leg muscles get tired or potentially moving into overstriding territory in later stages of a run.
Reading This Graph: Step Length (in m or ft) is shown on the vertical axis and time (split km or miles) is shown on the bottom axis. The thick blue line is the continuous trace of step length. The values above the split number represent the average step length value for that split. If the run is longer than 6 splits then swipe right to see later splits.
Pace Profile graphs in great detail the evolution of a runner’s pace over a run and highlights those sections of the run where pace has increased or decreased and also provides the split-level detail (in the table format below the graph). By analyzing the pace curve and optionally superimposing on the cadence and step length detail the runner can begin to understand which of the performance factors is causing a decrease in pace later in the run and therefore understand more about the type of training they may need to do. The runner will get a feel for the specific cadence and step length combination they use when running fresh or fast and therefore what can be considered their optimal combination for their current fitness/training level.
Reading This Graph: Pace (in min/km or min/mile) is shown with the white line, with values provided on the left-hand vertical axis (faster pace shown as a higher value), and time (split km or miles) is shown on the bottom axis. You can choose to superimpose either the Cadence trace (pink line, values provided on the right-hand vertical axis), the Step Length trace (blue line, values provided on the right-hand vertical axis), or All traces (no values shown on the right-hand vertical axis).
Pace Profile – Case Studies
We can use Pace Profile to understand how pace, cadence, and step length are interacting during different stages of a run. In Example A below we can see that our runner manages to hold very consistent form for the first 7 km of the run, running approximately 04:20 min/km pace with a constant cadence and a slightly more variable step length for these splits. From split 8 onwards the pace begins to drop and we can see that cadence drops slightly in later splits but the biggest reduction is with step length. This suggests that local muscular fatigue is causing less force to be expressed during ground contacts and suggests that this runner would benefit from some strength work and muscular endurance work (e.g. hill repeats) as part of their training.
In Example B, pace drops considerably in later splits (splits 5 and 6) but this time is due to a drop in both cadence and step length to a lesser extent. This may be a deliberate strategy on the part of the runner to “stride out” in later stages of the run, but if not then it could indicate that the runner is trying to maintain pace in the face of diminished cadence by artificially increasing step length above their unfatigued value (early splits). In this case, the runner is “overstriding” and needs to be wary of using this strategy because of the likely increase in body loading and injury risk this brings about.
Example A: Dropping step length
Example B: Dropping cadence and overstriding