A wrist based GPS is a great tool for tracking time and distance while running. All you need to know is how to press start, stop and save. As a coach and runner, I’ve noticed that many of my fellow runners aren’t doing much else with the data from these smart devices. Here is a quick introduction to three metrics to use when chasing your next PR, planning balanced training loads and looking to improve your form and efficiency.
Most GPS devices now have a way of monitoring cadence. Cadence is defined in steps per minute (spm) and allows a runner to know the speed of their leg turnover. While there are many different opinions on cadence, it is generally agreed that somewhere around 180 spm is the sweet spot for running efficiency and economy. Cadence is calculated either from the device as your arm swings, from a foot pod, or a heart rate strap, where advanced monitoring is picking up the rise and fall that occurs when running. When looking at this data after a run, it is possible to see what happens to cadence in different situations such as climbing a hill, running fast, descending, or even over time as you start to tire. If your cadence is below 165 it is likely your running efficiency is affected. Work to improve cadence in small increments using drills and by inserting cadence sets into your runs with 30 seconds on, 30 seconds off. Ideally you want to allow your new form to develop over time to prevent injury and allow for a neuromuscular connection so it becomes normal and habitual.
Some of the latest wrist based running devices include heart rate measured on the wrist. The reliability of this seems to be slightly less than the chest strap which has been used for many years. Nonetheless, having heart rate collection of any sort is very useful to a runner who is training to become fitter and faster. Knowing individual lactate threshold heart rate, the point at which a body can no longer utilize all of the lactate it is producing, is essential. This can be discovered through simple field testing as a 30 minute test, in racing, or even lab testing. With these personal heart rate numbers in hand collecting heart rate data can add an objective and scientific explanation to rate of perceived exertion (RPE) and can also help illuminate what happened in a race or workout. If an athlete in a marathon looks back over a race file and sees a heart rate that is higher than normal at the beginning of the race, perhaps from effects of heat or improper pacing, they can start to understand the causes of a drop in pace later in the race. If going for a long endurance run, an athlete can set a heart rate cap and make sure they stay beneath it for the duration. This metric is very good for an athlete who gets hung up on pace during training. Heart rate is responsive to terrain, wind, heat, stress and fatigue.
Pace and Auto Lap
There are many options for monitoring pace during a run. I’ve observed a lot of runners who leave their watch settings with whatever it came with from the factory. Often this is average pace or current pace. Let’s give this some thought. When doing interval workouts, it is helpful to know the average pace of the lap and also the current pace if it is a shorter bout of work. This allows you to determine the exact pace needed. Perhaps a long endurance run is better served with overall pace. Using the auto lap feature generates a pace guide, although the runner may be going on rate of perceived exertion (RPE) or perhaps using a heart rate cap. Turning the auto lap feature OFF is a must for interval work in which data is collected in self selected intervals and can be created by using the LAP button between intervals. I remind runners that current pace can be swayed by faulty satellite connections and not to panic if suddenly RPE and the data don’t jive. Remember, the device needs to collect data as you are moving forward, so for the most accuracy on an interval, pick up the pace for 4-6 steps before hitting the lap button.
Cadence, heart rate and pace are three metrics that can dramatically change how you train and help you improve as a runner. Using them individually, or together, can help your pacing, efficiency, form, and economy, and will help you train and race more intelligently.