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RUNNING: First steps with a power meter

Basic concepts to train running with a power meter like Stryd.
For a better understanding, we recommend to read first our Blog article "First steps with a cycling power meter".

A running power meter is quite different from a cycling power meter from the moment that they estimate data with an algorithm instead of providing readings from a gauges system.

The purpose of a power meter is to provide another perspective of data like: stride length, cadence, X/Y movement with oscilations, ground contact time, wind effect, economy, stride stiffness and of course the "power".

It's like, we put our physiology inputs in a box, shake it with temperature, humidity, fatigue, wind and we get the power meter running components.

In our cycling power article we have talked about the physiological effort, here we jump directly to the muscles implicated while running.

Muscles used to run

Body implication while running

Author: FitPage

Running requires some implication that are genetic while other aspects can be trained:

  • Skull and body surface that help to dissipate the heat, this one is genetic. 
  • A long legs increase the stride length, while the relation of torso/legs define a runner dynamics. 
  • The foot arch helps like a spring, that's why a lot of shoes are high arched. This can be corrected with the proper insoles. 
  • Achilles tendon strength and length, determines our propension to injury but also how we store the energy on each stride. 
  • Main muscles: abdominals, glutes, quads, hamstrings, tibials and calfs. We want them lean but strong. 

The muscles and tendons can be trained to gain mobility, elasticity, strengh and section. We do so with strength mobility routines, weights and pliometry.

The running biomechanics might need a full new article, because in just 1 second me can make more than 3 strides. It is very hard to follow with the human eye and even harder to correct immediately. 

The running technique requires years of practice and repetition.

The running cycle has an aerial phase and a ground phase for each leg, while we pay attention to certain parts as the landing, the swing, stride and takeoff. Actually we focus in two components:

  • Cadence: how fast we move the legs, this value is around 180 spm (steps per minute).
  • Stride length: what distance can we make with two steps, a full cycle.

The cadence can be trained with sprint and coordination drills, but also flexibility. While the stride length is generally improved with strength workouts. 

Especifically we can work the running components by separate, like improving the ground contact time, the reactivity on the takeoff, landing from mid foot to toes, the arms coordination, the feet path. Well... lots of them. Contact us to get some help.

The running cycle

Author: Borja Muñiz Pardos.

Improve your running technique not only has time goal effects, also benefits for your health as prevents injuries. 

Running is well known for being the sport that leads to more injuries in triathlon. Some athletes have capped their training time because we know that certain durations turn into injury risks. With some technique drills and running strength you can achieve greater results.

How is a running power meter

Stryd power meter

Author: TRIMAX

We have less options about choosing a running power meter in comparison to a cycling power meter. 

All our athletes use Stryd, which is a foot pod placed in our shoes (only one side). It uses a well keeped algorithm that calculates a power value from the internal sensor. 

Stryd can store each workout data itself and view it in its own mobile APP, but for real time visualization we will need a Garmin watch with one or two IQ data fields. 

We get the most of it when a heart rate strap is used in conjunction with a power meter, allowing us to study the cardiac drift in relation to the running power. 

A running power meter estimates the power, which means that in flat conditions the displayed W number has a direct relation to our pace, but when used in irregular terrains provides complimentary information that the pace can't show. 

Another advantage is the bunch of metrics that we get in direct relation to efficiency and fatigue.

In conclusion: You can achieve a higher power by making more force on your cranks or by moving them faster.

What is better? While following a training plan you will learn to succeed on high cadence trainings as well as low cadence trainings. By doing so you start to figure out how feels better, checking your heart rate, effort perception and power. We at TRIMAX are here to help you with that!

Retrieved data from a power meter

Even some athletes find that running power meters still have a lot to develop, we use it a lot for the running dynamics metrics. 

The data obtained can show us information that the pace can't, like: cadence, stride length, vertical oscillation, the "X" part of the stride, the "Y" part of the stride, the ground contact time, the efficiency factor, the flight time and the wind affectation. 

With all that information we have a better understanding of the fatigue role.

EXAMPLE:

This workout shows 8 x 1 min efforts during a training session. It was performed indoors in a treadmill, reaching speeds around 19 km/h.

The goal of the workout was to develop speeds closer to the maximum aerobic running power, while the athlete was getting confident in his capabilities.

The yellow line represents the normalized power, while the blue line represents the VO2max estimation.

We also take a look at the purple line that represents his functional reserve capacity in terms of anaerobic energy.

After the workout, on our WKO dashboard, we found out that the athlete doesn't really need to hit 19 km/h for our purpose, and the next speed session he will work around 18 km/h which is enough to improve his VO2max.

From the workout we get this custom chart for a better understanding of the numbers part. For short repetitions we prefer to look at P.average instead of NP. 

As it was a VO2max training we want to look at the maximum heart rate achieved after every hard effort, as well as the VO2max information that we have in a different dedicated chart.

We also highlight the cadences improving from 184 spm to 197 spm with the speed, as well as the stride length from 1,45 m to 1,59 m for a 1,67 m tall athlete (85 cm legs). As the cadence is quite good, we can make recommendations on focusing over the stride length for the next session. 

The vertical oscillation improves with the repetitions from almost 8 cm moving to lower 7 cm, which means less bouncing by a better technique. This effect happens a lot during the workouts, we need time to progress on our technique during a session. 

The ground contact time was always under 200 ms which is a barrier often analyzed. 

Then we have other efficiency factors like the relation of our X impulse over our Y vertical used (Form power). We should try to run under 22% of vertical impulse. This athlete achieves values between 20-22%.

We could make a new blog post about Stryd data, but please contact us if you have any doubts.

We like training indoors from time to time because it represents an opportunity to focus on our technique too, using a mirror or just paying more attention. 

The coach has closer access to speak with the athlete and can provide instant feedback while running full gas on the treadmill. Training indoors also allows us to apply small increments of intensity while experiencing those small variations.

How to cross power data with other channels

Every data channel has a linear behavior but not at the same ramp rate, so they can't be compared exactly the same way.

In the example below we have a sprint triathlon run leg, which is performed mainly at a threshold intensity, sometimes higher.

The channels are: power, pace and heart rate. 

As we mentioned before, a power channel is parallel to a pace channel if the course is flat, like this one. They wouldn't be like this in a rolling course. From a well paced intensity, our athlete manages to run at a variability index of 1.00 (steady), slightly above pure threshold IF=1.03 . 

In this situation, all channels behave like full threshold bars.

If the power in this situation behaves exactly like the pace, why do I want to buy a running power meter?

  • When the course has ups and downs the pace is hard to follow while the power it's more smooth. 
  • We can see other metrics as stride length, cadence, LSS and all the others commented earlier.
  • The cardiac drift 5,98% in the example, it's smoother in a power channel than in a pace channel. 

Yes you can survive without a running power meter! But in this game all the information that we can have makes the difference. Marginal gains.

Running FTP vs Cycling FTP

Running FTP and cycling FTP are different. It's just a coincidence if you have the same number, something that can happen.

In our manual zones labeling, we study the number positions that correspond to aerobic states, anaerobic and the two thresholds aerobic/anaerobic. Let's say that the running zones are narrower in comparison to the cycling zones that have more range.

 

Cycling with power has great possibilities to go over our threshold value x5 or x6 times until the Pmax, because it's measured with gauges.

 

At this moment the running power meter uses an estimation model that is not accurate por readings far from our threshold (up and down). We should use it for zones from light aerobic to VO2max. It's not suitable for warm up powers or anaerobic powers.

Running power duration curve

The running power duration curve looks similar to the cycling PDC, but it's "flatter" because of the gauges/estimation method. 

We use the same methodology to look for maximum values and progress. Once we get some top values, our race goal stays around 5W of possible error, which provides a total confidence of our pacing for a certain distance from the start line. 

At TRIMAX we find the running power meter as a key element in our long aerobic runs, especially those ones after the bike. But also in the VO2max sessions to hit just the MAP number.

CONCLUSIONS

    1. A running power meter it's not such an important tool like a cycling power meter, especially if we will perform mainly in flat races. But it's a good extra point.
    2. In conjunction with our running power meter, we will need a compatible smartwatch to connect it for data in real time.
    3. A running power meter provides important biomechanics channels, it's also used as a technique drill tool furthermore a performance element.
    4. It's important that we have the right post-workout analysis tools to understand all the information generated.
    5. Running with power will be more beneficial in conjunction with a heart rate device.
    6. We can highlight the running power meter advantages while doing long aerobic workouts and also during VO2max sessions.

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