Pairing and calibrating a Polar stride sensor

Applies to: M400, M430

Pair a Stride Sensor with M430/M400

Make sure the stride sensor has been correctly attached to your shoe. For more information on setting up the stride sensor refer to the user manual of the stride sensor.

There are two ways to pair a stride sensor with your M430/M400:

1. Press START in time view to enter pre-training mode.
2. Touch your stride sensor with M430/M400, and wait for it to be found.
3. The device ID Pair Polar RUN xxxxxxxx is displayed. Choose Yes.
4. Pairing completed is shown when you are done.

or

1. Go to General Settings > Pair and sync > Pair other device and press START.
2. M430/M400 starts searching for your stride sensor.
3. Once the stride sensor is found, Polar RUN xxxxxxxx is displayed.
4. Press START, Pairing is displayed.
5. Pairing completed is displayed when you are done.

Calibrate the Stride Sensor

Calibration of the stride sensor improves the accuracy of speed/pace and distance measurements. It is recommended that you calibrate the stride sensor before using it for the first time, if there are significant changes in your running style, or if the position of the stride sensor on the shoe is dramatically changed (e.g. if you have new shoes or if you switch the sensor from your right shoe to your left one). The calibration should be done at the speed you normally run. If you run at different speeds, the calibration should be done at your average speed. You can calibrate the stride sensor manually or automatically.

When training with a stride sensor you can choose to use speed data from GPS or from the stride sensor. To set this go to Settings > Sport profiles > Running> Stride sensor > Choose sensor for speed, and choose Stride sensor or GPS.

Manual Calibration

Manual calibration can be done in two ways. You can run a distance you know, and set the correct distance in Quick menu. You can also set the calibration factor manually if you know the factor which gives you accurate distance.

Set Correct Lap Distance

1. Press START in time view to enter pre-training mode, and scroll to the Running profile.
2. Start a session, and run a distance you know that is more than 400 meters.
3. When you have the ran the distance, press START to take a lap.
4. Press and hold light to enter the Quick menu, and choose Stride sensor > Calibration > Manual > Set correct lap distance
5. Set the actual distance you have ran. The calibration factor is updated.

Set Factor

To calibrate the stride sensor manually by setting the factor, choose Settings > Sport profiles > Running> Stride sensor > Calibration > Manual > Set factor: If you already know the factor which gives you accurate distance. Calibrated. Factor: xxxx is displayed when you are done.

Automatic Calibration

Automatic stride sensor calibration is done based on GPS data and it happens in the background. Current pace, stride length and cumulative distance will be updated and shown correctly after the automatic calibration. Your speed is shown in gray on the display until the calibration is complete. If you manually calibrate your stride sensor later, the GPS based calibration factor will be overwritten.

The automatic calibration is performed twice, and the average of the two calibration factors is used. In your next training session, the average of your previous calibration factor and the factor obtained during that session is used.

The automatic calibration starts after 100 meters. Following criteria has to be met during the calibration distance of 500 m.

• At least 6 satellites have to be available
• Speed has to be at least 7 km/h
• Ascent and descent are less than 30 meters

When running on different surfaces (e.g. road, trail), use a different sport profile for each of them to achieve the best calibration for each surface.

To calibrate the stride sensor automatically, choose

• Settings > Sport profiles > Running> Stride sensor > Calibration > Automatic

Running Cadence and Stride Length

Cadence* is the number of times the foot with the stride sensor* hits the ground per minute. Stride length* is the average length of one step. That is the distance between your right and left foot contacting the ground. Running speed = 2 * stride length * cadence. There are two ways to run faster: moving your legs at a higher cadence or taking longer steps. Elite long distance runners typically run with a high cadence of 85-95. On uphills, typical cadence values are lower. On downhills they are higher. Runners adjust stride length to gather speed: stride length increases as speed increases.Yet one of the most common mistakes novice runners make is over-striding. The most efficient stride length is the natural one – the one that feels most comfortable. You will run faster in races by strengthening your leg muscles so they take you forward with a longer stride.

You should also work on maximizing cadence efficiency. Cadence does not progress easily, but if properly trained, you will be able to sustain it throughout your runs and maximize your performance. To develop cadence, the nerve-muscle connection needs to be trained - and reasonably frequently. A session of cadence training a week is a good start. Incorporate some cadence work into the rest of your week. During long easy runs, you could include some faster cadence every now and then. A good way of improving stride length is to undertake specific strength work, like running hills, running in soft sand, or running up steps. A six-week training period including strength work should result in noticeable improvements in stride length, and if combined with some faster leg speed work (such as short strides at best 5km pace), noticeable improvements should be seen in overall speed, as well.