The Polar RCX5 is not just a mere watch. It calls itself a “fitness computer” and it lives up to its name by analysing your statistics on the move to help you get the most out of your fitness sessions. It all starts by monitoring one particular marvel of technology - your heart.
If you work at 50-60 per cent capacity you improve overall health and recovery rate. At 60-80 per cent you’ll improve endurance. Go even further and you’ll develop performance and speed. And the RCX5 can help keep you in the right zone while you’re working out.
You can throw more data at your fitness programme by adding a stride sensor, which measures your speed and pace as well as your average length of footfalls. Once we calibrated the unit over half a mile, we found it was fairly accurate when matched against a GPS unit. A 5.7 mile run was recorded as 5.8 using only the stride sensor.
That's less than a 2 per cent variance, and we tried to throw it off by changing our gait and putting in the occasional sprint, yet the sensor could judge not only the average length of our stride at 3ft 5in, but the type of step we were taking, be it a light walk or a heavy run.
However, the sensor itself is twice the size of the Nike Sportwatch monitor which can fit into the sole of a compatible running shoe and tested extremely well in the tunnels during our test at the Paris Marathon.