Accuracy and Repeatability of the Polar^®RS800sd to Evaluate Stride Rate and Running Speed

Abstract

The purpose of this study was to evaluate the accuracy and the repeatability of a new running computer system (RS800sd, Polar, Kempele, Finland) which included the measurement of running speed (RS) and stride rate (SR). Eight well-trained triathletes participated in this study. First, they completed an incremental continuous maximum test on a treadmill (from 12 km x h (-1) to 18 km x h (-1)) at 0% grade. Then the subjects took part in a second test to determine RS800sd intra-reproducibility to evaluate running speed. They ran twice during 5 min at a pace corresponding to their maximal lactate steady-state. During these two tests, RS and SR were recorded by the RS800sd system, by an optical sensor system (for RS) and a force-sensitive device (for SR). No difference was found between the RS800sd system and the reference systems both for RS (ICC=0.95) and SR (ICC=0.69). Moreover RS measures were statistically repeatable. This study provided evidence for the validity of the RS800sd system for measuring the kinematic characteristics of running (speed and frequency). Further investigations are needed to replicate these findings at lower running speeds, notably during walking to assess its capacity to evaluate physical activity in natural conditions.

Influence of gender on pacing adopted by elite triathletes during a competition

“…This is a very small commercial device (3.5 9 0.7 cm), light in weight (20 g) with a time-sampling mechanism that allows it to provide chronological measures of running speed. Its accuracy and reliability have recently been validated (Hausswirth et al 2009). Three days before the race, the s3 sensor was calibrated, as recommended by the manufacturer, to integrate each runner's stride characteristics.…”

Method analysis of accelerometers and gyroscopes in running gait: A systematic review

“…Any differences could also be due to the weak comparison method of 2D analysis and also stance would have been identified here as ground contact time, as opposed to with the sensor data where it was identified by level of rotational movement. By using the above methods, the use of accelerometers and/or gyroscopes to derive stride frequency has been validated 11,14,51,52 and also been successfully used to derive stride frequency changes with speed 36 , fatigue 23,31 and its relationship to jump performance 50 .…”

“…Of the 38 articles included in this review 23 articles utilised accelerometers and/or gyroscopes during running gait to identify coach orientated kinematic parameters (See Table 1.2). 48 Bergamini et al 17 Bichler et al 18 Cooper et al 19 Hausswirth et al 11 Heiden et al 49 Le Bris et al 31 Lee et al 32 Lee et al 47 McCurdy et al 50 McGrath et al 13 Mercer et al 35 Mercer et al 36 Neville et al 51 Neville et al 52 O'Donovan et al 20 Purcell et al 53 Stohrmann et al 22 Stohrmann et al 21 Stohrmann et al 23 Tan et al 14 Wixted et al 54 Yang et al 15 Step/Stride Frequency…”

“…Other parameters identified are foot strike type 21,23 , heel lift 22,23 , running speed 11,15 , knee angle 19 , sprint time 50 and arm movement, trunk forward lean and shoulder rotation 23 . Although measurements such as angle derivation and speed may not be commonly identified using accelerometers and/or gyroscopes this information does provide insight into advancing capabilities of these low cost transducers whilst also providing support for their validity within this research.…”

“…While previous optical measurement systems allow for acceleration calculation error, during the differentiation of displacement and velocity measurements (such as 2D image analysis), accelerometers avoid this while also having the benefit of utilising one or multiple axes 3 . This has led to accelerometers being successfully validated for identifying a number of parameters when measuring running gait including centre of mass (COM) vertical displacement 10 , stride parameters and running speed 11 , and angular velocity 12 . Similar to accelerometers, gyroscopes are portable, lightweight and provide direct measurement, in this case, of angular velocity.…”