A cycle ergometer mounted on a standard force platform for three-dimensional pedal forces measurement during cycling

Mornieux, Guillaume; Zameziati, Karim; Mutter, Elodie; Bonnefoy, Régis; Belli, Alain

doi:10.1016/j.jbiomech.2005.03.020

Cited by 17 publications

(21 citation statements)

References 31 publications

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“…This error was comparable to the ± 5 % mean percent error obtained by Broker and Gregor [4] and Newmiller et al [16] or to the > 6 % RMS error reported by Mornieux et al [15] for other pedal force measurement systems. The mean absolute error of -0.22 N (F T ) and -4.25 N (F R ) was comparable to the accuracy values of the dynamometer presented by Boyd et al [3].…”

Section: Discussionsupporting

confidence: 87%

Development and Evaluation of a New Bicycle Instrument for Measurements of Pedal Forces and Power Output in Cycling

Stapelfeldt¹,

Mornieux²,

Oberheim³

et al. 2007

Int J Sports Med

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Determination of pedal forces is a prerequisite to analyse cycling performance capability from a biomechanical point of view. Comparing existing pedal force measurement systems, there are methodological or practical limitations regarding the requirements of scientific sports performance research and enhancement. Therefore, the aim of this study was to develop and to validate a new bicycle instrument that enables pedal forces as well as power output measurements with a free choice of pedal system. The instrument (Powertec-System) is based on force transducer devices, using the Hall-Effect and being mounted between the crank and the pedal. Validation of the method was evaluated by determining the accuracy, the cross talk effect, the influence of lateral forces, the reproducibility and, finally, a possible drift under static conditions. Dynamic tests were conducted to validate the power output measurement in reference to the SRM-System. The mean error of the present system was -0.87 +/- 4.09 % and -1.86 +/- 6.61 % for, respectively, the tangential and radial direction. Cross talk, lateral force influence, reproducibility and drift mean values were < +/- 7 %, < or = 2.4 %, < 0.8 % and 0.02 N x min (-1), respectively. In dynamic conditions, the power output measurement error could be kept below 2.35 %. In conclusion, this method offers the possibility for both valid pedal forces and power output measurements. Moreover, the instrument allows measurements with every pedal system. This method has an interesting potential for biomechanical analyses in cycling research and performance enhancement.

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Section: Discussionsupporting

confidence: 87%

Development and Evaluation of a New Bicycle Instrument for Measurements of Pedal Forces and Power Output in Cycling

Stapelfeldt¹,

Mornieux²,

Oberheim³

et al. 2007

Int J Sports Med

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show abstract

“…The bicycle frame, including the flywheel and friction system, was fixed aside from the force platform, in order to avoid any mechanical contact with either the gear mechanism or the steel part, and in such a way that the original dimensions of the whole bicycle were maintained. The force platform used was equipped with four piezo-electric transducers, each measuring the three-dimensional forces applied (for details see Mornieux et al 2005).…”

Section: Instrumentationmentioning

confidence: 99%

“…RF ¼ 0; RM ¼ 0) with an accuracy better than 4%. The details of the pedal forces computation have been described elsewhere (Mornieux et al 2005). From the three-dimensional pedal forces (i.e.…”

Section: Pedal Forces Computationmentioning

confidence: 99%

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Relationship between the increase of effectiveness indexes and the increase of muscular efficiency with cycling power

Zameziati

Mornieux²,

Rouffet

et al. 2005

Eur J Appl Physiol

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We determined the index of effectiveness (IE), as defined by the ratio of the tangential (effective force) to the total force applied on the pedals, using a new method proposed by Mornieux et al. (J Biomech, 2005), while simultaneously measuring the muscular efficiency during sub-maximal cycling tests of different intensities. This allowed us to verify whether part of the changes in muscular efficiency could be explained by a better orientation of the force applied on the pedals. Ten subjects were asked to perform an incremental test to exhaustion, starting at 100 W and with 30 W increments every 5 min, at 80 rpm. Gross (GE) and net (NE) efficiencies were calculated from the oxygen uptake and W(Ext) measurements. From the three-dimensional force's measurements, it was possible to measure the total force (F(Tot)), including the effective (F(Tang)) and ineffective force (F (Rad + Lat)). IE has been determined as the ratio between F(Tang) and F(Tot), applied on the pedals for three different time intervals, i.e., during the full revolution (IE(360 degrees)), the downstroke phase (IE(180 degrees Desc)) and the upstroke phase (IE(180 degrees Asc)). IE(360 degrees) and IE(180 degrees Asc) were significantly correlated with GE (r = 0.79 and 0.66, respectively) and NE (r = 0.66 and 0.99, respectively). In contrast, IE(180 degrees Desc) was not correlated to GE or to NE. From a mechanical point of view, during the upstroke, the subject was able to reduce the non-propulsive forces applied by an active muscle contraction, contrary to the downstroke phase. As a consequence, the term 'passive phase', which is currently used to characterize the upstroke phase, seems to be obsolete. The IE(180 degrees Asc) could also explain small variations of GE and NE for a recreational group.

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“…where N is the number of samples, f is the degrees of freedom of the calibration matrix, and FS is the maximal load value utilized to calibrate the sensor (as seen in Table 1). Both parameters are widely used in literature to define the accuracy of a sensor [16,17] though, to our knowledge, they are missing in literature addressing seat post sensors.…”

Section: Of 10mentioning

confidence: 99%

Design and Calibration of an Instrumented Seat Post to Measure Sitting Loads While Cycling

Dieltiens

D’hondt

Juwet

et al. 2020

Sensors

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Traditional instrumented seat posts determine context-induced seat loads to analyze damping properties. This paper presents an enhanced instrumented seat post able to measure all six load components to resolve user-induced seat loads. User-induced cycling loads consist of all loads the user applies to the bicycle during cycling and is measured at the steer stem, the seat post, and the pedals. Seat loads are essentially uncharted territory, as most studies only address pedal loading to study cycling technique. In this paper, a conventional seat post is redesigned by equipping it with a u-shaped component and strain gauges. The instrumented seat post is straightforward thanks to (i) the simple design, (ii) the gravitational calibration method, and (iii) the permitted clearance on the strain gauge alignment. Analyzing mean seat loading in function of the pedal cycle can provide extra insights into cycling technique and the related injuries. It is an interesting addition to the universally adopted method of utilizing singular pedal loads.

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A cycle ergometer mounted on a standard force platform for three-dimensional pedal forces measurement during cycling

Cited by 17 publications

References 31 publications

Development and Evaluation of a New Bicycle Instrument for Measurements of Pedal Forces and Power Output in Cycling

Development and Evaluation of a New Bicycle Instrument for Measurements of Pedal Forces and Power Output in Cycling

Relationship between the increase of effectiveness indexes and the increase of muscular efficiency with cycling power

Design and Calibration of an Instrumented Seat Post to Measure Sitting Loads While Cycling

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