Calculation of Running Economy with a Biomechanical Model versus Indirect Calorimetry

Lennart Gullstrand, Daniele Cardinale, Johnny Nilsson

Abstract

The interest in running economy (RE) analysis, based on metabolic and biomechanical measurements (BM), have increased during the previous decades. In this study a new “body marker-free” method MotionMetrix Inc., Stockholm, Sweden), based on two depth sensitive cameras were used to capture the runners motion during treadmill running. A 3D segment model was generated and after kinematic and kinetic analysis a number of running parameters were derived. Running economy is originally defined as the metabolic cost from measurement of oxygen uptake (VO2) in mL·kg-1·min-1 at submaximal and steady state velocities (1) and is here compared to energy expenditure expressed in J·kg-1·min-1 calculated from the new biomechanical model. Seven well trained middle- and long distance runners, with a VO2 max of 67.8 ± 5.1 mL· kg-1· min-1, volunteered in the study. Four submaximal (12, 14, 16 and 18 km·h-1) speeds were performed on a high precision treadmill and VO2 was measured with a validated metabolic chart (OxyconPro) in the mixing chamber mode simultaneously with the capture of the running motion. The biomechanical model used segments of the body movements which were calculated to represent one whole centre of mass movement. The correlation coefficient calculated between VO2 related to body mass (mL· kg-1· min-1) and BM energy expenditure (J·kg-1·min-1) was 0.854 and significant. When VO2 was recalculated to the same unit of EE by using the de Weir (1949) formula, resulted in the same significant correlation vs. BM EE. Nevertheless, the EE values from the 2 methods differ 20-40 % (Coefficient of Variation 7.8 %). The new "body marker free" method is of great interest as it allows evaluation of RE without manual attaching body markers and the use of expensive respiratory equipment. Thus, the participants are not connected to any measurement device that may restrict the running movements. In addition, interesting data for evaluation of RE, such as stride rate, stride length, foot contact time and vertical displacement (Vdisp), can be obtained. These are possible biomechanical factors influencing RE. Unexpectedly, specifically the centre of mass (CoM) Vdisp data in this investigation showed a low, not significant correlation to VO2 derived RE. COM Vdisp is in the literature regarded as one of the more important sub factors influencing RE. There may be several biomechanical reasons for the EE discrepancy between the 2 methods. It is for example unknown if the model accounts for stored elastic energy in stretch-shortening cycle components, which would add to the BM EE and reduce the difference. However promising, we intend to further validate the actual method against a more sophisticated optoelectronic set up with multi joint reflectors, which may be regarded as a biomechanical gold standard.

References

  1. Costill, D., Winrow, E., 1970. A comparison of two middleaged ultra-marathon runners. Res. Q., 41:135-139.
  2. Cavagna, GA., Kaneko, M. Mechanical work and efficiency in level walking and running. 1977. J. Physiol,, 268, 467-481
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  4. De Weir, JB., 1949. New methods for calculating metabolic rate with special reference to protein metabolism. J. Physiol. 109, 1-9.
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Paper Citation


in Harvard Style

Gullstrand L., Cardinale D. and Nilsson J. (2015). Calculation of Running Economy with a Biomechanical Model versus Indirect Calorimetry . In - icSPORTS, ISBN , pages 0-0


in Bibtex Style

@conference{icsports15,
author={Lennart Gullstrand and Daniele Cardinale and Johnny Nilsson},
title={Calculation of Running Economy with a Biomechanical Model versus Indirect Calorimetry},
booktitle={ - icSPORTS,},
year={2015},
pages={},
publisher={SciTePress},
organization={INSTICC},
doi={},
isbn={},
}


in EndNote Style

TY - CONF
JO - - icSPORTS,
TI - Calculation of Running Economy with a Biomechanical Model versus Indirect Calorimetry
SN -
AU - Gullstrand L.
AU - Cardinale D.
AU - Nilsson J.
PY - 2015
SP - 0
EP - 0
DO -