Bioharness(™) multivariable monitoring device: part. I: validity

Abstract

The Bioharness(™) monitoring system may provide physiological information on human performance but there is limited information on its validity. The objective of this study was to assess the validity of all 5 Bioharness(™) variables using a laboratory based treadmill protocol. 22 healthy males participated. Heart rate (HR), Breathing Frequency (BF) and Accelerometry (ACC) precision were assessed during a discontinuous incremental (0-12 km·h(-1)) treadmill protocol. Infra-red skin temperature (ST) was assessed during a 45 min(-1) sub-maximal cycle ergometer test, completed twice, with environmental temperature controlled at 20 ± 0.1 °C and 30 ± 0.1 °C. Posture (P) was assessed using a tilt table moved through 160°. Adopted precision of measurement devices were; HR: Polar T31 (Polar Electro), BF: Spirometer (Cortex Metalyser), ACC: Oxygen expenditure (Cortex Metalyser), ST: Skin thermistors (Grant Instruments), P:Goniometer (Leighton Flexometer). Strong relationships (r = .89 to .99, p < 0.01) were reported for HR, BF, ACC and P. Limits of agreement identified differences in HR (-3.05 ± 32.20 b·min(-1)), BF (-3.46 ± 43.70 br·min(-1)) and P (0.20 ± 2.62°). ST established a moderate relationships (-0.61 ± 1.98 °C; r = 0.76, p < 0.01). Higher velocities on the treadmill decreased the precision of measurement, especially HR and BF. Global results suggest that the BioharressTM is a valid multivariable monitoring device within the laboratory environment. Key pointsDifferent levels of precision exist for each variable in the Bioharness(™) (Version 1) multi-variable monitoring deviceAccelerometry and posture variables presented the most precise dataData from the heart rate and breathing frequency variable decrease in precision at velocities ≥ 10 km·h(-1)Clear understanding of the limitations of new applied monitoring technology is required before it is used by the exercise scientist.

Keywords: Physiological technology; exercise; precision of measurement.

Figure 1.

Picture of the Bioharness^TM as worn by a subject participating in the testing process.

Figure 2.

Residual versus predicted plot demonstrating the relationship for (a) BF, (b) HR, and (c) ST.

Figure 3.

Trend in data between mean foot steps (- -▲- -) and mean VMU (-□-) per active stages of treadmill protocol (nb. Treadmill stages 1 to 5 refers to 4 km.h^-1 to 12 km.h^-1 respectively).

Figure 4.

Scatter plot demonstrating the relationship between (a) Bioharness BF and Criterion and (b) Bioharness HR and Criterion across all velocities on treadmill. Nb. line of identity (- - - -), regression line (^_____).