Validity of the ActiGraph GT3X+ and BodyMedia SenseWear Armband to estimate energy expenditure during physical activity and sport

Abstract

Objectives

The purpose of this study was to assess the validity of the ActiGraph GT3X+ (GT3X+) and the BodyMedia SenseWear Armband (SWA) to estimate energy expenditure (EE) during physical activity and field sport movements.

Design

Criterion validity.

Methods

Twenty-six active adults completed a single 90 min session involving alternating intervals of exercise (5 min) and recovery (10 min). Exercise involved walking (4 km/h), jogging (8 km/h), running (12 km/h) or a sport-simulated circuit (three intervals). Participants wore two triaxial accelerometers (GT3X+ and SWA) and a portable gas analyser (MetaMax 3B), used as the criterion measure.

Results

Total EE was significantly underestimated (p < 0.01) by the GT3X+ (mean bias ± SD: −374.5 ± 132.84 kJ; % difference = −29.3%) and SWA (−244.3 ± 148.0 kJ; −18.2%). Overestimations were made by both accelerometers during the walk (GT3X+: 27.4 ± 30.8 kJ; SWA: 32.1 ± 15.4 kJ) and jog (38.0 ± 30.0 kJ; 34.5 ± 31.6 kJ). Underestimations were evident during the run (−41.2 ± 25.1 kJ; −43.8 ± 33.5 kJ) and circuit (C1: GTX+: −127.2 ± 41.6 kJ; SWA: −86.1 ± 40.2 kJ). Error of estimation increased in magnitude as the intensity of exercise increased (GT3X+: 40.8–143.0 kJ; SWA: 35.5–102.0 kJ).

Conclusions

The ActiGraph GT3X+ and BodyMedia SWA do not provide valid EE estimates across a range of exercise modalities and intensities when compared to a criterion measure. Poor accuracy and large precision errors, particularly during high intensity and intermittent movement patterns, suggest these devices have limitations and should be used cautiously in the field.

Introduction

Accelerometers are a useful tool in physical activity monitoring, overcoming issues associated with some older, subjective methods.1, 2 They have become more affordable, accessible and accurate in recent years,³ and consequently are now one of the most commonly used methods to objectively measure physical activity.3, 4 More recently, accelerometers have also been used in research to estimate energy expenditure (EE).⁵ Specifically, using predetermined algorithms based on representative sample populations and activities, accelerometers have been used to estimate total EE in laboratory settings and free-living conditions.⁶ As a result of the increase in usage there is ongoing research into the validity of these devices.

The accurate assessment of EE is important as it provides one half of the energy balance equation and therefore has implications for energy intake, energy output, or both depending on an individual’s circumstances (e.g., to gain, maintain, or lose body weight and/or to meet energy demands).⁷ As such, monitoring and manipulating physical activity and nutrition to achieve the desired energy balance is evident in advice given to diverse groups that range from athlete populations, who can experience seasonal changes in EE and often negative energy availability,⁸ to those overweight or obese.9, 10 In these circumstances, prescribing and quantifying physical training or activity should therefore extend beyond measures of volume and intensity to include the associated EE, which reflects the product of the two. Wearable sensors have the potential to provide this information.

Two commonly used accelerometers in research are the ActiGraph GT3X+ and the BodyMedia SenseWear Armband (SWA).¹¹ Despite evaluation for the use of these accelerometers to estimate EE during low to moderate intensity activities such as continuous walking and jogging,12, 13, 14 or during a combination of sedentary activity, aerobic and resistance exercise,¹¹ their validity in higher intensity activities and in variable and intermittent movement patterns is relatively unknown. Of the little research undertaken in sporting contexts, only one study examined the validity of the GT3X+¹⁵ and two investigated the SWA,16, 17 with all three studies showing substantial underestimations of EE during sport related movements.

Locomotor activities in many field and court sports range from walking through to sprinting, and include acceleration, deceleration and change of direction.¹⁸ These movements are also characteristic of those observed in free-play and unstructured games. Importantly such activities are well suited to meeting international guidelines that focus on time spent in moderate to vigorous activity.¹⁹ As sport is a major component of physical activity, and given recent evidence that suggests that the validity of accelerometers to estimate EE is compromised at higher exercise intensities, there is the need to further investigate in this context. Therefore, the aim of this study was to assess the validity of the ActiGraph GT3X+ and the BodyMedia SWA to estimate EE in physical activity and sport related movements, including high-intensity and intermittent movement patterns.