Quality of Ambulant Measures of Distance, Speed, Load and Energy Consumption During Military Operations

Abstract : During training and operations, soldiers are exposed to a number of factors that influence their physical and cognitive performance. These factors are induced by the environment (e.g. heat, altitude, dust, wind, rain), physical job requirements (e.g. carrying loads, walking, sleep deprivation) and mental stress (e.g. decision making, exams, combat stress). The majority of these factors have a negative impact on the operational readiness of soldiers. In 2008 a 4-year research program called 'Military Performance and Health Monitoring' was started. One of the goals of this program is to test or develop devices for ambulatory monitoring of environmental, physical and mental factors. In this paper, we describe three separate studies that focus on the quality of measuring devices. Studies 1. Validity of the Sensewear Pro3 Armband in estimating energy expenditure and sleep duration. The validity of the Sensewear Pro3 armband towards energy expenditure was measured on a treadmill. Ten healthy subjects performed a series of tests. Variations were made in walking speed (4, 7 and 10 km/h), load (0 and 23 kg), arm position (with and without arm swing), slope (0% and 10%) and clothing (with or without additional clothes). Energy consumption was measured by indirect calorimetry (Metamax 3b, Cortex). The ability of the Sensewear to measure sleep duration was measured over 5 days in 4 subjects. Sleep duration was also monitored by use of a log. 2. Qualifying load, speed and slope by use of accelerometry. In this study the influences of variations in speed (3, 5 and 7 km/h), load (11, 24 and 36 kg) and slope (0% and 5%) on the output of a triaxial accelerometer (Spi-Elite, GPSports) was measured. Eight subjects participated in this study. 3. Quality of GPS signals in measuring distances. GPS data is known to be less accurate in urban areas or in forests. In this study, different GPS systems were compared in open terrain, forests and during a zigzag track.