The Effect of Vehicle Motion (Cab Vibration) on Accelerometer Cut-Point Determined Moderate-to-Vigorous Physical Activity in Heavy Goods Vehicle Drivers

This study aimed to determine the impact of cab noise when driving Heavy Goods Vehicles (HGV) on cut-point estimated moderate-to-vigorous physical activity (MVPA) from wrist-worn accelerometers. First, we investigated the impact of cab noise on accelerometer output during HGV driving and then on cut-point estimated MVPA in HGV drivers. A GENEActiv accelerometer was located beneath the seat in six HGVs for 8 days. Acceleration recorded during driving lay predominantly (~94%) within the sedentary range (<40mg). HGV drivers (N = 386, 47.9 ± 9.3 years) wore a wrist-worn GENEActiv and a thighworn activPAL simultaneously for 8 days covering workdays and nonworkdays. MVPA recorded by the activPAL excludes seated transport, thus provided the criterion. Wrist accelerometer MVPA was classified using two cut-points approximating 3 metabolic equivalents (MVPA100mg) and 4.3 metabolic equivalents (indicative of brisk walking, MVPABRISK_WALK). Acceleration classified as MVPA100mg or MVPABRISK_WALK during activPAL-determined seated transport was considered erroneous. Across all-days, activPAL MVPA was 15 (interquartile range: 9, 26) min/day. Compared with activPAL, MVPA100mg was 100 min/day higher (95% limits of agreement ±53 min), but MVPABRISK_WALK similar (mean bias = −2 min/day, 95% limits of agreement ±15). On workdays, 23 (interquartile range: 11, 52) min of MVPA100mg and 2 (1, 7) min of MVPABRISK_WALK were erroneous. However, on nonworkdays, only 4 (3, 14) and 0.4 (0, 1) min, respectively, were erroneous. In conclusion, MVPA may be erroneously captured using cut-point analyses of accelerometer data in HGV drivers. However, this was substantially reduced by using an MVPA cut-point indicative of brisk walking, which also approximated activPAL estimated MVPA.