Concurrent Validation of T-REX Accelerometer

Purpose: To examine the concurrent validity of the T-REX accelerometer assessing physical activity against indirect calorimetry (oxygen uptake) and two different accelerometers (Actical and ActiGraph). Methods: Fifty healthy volunteers (25 men, age 23.5 ± 1.7 years; 25 women, age 22.4 ± 2.0 years) participated in tests using treadmill protocol. They walked or ran on a treadmill at four different speeds (4, 6, 8, and 10 km·h -1 for men and 4, 6, 7.5, and 9 km· h -1 for women) for 5 min at each speed. During the test, the T-REX (Taewoong Medical Co., Ltd., Korea) was attached at five locations on the body (ankle, arm, chest, waist, and wrist), the Actical was attached at two locations (waist and chest), and the ActiGraph was worn at the waist. Oxygen uptake (VO 2 ) was measured using a portable device during exercise, and metabolic equivalents (METs) were calculated. The validity of the T-REX was assessed using Pearson correlations and Bland-Altman plots. Results: There were strong associations between T-REX and VO 2 in men (r = 0.92-0.95) and women (r = 0.83-0.91) on the treadmill test (p< 0.001). Associations between the T-REX and two different accelerometers (Actical and ActiGraph) were also strong (r = 0.89-0.98). Similar associations were also observed between VO 2 and Actical (r = 0.87-0.95) and between VO 2 and ActiGraph (r = 0.85-0.87). In the Bland-Altman plots, there were no statistical differences between VO 2 and five T-REX sensor locations in both men and women (all p >0.05). Conclusion: The T-REX has a high concurrent validity with VO 2 in assessing energy expenditure in men and women. This device might be an alternative to conventional accelerometers.