Concurrent validity of the PAM accelerometer relative to the MTI Actigraph using oxygen consumption as a reference

Area of Science:

• Physical Activity Measurement
• Biomedical Engineering
• Exercise Physiology

Background:

• Objective physical activity monitoring is crucial for public health.
• Accelerometers are widely used to assess physical activity and energy expenditure.
• Validating new devices against established measures is essential.

Purpose of the Study:

• To determine the concurrent validity of the Personal Activity Monitor (PAM) against the Actigraph accelerometer, using oxygen consumption (VO2) as a reference.
• To evaluate the test-retest reliability of the PAM device.

Main Methods:

• Thirty-two healthy adults performed treadmill and stair walking wearing PAM, Actigraph, and Cosmed K4b2.
• Concurrent validity was assessed using correlation coefficients and agreement in energy expenditure (EE).
• Test-retest reliability of 296 PAM devices was evaluated using a laboratory shaker, calculating intraclass correlation coefficients (ICC) and coefficient of variation (CV).

Main Results:

• PAM and Actigraph showed strong correlations with VO2 during treadmill walking (r(2)=0.82 and 0.64, respectively) and stair walking (r(2)=0.93 and 0.74, respectively).
• PAM and Actigraph accelerometers demonstrated comparable validity (r(2)=0.95 for treadmill, r(2)=0.65 for stair walking).
• PAM exhibited high test-retest reliability (ICC=0.80, intra-CV=1.5%). Both devices underestimated EE.

Conclusions:

• The Personal Activity Monitor (PAM) is a valid and reliable accelerometer for assessing physical activity.
• PAM demonstrates comparable validity to Actigraph and can effectively rank individuals by energy expenditure.
• PAM is suitable for objective monitoring of habitual physical activity.