Table 1 Standardized activity protocol used for the laboratory condition

Standing

Upright standing at a height-adjusted desk.

5

Sitting

Sitting on a chair at a height-adjusted desk.

Lying (supine)

Lying down in supine position with or without head on a foam pillow

3

Lying (side)

Lying down on the left side with or without head on a foam pillow

Lying (prone)

Lying down in prone position with or without head on a foam pillow

Walking (slow)

Walking on treadmill with 0.5 m/s

Walking (moderate)

Walking on treadmill with 0.8 m/s

Walking (fast)

Walking on treadmill with 1.2 m/s

Running (slow)

Running on treadmill with 1.8 m/s

Running (moderate)

Running on treadmill with 2.3 m/s

Running (fast)

Running on treadmill with 2.8 m/s

Cycling (slow)

Cycling with 50 Watts and 40 rpm

Cycling (moderate)

Cycling with 75 Watts and 60 rpm

Cycling (fast)

Cycling with 100 Watts and 80 rpm