2.4. Visual-Analog Scales
fatigue
The participants completed 100 mm anchored VASs before and after baseline testing, 1 h, 2 h, and 3 h after the ingestion of each supplement on visits 3 and 5, and twice on visits 2 and 4 (before and after their first cognitive testing session). The VASs were anchored with “Not very focused”, “Very low initiative”, or “Lowest Possible” and “Highly focused”, “Very high initiative” or “Highest Possible” and assessed subjective ratings of energy, sustained energy, mental stamina, ability to focus, ability to concentrate, motivation to accomplish difficult tasks, drive, vigor, positive outlook, mood, feeling of well-being, and ability to tolerate stress. Again, the two values (before and after the first cognitive testing session) for each subjective rating on visits 2 and 4 were averaged and then used in the statistical analyses as the participants’ baseline. The validity and reliability of the VAS for assessing fatigue and energy have been previously established [