Assessment of a Treadmill Speed Incline Conversion Chart: A Validation Study.

Area of Science:

• Exercise Physiology
• Sports Science
• Biomechanics

Background:

• Treadmill training is a common method for assessing and improving cardiovascular fitness.
• Accurate conversion charts are essential for standardizing exercise intensity and ensuring training efficacy.
• Existing charts may not accurately reflect physiological responses across a wide range of inclines.

Purpose of the Study:

• To evaluate the validity of the HillRunner.com treadmill speed incline conversion chart.
• To compare physiological and subjective measures across different speed and incline combinations.
• To assess the accuracy of the American College of Sports Medicine (ACSM) VO2 prediction equation at various inclines.

Main Methods:

• Experienced runners (n=33) completed 6 randomized 5-minute stages at speed/incline combinations from the HillRunner.com chart.
• Physiological measures included oxygen consumption (VO2), heart rate, and blood lactate.
• Subjective measures included rating of perceived exertion (RPE).

Main Results:

• The HillRunner.com chart was validated at inclines up to 4% with no significant effect on physiological or subjective measures.
• At inclines of 6% and above, significant increases in VO2, heart rate, blood lactate, and leg RPE were observed.
• The ACSM VO2 equation underestimated oxygen consumption in trained runners up to 8% incline.

Conclusions:

• The HillRunner.com chart is only valid for treadmill inclines at or below 4%.
• Treadmill stages above 4% incline result in higher exercise intensity than predicted by the chart.
• The ACSM VO2 equation requires adjustment for trained runners at inclines up to 8%.