We regularly receive interesting practical questions from our readers. We are happy to answer them, so don’t hesitate to contact us at www.thesecretofrunning.com. Last week, Marcel van Boxtel e-mailed that his track coach designs the pace of his interval sessions based on his 10-K time. This is very common. Depending on the interval distance, the coach will indicate the pace by the number of seconds per 100 meters. Marcel prefers to switch from pace-based to power-based interval training. Because that is better and more scientific, Marcel rightly says. We agree with him, also because the power (in Watts) is immediately visible. You don’t have to wait until the first 100 meter mark to check if you are on schedule.