Zwift Hour of Power: Can a 60-Minute Zwift Race Work as a Test? Dr. Stephen Seiler explores whether a Zwift race of about 60 minutes can be a decent substitute for a 60-minute FTP test. Dr. Stephen Seiler Jan 18th 2021 Dr. Stephen Seiler explores whether a Zwift race of about 60 minutes can be a decent substitute for a 60-minute FTP test. This content is for Library, Listener, and Forum members only.Listener Membership is FREE. Please join now.Log In Join Now