Until last night, I have been mentally counting to time the duration of my PE stretches. It occurred to me while doing Tabata squats, which I time with a Nike sports watch, that timing my PE stretches using the watch timer would prevent me from losing count and, since I normally stretch while watching television, allow me to sort of multi-task.
Anyway, the standard Tabata protocol is to perform a selected exercise in alternating intervals of 20 seconds work and 10 seconds rest, for a total of 4 minutes - 8 work intervals. I set my watch to count intervals of 35 seconds alternated with 10 seconds of rest. I used the extra 5 seconds to account for adjusting my grip.
Obviously, using a timer doesn’t change the efficacy of the stretch, it just automates the timing, which makes it more convenient for me. There are several sports timers available, including watches such as the Timex Triathlon and the Nike line of sports watches, as well as the Gymboss sports timer that gets rave reviews on several fitness sites.