In my resistance training workouts, I've always struggled when it comes to complying with 'slow repetition rules' that accompany many routines. Whether it is '4 second contraction, 3 second relax' or '5 second concentric phase and 5 second eccentric phase', I've never been able to consistently go slow enough. Towards the end of any set, I get so focused on just finishing I tend to ignore everything else.
So earlier this week I tried a new trick, with the help of my handy smartphone: Using a metronome application to help me keep a steady pace. In my case, I downloaded and installed Mobile Metronome Plus from the Android market (there are many similar apps available from the iPhone AppStore as well).
Although this app was really intended for use by musicians, I was able to configure it to 'chime' at a rate of 12 beats per minute (1 beat every 5 seconds) with a 20/4 time signature (4 sub-beats per 5-second beat). This resulted in a repeating pattern of 'tick-tick-tick-tick-tock'. With my headphones on, and this rhythm being piped into my ears, it was suddenly very easy to maintain a '5 second concentric phase, 5 second eccentric phase'.
If you're following a workout that requires the use of slow/timed repititions, give this a try.