Tabata Smartphone App - $1.99
If you want to add in sets of CrossFit-related high-intensity interval training when you’re working out on your own time, try the Tabata method, which requires 20 seconds of ultra-intense exercise (about 170% of VO2 max) followed by 10 seconds of rest, for 4 minutes or 8 rounds. Do this with exercises that use large groups of muscles like push ups or front squats. You will need a good Tabata stopwatch app.
Available at iTunes.com.