High intensity workouts are a quick way to see amazing results, feel great and not consuming hours of your day. In fact, doing just one HIIT workout per week will increase your metabolism for at least 24-hours and give you the edge you need to really start seeing results. Whether your desired results are weight loss, an increased fitness level, increased speed and quick twitch muscle results, or just a really (and I mean REALLY) good workout, this will do all of those things.
Here is a track workout I did a couple weeks ago. It took me about 40 minutes and was hard to complete the last 2-200m sprints, but well worth the effort. If you are a beginner, I would decrease each set by half of the reps (ie...1-800m, 2-600m, 3-400m, 4-200m sprints) but don't decrease the intensity. That is where you find your results.
Here it is! And if you don't have access to a track...I have included a time-based interval below, for each section which are great for rowing, swimming, elliptical machines, cycling/spinning, etc.
Track Workout:
1/2 mile warm up
2 X 800 meter sprints (30 seconds rest between each sprint)
REST 1-2 full minutes
4 X 600 meter sprints (30 seconds rest between each sprint)
REST 1-2 full minutes
6 X 400 meter sprints (20 seconds rest between each sprint)
REST 1-2 full minutes
8 X 200 meter sprints (10 seconds rest between each sprint)
1/2 mile cool down (slow run, jog, walk)
Stretch major muscle groups (quads, hamstrings, back, shoulders, triceps, chest)
Time-based Workout:
(also good for swimming, rowing, ellipical, treadmill and cycling training, too!)
5-7 minute warm up (slow run, jog, walk)
2 X 3 minute sprints (30 seconds rest between each sprint)
REST 1-2 full minutes
4 X 2 minute sprints (30 seconds rest between each sprint)
REST 1-2 full minutes
6 X 1.5 minute sprints (20 seconds rest between each sprint)
REST 1-2 full minutes
8 X 45 second sprints (10 seconds rest between each sprint)
5-7 minute cool down (slow run, jog, walk)
Stretch major muscle groups (quads, hamstrings, back, shoulders, triceps, chest)