After more than 25 years in the fitness it's safe to say that I have learned a few things. Like the impact that Smartraining can have for one and the other is the beauty of the Tabata Protocol. It's such a clean and efficient interval workout and it's the only cardio workout to my knowledge that has the ability to produce both aerobic and anaerobic gains concurrently (see study). It can be done for a great cardio workout or even a circuit-base workout on the strength side if you like. The original design was the brainchild of Izumi Tabata, PhD and his research was performed with test subjects exercisng on a bike. His research involved a training protocol that included a 2:1 work to rest ratio that was repeated for 7-8 intervals. Test subjects used a workload on the bike that corresponded to 170% of their VO2 max and following 6 wks of training (5x/wk) they saw a significant increase in both aerobic and anaerobic performance. You, however, have the option of performing similar "modified" workouts on an elliptical machine, ergometer, running and swimming to name a few.
A couple of great training options: wear a heart rate monitor and try Gymboss to monitor your sets.
This type of moderate to intense workout should be performed by someone who is well-conditioned and if not, try the warm-up and then a couple of easy intervals and cool-down and slowly progress over time. This type of interval workout is great to add in once a week to your regular routine.
A typical Tabata Protocol might look like this:
20 seconds of all-out work followed by 10 seconds of recovery x 8 sets (4:00)
Tabata I, Nishimura K, Kouzaki M, Hirai Y, Ogita F, Miyachi M, Yamamoto K. Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max.
Med Sci Sports Exerc. 28(10):1327-30, 1996
Martin J. Gibala, Jonathan P. Little, Martin van Essen, Geoffrey P. Wilkin, Kirsten A. Burgomaster, Adeel Safdar, Sandeep Raha and Mark A. Tarnopolsky. Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance.
The Journal of Physiology, 575, 901-911, 2006
Read about Tabata Science