The 12-3-30 workout: What are the pros and cons?

The 12-3-30 workout is a relatively simple but effective cardio exercise routine that primarily involves walking on an incline using a treadmill. The name refers to the rules: You walk on a 12% incline for 30 minutes and aim for a speed of three miles per hour. Is the 12-3-30 workout worth a go? Personal trainer Amanda Place, the founder of Sculptrition, has given us her verdict.