Yes, absolutely. More and more research shows that shorter duration/higher intensity workouts yield higher benefits/results. Basically, it just boils down to hard work. But the truth is, the longer the effort the lower our intensity. If you run 10 miles your intensity (power output) will be lower than if you run multiple 400 meter sprints. At CrossFit Guelph we do go beyond 30 min on occasion, but the majority of our workouts are shorter in duration. If you have a shorter workout, you can work harder by nature which can lend to a better response, especially combined with the movements we do. No matter who you are or what workouts you do, without hard work you will not receive results, which is why we encourage you to work to the limits of your physiological and psychological tolerances.