Up Cardio Intensity For Greater Power

If you have 4 weeks to improve aerobic performance, what’s the best approach? A study published in The Journal of Sports Medicine and Physical Fitness investigates 3 different training programs using 30 athletes in their mid-30s.
 
Before and after 4 weeks of training, subjects were tested for heart rate and power production. Some increased workout intensity during the program while others performed a uniform intensity each week. A third group trained at their own pace. Increasing the intensity significantly increased total power.