A regimented method of progressing an athlete during training is to use the 10% Rule. This rule states that the athlete’s progression should comprise no more than 10% of their total volume the previous week. For example, while training for a marathon an athlete accumulates 30 miles during Week A. By using the 10% Rule the athlete would increase their mileage by 3 miles to reach a total of 33 miles for Week B.
Now, this 10% volume progression becomes more complicated with multiple sports such as triathlon. It is less likely that the athlete will develop overuse injuries from cycling or swimming when compared to impact sports such as running, but a regimented progression is advised to prevent injury. Increasing 10% of the mileage for running and cycling, and meters/yards for swimming should be done for each discipline. For example, while training for an Olympic distance triathlon the athlete accumulates 1000 meters swimming, 40 miles cycling and 10 miles running during Week C. By using the 10% Rule for each discipline the athlete would accumulate 1100 meters swimming, 44 miles cycling and 11 miles running during Week D.
This progression does not apply to a healthy, experienced endurance athlete. These athletes typically have trained with a coach or independently progressed themselves towards a more rigorous training program that allows them to be more efficient with their time. Athletes new to the endurance realm should utilize the 10% Rule to build a strong base and then become more aggressive with their training or, better yet, get a coach or join a training group.