I have been reading a lot of different stuff online regarding the type of training that is best for athletes. Heart rate, power, perceived effort, low intensity vs high intensity... The list goes on. The majority of athletes I coach, I use heart rate. Here is my take.
As a coach, when it comes to prescribing a workout for an athlete, I take a few things into consideration.
1) How long will the session be?
2) What is the purpose of the session?
3) How "hard" should the athlete be pushing during the session?
The answer to the first question is generally pretty simple: I give a time goal and once in a blue moon it's a distance goal.
The answers to #2 & 3 are a bit more abstract. In most cases though I will give an athlete his or her workout via heart rate zones. Below, I will attempt to give an explanation of how/why to train with a HRM.
Before heart rate monitors came about... Coaches would generally give athletes some sort of speed at which to train (i.e. pace per mile for runners or time per 100m for swimmers) ... or often by perceived effort (such as "go hard" or "go easy"). Cyclists can achieve this same concept by using a power meter. In most cases, especially for workouts that are supposed to be "easy/moderate" I choose to use the heart rate monitor as my feedback tool.
How does a coach determine an athlete's training zones?
There are a number of ways to do this. Some coaches prefer to use an athletes maximum heart rate to determine an athletes zones. Most readers are probably familiar with the 220 minus your age approach to determine zones. Some coaches also have athletes have their blood tested during training to figure out their lactate threshold and determine zones off of that.
With the majority of my athletes, I use Phil Maffetone's method of 180 minus the athletes age, followed by making adjustments based off the athletes current fitness level and experience. This formula will give you your "Maximum Aerobic Function (MAF)" or "Maximum Aerobic Heart Rate(MAHR)". Bear in mind, this is NOT "Max heart rate". This number is a guideline for where you can make the most AEROBIC gains.
So what is the importance of training at this number? Training your aerobic engine can be one of the most important, and under-estimated priorities in this sport of triathlon, or any endurance sport for that matter. When training and racing, the energy required will come from two different sources: 1) muscle and liver glycogen. 2) Body fat.
Using glycogen for energy can be very limited as the human body can only store 90 to 120 minutes worth of it. Fat on the other hand is virtually limitless if your body knows how to tap into it. To teach your body how to tap into fat for energy, it requires the athlete to do a significant amount of training at a lower heart rate then they are generally used to, which means that the athlete will need to slow down quite a bit, especially during the base building phase of their training. As the athlete becomes more efficient at burning fat, he/she becomes faster at a lower heart rate and by burning fat instead of carbs/sugar/glycogen for fuel.
So many people are afraid of this concept (low heart rate training) because they feel like they have to train fast all the time in order to race fast. Obviously the plan is not to race easy. This is one of the biggest misconceptions of this type of work. The key here is to build a big aerobic engine, then sharpen the knife with higher intensity training as the race gets closer and you have developed your systems with lower intensity training first. Once its time to go "hard", your body is going to be ready for it, and you will see much bigger gains.
I am a believer that this type of training can be useful for any athlete, although every athlete may vary slightly in their approach to see maximum gains. This is where having a coach or advisor guide you through the process can help greatly.
This type of training takes lots of patience and discipline, most people just want to go hard every day, and when they think they are going "easy", they are really just training less hard than usual, but aren't truly going easy. Using a heart rate monitor does not allow you to cheat. If you are following the right plan and paying attention to the HRM, you will truly be able to go "easy" on easy days and "hard" on hard days.
This can be a confusing and heavily debated subject. If you have any questions on this type of training. Feel free to ask.
PAUL DUNCAN JR