High Intensity Training – Part 1

High intensity training when included in a triathletes weekly program delivers many benefits.  Benefits such as greater muscular endurance and increased cardiac output efficiency, but it is also buyer beware.

High intensity training while delivering great benefits to improve performance also has a higher risk of injury and done too much can lead to burnout, illness and a decrease in performance. That is why it is important for triathletes to understand what it is and why you should include it in your program.

Let’s firstly look at muscular endurance.  One of the key factors we should consider in training is improving our fatigue resistance. By improving our muscular endurance, we limit the fatigue process and can therefore maintain speed and power for longer.

When doing high intensity training, we recruit fast twitch muscle fibres and make them more fatigue resistant.  In endurance events such as triathlon it is not about those who speed up towards the end of the race but who slows down the least.  And it is our muscular endurance that determines how well we do this.

The other main benefit from a physical perspective is improved cardiac output efficiency.  By performing high intensity training we improve our body’s ability to transport oxygenated blood to the working muscle.

Along with the physical benefits there are psychological benefits to high intensity training.  High intensity training can be extremely difficult. By completing hard, demanding, and high intensity training sessions a natural side effect is greater confidence.

One of our brain’s primary functions is to protect us and that is why during high intensity training we hear that little voice in our head that says it is okay to stop, to slow down or give up. However, by persevering and completing these hard high intensity sessions we’re improving our mental resilience and further developing fatigue resistance.

The challenge for triathletes is knowing how hard and how much high intensity training to do.  From my own personal experiences and through my career as a coach I have seen how getting this wrong can lead to injury, illness, burnout and poor performance.

In terms of how hard there are a several ways it can be measured.  And with the technology available to measure just about everything I like to keep things simple.  A heart rate monitor and rate of perceived exertion are my preferred ways to measure training intensity.

Heart rate monitors give us instant information as to what is happening internally.  While heart rate is affected by variables such as weather, training terrain, hydration levels and stress it is in my experience the best measurement for determining training intensity.

Used in conjunction with rate of perceived exertion on a scale of 1-10 with 10 being all out maximal effort and 1 being rested, high intensity training is 8-9/10. At that intensity our heart rate would be 80 percent and above of it’s maximum.  We would also be breathing very heavily, only able to talk in 3-4 word sentences at best and it is generally quite uncomfortable.

Now that we know what high intensity training is, it’s benefits, potential negative side effects and how to measure it the next question is how much of it should we do?

Firstly, it is contextual to the athlete and the event they are training for. And secondly what type of responder are they?  Some athletes respond to and absorb high intensity training very well while others don’t.  This is where the law of specificity should determine how much high intensity training someone should do.

Races such as sprint and even standard distance triathlons will see athletes race the entire event at 80-85% of their maximum heart rate while an Ironman event will be more 70-75% of their maximum heart rate. Therefore, following the law of specificity, you would include more high intensity training if you were training for shorter distance events.

The more experienced an athlete you are the more, high intensity training you may be able to absorb. However even for experienced athletes I would not recommend more than 4-5 high intensity training sessions per week.  A beginner level athlete might do 1-3 high intensity sessions per week, but both are dependent on their overall training load and the event they are training for.

My overriding principle that I follow to help determine training intensity is a polarized model. You can read about it more here.   This follows a formula that says about 80% of total training volume is at an aerobic intensity of 70-75% of maximum heart rate and under while the remaining 20% is the high intensity training at 80% and above of maximum heart rate.

Whilst this is a principle that I follow I always look at the athlete in front of me. I have had athletes do a 60/40 split and others do a 90/10 split. And then within the high intensity training some will be at a threshold level of 80-85% of maximum heart rate while some may do very little threshold training and more at 85-90% of maximum heart rate.

In part 2 of this blog to be released next week I’ll go into how it can be applied in a program and the different types of sessions across swim, bike and run.

About Mark

Mark is one of Australia's most experienced and knowledgeable triathlon coaches. With over 25 years experience coaching at all levels from kids, youth, adult and elite professional athletes across the World. He loves seeing people change their lives through triathlon.

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