High Intensity Interval Training or HIIT, comprises repeated short bouts of sprints or high intensity exercise followed by lower intensity recovery, and unless you’ve been training in a cave for the past two years, HIIT has been a major talking point in the gym.

The past week has seen a few people asking me about this type of training though, after an Australian Science Program(Catalyst) dedicated an entire episode to research performed on HIIT and the surprising effect on the bodies cell mitochondria, which are responsible for taking oxygen from the blood to produce energy for muscles.

The research results suggested that cell mitochondria not only adapted to the increase in stress, but also increased in number and improved function by 30% within the first 4 weeks. The research also showed that the high intensity training, especially sprinting, worked better as the participants needed to recruit all of their muscle fibres at once, compared to low intensity exercise that only used the muscle fibres that were needed. The research is not only showing that this improvement to mitochondria function could help obesity, cardiovascular disease and type two diabetes, but also be linked helping with improvements in ageing and Alzheimer’s.

Catalyst completed their own set of training for a four month period with a goal to complete three 20 minutes training sessions per week. The four month period did show some positive results, with the training increasing the participant’s VO2max from 36 to 40, she lost 1.5kg of fat and 6 cm from her waist and was able to run 9km non stop when she could not even run 3km before the training started.

So when one of the questions posed to me, was for a HIIT session for swimmers, it made sense that if you could set up a training set, making sure that the intensity and technique were also correct, you would be training your cell mitochondria from your entire body to become more efficient.

I have been using the following HIIT swim training session for the past two weeks and it gives you a 200m warm up and cool down and only totals 1km in distance. The sprints are to be performed flat out with the recovery being performed actively with breaststroke and freestyle. The recovery should be double the time of the sprint, so if you are sprinting freestyle for 40 seconds, you need to give yourself 80 seconds in the recovery period.

Warm UP:
200m warm up – freestyle at a easy pace
Rest for 1 minute
Main Set:
50m sprint – freestyle sprint
50m slow – breaststroke 25m/ slow freestyle 25m
50m sprint – freestyle sprint
50m sprint – freestyle sprint
50m slow – breaststroke 25m/ slow freestyle 25m
50m slow – breaststroke 25m/ slow freestyle 25m
50m sprint – freestyle sprint
50m slow – breaststroke 25m/ slow freestyle 25m
50m sprint – freestyle sprint
50m slow – breaststroke 25m/ slow freestyle 25m
50m sprint – freestyle sprint
50m slow – breaststroke 25m/ slow freestyle 25m
Rest for 1 minute
Cool Down:
200m cool down – freestyle at a very slow pace

I am not 100% convinced that this is the best approach to improve endurance especially when training for larger distances. A four point increase to my VO2max would put me into the seventies though, so I am keen to see more research, and possibly what combining HIIT training with usual endurance training methods would result. I have added the above training session as my Sunday afternoon swim and have enjoyed the extra variety it’s added. It’s a tough session but you get out of the pool feeling fresh.

Below is a link to the episode of Catalyst
http://www.abc.net.au/catalyst/stories/4319131.htm

Vince Sesto

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