Whenever I tell my bootcampers that we have interval or sprint training I guarantee two things will happen.
1. If I tell them before a session then numbers go down. Some people just don't fancy it as there is just nowhere to hide. You have to put one foot in front of the other fast.
2. If I tell them on the day then there is a lot of chuntering. I get called a lot of names, more so than any other session.
At the end of the session everyone is buzzing and there is a feeling of really achieving something. Sprints and interval work are a little bit like taking medicine. It tastes horrible but you take it because you know it does you the world of good.
This tells me that these sessions are some of the hardest we perform. If performed properly they take people right to the edge of their mental and physical fitness. However we're not just doing this to inflict pain and suffering and to fill 20minutes. Every protocol I use with my one to one personal training clients or my bootcamp gang is based on science.
There is a lot of evidence in the public domain demonstrating the benefits of sprint training. A study by Hazell et al (2014) was published in the Journal of Applied Physiology, Nutrition & Metabolism. It was called "Running sprint interval training induces fat loss in women." This was one of the first studies to look at the effect sprint/interval training had on women. As I train a lot of ladies it got my attention straight away. I have read it many times trying to extract data to make my sessions more effective.
The authors wanted to know what the effect of three sprint sessions per week for six weeks would have on the body composition of women. The protocol was based indoors on a treadmill. Participants had to perform 4-6 "all out" 30seconds sprints with a 4minutes recovery in between. That's 4minutes rest between each set. That should tell you that "all out" means "all out" not 80% or a fast run. It's everything you've got from second 1 to second 30. If I had to judge the intensity by a talk test then it would be 1-2 word answers. If you can talk for 5 words then that's roughly 70%.
The study published the following results.
- Training decreased body fat levels on average by 8%.
- Training decreased waist circumference by an average of 3.5%.
- Training maximum oxygen consumption by an average of 8.7%.
- Peak running speeds increased by 4.8%.
It should be noted that there were no changes in diet from week 1 to week 6. The participants ate the same amount of calories throughout the experiment. This monitored through food diaries.
So the take home message is this. If you want to be a faster runner, lose fat and have a slimmer waist then get interval training. Keep the sessions short and move fast.
We start using this protocol and others like it this week at bootcamp.