Reply To: Add some spice :)
After reading the post from @doc I added 3 times a week hypoxia training into the workouts. My group consists of 8-12yo swimmers. I also tested hypoxia training with a triathlete. Hypoxia training set was 12-16x25F at 200F pace 20s rest with exhale-hold breath technique.
After the hypoxia training swimmers had some rest followed by one USRPT set.
We had a swim meet the weekend before I started with hypoxia training so I used the race times as a starting point. Last weekend was our last swim meet for the saison. Race times from there have been compared with the first meet. I have found an improvement of 1.96% for the swim group.
The performance improvement from the group was better than another group in the same club which didn’t use hypoxia and USRPT training but went to the same swim meets. Details of my group can be found in the attached file.
Triathlon race times are hard to compare but I could find some competitors in the same races and tried to asses if there are any positive affects with hypoxia training. The improvement for the triathlete was better than the swim group’s improvement.
Hypoxia training might be beneficial if you use the exhale-hold technique. Based on my findings parts of the improvement of my group could be related to this kind of training. If you look for scientific proof I would recommend to order the book from here http://www.hypoventilation-training.com/.