This seems to be the new buzz word in training these days. In the last year or so, I have seen an increasing number of online coaches, online magazines, web sites, and blogs touting the benefits of utilizing high interval sets to stimulate gains in endurance in a fraction of the time as doing high volume low intensity training. Recently, I received a newsletter from CTS with a link to Science Daily with an article about HIT training. Why I even saw CNN resident medical correspondent Sanjay Gupta this past week advising millions of Americans to do 10 sets of hill repeats with 1 minute rest breaks as a "short cut" to gaining fitness.
Traditional long even training started with a base period of slow long sessions designed to increase endurance before moving on to spedd building during the build and peak phases. The basic premise of HIT is to make the best use of time by incorporating intervals into your session. Sets of intervals of high intensity with adequate rest between efforts is reported to have similar benefits to gaining endurance fitness as moderate longer duration training.
So here is my 2 cents. I have always been a proponent of smart training. In the first year or two of training, you will see improvements in fitness with any training. Basically anything that gets you off the couch is enough of an increase in activity to get you to your goal of finishing your event. For a new athlete, a ride here, a run there, few swims, will result in significant gains in fitness. But eventually you reach a plateau, and you have to start putting thought into your training. Mixing in high intervals is a key part of that. Hill repeats, speedwork on the track, and race simulations, should all be mixed in with longer endurance sessions. All training should be done with a purpose, and junk miles should be eliminated.
But I also think there is a place for the long endurance workout. I can't see how an athlete can complete a 11 hour Ironman with a 6 hour bike split and a 4 hour run split if their longest training ride was only 3 hours, and longest training run was only 1 hour, no matter how many intervals were done. If for no other reason than mental preparation, I really think that some training should be done with distance in mind. Nothing gets your mind ready for a long Ironman day than a couple of 5 to 6 hor rides during your training.
The difference is that in a program focusing on HIT, speed is built along the way so those long distance rides can be done at a higher pace. Ultimatly you'll see speed gains right from the start of the program instead of waiting until you finish your base period. The biggest benefit I see is during the winter for athletes preparing for an early season event. A 1 hour, well planned interval sessions on the trainer may be easier to handle than a 2 hour "EASY" ride. For me, no 2 hour ride on a trainer is easy.
Finally, HIT may not be for everyone. Intervals are hard. Some people may simply enjoy a 2 hour run at easy or moderate pace than 45 minutes of hill repeats, or speed intervals at the track, so there is definately personal preferance involved.
Anyone with an opinion on HIT, are incorporating it into their plan, maybe preparing for an upcoming long event, send it along. I'd love to find out what everyone else thinks.