Interval training is when you alternate between more intense and less intense exercise within a set period of time. For example, you pedal as hard as you can on a stationary bike for 20 seconds, and then you pedal at a more casual pace for 40 seconds. You repeat this 10 times for a total of 10 minutes on the bike. It's supposed to be as effective at getting you in shape as pedaling moderately for 30 minutes.

You can apply the same concept to developing concentration.

Example 1
While you're walking down the street, remain acutely aware of the sensation of walking for 20 steps. You can focus exclusively on the bottoms of your feet, or you can concentrate on the muscles in the posterior chain (butt and hamstrings). Then allow your concentration to slacken and broaden (but don't just daydream) for 40 steps. When that's easy, do 30 steps with intense concentration, 30 with slack concentration. Then 40 and 20 and so on.

Example 2
While driving, remain acutely aware of the experience of driving (in whatever way is safest for you) for half a mile, then let the attention slacken a bit for half a mile. Subdivide as you did during walking.

Example 3
While sitting in a meeting, do the same thing with the breath: for a minute, be focused solely on the sensation of the breath wherever you feel it best, and then let go for a minute.

The idea behind this approach is to get comfortable with continuously resting the mind on one object for longer periods of time. Too often we practice concentration for some period of time - say, 30 mins - and the mind goes on and off the object for that period of time. This is actually a lot less effective than having the mind rest on the object without break for a shorter period of time.

Don't try to penetrate the object with insight. Imagine a cloth draped over an object = X. Insight is like feeling all around the cloaked object to get a sense of what's underneath. This exercise is more like touching the surface so gently that you're only touching the cloth but not the object underneath - and just keeping the hand there in one spot.

Hi Fitter,
this is something I have been thinking about as well lately, namely using the HIIT (high intensity interval training) technique, which is very effective at building physical strength, endurance etc., in the realm of meditative skill development.

I can attest to the usefulness of the technique in the physical area - it seems that the body adapts a lot better to short bursts of intense demands at the outer edge of one's current abilities compared to long averaged-out training at low or medium intensity (say, running on a treadmill for 30mins). By pushing oneself to the absolute maximum, the body constantly keeps over-compensating (muscle growth), whereas it will very quickly get used to the less intense training, even if stretched out over longer training time (body stops adapting quickly, which results in less than optimal training yields given the invested time and energy).

Now obviously training one's concentration is different from trying to get a sixpack, but I still think that the same principles should apply. There is something to be said about brain plasticity and our mental ability to adapt and improve when challenged in certain ways, just as the body adapts when repeatedly faced with physical demands.

Your proposals are interesting, however I think what might be improved upon is the stressed amount of intensity in the "active" periods (as opposed to the periods of rest, where you basically just do nothing). Of course I am aware of the fact that the super intense bear-down on the object kind of concentration is not the suggested and skillful way to go, but maybe these ideas can somehow be tweaked somewhat to challenge the practitioner a little bit more, if not in intensity than at least in continuity of concentration (which as you have shown yourself is the real key to getting somewhere useful).

Anyways, I think this could really be helpful for a lot of yogis. It ist really easy to waste a lot of time basically daydreaming for 45mins (half-assedly coming back to your breath from time to time) until the timer goes off, and thinking you are doing great concentration practice. (I at least am certainly guilty of this)

I've done something like that in order to improve khanika samadhi; what happened was that after a while it was not so clear how to back off, 'cause momentum was keeping itself.

Any results with this? Seems similar to what I have read about tibetan samatha training with 15-20 minute sitting periods with breaks between where you loosen up a bit.

Yes, this reminded me of how Namkhai Norbu teaches shamatha, except in his version it seems like the emphasis is not so much on oscillating back and forth. It's more about using the intense focus phase to be able to lock onto the object (or the lack of objectification, depending on the phase of practice). So you just focus down hard until you are staying with it, then ease up and see if you can stay with it then as well. You go back and forth until you don't need to focus down any more but can just remain open and simple without the rising and passing of thoughts distracting you.

What sorts of experiences have you gotten with your approach Fitter?