Training involves alternating hard work with recuperation. Hard work damages the body; the subsequent recuperation not only repairs the damage but actually make the body stronger than it was before – so called ‘super-compensation’. Many training programs recommend two or three hard sessions a week separated by easy days. This seems a sensible way to produce the required super-compensation, but is it the most efficient? Efficient training requires a big enough stimulus from the hard sessions to mobilise the super-compensation response, and then a long enough recovery to allow the super-compensation to occur.
Older athletes face a double whammy. Our muscles can tolerate only moderate training stress, and recovery of damaged tissues takes longer – this is easily illustrated by observing a superficial bruise – a trivial knock that once might have produced a small bruise that disappeared in a few days now produces a large purple blotch that takes several weeks to resolve. So we oldies are less able to tolerate hard shocks but nonetheless need to spend longer recuperating.
Pondering the unfairness of this double whammy led me to wonder what it is that induces super-compensation. Possibly it is the stimulation of hormones such as growth hormone and anabolic steroids. It is well know that old folk produce less growth hormone and anabolic steroids than youngsters; maybe that is due at least in part to subjecting our bodies to less stress. If it is the magnitude of the initial stress that determines the amount of super-compensation, maybe what we need to do is to find a safe way of producing a bigger stress in the first place.
The principle of interval training is that we can accumulate a fairly large total stress in one training session by allowing a degree of recovery between repetitions. A recovery period of a few minutes allows replenishment of oxygen and at least partial clearance of lactic acid, but is too short to allow replenishment of fuel stores (which takes a few hours) or synthesis of new muscle proteins (which might take as much as a day).
So maybe the safest way to accumulate enough stress to produce maximal super-compensation is to spread out the repetitions over a period of 24 hours or more. This of course is similar to the principle of crash training, which has become quite popular among serious athletes in recent years. Training hard for several consecutive days and then allowing adequate recuperation can produce greater benefits than an equivalent amount of work done on alternating hard and easy days – provided one avoids breakdown during the few intense days.
Yesterday, in a tentative test of the recovery of my calf muscle, I did 2x1Km at a pace that induced a heart rate around 140 – which for me is in the upper aerobic zone. That was almost certainly too small a stress to induce maximal super-compensation. So today, I decided that rather than having an easy day before stepping up the intensity in a subsequent session, I would do a slightly harder session and then have two fairly easy recuperation days. I did 3x1Km in the upper aerobic zone. Of course a total of 5x1Km in the upper aerobic zone can scarcely be described as a heavy total training load – but as a rather cronky old-timer, I need to take things cautiously.
Yesterday I ran on a soggy woodland path. I estimated that the uneven boggy surface increased the work load by about 5% and slowed me down by about 10-15 sec per Km. So today I ran on the riverside path which has a much firmer surface. The times for the three 1Km repetitions were 4:27; 4:27; 4:27; (pleasing evidence that my pace judgment is still fairly consistent) and mean heart rate recordings were 140, 142, 143. Thus heart rate was only marginally higher than yesterday but pace was 17 sec faster.
So far so good. I will see how a program based on back-to-back interval sessions works out – though a least for the time being, the sessions will be of very modest intensity.
Ewan, thanks for your comment on the dangers of allowing the muscles to cool too much between repetitions at this time of the year. I warm up thoroughly (about 20-30 minutes of jogging with some easy paced stride-outs) and I jog fairly briskly between the repetitions.