which makes the running uncomfortable, although not painful; but if I continue, after about a full mile the feeling starts to go away and I can comfortably continue until my first walk break. Yesterday I noticed that when I resumed after the walk break the feeling came back, although it didn't take quite so long to fade.
I have been running (off & on, mostly on) for 25 years, have completed half marathons in the past but this past year have been much less active. I did fairly easily complete a 4 miler on Thanksgiving however have been only been walking, doing beginner's yoga and TRX training since then. That is why I am doing the run/walk/run routine to get back up to speed. I've never experienced anything like this before.
Does anyone have any ideas what is going on? Thanks!
Although this may not be much comfort at this point in time, early onset of muscle fatigue, or easily induced soreness during exercise, is a very common complaint for those who return to exercise after a long layoff.
Two short explanations: (1) Exercise affects hormones responsible for how much of our tissue is devoted to consuming energy, and how much is reserved for storing it. During a long layoff, there is generally a movement from the former to the latter, even if there is no change in total weight of all tissue. (2) The physiology of the muscle tissue that remains begins to change during this time, from stronger/less energy efficient, to weaker/more energy conserving.
The result is tissue that is more easily irritated, injured, or failing to function on demand. When you jump back into your training schedule, you can expect a reversal of the two processes in the previous paragraph, but in the same order. This means that without a gradual building up to your (once old) new training schedule, it's gonna hurt. There is also the likelihood that muscle mass has fallen in proportion to adipose tissue, which means the old workouts are being run with less muscle at the same or greater weight load.
Vigorous exercise will stimulate the production of human growth hormone after exercise, and during quality sleep at night. This in turn will result in the gradual re-absorption of weaker muscle fibers, and replacement with newer, stronger ones, as you continue to exercise on the muscles under construction. This process tends to hurt. A lot. The reduction of adipose tissue will be ongoing.
While you must be patient and wait for these processes to complete (they won't unless you continue to endure), there are some things you can do to keep what tissue you have functioning better and longer. First would be to adopt the flattest footstrike you can manage for your aerobic training. This isn't just about a "mid-foot strike," but about delaying toe-off as long as possible while the rear-calf plantarflexors slowly rebuild. Second, you will benefit, as I and countless others have, from self-massage to the lower calf muscles to relax out the tight fibers that make the whole thing seem to hurt, when most of the muscle is probably just fine.
Some explanation here: As you run, it is often believed that all the fibers of your muscles contract in unison when you use them. Turns out this is not so. Your brain rotates its use of portions of the muscle to rest some fibers while others are working. The more efficient an athlete you become, the greater a percentage of your total muscle fibers can be used at any given time, because they are stronger and more durable - but the less have to be used during aerobic training, because the few you wind up using are stronger, and last longer.
After a long layoff, your muscles become incapable of this kind of power and endurance, which fits in well with your walk/run schedule right now. I'd tinker with the percentages if I were you, and allow the adaptations to take place over the next few months. The rule of thumb is, a month off, two months back to where you were when you took your break. Personally, after a six-month break, it took me more than a year to get back to where I had been. But there may be a short-cut for you worth trying!
The workouts you are doing now are probably, minus a certain percentage of walking, what you want to continue doing. While I firmly believe that running is the best way to train to run, the type of running you want to eventually do (endurance running) may not be the fastest route to training for it. If I were you right now, I would do what I wish I had known how to do after my long layoff.. Shift from prolonged aerobic exercise to shorter sessions that incorporate short bursts of anaerobic high-intensity exercise. This may sound counterintuitive, but it has a physiological basis. Only anaerobic exercise is going to stimulate the shift in HGH production you need to start building muscle tissue quickly. Oh you'll get there eventually the slow way, but you will be no safer from injuries logging more miles on tired muscles with more repetitive motion.
In this specific case, I would replace each hour of slowly slogging it out, with 20 minutes of high-intensity repeats, perhaps twice a week. The total load on your recovering muscles will be less, but the effect on tissue strengthening will be greater, with less time invested. After allowing a few weeks to slowly build up your program, divide the 20 minutes in this way: Warm up gently with two minutes of slow jogging. Using a sport watch that displays seconds elapsed, do 8 repetitions of 30 seconds of fast running immediately followed by 90 seconds of slow jogging. Every two minutes you are repeating this cycle for a total of 8 repeats. Your heart rate should not max out after 30 seconds, but may get close by the last couple repeats. Conclude with a two-minute jog as your cool-down. You could start this with one or two repeats at first, and add an extra each week until you reach eight. Doing this kind of workout for more than 20 minutes would be a waste of time unless you are a professional or an elite athlete.
While this kind of anaerobic workout will challenge your muscles more, it will be for a much shorter time with more recovery built in. The object of course, is to stimulate new tissue regrowth as quickly as possible. If this is not your goal, slow and steady may get you back to where you want to be by sometime next year. Whatever you do, give your body some time to adjust to the changes. You don't have the same body you had before, but if you continue to train, you will gradually trade this one in for the one you want, perhaps even better than before!
A link from New Zealand physician Jonathan Kuttner about the physiology of post-exercise soreness after a layoff, followed by his account of a case of calf soreness in a competitive athlete that almost resulted in unneeded surgery...
Thanks so much for the detailed response! I will indeed switch up my training to incorporate the repeats; and also the massage, which has never been part of my routine. I was afraid that the achiness might be related to issues with blood flow. Having it start early, then get better, is confusing to me and not what I would have expected from decreased fitness. I've just never had problems with muscular fatigue or cramps when resuming workouts at the level I do-- the cardiopulmonary fitness has always been my limiting factor!