The aspect of running that requires greatest judgment is deciding when to persist despite tiredness or pain. The safe simple answer is never run through pain. However at least for a person approaching his mid-sixties, this apparently simple answer is not really simple. It is rare that there is no trace of discomfort in muscles or joints, and judging when to persist and when to desist is often tricky.
In accord with my plan to increase intensity a bit, this week I planned 8x400m at 8/10 of maximum effort on Thursday and 6x1Km at 4:20 per Km (estimated 5K pace) on Saturday.
Thursday’s 8x400m session went well. I ran on the somewhat overgrown grass of an abandoned sports field, and was pleased to find that I could run with a feeling of fluency. I did not wear a watch and have little idea of my pace. It felt like a 58-60 second pace used to feel in my youth, which probably means the actual pace was about 85 sec per 400m. The only niggle was a slight tension in my right calf that developed during the 7th repetition. I usually run with a forefoot landing, which is gentle on the knees but places more strain on the calf muscles. (See http://www.sportsscientists.com/2007/09/running-technique-part-ii-scientific.html for the scientific evidence). So for the eighth repetition I adopted a mid-foot landing and concentrated especially on lifting my foot from stance using hip flexors and hamstrings, while avoiding any trace of pushing off using calf muscles. The tension in the right calf caused no further trouble. I arrived home feeling satisfied that I had achieved my target and had avoided injury.
On Friday I had slight stiffness in quads and hams, but no pain in my calf. I did 3 sets of 20 body-weight calf raises standing on one leg, on right and left leg, with only a barely perceptible trace of discomfort in my right calf.
One Saturday I set out to do the 6x 1Km on the trail in Clifton Wood, as planned. The weather has continued mainly fine in the past week and the trail was fairly firm underfoot, apart from two muddy patches. A deepening layer of autumn leaves covered the ground, obscuring the tree roots, and the dappled sunlight filtering through the trees compounded the difficulty of identifying treacherous obstacles. However I love running in the woods, and despite my multiple musculo-skeletal weaknesses, I have only ever once seriously twisted an ankle – that was when carrying my young son on my back down a steep and stony hillside many years ago. I think I have fairly tough ankle ligaments as a result of lots of hill walking in younger adult life. So I decided that the delights of running though autumnal woodland justified the risk of ankle injury.
The first three repetitions went well. The times were 4:13; 4:18 and 4:14 per Km and my average heart rate recordings were 140, 143, and 142. At the halfway point on the fourth repetition, the tension in my right calf returned. As on Thursday, I adopted a mid-foot landing, but within a further 200m it was clear that the tension was increasing. What I had not taken into account in that this part of the path rises gently uphill over an irregular root-ribbed surface, and re-distributing the load onto my heel in mid-stance to alleviate tension in the Achilles tendon and calf was less easy than it had been on a level grass surface on Thursday. I slackened the pace for the remaining 300m. I was pleased that my time for the fourth Km was 4:16 and average HR was 143. However, gentle stretching of gastrocnemius and then of soleus revealed that there was a definite tear of soleus – the deeper of the two calf muscles that is mainly active when knee is flexed. Thus the features of my current style that I have developed to protect my vulnerable knees- forefoot landing on a slightly flexed knee, combined with the demands of running uphill on an irregular surface, had been my undoing. I abandoned the session and am now sitting with an ice pack over my lower calf – though unfortunately soleus is deep and less accessible to the benefits of ice. So, my plan to increase intensity has produced pleasing evidence that I can still run fairly fluently at moderate pace, but I am now nursing an injured muscle.