I tried to attempt a faster pace. On 12th December I tried larger stride length, it was a 5.97k run, my back complained but my legs were alright. On 19th December, a 6.22k run, recovered from back pain, other than that felt nothing wrong. On 22nd December, again deliberately tried larger stride length, less frequency, I started to feel pain at inner side of my knee.
On 24th I went for a walk along the lake it was at least 2k. Next day on 25th I went for a X'mas run, bad move, my muscles have not recovered. I felt pain at the left knee and my right leg a bit of cram after the run. All these troubles were later confirmed after another run on first day of the new year.
Here comes a research project, why my legs are complaining?
Initial finding was that it could be the Iliotibial band that caused the pain around the knee. Where is your IT band, look here. The weather has been cold recently and may be I have not done stretching sufficiently or correctly before the runs. Knowing what to do is one thing but putting it in practice is another. Especially when weather is cold I really like to get myself up to speed as soon as I could. You will see if you have the same symptoms and how to do self treatment from here. The possible causes listed there are
- Exercising on hard surfaces;
- Exercising on uneven ground;
- Beginning an exercise program after a long lay-off period;
- Increasing exercise intensity or duration too quickly;
- Exercising in worn out or ill fitting shoes;
- Excessive uphill or downhill running.
I think my problems are 1, 4 and 5. From this article it recommends that I should be getting cheaper shoes and replace them more frequently. Certainly my running shoes have done more than 400 miles now.
After reading enough about IT band I found my case may not be that serious. It could be just stress fatigue or fracture. From here this is due to muscles that become unable to support the skeleton during impact (e.g. long runs) as the foot strikes the ground. Instead of the muscles (with a pair of proper shoes helping) absorbing the shock the load is transferred to the bone. The term fracture could be scary but this one says that the term 'stress fracture' is a misnomer.
I'm now pretty sure this is my case because I don't feel cracking/rubbing noise underneath my patella (knee cap), no trouble walking up stairs, nor I felt anything muscles related after few hours of rest. However I felt sustained mild pain at the front of my left patella and along the lower part of right tibia (shin bone). A longer than normal rest and some food supplements may be good according to this.
I just ran last Sunday 10th at super slow pace and small stride to confirm my theory. I'll be running once per week and at the most 5k in the next few weeks to slowly get back to my usual pace.