This is my second week at 20km, just a little bit over actually, with a 'long' run of 9.7km. As I was completing today's run I became aware of the lateral part of my left patellar tendon, but no more than that. I also did my physio exercises without tweaking it at all prior to the usual rollering and stretching.
The run felt a little hard work, I think there were many reasons for this. Probably most significant is cadence, I'm sure that cadence of 180 steps per minute is harder work than going at a lower rate, even if the steps are small. This study was focussed on the POSE method and showed a decrease in efficiency in contrast to the advertised outcomes. A rummage around PubMed hasn't revealed any other papers relating cadence to efficiency. However, I've been advised to adopt a higher cadence to avoid overstriding and facilitate healing so efficiency may be the cost I have to pay; it does seem that load is reduced with increased cadence (see here and here although the evidence quality is very low and this is probably where it all comes from!).
Second, I think I'm out of practice. Apart from a few walks I've not been doing aerobic exercise for longer than an hour - either running or swimming.
And third, I did some unaccustomed gardening yesterday.
Overall I'm starting to feel a little more positive and believe that some recovery is discernible.