While still in considerable pain I decided to go for a swim on Saturday.
I went to the local pool with no plan other than: swim for an undetermined amount of time.
I jumped in and swam. Intending to do a warm-up before deciding what to do. That warm-up never ended.
I finally finished off with 3,100m in 49 minutes. A nice easy swim.
Topped it off with 10 minuted in the Sauna.
This shows my lack of form and fitness. Pace dips, SWOLF increases considerably throughout the set.
The fix is simple: swim more.