Today was a day for a harder bike session. I did what is called an over under workout based around my threshold power. This is a workout with relatively long intervals, where the effort varies from slightly under to slightly over my threshold power.

The particular workout that I did, consisted of four, six minute intervals. Each interval was two minutes just under FTP, one minute just over FTP, followed by the same two minutes under and one minute over.  These type of intervals are all about teaching your body to deal with lactate and other byproducts of anaerobic processes.

Those one minute sectors where I am riding over threshold, floods my muscles with the byproducts of anaerobic glycolysis.  This includes lactate and associated hydrogen ions.  The hydrogen ions create an acidic environment that leads to a decline in muscle performance.  You can only exercise above this lactate threshold for a small amount of time. A minute in this space is manageable.

After flooding my muscles with these byproducts, returning to an effort just under threshold power, allows my body to flush itself by processing these chemicals aerobically. The better your body is able to handle the byproducts, the more you can push high efforts.

I enjoyed my over under workout ride today. It was tough but ultimately manageable. I will allow my body to recover tomorrow, before a longer endurance ride on Sunday.