I ran a search for posts on this topic, and the gist is people asking if they should try it and the responses generally being “no”. I recently starting riding this way due to a left leg hamstring/glute strain so figured I’d chime in. And shout-out to Kurt B. for telling me to focus on healing as my priority - I was trying to ride through the injury with easy Z2 rides which were not helping at all.
There are two methods for SLC - with or without a counterweight on the free pedal. If you do not use a counterweight you will find it very difficult to ride for an extended period of time. My first ride was basically 40 minutes of 4 minute Z2 efforts with 1 minute of rest, so 8x5. Since the leg has to continuously exert effort down, back, up, and over you can really feel it burning after a few minutes.
Using a counterweight removes the need to pedal back and up, so you get the brief respite you need to avoid hydrogen building up so rapidly. Most studies use a 20 pound weight - I’ve been using 7.5 pounds though if I went with 10 I’d probably find the work far more comfortable. 20 pounds seems like too much of a boost IMO.
So, with a 7.5 pound counterweight, I’m riding 1 hour at Z2 and it is really uncomfortable. It’s doable and it doesn’t hurt like a Z4+ effort, but there is a non-stop dull ache in the muscles - it’s very noticeable - and studies point to this kind of work as highly beneficial for peripheral adaptations. I plan to increase beyond an hour, either 1:15 or 1:30, and incorporate short efforts with more resistance so I’m at the same power number as a bilateral Z2 effort for a few minutes at a time.
If anyone is injured and thinking of SLC or has done it in the past I’d be interested in your thoughts.