LISS/LSS falls in the "Endurance" category in TB. They're mostly used during an initial Base Building phase along with progressive strength-endurance circuits. Strength-Endurance also falls in the "Endurance" category but trains a different energy system (muscular endurance).
General guidelines:
- at least 3 per week
- minimum 30 minutes (up to 120mins for advanced)
- 6-12 weeks
- within 130-150bpm or use talk-test
- doesn't have to be running, can be swimming, rucking, biking, MMA circuits/but specificity is encouraged (if you're military, then most of your "E"s should be running/rucking ex.)
After Base you transition to tempo/speed work and lactate threshold tolerance.
This is all in TB2, as are the actual Base + Continuation templates & workouts.