The single-leg lying leg curl is a popular machine-based exercise for the legs, particularly the hamstrings. It is similar to the seated leg curl, but the open hip angle in the lying leg curl may incorporate more glute and calf activation. It is usually performed for moderate to high reps, such as 8-12 reps per set or more, as part of a leg pre-exhaust or as a muscle-building movement for lower-body training. Performing it one leg a time allows you to focus on the mind-muscle connection of each leg and address muscle imbalances.
Builds size and strength in the hamstrings
Also works the glutes and calves
Helps with size or strength imbalances between legs
Many lifters say they "feel" this movement more effectively than seated leg curls