Lying Leg Curl vs. Seated Leg Curl
The seated leg curl loads the hamstring in a longer state vs. the lying leg curl, which loads the hamstring while it’s in a comparatively shorter state.
This makes the seated leg curl more effective at activating the hamstring muscles and triggering hypertrophy.
Both movements are roughly equally effective at building hamstring strength.
Pros and Cons
Lying Leg Curl Pros
- Lying leg curls put less strain on the low back compared to the seated leg curl, which may be an important consideration for individuals with existing lower back injuries.
- A 2015 study found that the lying leg curl elicits greater activation of the lower lateral and lower medial hamstrings compared to the stiff legged deadlift (SLDL). This makes it a reasonable alternative to the SLDL for lower hamstring development, though it’s worth noting that the SLDL activates many more stablization muscles in the core and lower back vs. the lying leg curl, so the lying leg curl is not a complete replacement for the SLDL.
Lying Leg Curl Cons
- The lying leg curl has less hip flexion than the seated leg curl, which results in less muscle activiation in the hamstrings. This makes it slightly less effective for hamstring hypertrophy.
- This movement requires specific equipment which is likely to only be found at larger commercial gyms.
- As this is a machine movement, it will not engage smaller supporting muscles involved with stablization in the same way that, say, a romanian deadlift would. This downside also applies to the seated leg curl.
Seated Leg Curl Pros
- Seated leg curls resulted in more muscle hypertrophy in the hamstring vs. the lying leg curl in this 2020 study. This is because it targets the hamstring while it is in a lengthened state. This lengthened state is the result of the greater hip flexion while performing the movement.
Seated Leg Curl Cons
- As this is a machine movement, it will not engage smaller supporting muscles involved with stablization in the same way that, say, a romanian deadlift would. This downside also applies to the lying leg curl.
- May aggravate existing injuries in the low back, especially the L5-S1 spinal motion segment.
When to Do an Exercise
When to do a lying leg curl
Anyone with a heightened risk of a low back injury that wants to build size and strength in their hamstrings should consider doing lying leg curls.
Because of the reduced hip flexion, a lying leg curl should be considered by individuals that are looking to develop hamstring strength and size, but want to lessen the impact on their lower back.
If an individual is not at an elevated risk of injuring their low back, then a seated leg curl is generally superior to the lying curl.
When to do a seated leg curl
A seated leg curl appears to result in more muscular hypertrophy in the hamstrings when compared to the lying leg curl.
Individuals looking to develop the size and strength of their hamstrings should consider adding the lying leg curl to their workout routines.
Both the lying leg curl and the seated leg curl work the three main muscles of the hamstring: the biceps femoris, the semitendinosus, and the semimembranosus.
Lying Leg Curl Muscles Used
A lying leg curl primarily works the hamstrings, but also engages the calf muscles and glutes.
- biceps femoris
Seated Leg Curl Muscles Used
A seated leg curl primarily works the hamstrings, but also engages the glutes and hip flexors.
- Hip flexors
How to do a lying leg curl with proper form
- Lie face down on the machine and position the roller pad between your calves and ankles.
- Grab the support handles to help stabilize your upper body.
- Flex your knees while pulling your ankles as close to your glutes as you can. It’s important to keep your hips on the bench during this movement.
- Briefly hold, then slowly return your ankles to the starting position.
Here’s an excellent video from Renaissance Periodization showing how to perform the lying leg curl with perfect form and how to avoid common mistakes.
How to do a seated leg curl with proper form
- Adjust the seat so that your knee joint is roughly adjacent to the pivot point of the leg curl pad.
- Position your feet so that the pad is sitting a couple inches above your sneakers.
- Pull in the upper pad so it is snug against your thighs. It should be above your knees.
- Pull your feet down, squeezing at the bottom of the movement when your shins are perpendicular to the floor.
- Slowly allow your feet to return to the starting position of the movement.
Here’s a helpful video from Scott Herman Fitness with tips on how to perform a seated leg curl with the correct form.
Frequently Asked Questions
What does the lying leg curl do?
A lying leg curl activates the hamstrings via knee flexion. It is especially effective for targeting the lower lateral and lower medial hamstrings.
Are lying leg curls effective?
Yes, a 2015 study found that lying leg curls do a better job of activating the lower hamstring muscles than the stiff-legged deadlift.
However, lying leg curls are not quite as effective for building muscle size when compared to the seated leg curl. If both movements are available to you, the seated leg curl is a bit more advantageous for hamstring hypertrophy.
Which is better, the lying leg curl or the seated leg curl?
When it comes to triggering hypertrophy, according to a 2020 study, the seated leg curl is more effective than the lying leg curl. The same study also concluded that they’re about equally effective for developing strength in the hamstrings.
So if you have the choice between the two, you probably should go with the seated leg curl.
If you have existing low back injuries, the lying leg curl may be a better choice, as it puts less stress on the low back than the seated leg curl.