Here's what you need to know...

1. Sliding leg curls are the real deal. They hammer your hamstrings in a unique and painful way.
2. Unlike some exercises, they can be trained with higher frequency, which makes them ideal for fast hypertrophy gains.
3. Sliding leg curls can be systematically progressed or regressed to match your strength level so you can experience consistent long-term gains.

Sliding leg curls are no joke. I've absolutely buried top athletes with those "wussy" sliders. And I'm talking super strong guys that can squat and deadlift obscene weights and do glute-ham raises like nobody's business.

From a programming perspective, not only do they absolutely torch the hamstrings while being easy on the lower back and knees, they can also be done with a higher frequency, which is beneficial for building both size and strength.

However, like any exercise, you can eventually get good at sliding leg curls. That's when you need to use progression, and sliding leg curls can be progressed to the point of being downright tortuous.

So here are some devilishly effective progressions of the standard sliding leg curl. All of these can be performed using a slideboard, sliders, or anything else you can McGyver. Just use them on any slick surface.

Remember, the key is to find the right progression for your current level and then strive to move forward from there.

1 – "Squeeze" Sliding Leg Curl

These are just regular sliding leg curls done while squeezing something like a small foam roller or medicine ball between your knees. Here's what it should look like, as demonstrated by Eirinn Dougherty.

I've seen coaches and trainers use this method with glute bridges and I just applied it to sliding leg curls, which is really a bridge derivative even though it's more of a hamstring exercise than a glute exercise.

Interestingly, I started trying it as a way to get more bang for the buck by strengthening the adductors, but I quickly noticed that exercise form started to improve when athletes were forced to squeeze something.

People tend to screw up sliding leg curls by flexing at the hips (i.e., letting the butt sag), which takes the glutes out of it and greatly diminishes the usefulness of the exercise. However, when they're forced to squeeze something, they do a better job of keeping the hips up and the glutes engaged. So besides working the adductors, it's also become a good teaching tool.

You can also use heavier implements as you progress to increase the challenge to the adductors.

2 – Resisted Single-Leg Sliding Leg Curl

Single-leg sliding leg curls are a great progression once you've mastered the regular version, but how can you employ progressive overload beyond just doing a ton of reps?

Well, two ways, and both can be great depending on what you're looking to achieve.

The simplest method is just to put of small plate on top of the slide pad, or if you're using a slideboard, put a small weight on a towel.

A little weight goes a long way, so even five pounds will make a big difference and ten pounds will transform the exercise into an absolute monster.

Another option is to drape chains, a weighted vest, or even a weight plate over your hips.

I like this method because it increases the challenge for the glutes on what's otherwise more of a hamstring exercise.

3 – Body Curl

Body curls are a great progression/variation from sliding leg curls. Instead of keeping your torso fixed and sliding with your feet, keep the feet stationary and move your body back and forth.

They work best with a slideboard, but you can make due by putting a couple of sliders underneath a plate and resting your shoulders on top of the plate.

The form cues for body curls are the same as for sliding leg curls, meaning you want to keep the hips up by thinking about keeping a straight line from your shoulders to your knees.

I have a light weight on my hips in the video, but start with just bodyweight.

4 – Barbell Body Curl

Once you're comfortable with body curls, you can begin to load the hips to increase the challenge for the glutes. Start by using chains or a weighted vest, but eventually you can progress to using a barbell like you would for barbell glute bridges.

5 – Single-Leg Body Curl

I've done tons of hard hamstring exercises, but single-leg body curls may very well be the toughest of the lot, even when just using bodyweight.

It took me a long time to progress to them, and even when I could do regular sliding leg curls with 135 pounds on my hips, I still couldn't even do one rep of these bad boys.

To build up to doing the true single-leg version, try the single-leg eccentric version, which is also a great exercise in its own right.

Bridge up normally, then push out on one leg and pull back in with two legs.

Be prepared to walk funny afterwards.

How to Incorporate Them

Add these exercises in towards the end of lower body workouts after your heavier work, or add them in on off days or upper body days for supplemental hamstring work.

You can do them up to four times a week without issue because they're very easy on the joints. It's definitely an exercise that lends itself well to higher frequency training, making it a great choice if you're looking to bring up lagging hamstrings.

When you first start doing them you'll likely struggle, but make it a goal to get good at them and work through the progressions outlined. You'll find that your hamstrings will get bigger and a whole lot stronger in the process.

Probably the biggest thing holding you back from adding sliding leg curls is your own insecurity about doing something that isn't "manly." Get over yourself! Try these sissy exercises – I'll bet you'll be humbled and sold all at once.