Strengthen Your Core and Loosen Your Hamstrings

Core training is what fitness is all about these days. Ten years ago, “core training” was basically crunch variations along with an assortment of leg raises. Then Dr. Stuart McGill came along and changed the game. Thanks to his terrific research, Dr. McGill taught us that the ability to brace the core, and maintain that position for time, improves back health and performance. When I say “brace,” I’m referring to that core tension you instinctively create when someone is about to punch you in the stomach. You don’t need to bend your spine around like a twig to get the most bang for your core training buck.

McGill’s research also shows how detrimental spinal flexion can be. Each time you do a normal crunch, your spine flexes. It’s the repeated flexion of the spine that can lead to all sorts of nasty problems such as disc herniation. And when you bend over to pick up a weight while your spine is rounded the story gets even worse. In order to protect your discs and nerves from undue stress it’s essential to learn how to properly brace your core.

Now, teaching someone to brace their core isn’t as easy as it sounds. Sure, we can all tense our abs, but most of us can’t maintain that tension while moving our body, especially when an external load is added to the mix. A simple way to train someone to maintain core tension is with the plank. Most people should be able to hold the regular plank for 90 seconds. This core endurance is essential to keeping your back healthy and strong.

However, we’ve been inundated with pics, articles, and videos about the plank, so doing that exercise probably doesn’t sound new or exciting to you. That’s why I want to show you two of my favorite core exercises once people are ready to move past the regular plank.

The first exercise is called “Stir the pot,” and I learned it from Dr. McGill. It’s an outstanding exercise to build core stability strength. Here’s how you do it.

First, rest your elbows on a large swiss ball with your body in the plank position – body straight from neck to ankles and core braced tight. Second, make circles with your forearms/elbows so the ball rolls around without moving your body. This exercise is tougher than it looks when you do it right. You’ll feel muscles working all the way down to your spine. As you get accustomed to the exercise focus on making larger circles. The goal of this exercise, or any core exercise, is to make it as difficult as possible.

The second exercise, the “leg curl with single leg balance,” I learned from Dr. Craig Liebenson, owner of LA Sports and Spine and a terrific doctor who specializes in everything related to the spine.

To perform this exercise, lie on your back with your legs straight and heels resting on a Swiss ball. Then, lift your hips as high as possible and perform one leg curl. Next, brace your core/hips super tight and lift the right leg in the air and hold it for 4-5 seconds. Do the same with the left leg. From start to finish it’s one rep. Perform 5 reps.

Not only does this exercise improve core stability strength and performance, but it also induces a surprising side-effect that I hadn’t measured before: it loosens your hamstrings.

Try it with yourself or a client who has tight hamstrings. First, perform a standing toe touch and make a note of how far your fingertips reach. Then, perform five reps of the leg curl w/single leg balance and test it again. It’s common to increase your range of motion 3-4 inches. Pretty impressive considering you didn’t do any stretching.

How does the leg curl exercise increase hamstring mobility? Before I answer that, let me explain why your muscles get stiff in the first place.

You see, when a muscle is stiff most trainers will stretch it. Immediately, the muscle will increase its range of motion. But here’s the important part that I’m sure you’ve experienced: the added range of motion from static stretching doesn’t hold. A few hours later, or the next day, the muscle is stiff again.

More advanced trainers will do deep tissue work such as the Active Release Technique (ART) to restore range of motion. This hands-on style of improving mobility and tissue health can be effective and I’ve used similar techniques for years. But again, the added range of motion doesn’t hold for long.

The problem with typical stretching or soft tissue techniques is that they don’t address the root of the problem. I’d say that 99% of the time the problem is actually in the spine. In order for a muscle to be flexible, the nervous system must get the memo that it’s safe to increase the range of motion. In other words, if you have super stiff hamstrings it’s likely the deep muscles that support and surround your spine aren’t firing correctly, or they’re just plain weak. So the nervous system puts the brakes on your hamstrings mobility.

The leg curl with single leg balance activates deep core and hip muscles that provide a strong foundation of support for your muscles to work against. This immediate neural enhancement (potentiation) allows the nervous system to release the brake that’s currently holding your hamstrings tighter than guitar strings.

And when you perform the “stir the pot” exercise right before the leg curl exercise it works even better. So, test your hamstring mobility by attempting to touch your toes, then perform one set of each exercise I posted above. Retest your hamstring mobility and prepare to be impressed. Continue doing these two exercises for one week and the increased range of motion will hold.

Get ready for a more effective approach to mobility training. It all starts at the spine.

Stay focused,

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17 thoughts on “Strengthen Your Core and Loosen Your Hamstrings

  1. Hi Chad,
    Any specific “test” you give your clients to see if their ready to move past the basic plank,side plank?

    Have a safe & fun trip!

    CW: Once they can hold the plank for 90s and side plank for 70s they’re ready to move on.

  2. Here’s a twist to the “stir the pot” exercise. I put my clients in the same position and make them write out the alphabet in BIG capital letters on the floor. They have to say the letter and then write it out. When they get to the letter “I” they have to dot the “I” even though it’s a capital letter. When the get to “O” they have to go over it twice: once one way then the other way. This isn’t the most popular exercise in my routines (that’s why I use it 🙂

    CW: Thanks for the tip. The good part about this exercise is that you don’t need to do many reps to get an effect. Just 2-3 sets of 3-4 reps in each direction is often enough.

  3. Re: Leg Curl w/Single Leg Balance

    Back when I used to work out to Cathe Friedrich dvd’s she did that move. Except in her version she rolled the ball in and out with one foot while holding the other leg in the air. Repeatedly. Chick is FIT. I never quite got there myself…

    CW: Yep, that’s a great move too. But this is the place to start.

  4. Hey Chad,

    Thanks for this post, I hadn’t thought of these variations and after trying it my toe reach – test actually did improve quite a bit!
    I will let some of my clients try it as well this week.



  5. I’m glad I saw this. It looks like I have a case of lordosis. I’ll admit I’ve let myself go, got lazy and too much sitting at a desk. I have a weak “core”, weak glutes and lower back pain. I’m lean and have a hard stomach but now I have a pot belly and look pregnant (trust me, I’m not). Will these exercises help with my problem and what frequency do you recommend? Can I do them daily? I just dug out my copy of Huge in a Hurry. I’m going to do that again and I’d like to add these exercises.

    CW: Yes, this exercise will strengthen all those areas. You can do it daily. Twice a day if you prefer.

  6. Dear Chad,
    Don’t You know of a potentiation excercise that loosens the calves? My calves are very tigth and the effect of stretching (which I do at least twice every day) lasts only for 2-3 hours at most (supporting what You wrote). I stretch my calves that often because I have incidentally noticed that it loosens my neck muscles more effectively than anything else I have tried so far. My neck (and also my shoulders to some extent) causes I hell a lot of a trouble for me being stiff and painful especially at nights when I lie down in a miserable attempt to sleep… I wake up numerous (sometimes 20-30) times every night because of that. I’ve seen several professionals in the past 15 years that I’ve had this problem and they haven’t found any serious health condition…
    Or, if You know of a similar excercise of long-term effect which loosens the neck directly I would, of course, be extremely grateful too.

    All the best to You,

    CW: It sounds like you have a serious case of inflammation running through your body. You need to fix that first. Try my veggie fast I posted a few weeks back and I bet many of your problems will clear up.

  7. Thanks for Your reply, Chad. I’ll try to force myself to do what You said. If it suceeds (probably not to soon for several reasons) I’ll let You know about the results.
    All the best,

    CW: Keep in mind, you don’t have to follow such an extreme diet. If you spend one week eating nothing but fresh fruit, veggies, black beans, nuts, and wild fish you can produce the same reduction in inflammation. Try that instead.

  8. Just a word to describe this post: Beautiful! It always amaze me how elegant is the nervous system arrangment. God is an engineer and an artist. Chad I have a similiar experience. Doing heavy kettlebell snatches almost a year ago I strained my low back and it developed a nasty spasm. It was hard to even breathe at some times. Liniments and hot pads didn’t worked for long, but I remembered how much you emphazised reciprocal inhibition on some of your old articles, so I did a plank (and it felt REALLY heavy and was trembling) for 30-40 seconds and MAGIC! the pain and movement restriction disapeared instanly. The spasm returned, but I kept doing planks and I think my recuperation was like 40% shorter than the normal time span of such injury.

  9. Any way to do this without a Swiss ball?

    CW: Unfortunately, no. You need the instability from the ball to induce the desired effect.

  10. Hi Chad, Johnny here. I’ve just started doing some kickboxing and I’m having problems with kicking anything above my waist due to my lack of flexibility. I’m intrigued by your stretching/mobility philosophy. I tried the hamstring method you explained and it worked wonders on my front kick. Will you be releasing more articles/publications on a full body scale (i.e. stretching the groin to improve your splits)? Thank you.

    CW: Glad it helped. I’m working on a follow-up.

  11. Chad, gave that hamstring exercise a go and got immediate improvement in hamstring flexibility.

    Many thanks,

  12. Chad, thats a very nice article, but i have a question for you.

    Planks are isometrics right, you hold that position and your abs are in a tense position. Well so are Lsits, what do you think of Lsits as a way to strengthen your core in the same fashion?

    Im using GTG (where you do the exercise every day submaximal to increase its endurance) to increase my Lsit time, i am at around 5 seconds, however i want your word on this.

    What do you think? The reason i ask this is because i dont have a swissball at home, and most of my workouts are only bodyweight since stuff im trying to acheive include handstands, planches, front and back levers etc…

    CW: The Lsit is good as long as you keep an arch (lordosis) in your lower back.

  13. CW,

    Not sure if this is the place to ask this question or if it matters. I’m not sure if you monitor comments to old articles or not. I have been reading some of your old posts and I wanted to ask you questions about the Build More Muscle, Strength, and Power… at the same time article.

    When doing the three on one off format of this what kind of rest do you recommend for each day, especially with regard to the power days.

    I also wasn’t sure if you recommended a similar format for the strength and muscle days as you do in your full body workout programming articles. ie. A1 rest A2 rest A3 rest and repeat, or if we should complete all sets for an exercise before moving to the next exercise.


    PS: I bought the Body of Fire program and both my wife and I loved it. Keep up the good work, it’s great to see training evolve from a scientific perspective tempered by real world application.

    CW: For power training I keep the rest between exercises around 30s. A circuit might be: KB swings, rest 30s, med ball throws, rest 30s, sledgehammer swings, rest 30s, repeat for 8-10 rounds.

  14. Chad,

    My hamstrings have some slight pain while doing the single leg raise portion, obviously in the leg balancing on the ball. I’ve never never any hamstring injury besides the occasional pull. I have strong hamstrings, able to do RDLs, regular deadlifts with no problem. Should I skip this exercise or is still safe even with some pain?

    CW: That pain is likely coming from your spine. You might have an irritated sciatic nerve. Get it checked out.

  15. Hi,

    A couple things:

    First, would it be okay to do this in your warm-up before, say, deadlifting? They say not to stretch before lifting but since this isn’t a stretch should be okay, right? I have trouble stretching out my hamstrings enough to get in a good position for deadlifting, thought this might help.

    Secondly, any similar exercise/recommendations for hip flexor mobility? I sit at work all day and my hips are tight and it’s buggerin’ up my lower back


    CW: Yes, this is an ideal warm up for the deadlift or any other demanding exercise. To loosen your hip flexors check my previous post on fixing your single leg squat. There I show a video for stretching the hip flexors.

  16. Great article CW!
    If these exercises were to be done before a work out , would they not fatigue or pre-exhaust some of those core muscles and potentially leave you at risk of injury as they might give out sooner during other exercises than if they were done after a workout? Is this incorrect thinking ?

    CW: That is incorrect. These exercises facilitate (enhance) core activation. Try them before your next deadlift or squat workout and you’ll see what I mean.

  17. Hey, Chad

    Some great core exercises there. These will really work and define thpse stubborn abdominal muscles. I especially like the single-leg balance on ball for really feeling the burn in those abs. I feel it the next also!

    Great job.

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