The ‘Walk, Don’t Run’ Exercise Theory

Olympics Day 15 - Athletics

Workouts falling in the less-is-more category have recently (/seemingly) become the fitness activity of choice. First, there was Aqua Studio's low-impact underwater cycling. Then, we tried out the Bar Method class, and its prescribed hundreds of minuscule lifts and bends, making our thighs quake, and then ache like never before. And, confirming the three’s-a-trend theory, we recently heard whispers about a trainer named Key Son who helps the likes of Daria Werbowy, Doutzen Kroes, and Marisa Tomei tone their bods by barely moving. Well, not exactly. His theory involves modified, beyond-basic movements—reaching, pulling, tiny lunges—and super light cardio (i.e., walking, not running).

So, we sped-walked over to our phones to give Son a call about his don’t-move (much) workouts. Since graduating from Cornell with a doctorate in sports medicine, the Ivy Leaguer has spent nearly two decades as a trainer, helping over 150 models (including Céline's own Daria, who he describes as "very disciplined" and "easily the most symmetrical and most athletic model I’ve ever worked with") saunter their way to fighting shape. After trying "everything" else out there in the fitness world, he swears that he hasn't found anything more effective in helping women get long and lean than "low-impact, modified exercises," also known as very small movements, which, Son explains, "apply stress specifically to the areas the client wants to work on and, as a result, the body responds by toning and tightening in the right places." We asked him to explain the theory behind toning vs. bulking, walking vs. running, and more:

The reasoning: “I work primarily with actresses and models looking to prepare for movies and commercial shoots. In these industries, everyone’s looking for structured shoulders, a thin, flat waist, long, lean legs, and toned hips... I tend to stay away from exercises that increase size. Also, time tends to be an issue for everyone, so I’ve created a workout where, in a small amount of time, you generate as much power as you can by combining resistance training with specific exercises to mold and sculpt the shape you want, decrease body fat, and strengthen your core. It makes the agencies happy. [Laughs]”

Don't buy into bulk: “My technique is very different. A lot of methods of training involve a lot of squats and jumps, which builds size on the hips and legs. Also, I don’t normally recommend spinning, because you end up exerting your outer-thigh muscles, which, when used extensively, will get bigger. Not only that, but there’s a lot of torque on your knee, so biomechanical issues can arise, and you build up the connective tissue surrounding the muscle—that, too, will get thicker. The same thing happens with gymnasts’ legs—they get larger, and that’s fine if that’s what you want. Generally, I say spinning every once in a while for fun is okay, but I wouldn’t recommend it as an exercise throughout your entire career."

Setting pace: "Depending on a person's structure and proportions, running may or may not be beneficial. I have to actually see them and find out whether they have predispositions to putting weight on in their lower bodies, or if they have longer or shorter torsos compared to the length of their legs. If a person's legs are on the shorter side, I’ll usually have them walk instead of run, because muscles develop quickly in the legs, and can bulk. For walking, I recommend 30-45 minutes to start with, two to three times a week, and then maybe build up to an hour, three to four times a week, at a very consistent pace, just under jogging. And never, ever with incline. You don't want to build the calves, either."

"Every program should have the following  components," Son explains. "Here they are:

1. Warm up and flexibility exercises, to get the body moving.

2. Balance and coordination exercises, to challenge the stabilizations systems of the body and develop communication between the muscular and nervous systems. This is a great way to alter body composition, because the body has to employ more muscles to stay balanced, and, as a result, more calories are used. It’s especially effective when you use multiplanar movements, like standing on one leg while pressing the arms forward like a push up.

3. Strength training exercises, like push and pull movements, and rotational movements done at varying speeds, in the standing position, where the body uses the most calories. Use a resistance band or body weight to improve cardiovascular efficiency, increase lean body mass, tissue strength, and bone density, and decrease body fat.

4. Core stabilization exercises, like a floor bridge and crunches to form proper muscle balance, building a foundation to move efficiently. Always pull in the abdominal region to improve posture and maximize your strength, power, and endurance.

"As long as you incorporate those four things, you should be successful with any kind of routine," the trainer adds. Got all that? In case you're interested in a sample routine (we were), Son put together an extra special workout, just for ITG.

Photo via Getty.

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  • beeswaxnoneofyour

    I started doing Pilates (mat) about a month ago, and I tell you, as a mere mortal, you do a session thinking, yeah, I'm not sweating buckets so this will be easy - uh, no. You work muscles you never knew you had - until the next day when you are sore as he**!! I have to say though, It is brilliant. More flexibility, more strength and balance, and you're elongating, not bulking. As a short person my legs muscles bulk way to easily doing hard cardio.

    • Janet Lee

      Yeah, I forgot to stretch my abs and quads after Pilates one day and I couldn't move those parts of my body the next day! Lesson learnt!

  • Joyce

    I'm also working hard almost everyday this month! And I'm lovin' it!
    With love,


  • Victoria

    I WANT THIS ROUTINE. especially if i can look like daria. thank god someone understands that i shouldn't do lower body weights because my legs are short and bulk so easily!

    • Sharon Dennis

      I just learned 1 week before a 2 mile walk that I should not have been doing leg presses. Now my leg muscles are requiring extra energy and aren't made for walking.

  • olga

    that's 1 reason I check ITG everyday, you're on it!!!
    so tunned in...this stuff is really interesting and really balanced.
    please share with us all the good information.
    great work ITG you're the best.

  • sp1315

    Love his advice. I have never even tried Soulcycle but many people who love them usually get large leg muscles. I am a sucker for lengthening muscles so this should be very good. Until then I will stick to my beloved Tracy anderson who kicks my tush like no one elso!

  • JC

    Daria is HANDS DOWN the best body in the biz! I've always wondered who she trained with.

  • janet

    So looking forward to this smart and sane workout. Thank you!

  • enic

    Instead of demonizing bulk, how about just accepting that when we're exercising and being healthy--through whatever activities and foods make us happiest--that's when our bodies are most beautiful? Some people are going to have big muscles, some people are going to have definition, some people are going to have roundness and curves. Perpetuating the idea that if we all just conformed to a certain exercise routine we'd all have the same ("ideal") shape is unrealistic and damaging.

    • Guest

      Everyone has a right to their own definition of what's attractive. Personally, I find bulk on a woman ugly. When I gave up the stairmaster, spinning, and squats (which kill the knees, anyway) I finally got the long, slim legs I always wanted. If someone else likes a different look, she should go for it. But bulk is definitely not my thing.

      • Guest X

        Re: Squats — "An easy exercise to target those muscles is the squat. Although many of us have heard that squats harm knees, the exercise is actually “quite good for the knees, if you do the squats correctly,”

        Been debunked as a myth for a while. Many people do not perform squats correctly and that leads to joint pain and instability.

      • EMR

        My boyfriend is a physiotherapist and helped me get over the myth that squats harm the knees. Squats on a guided machine harm your knees, because you don't build stabilizing muscles while over-developing your quads. Free-weight squats are one of the best ways to make sure you will have strong, healthy, and stable knees because the micro-corrections your stabilizing muscles make allow you to gently build strength for every-day tasks.

      • enic

        I don't do any of those things and I have muscular (beautiful!) legs. Regardless of what activities I'm doing (usually vinyasa yoga 4-5 days a week and at least 45 minutes of walking a day) and what I'm eating, I'm always going to have strong, muscular calves.

        The length of your legs is the length of your legs, so my 5'4" long-torsoed body is never going to have "long, slim legs." Even if we wanted to, we couldn't all shape our bodies to look exactly the same.

        Similarly, even women who do want to bulk up generally won't, regardless of how many dead lifts they're doing and protein shakes they're drinking. There's no need to perpetuate the myth that if women lift heavier weights, they'll bulk up. Some people will just have bigger/smaller more/less defined muscles. People aren't just naturally thin and super-cut/toned because they won a willpower or exercise-expertise contest--genetics are playing a part too.

      • sandmanda

        Squats most certainly do not harm knees, especially if you have correct form. Similar to yoga poses, people have different joint range. To adjust for your natural knee rotation, just do modified squats (should width stance, close stance on leg press, sumo squat, lie squat, etc). There are a multitude of variations available to adjust to personal comfort level.

    • sandmanda

      Exactly. I think appreciating the body in motion and the feeling of exercise is a better message to have than the goal of 'demonizing' bulking, like you said.
      One of the toughest things for people who first begin working out is learning in what way to ENJOY it.

  • Cat

    I am totally on board this ship, I just wish I had the money to have my personal trainer... Alas, I am a student and all my money goes to nice shoes (because good shoes make anything look good) and skincare (duh). HOWEVER, I have been printing out workouts from Women's health mag online - they are pretty much what Key describes here and I would really recommend them to anyone with a small budget wanting to train at home. I bought an exercise ball, a resistance band and some ankle weights a few weeks ago, and so far I am really liking it. Yesterday my boyfriend told me out of the blue that my legs look really toned and I almost cried of joy. I've only been doing it for 3 weeks, but I have high expectations for the months to come!

  • Vivienne

    Sooooo he basically works girls that are naturally thin, have almost no hips, non-existent waistlines and 5% body fat and I'm supposed to be impressed when they show moderate muscle definition? If there's no fat on the body to begin with, it's not terribly difficult to get some abs and lean-looking legs. Sorry not impressed. Now take an overweight woman and get her to look like that without starving her on Tracy Anderson's 900-cals a day diet, and then you've got a novel idea.

    Bottom line - every year (now it seems every month) there are new weight-loss and diet fads. People get crazed about them for a few months and then move on.

    • Nico

      Yes! My thoughts exactly.

    • unvanquished

      Marisa Tomei does not look like she is "naturally thin". She has realistic, ladylike curves but great long lean arms and legs.

  • Nico

    Me too! Thank you. I box. Im 5'4" and Im 130 and you know what? Ill never look like Daria and its ok, I can punch an attacker in the face. Win!

    • softy

      I'm 5'4 and 98 pounds like Karina, and I can also punch an attacker in the face, because weighing less does not mean I am weak. Win!

  • Fabiana

    Loved the article!! but...spinning for fun? hahaha

  • Chantel

    Great article.

  • Karina

    I really wish women would stop responding to what they take as aggressive comments on their body types with even more aggressive, exaggerated passes at another body type.
    I am 5'4 and 98 lbs, I have small everything. It is so hurtful when I read attacks on my body type by women who are advocating a new perception of beauty by calling my natural, female body "gross", "resembling a prepubescent boy", or in this case, "of a North Korean prison camp inmate". I have never head anyone openly criticise rounder shapes in such a horrible way, and receive support and applause from others. It is extremely anti-feminist of you to body shame that way.
    The same way you are hurt by society's fetish with a lean feminine figure, I am hurt by the (admittedly smaller) sector of society that is apparently repulsed by the body nature gave me.

    • Nico

      I think 98 lbs at 5'4" is supposedly very underweight, like unhealthily so. I hope youre healthy. That was the weight/size of the Black Swan actresses when they starved themselves for their roles...I think 110 is considered on the low end for your height. Not making a facetious comment btw. Just hope youre healthy.

      • enic

        Just because Karina is confused about what thin privilege means doesn't mean we need to concern troll here.

        • Karina

          I'm not confused about what thin privilege means at all. Like I said, I understand that the sector of society that rejects a thin female body is very much smaller than those who admire it.
          It doesn't take away from the fact that when someone with a fuller figure than me says she finds my body repulsive, reminiscent of a prepubescent boy or a victim of war-related starvation, it HURTS me.

      • Karina

        I eat very well and exercise regularly. My annual medical checkup has come back positive in every way.
        Thank you for your concern, though I wonder if you just as easily and openly express concern for women who are clearly 10-20 lbs. overweight as well. I would also like to see what their reactions would be to your comments.

        • formerSwan

          make sure you're still getting your period. I've been at your height/weight, and it stopped. that's the #1 sign something isn't right.

        • formerSwan

          make sure you're still getting your period. I've been at your height/weight, and it stopped. that's the #1 sign something isn't right.

        • softy

          THANK YOU. i hate how being skinny is synonymous with being unhealthy these days. it's totally okay to be 10-20 pounds overweight, but under? GRAB THE PITCHFORKS.

    • enic

      "I have never head anyone openly criticise rounder shapes in such a horrible way"


      • Karina

        I don't know if you stopped reading there but immediately after that I said: and receive support and applause from others.

        Most people I know at least think twice before making comments on someone's body if they are overweight as opposed to underweight. It is considered bullying if you openly tell someone that they don't look good at all being that fat, however I constantly receive comments on how I would look so much better if I gained weight.

      • Guest

        I think the point of that sentence of Karina was the receiving encouragement part that you left out.

    • Maggi

      I hear you Karina. A reactIonary stance is not helpful, nor attractive. Instead of judging other body types why not just radiate beauty. If an article doesn't appeal to you yet here are far more constructive ways to do so than to compare thin women to 'north Korean prison inmates'. Way to go with the racial slur too (sarcasm).

  • Barrio

    Sorry y'all, strong IS the new sexy.

  • Rebecca

    Sorry y'all, strong is the new skinny.

  • EMR

    I'm really not enjoying these workout-focused ITG posts.

    I have thunder thighs and wear shorts when I work out, because I like shorts.

    I do not want a Tracy Anderson-style diet of 900 calories a day.
    I personally like looking strong, with defined leg muscles that were built by things like squats, spinning, and running.
    I understand that ITG is a fashion website and it is evidently fashionable to look like a fashion model. But one of the things that I also love about ITG is that they celebrate diversity, whether it's in sexuality and feminity (the Tegan and Sara post), ethnicity (too many posts to count!). I would love to see that diversity extended to women's body types, like those who have bulked through cross-fit and have insanely strong biceps and calves that look hot in a sleeveless dress.
    There is absolutely nothing wrong with looking like a fashion model, if you have been dealt those cards, and I do understand that Key Son works with women that want and need to look that way. There is, however, something wrong with demonizing bulk and women who choose to squat or do calf raises with 1.5 times their body weight.

    • ITGNick

      I'm with you. Definitely want to get all sort of fitness perspectives on the site. Working on it. Also! Email me ( if you have any suggestions for people we should interview...

      • Vivienne

        CHRISTMAS ABBOTT!!!! That is one sexy biotch. Not my ideal for how I want my own body to look based on the clothing I like, but she is strong, sexy and gorgeous.

      • harasscott

        Jessica Long Multiple gold Paralympic swimmer, strong, fit and drop dead gorgeous!

      • EMR

        Thanks for the reply, Nick! I'm going to do some digging this weekend and find a muscular, sexy, glamorous woman who is worthy of an ITG article!

      • Kathy

        I highly recommend Brynn Jinnett of Refine Fitness! She's created a cult following with her amazingly effective Refine Method class in NYC. I'm obsessed with these classes. Also,she's whip smart and spent years doing deep research on exercise. And she's diametrically opposed to the notion that women shouldn't be lifting heavier weights, so she would definitely provide a refreshing perspective.

      • EMR

        Here's a start - model turned crossfitter who has gained 15 lbs of muscle and is still a size zero.

      • Ash

        Bizzie Gold, creator of Buti . Her classes are a mix of plyo, yoga, tribal dance & belly dance. !

      • Peter

        You should do a top shelf with Coco from Ice-T and Coco. I must know how she became so elegant and demure.

        • Saucy

          LOL. Do you people even get what ITG is about? Do you even understand their aesthetic?

        • softy

          oh my God i know i'm 3 months late but i'm dying.

  • IMeanReally

    There is a difference between the fashion industry's weird obsession with who can get the smallest and a clinically diagnosed eating disorder. I know because I'm a former anorexic who bottomed out at 5'5", sub 100 pounds. Now I have more healthy attitudes towards diet and exercise, and towards my own self worth. Yet I am constantly bombarded with images that glamorize a body no healthy woman could achieve, even with a naturally slight frame and a fast metabolism.

    There's a difference between being naturally small and losing your period, being covered with downy hair, experiencing reduced blood circulation, etc. The fact that you don't realize that women are being beaten into this mold by the media (especially the fashion world) makes me think that either a. you're suffering from disordered eating or b. you're incredibly ignorant of your body privilege. Either way, you sound like a rich white dude who constantly complains about reverse racism.

    • Karina

      I don't really understand why you're explaining the difference between being naturally thin and suffering an eating disorder to me.
      It is one thing to say that in the fashion industry, as well as in society, there is definitely an obsession with general thinness. It is a complete other to bring the word STARVATION into the conversation. The user I initially responded to accused models and, for some reason, housewives, of deliberate and competitive STARVATION. I don't know if now you'd like me to explain the difference between dieting and starvation to you? I think we can both agree that when willing starvation is in the picture, so is a god damned eating disorder. So thanks for the explanation but perhaps you could try to read things twice before reducing me to either eating disordered, or ignorant of the concept of body privilege.

      So excuse me for pointing out that extremely impolite and downright hurtful comments on my body type are not right. You can say I sound like a rich white dude complaining about reverse racism but I believe you're missing my point. So here's a copy/paste of my point:

      The fact that so many larger women believe the way to stop body shaming is by reverting it to another body type is ridiculous, anti-feminist and ineffective. Making yourself feel better about your body by making someone else feel bad about theirs is WRONG. Listen up ladies, we are not each others' enemies.

      PS: When referring to yourself in the future, the correct term is "I am a former anoretic". Not to be a grammar nazi, but perhaps it would help your case to get the basic terminology of the matter right next time you accuse someone of ignorance on the subject.

  • kathS

    I understand people want to celebrate different body types and different kinds of workouts, but I think this interview was pretty very b/c he is clear that he is employed by modeling train look like models!

  • Cece

    I am thin because of a medical condition. I am lucky if I can keep down 400 calories a day. Friends tell me all the time at least you are thin as if that is the right way to be thin. I would take the extra pounds any day. I guess my point is that we don't know what is going on with other people and we should be sensitive to women of all sizes before making comments about their weight.

  • Saucy

    Since there seems to be a problem with reading comprehension, please see the following:

    “I work primarily with actresses and models looking to prepare for movies and commercial shoots. In these industries, everyone’s looking for structured shoulders, a thin, flat waist, long, lean legs, and toned hips..."
    The purpose of this article is to allow Key Son to showcase what he does for women IN THESE INDUSTRIES. It's not a personal attack on your workout routine.

  • unvanquished

    Sorry but the the only reason I go anywhere near a gym is to look nice. I do pilates 4 times a week and it is miserable and I run three times a week and think I'm dying the whole time. I don't enjoy it and if those exercises made it harder and not easier to fit into my clothes then I definitely wouldn't do them.

  • fitnessstylist

    That trainer wrote a book called The New York Model Workout.
    Theres also a version for iPad.