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Bulletin #24 – Activating Muscular Growth

Mention the words “Belt Squat”to anyone’s who’s trained at the ParrilloPerformance Gym in Cincinnati, and you’llget a reaction that’s a mixture of fear andnausea. The mere thought of belt squatsis enough to make most people need to sitdown. There’s really nothing quite like it.Anyone’s who’s done it will agree that itis the most mentally and physically de-manding exercise ever developed. The beltsquat will take you to a new level of in-tensity.At this time, the Parrillo Perfor-mance Gym is a private gym, not open tothe public. It’s really more of a researchfacility than a gym.

Parrillo Performance

We experiment withnew equipment and new techniques, de-veloping the next generation of bodybuild-ers. We work with a lot of top competi-tive amateurs trying to make it to the nextlevel and break into the professional ranks.We also deal with a lot of professionalcompetitors, all the way up to peopletraining for the Olympia.I guess you could say that’s ourspecialty — taking people to the next level.That’s really what brings me the most sat-isfaction and is my biggest reward —helping people realize their dreams. Andthis applies to everyone from the over-weight 45-year-old mother of three to thenext Mr. Olympia. Everybody wants tolook good, feel good and have more en-ergy. Everybody has a dream. What keepsme going are the people who call in to tellme they’re in the best shape of their lives.I get just as excited whether it’s someonewho’s used our program to lose those 30extra pounds they’ve been struggling withfor years, or someone who’s just won hisfirst contest.Among conventional bodybuild-ing exercises, most people would agreethat a set of squats taken to complete fail-ure is the most demanding.

I developedthe belt squat to take people to the nextlevel of intensity — it’s probably the ulti-mate plateau-buster. The belt squat is aspecial machinewhere the traineewears a harnesswhich suspendsthe weight be-tween his legs.This arrangementtakes the stress offthe lower back, al-lowing you tomaximally over-load the legs. It’sthe same move-ment as the con-ventional squats,except you can usea lot more weightfor a lot more reps.Of courseyour legs willgrow. This will bethe highest inten-sity exercise yourlegs will ever expe-rience. But theamazing thing about the belt squat is theoverall effect it has on your entire body.It allows you to take your whole body tofailure, including all of your energy pro-ducing systems. You will be breathing ashard as you can, your heart will be pump-ing as hard as it can, and every cell inyour body will be trying to produce en-ergy as fast as it can. Adding belt squatsto your routine will strengthen your car-diovascular system and improve oxygendelivery to your muscles.

The belt squatis unique among resistance training exer-cises in that it truly combines extremesof intensity in both anaerobic and aerobicwork. It is well-documented that high-in-tensity aerobic training increases capillarydensity in muscles, as well as the numberand size of mitochondria (1). It also in-creases the level of enzyme systems in-volved in energy production (1). Thesefactors act to increase the anaerobicthreshold — the maximum intensity ofpower production you can achieve aero-bically (1).No doubt you’ve heard thatanaerobic training and aerobic trainingelicit different adaptive responses which,to some extent, work against each other(2). In other words, strength training andendurance training are not completelycompatible, and if you want to maximizeyour results in one form of training, youshould avoid the other form. Everybody’sfavorite example is to compare the phy-siques of a marathon runner with a body-builder. To be sure, endurance trainingimproves your endurance and strength-ens your respiratory and cardiovascularsystems, but marathon runners don’t havebig muscles — not even in their legs.Marathon runners don’t want bigmuscles, because too much weight wouldactually slow them down. For them, it’sthe ratio of strength to weight that’s im-portant. All they care about is how far and how fast they can run. So for whatthey want, their training style is appropri-ate.

All bodybuilders care about, on theother hand, is getting big muscles. So theylift weights a lot and don’t run much. Toomuch running can actually cause yourbody to break down muscle tissue to sup-ply amino acids to burn as fuel. This wouldbe a disaster for a bodybuilder. So youdon’t find too many endurance athleteswho can squat 405, and you don’t findtoo many bodybuilders who can run amarathon. This is all well and good —decide what your goals are and train ap-propriately to attain those goals.Here’s what’s going on: All formsof exercise of sufficient intensity repre-sent a stress on the body. The body re-sponds by adapting to that particularform of stress, so it can tolerate it betterthe next time around. Strength training(resistance training, weight training) rep-resents a severe stress on the muscle fi-bers that make up your muscles, andthey respond by building bigger, stron-ger fibers (1,2,3). This, of course, re-sults in bigger, stronger muscles.

Endur-ance training (running, biking, etc.) rep-resents a stress on the aerobic energyproducing capabilities of the body, andthe body responds by increasing its abil-ity to produce aerobic energy. To run amarathon, you don’t need extremelystrong legs, but you need to be able toproduce a lot of energy sustained over along period of time. It’s not easy. Aerobicexercise training therefore results in astronger heart and more blood vessels todeliver more oxygen to muscles. It in-creases mitochondria number and size inmuscles. Remember that mitochondria arethe furnaces inside cells where foods areburned (combined with oxygen) to pro-duce energy. Increasing capillary and mi-tochondrial density in muscle increases itsability to produce energy.So to a large extent, the dogmayou’ve heard about the “incompatibility”of strength and endurance training is true.One form of training results in biggermuscles, and the other form results inhigher energy producing ability. If yourbody’s adaptive reserve is split trying toachieve both goals, your progress on ei-ther will be compromised compared to ifyou were performing only one type oftraining. And at this point in the argumentmost people think they’ve reached theconclusion and stop thinking about it, andtherefor miss and important point.Consider the following: Let’s talkabout a bodybuilder who’s been traininghard and eating right for a few years andhas put on 50 pounds of muscle. Althoughhe’s very happy with this achievement,lately he’s seen his progress slow downand he really hasn’t changed much in thelast year. He believes he has probablyreached his “genetic limit.” He has basi-cally gone as far as conventional trainingand dietary strategies can take him.

Feel-ing that it’s genetically impossible to in-crease size much more, he shifts his em-phasis on “refining” his physique and per-fecting his symmetry. Many professionalbodybuilders are at exactly this level andstay there for the rest of their careers.The smart ones come to Parrillo Perfor-mance at this point. If there is a geneticlimit, we haven’t found it yet.Now let’s take a microscopic lookat his muscles. We see huge muscle bel-lies with huge, hypertrophied muscle fi-bers. Crammed wall to wall with contrac-tile proteins — actin and myosin. Hismuscles have reached a “steady state” —a term from thermodynamics which de-scribes a system where flow of matterand energy into the system is balanced byflow of matter and energy out of the sys-tem. Here, protein anabolism (building up)is balanced by protein catabolism (tearingdown). Flow of amino acids into themuscle equals flow of amino acids out ofthe muscle, so his muscles stay the samesize. Now think about what would hap-pen if we could somehow double the cap-illary supply to his muscle. Blood supplydoubles, the flow of amino acids and glu-cose into his muscle doubles and his abil-ity to carry waste products away fromhis muscle doubles. Is it possible that ifwe could increase the supply of nutrientsand energy to his muscle that we couldget it to grow again? Could it be that whena muscle gets very large, maybe the rea-son it stops growing is it becomes lim-ited by its supply of nutrients and oxy-gen? Of course may factors are involved,but we believe this is one of them.So while strength training andaerobic training do represent differentadaptive responses and interfere witheach other in the short term, there comesa point in muscular development whereincreasing blood supply to a muscle mayhelp overcome a growth plateau. Doesthis mean I recommend bodybuilders be-gin running marathons? Of course not.I’m just saying that a certain amount ofhigh-intensity aerobics may increase nu-trient and oxygen supply to a muscle andhelp it grow better. You think you’vereached your genetic limit? I think not. Afew weeks of belt squat training, andyou’ll be growing again.


1. McArdle WD, Katch VL. ExercisePhysiology – Energy, Nutrition andHuman Performance. Lea & Febiger,Malvrn PA, 1991

2. Hatfield FC. Hardcore Bodybuilding -A Scientific Approach. Contemporybooks, Inc., Chicago, 1991.

3. Lieber RL. Skeletal Muscle Structureand Function. Williams and Wilkins,Baltimore, 1992

2018-03-13T11:10:38-04:00 May 15th, 2009|Technical Supplement Bulletins|

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