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Bulletin #25 – Activating Muscular Growth: Part II

Conventional wisdom has it thatstrength training and endurance trainingare incompatible, since they elicit differ-ent adaptive responses that compete witheach other (1-3). This is true, at least inthe short term. Last month I introducedthe concept that at some point in themuscle’s growth it may become “perfu-sion limited,” meaning that any furthergrowth is limited by the muscle’s bloodsupply. Increasing the vascular supply toa muscle will allow for greater delivery ofnutrients and oxygen and greater removalof wastes. Ideally, a bodybuilder wouldlike the benefit of increased capillary den-sity in muscle which accrues from high-intensity aerobic exercise without the cata-bolic effect that comes from running amarathon. The belt squat is probably thebest way to achieve this.The amazing thing about the beltsquat is not that it makes your legs grow— everybody expects that. The amazingthing is the overall effect it has on yourwhole body’s ability to produce energyand perform high intensity exercise. Ifyour strength and muscular developmentare at a plateau, the belt squat is a greatway to blast through it — no matter whatmuscle group you’re having trouble with.The belt squat increases your cardiovas-cular reserve and your anaerobic thresh-old.

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Cardiovascular reserve is the abilityof your cardiovascular system to deliver“extra” oxygen above what you normallyneed. In other words, it’s your ability toincrease oxygen delivery to muscles dur-ing times of intense exercise. Anaerobicthreshold is the maximum intensity of ex-ercise (power output, which is work perunit of time) your body can perform aero-bically, before the anaerobic pathways kickin. Simply put, the partner-assisted beltsquat is the most intense exercise you’llever do. Acquiring the ability to exercisethat intensely will carry over into yourother exercises.I think the key point about thebelt squat is that it pushes all three of yourenergy producing systems to their limit.Let me explain. Your body has three mainenergy producing pathways that are usedduring exercise. These are the phosph-agen system, the lactic acid system andthe aerobic system. All work performedby the body, including muscular contrac-tions, is directly fueled by a molecule calledATP, adenosine triphosphate. ATP is a“meta-stable” chemical compound whichis made inside all cells of the body andpowers their every function. ATP has a“high energy phosphate bond,” whichmeans that when ATP is broken down alot of energy is released.

This energy isthen used to power muscular contrac-tions, maintain ion gradients transmit nerveimpulses, synthesize proteins, and provideenergy for everything a cell needs to doto live and grow. While fat and glycogenrepresent energy storage molecules withinthe body, ATP represents and energy trans-fer molecule, acting as a molecular bridgebetween the energy contained in food andthe energy used by the cell. To summa-rize, the energy released when foodburned is used to make ATP, and the sub-sequent breakdown of ATP is the directenergy source for cells.A typical belt squat workout be-gins with some leg curls for a warm-up.This gets blood flowing into the musclesand warms up the joints. Two sets of eachare enough, for about 10-12 reps with amoderate weight. Be sure and hold thecontraction at the top. Next, two or threesets of leg presses are used to furtherwarm up the legs and to prepare you forthe squats. Start of light for about 15-20reps, then do a moderate set around tenreps, and finish with a fairly heavy setaround six reps. Be sure to go all the waydown on the leg press. You may evenwant to briefly pause at the bottom to geta good stretch. You don’t want to wearyourself out during the warm-up, but youdo want to get things flowing and loos-ened up. Next, stretch your quads andhamstrings, and walk around the gym fora few minutes to rest. Don’t get a drinkof water because you don’t want any-thing in your stomach. This is a good timeto pray and make sure all your importantpapers are in order.

We intentionally placeour belt squat by the back door of thegym. If this is not the case in your gym,get a trash can and put it by the belt squat.The belt squat is strictly a part-ner-assisted exercise. We like to have agroup of four people on the belt squat days.This allows for three spotters, which youwill need to take it to the absolute limit (atleast one spotter is required). We usuallydo four sets each, taking turns. You de-velop pretty good friendships with yourbelt squat partners. I honestly think I canremember every belt squat workout I’veever done.The first thing you do is put onthe harness. Adjust the shoulder straps tofit your body and make sure the belt istight. Load the weight onto the weightcarriage and sit on it. Your partner willattach the straps through the hole in theplates, so that the weight is suspended bythe harness. Grab the handle and stand up, and your partner will remove theweight carriage, so that the plates arehanging between your legs. When usinga heavy weight, your partners will helpyou stand up. Removing the weight car-riage exposes “the pit” — a large slot inthe platform where the plates will travelas you squat. Place your feet slightly widerthan shoulder width with your toes angledout and your heels placed directly under-neath your shoulders.

Grasp the handlesecurely and keep your arms straight. Youwant to keep your arms locked out so youdon’t lose balance. If you maintain thisstance and keep your arms straight, youwon’t get injured. The worst thing thatcan happen is you lose the weight, whichjust means you sit down on it in the pit.The beauty of the belt squat is that it’s sointense and yet so safe. The harness takesthe strain off your lower back so you canmaximally overload your legs without fearof injuring your back. This is an extremelysafe exercise.We usually start with one plate,which is 100 pounds (we have special highdensity plates made up for the belt squat).Do this for about 20 reps. This is anotherwarm-up set, to getthe feel of the exer-cise. You will prob-ably need no helpfrom your partneron this set. Rackthe plate back on thecarriage, take off theharness, and give itto the next person.Next, stretch yourlegs, using one ofthe fascial stretchingexercises in theParrillo TrainingManual. You’re be-ginning to get apump, and it feelsgood — so far.After your trainingpartners their turns,it’s back to youagain.

This time wego up to 200 poundsfor about 15 reps.This is somewhat harder, but much easierthan squatting 200 for 15 reps on the con-ventional squat because your lower backis taken out of the movement. On yournext set you can either go for your heavyset or continue pyramiding by doing 300pounds for 10-12 reps. Have a spotterstand directly behind you on the platform.He will have his arms around you and holdthe belt in the center in the front. The spot-ter goes up and down with squatter, per-forming the exercise in parallel. The spot-ter provides just enough help to get youthrough any sticking points. On yourheavy set, you will be able to go at least100 to 200 pounds heavier than your maxwhen you didn’t have a spotter — ormaybe more. Five hundred pounds for abig guy is not uncommon. Take yourheavy set to complete positive failure. Youwill still be able to resist the weight on theway down, but you will need your spot-ters to get you up out of the hole. Onespotter behind you and one on each sideworks the best.The heavy set done to positive failure ataround 8-12 reps will stimulate your legsActivating Muscular Growth, Part IIThe Belt Squat Machine looks innocent enough.But once you’re on the platform with the harnessstrapped on, you’ll wish you had scheduled thatdentist appointment that you’ve been putting offfor the last two grow. The next set is the hardest and isthe one that will really stimulates your car-diovascular system. In this set we do 100reps with 100 to 200 pounds. This is es-pecially hard since you just went to fail-ure on your last set. We rotate spotterson this set because they go to failure too.Change spotters after every 20 reps.Next month, I’ll take you through a 100rep set of belt squats and explain the en-ergy producing systems involved.


1. McArdle WD, Katch FI, and Katch VL.Exercise Physiology – Energy, Nutritionand Human Performance. Lea &Feiberger, Malvern, PA, 1991.

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

3. Lieber RL. Skeletal Muscle Structureand Function. Williams and Wilkins, Bal-timore, 1992.

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

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