Isometrics - Isometric contraction, normally just called ISOMETRICS ,is one in which the muscle is activated, but instead of being allowed to lengthen or shorten, it is held at a constant length. This isometrics muscle contraction is not done through a range of movements but in a static position. Isometrics is based on the principles of creating muscular tension while opposing the force of an immovable object or gravity. Isometrics are done with high levels of intensity (70-100%) rather than repetitious movements typically for a period of 7-12 seconds. Once the muscle is relaxed after the contraction increases blood flow to the muscles occurs which equals more nutrition and energy uptake which in turn increases the muscle mass (size). Isometric exercise is a form of resistance training in which the participant uses the muscles of the body to exert a force either against an immovable object or to hold the muscle in a fixed position for a set duration of time. In this type of exercise, the muscle is contracted but does not change length during the exertion of force. Additionally the joint most closely associated with the effort remains static throughout the exercise.


Isometric Contraction

Isometric Contraction - Isometrics or isometric training has been around for centuries in such things as yoga and Chinese martial arts. Even Pilates utilizes isometric exercise as part of its training protocol. Isometrics is probably one of the very few exercise techniques that has been scientifically validated.

At the Max Plank Institute in the 1950's Dr. Hettinger and Dr. Mueller conducted scientific research into the field of isometrics. Their study showed conclusively that isometrics can increase strength by as much as 300% in less than 30 days!
Isometric Workouts were originally made famous by Charles Atlas - although he branded it as "Dynamic Tension" and iIn recent years isometric workouts have made a huge comeback especially in the field of rehabilitation therapy.The most effective way to use isometrics is by utilizing some form of isometric exercise equipment such as the Bullworker. In theory the concept can be applied to many forms of "resistance" training but in practice the Bullworker and its clones such as the Steel Bow are the ideal tools for this sort of scientifically proven muscle building. Dr. Hittinger and Dr. Mueller both utilized isometric exercise equipment to measure strength gains.

Isometric contraction refers to the case of strength training, in which the muscles contract, but do not change their length. The name isometric comes from the words 'iso' meaning equal and 'metric' meaning distance. In contrary to other dynamic muscle contractions that involve change in position, isometric contraction is performed in a static position. Physical activities based on isometric muscle contraction are known isometric exercises. Sometimes weight lifters and professional bodybuilders will incorporate some isometrics into their workouts, often in order to break through barriers and to attain new levels of muscle strength which in turn leads to new and increased muscle mass.

Advantages of Isometric Contraction Exercises

Isometric exercises can be carried out virtually anywhere! You can do them whilst sitting watching TV, while sunbathing, while you wait in line at the supermarket and well the list goes on and on. Everyday, we could if we want indulge in performing isometric contractions as a part of our day-to-day activities, such as carrying a suitcase or a carrier bag full of groceries. Isometrics are particularly beneficial with those with back pain as the muscles can be developed without further damaging the back and the resultant gains in (say) abdominal strength help to alleviate the stress on your back which in turn helps the back to heal as your stronger abs take the strain away from your injured back.

Often the main advantages are seen as maximal muscular contraction in a short space of time. Muscle building Guru Zak Lanzas uses isometric training with many of his corporate clients who simply do not have the time to go to the gym .Isometric contraction exercises lasting for 7 - 10 seconds at a time are sufficient to activate a group of muscles. When the resistance or weight is increased gradually, your muscle will become more stronger. However if you are looking to build large muscles rather than simply "tone" then you need to check out Extreme Bullworker Training.

Isometric can be performed without any specialised equipment. However if you want results faster and also you want to seriously increase your lean muscle mass then you will need to invest in a Bullworker or one of its clone variants.

This type of training though is intense in nature if done correctly, therefore if you have high blood pressure or any sort of heart condition then consult your Doctor before training. If your doctor has any questions as this type of training is when done correctly can have numerous additional benefits, then tell him to contact us and we will gladly pass on any information that might help.



Benefits Of Isometric Exercises.

Isometric exercises can be done without any kind of machines or equipment anytime, anywhere. If you have 10 seconds, you can work a muscle group without no one even noticing you are using isometric training. The convenience and time saving is one reason why isometrics are so popular and becoming even more popular as peoples lives get increasingly busy. Doing isometric exercises 7 seconds at a time during the day can substitute your workout -if done correctly and with a Bullworker it can be even more productive than a gym workout! A bold claim? Yes it is but we feel confident in saying this.

Even without a bullworker great results can be obtained. Ab Core Workout - isometric style - sit in a chair with your feet about 6 inches off the floor, suck in your belly button while tensing your abs. When that becomes too easy, simply push down on your knees with your hands while forcing to keep them from touching the ground. These are called abs isometrics and they will give your core muscles a good workout without getting out of your seat! So you can do these while watching TV, waiting for a meeting etc etc.

Pressing your palms together as hard as you can will work your arms, shoulders and chest. To work your neck and upper back muscles, cross your fingers behind your head, push your head back in your hands using your neck muscles while trying to push your head forward with your hands.

Find a wall to push up against or something you can pull against that won’t move like a door jam. The only thing you need to remember is to use as much force as possible for 10 seconds. Using maximum force will give you all the benefits an isometric workout has to offer.

If you have high blood pressure you should not engage in this type of activity because isometric exercises cause a spike in blood pressure. Although the blood pressure typically returns to normal rather quickly once the muscle is relaxed, the spike in blood pressure can be dangerous to those who already suffer from elevated blood pressure. If you suffer from high blood pressure but you really want to engage in isometric exercises, please consult with your doctor for tips on how to lower blood pressure first.

The following are examples of different forms of isometric exercises that help to improve the strength of muscles such as the abdominals, shoulders, quadriceps and calves.

The Plank
The plank engages a lot of muscles; in addition to strengthening your abs, you will also strengthen your back. The is one of the best core exercises that exists - but is not suitable if you have any sort of back related problem, or that is, not suitable until you have strengthened other parts of your core.

•Start out by lying flat on the floor.
•Slowly raise the body so you are resting on your toes and forearms.
•Keep the back flat and the abdominal muscles taut.
•Hold the position for 10-30 seconds.
•Repeat the exercise 2-3 times.

When this becomes easy, curl your toes under your feet to make it more difficult. You can also extend one arm forward for another difficult variation.

Isometric Squats
•Stand with your feet shoulder-width apart and your back firmly against a wall.
•Slowly slide down the wall until your thighs are parallel to the floor.
•If necessary, move your feet away from the wall to ensure your knees do not extend past your toes.
•Hold the position for 10-30 seconds.
•Repeat the exercise 2-3 times.

Much of the interest in Isometrics comes from the amazingly successful Charles Atlas.Starting in 1929 and continuing throughout the century he sold hundreds of thousands of his muscular development courses using a form of training he called "dynamic tension".

His courses sold through magazines and the advertising depicted caricatures of a scrawny kid on the beach getting sand kicked in his face by a big guy. The next caricature would show the scrawny guy coming back to the beach after completing the Charles Atlas workout. He'd come back big and buff and whip the bully and run off with the girls. If you look hard enough you'll still be able to find some of those ads in magazines today.
The exercises described in the course didn't use weights, rather they used bodyweight exercises and dynamic tension exercises. The course called for certain types of movements done in isometric fashion like pushups, where you hold yourself in a pushup position for a given time. I don't know how much muscle people have gained over the years using these programs, but what I do know is that certain concepts and training methods taken from his program can be extremely effective for the bodybuilder of today.

It's been said that in the iron game, nothing new is really ever invented, rather we just keep putting new twists on the same effective things and more effective ways of arranging and performing training methods that our founders discovered years ago.

It's also interesting how outdated training concepts, like kettlebell training, continue to resurface and are brought back to life and how these concepts are often found very effective today. One training concept that fits that bill is isometric training. It can be a very effective training style for you, but unlike the Charles Atlas programs, you will need to use weights.

What Is An Isometric Movement?

An isometric movement is a movement in which no movement occurs. An example is holding a weight in a semi-contracted and motionless state for a period of time. Another example is pushing on an immoveable object for a given period of time. Many of you have probably done the trick where you stand in a doorframe and with your hands by your sides, you press out again the doorframe as if you're doing a partial lateral raise.

You continue to push against the immoveable door frame for 30-45 seconds, and upon releasing the pressure, your hands tend to "float" up into the air. This is an example of an isometric movement.

It turns out Isometric exercises have several benefits for both strength athletes and bodybuilders.

Benefits Of Isometric Exercises:

Isometrics are purely "muscle" movements that place the stress entirely on the muscle fibers, eliminating reactive contribution, and even so they increase muscle motor unit recruitment above and beyond what you get from eccentric or concentric reps.
Activation refers to the recruitment of the motor-units in a muscle. One can recruit nearly all the muscle fibers during a maximal isometric contraction - something that doesn't happen with regular eccentric and concentric (down and up) repetitions. Basically, the more muscle you can recruit the more damage you can inflict and the more growth can occur. Not surprisingly, this dramatically enhances strength. Strength gains of 14-40% were found over a 10-week period using isometric action training.

Isometrics also allow you to prolong the Time under tension of a particular area or sticking point and thus add to the time the muscle is under tension as well. If you think about it, when performing the large majority of movements in the gym the actual working effect of those movements are over a very short range so a lot of the time spent completing repetitions is just wasted.
For example, when you do a bench press your pectorals are really only maximum tension in the range from just off your chest to ½ of the way up - the rest is all shoulders and triceps so if you consider the pause at the top you spend nearly 2/3 of the entire set working muscles OTHER than your chest.

The average set duration is something like 20-30 seconds. That means your chest may only be under tension for 10 seconds or less per set. With isometric training you can isolate a specific area of a movement for a given time thus prolonging the time the muscle is under tension which is largely responsible for the hypertrophy response.

Isometrics not only cause muscle breakdown themselves, but also cause an immediate increase in subsequent dynamic work as well, which basically means you can perform an isometric exercise and stimulate strength, growth, and actually have a strength carryover or an increase in strength with your next movement. This is something that has to be experienced but it is a welcome change. You can actually get stronger as the workout continues instead of having a loss in strength typical of most routines.

Isometric training done at a disadvantageous joint angle in a movement like near the bottom of a bench press or squat will have a strength carryover throughout all ranges of the movement.

Since isometrics stress the muscle vs the tendons, fascia, etc, they are useful for rehabilitation or training around injuries. I had a case of biceps tendonitis the for several months, and basically the only biceps movements I could do without pain were partial range lying cable curls and isometric preacher curls (stressing the bottom 1/3).
Not only is my tendonitis almost healed but my biceps have not lost any size and experimenting the other day I found out I am a good 15% stronger on every bicep movement due to the isometric preacher curls i've been doing.

Isometrics build muscle mass. In a recent experiment found an average size improvement of 12.4% for heavy isometric training and 5.3% with isometric training using weights equivalent to 60% of 1rm weight after a training period of 10 weeks.

Using Isometrics For Strength

To strengthen your bench press you could either get in a power rack and press the bar against an immoveable pin for a certain length of time, or hold a supra-maximal weight in a ¼ rep range for 6-20 seconds.

The first type of isometric movement, pushing against an immoveable object, is used only for strength, whereas the 2nd type, holding a weight and preventing it from moving, is best for strength as well as muscle growth. Personally, I prefer the 2nd type where you simply hold a weight in place for both strength and muscle growth.

Some say that when performing isometrics you will only strengthen the part of the movement you're training. For example if doing isometrics in a ¼ range bench press position you'll only strengthen that part of the movement. The truth is you will strengthen the part of the movement you're training, but you also get a 15-30 degree carryover and if you train at the most disadvantageous joint angle (like the bottom of a bench press or point in the squat where your thighs are parallel) you actually get a 100% strength carryover through the rest of the movement.

Strengthen your weak links and everything else strengthens as well. In other words, if you perform an isometric contraction a few inches off your chest in the bench press you'll tend to increase the strength of your entire bench press and the size of your entire chest! But if you only do isometrics over the easiest ¼ or 1/3 range in a movement you only get a 15-30 degree carryover.

If you really want to increase strength in a movement, using the bench press as an example, you'd simply use 3 different positions (bottom, mid-range, and top) and perform an isometric in each position. You'd perform isometrics in the contracted position near your chest, the midrange position, and then the extended position up top. A sample workout would be 2 sets of 10 seconds at each position with the lower position done first. For strength, each isometric contraction should last 20 seconds or less and ideally under 10 seconds.

Using Isometric Training For Muscle Growth

When using isometrics to increase muscle growth, you're able to put a muscle under high amounts of tension for a very long period of time. The total length of time a muscle is under tension is largely responsible for the amount of muscle growth stimulated from a workout. You will know just how effective this method is once you try it!

There are 3 ways to implement isometrics for muscle growth. The 1st in my opinion is the most effective form.

Isometrics For Time

You simply hold a weight equivalent to 50-80% of your 1-rep max in 3 different positions per exercise for anywhere from 30 seconds to 1 minute. Let's illustrate an example.

Say you're doing preacher curls. You load up the bar with 60-80% of your 1-rep max and execute your set by holding the bar in a slightly flexed position near the bottom of the movement for anywhere from 30 seconds to 1 minute. Obviously, the heavier the weight in relationship to your 1-rep max the shorter you'll be able to hold it.

After this set you rest a minute and then repeat in the same extended position. Next you complete 2 sets in the mid-range position, followed by 2 sets in the upper 1/3 of the movement. Follow this up with 1-2 sets of full range preacher curls and your bicep workout is over. Try this and I'm sure you'll find it's the most effective workout for muscle growth ever! The guidelines for this method are:

Load: 50-80% of your 1 repetition maximum
Length of time per set: 30-60 seconds
Number of sets per position: 1-3 per position
Number of positions per exercise: 3
Rest intervals: 1-2 minutes

Isometric Stops

The next method of using isometrics for hypertrophy can be done on any exercise, but it is more effective for exercises like pull-ups, rows, and curls unless you have a spotter. This isometric training method involves using isometric stops. Isometric stops allow you to increase the duration of a set and thus put more strain on a muscle.

Say for instance you're doing a set chin-ups and you've knocked out 8 reps and struggled on your last rep so you know you won't be able to complete another repetition. Most people would simply relax their arms and terminate the set. However, you can increase the duration of the set and place more strain on the muscle by lowering yourself under control and stopping the negative motion for 6 seconds at different positions on the way down.

So, using our chin-up example, after completion of your last positive rep you'd hold yourself near the contracted position for 6 seconds, lower yourself down about to mid-point and hold for 6 seconds, and then lower yourself down near the bottom and once again hold for 6 seconds. Do this and you'll definitely notice a difference!

I recommend you use isometric stops on your last set of an exercise where applicable. You can get good results just doing 1 six second isometric hold on the last rep of the set, but if you're up for it go for all 3.

Isometric Supersets

You can also superset an isometric with a full range movement. This will boost the working effect of the full range movement big time. For example:

Isometric bench presses*
Dumbell flyes x 10-12 reps
Repeat 3 times

* Hold near the bottom position for 10 seconds with heavy weight.

Explosive Variety Supersetting

You can also superset an explosive movement with an isometric movement. This variety is great for athletes who need to maintain explosiveness while packing on the mass. Pick a movement, any movement and using 50% of your 1rm perform 10 fast and explosive reps as quickly as possible. Next, without resting simply hold the weight in your weakest position for as long as possible.

Repeat 3 times

Give some of these training methods of the past a try and watch them elevate your muscle growth years into the future. I predict we will see a reintroduction of "Charles Atlas" type training into the programs of bodybuilders in the next year or so.


Thibadeau, C. "Theory and Application of Modern Strength and Power Methods" 2004

Isometric wall squats primarily work the upper quadriceps as well as the lower quadriceps, hamstrings, and gluteus muscles as stabilizer muscles. To perform an isometric wall squat:

•Stand with your feet shoulder-width apart and lean against a wall with most of the contact against your lower back.
•Gradually slide down the wall until your knees are at a 90-degree angle.
•Consciously contract the thighs and gluteus.
•Hold the position for 15 to 180 seconds.

An isometric muscle contraction, or static exercise, is one in which the muscle fires but there is no movement at a joint. In this type of muscle contraction, there is no change in length of the muscle, and no movement at the joints but muscle fibers fire. An example of isometric exercise includes pushing against a wall.
The benefit of isometric exercises are that they can be used for rehabilitation as well as general strengthening without placing stress on the joints.


The Bullworker is a isometric training mechanism designed for a quick workout. It can hit every area of the body. You can even be take it on vacations. Most people use this device to work their entire body each workout. It is an excellent way to build muscle.
at may be BULLWORKER originals or any of the clones including the Steel Bow, Iso7x, Bully Xtreme etc etc.

Traditional Bullworker Training


Most of the bullworkers including the clones have a built-in gauge to measure strength for each exercise. Typically all of the manuals list around 40 or so different exercises, but in reality the number and type of exercises, especially with products like the Bullworker X5, is unlimited as you can alter hand positions thereby hitting either different muscles or sections of muscles within a particular muscle group. The next few exercises are written to match the original intension of the designer Gert F Kolber, however if you want to go beyond the bounds of the norm check out EXTREME BULLWORKER TRAINING.

Chest compression: Hold the Bullworker in front by the handles about chest height. Slowly compress the device as far as possible and hold for 10 seconds, then release it. To hit the upper chest, hold and compress the device at chin level. Compress it at a lower angle to hit the lower chest. Some of the newer Bullworkers such as the X5 have inside grips that can be used to hit both the upper and lower chest, too. Grip with both hands in an underhand manner to work the lower chest. Hold it with hands overhand to work the upper chest. Start out by doing just 1 set of each. Later, work up to 3 sets. Do this with all exercises.

Chest cable twist: Grab the cables, holding the insides of the hands about 8 inches apart. Slowly twist each end as far as possible. Hold for 10 seconds, then release.

Shoulder compression: Hold Bullworker behind the neck, compress for 10 seconds and release. All exercises should be held for 10 seconds.

Shoulder exercises with the cables: To work the anterior or front deltoid, hold the Bullworker in front. Hold one hand on the lower cable with an overhand grip. Grip the top cable with the other hand. Slowly pull the top cable up using similar tension on the lower end for leverage.

To hit the lateral side of the deltoids, hold upright and pull both ends outward. For the posterior head, bend at the waist, put the device between the legs and pull outward.

A one-arm upright rows can be done by holding the Bullworker horizontally. Pull up on one cable while holding the other end steady.

Back exercises: There are several good exercises for the back. To hit the lats, hold one end of Bullworker vertically against the top of the left thigh. Grip the other end at an angle. Bend the waist and pull the weight in toward the thigh. Repeat with the other hand. Try the exercise sitting as it isolates the lats more.

Bent over rows can be performed by stepping on one end of the cable and lifting up with both arms. Using that same grip, perform a deadlift by using only the lower back to pull up.

Arm exercises: For triceps, kneel on the floor, keeping one end of the device against the knees. Press down and hold. Another exercise is to hold the Bullworker as if using a bow and arrow. Gradually pull one cable away from the body. Pushdowns can be performed by pushing down on the cables, holding the Bullworker vertically.

For biceps, hold the bar vertically. Pull up on the top end while holding the bottom steady. Next, hold the bar horizontally and pull up on one end of the cable, holding the other end steady. Concentration curls can be performed with one or both hands. Assume a seated position, lean over, put both feet on top of one cable and pull up.

Bullworker Exercises For Lower Body
Work those thighs, hamstrings and calves. Hold Bullworker overhead and do 10 to 25 squats for the quadriceps. Next, sit down, hold one cable down with the foot and pull up on the other end. This is a leg extension that can add definition to the thighs. A third exercise hits the outer thigh. While seated, with the Bullworker on the floor, hook both feet through the cables. Slowly pull each leg outward.

Hold one cable with both feet, bend over and do a stiff-legged deadlift for hamstrings. Leg curls can be imitated by looping holding one cable with both hands and pulling back with each leg.

Calves can be worked in a seated position. Holding the cables with both hands, push the other end down with the foot. Switch legs. There are two variations of this exercise. Straightening the leg will hit the lower calf more directly. Bending the leg and pushing the cable downward will hit the gastrocnemius more directly.


The basic principal behind the original bullworker was that of isometric muscle contraction. Isometric contraction, is one in which the muscle is activated, but instead of being allowed to lengthen or shorten, it is held at a constant length. This isometrics muscle contraction is not done through a range of movements but in a static position. Isometrics is based on the principles of creating muscular tension while opposing the force of an immovable object or gravity. Isometrics are done with high levels of intensity (70-100%) rather than repetitious movements typically for a period of 7-12 seconds. Once the muscle is relaxed after the contraction increases blood flow to the muscles occurs which equals more nutrition and energy uptake which in turn increases the muscle mass (size). Later on the principals behind the bullworker were enhanced so as to make it more of a muscle building, as opposed to just pure strength building piece of home gym apparatus with the introduction of repetitions. This involved several repetitions pushing or pulling and releasing throughout the full range of the movement (or as far as your strength would allow you) and on the final repetition then doing the traditional bullworker hold phase or isometric contraction.



The Bullworker

The Bullworker is one of the few meaningful brands in the field of muscle building. At this point we do need to make clear that we fully acknowledge any or all trademarks and the terms used are purely to assist with identification. Virtually all of the top physiques of a certain area have tried or used the bullworker at some stage although many moved away from the product due, not in small part, to the instructions that came with both the original and current variants of the product as they have all failed to appreciate what muscle really need to grow. For training programs recommended by the manufacturers check out our bullworker training chart. Part of the reason for the development of this site is in Bullworker terms to "go where no man has gone before" and address the outer limits of the product exploring extreme training programs aimed at getting extreme results. We will also look at the products in terms of rehabilitation and weight loss but in the main the focus of this site is on pure natural muscle building but at a level way beyond the originally envisaged scope of the product.



EXTREME MUSCLE BUILDING - only for adults 21+ who want to add large amounts of muscle and burn excess body fat.

The Bullworker was invented by Gert F Kolbel in the 1970's when he adapted an original patent belonging to Arthur A Pons. The Bullworker is probably the most successful piece of home gym equipment sold via mail order and joins the likes of Charles Atlas as being a true pioneer in the world of muscle building alongside Eugene Sandow, Arthur Jones, John Little and Joe Weider.

Bullworkers - All trademarks recognised and acknowledged & are used only for purposes of description.

The Bullworker - the ultimate portable home gym