In my 30 plus years of being involved in fitness as a competitive bodybuilder, teacher of over 5000 personal trainers, trainer of athletes and owning fitness clubs and gyms, I have experimented with many workout methods to determine the most effective way to increase muscular strength and hypertrophy (muscle growth). Without a doubt Hi-intensity weight training has produced the best results for me personally, and for the multitude of people I have worked with. Scientific studies have overwhelmingly proven that intense progressive resistance workouts are the best form of training to achieve appreciable incremental muscular strength and muscular growth in the shortest period of time. Through trial and error and compiling the best features of various workout methods such as Nautilus, free weights, concentric, eccentric, static, faradic stimulation, pre-exhaustion, and periodization, I developed my 3 phase HIT3 Workout system. In this article we will focus on Phase 1, the physiology of performing a set of Hi-Intensity (HIT3) exercise. I will use the Leg Extension for the quadriceps as an example.
Phase1 is the basic fundamental of HIT3 training, performing an exercise for a body part to total muscular failure. An exercise performed to total exhaustion, (when no more repetitions can be completed), will result in the stimulation of highest percentage of muscle fibers for hypertrophy. Any additional sets of the same exercise would lead to overtraining and would be counterproductive. Actually, decreasing muscle strength and the potential for the muscle growth.
Muscle Contraction and Hypertrophy
The leg extension exercise is performed by sitting in the machine, with the quadricep muscles in the full stretched starting position. The lower part of the quadriceps muscles join at the kneecap and are attached to the quadriceps tendon, which is attached to the patella. The upper part of the quadriceps attach to the inguinal ligament below the groin. The exertion by the quadriceps, forces the lower leg area (the curvature of where the front of the foot and shinbone meet) to push against the roller pad of the Leg Extension machine. As the leg straightens, the roller pad attached to a movement arm, lifts the weight stack. Lifting the weight by the force of the quadriceps is called a concentric contraction. Muscle contraction is achieved when the myofibrils containing sarcomeres compress together to shorten. This occurs when Myosin and Actin, (which make up the myofibrils) slide beside each other causing the shortening of the sarcomere.
Muscle Fiber Recruitment
In the starting position of the exercise, a low percentile of the total available quadricep muscle fibers are involved. As the quadricep muscles begin to perform the movement, only the required number of muscle fibers are recruited to contract in order to complete the repetition. Without movement, a muscle cannot produce any significant amount of power. Muscle fibers can only perform work when they contract against resistance by reducing the length of their sarcomeres. As a builtin safety measure, muscle fibers cannot all contract at the same time. Such a force could injure them by ripping the muscle fibers away from their tendons.
The stress of the muscle contractions, due to the exercise being performed, causes micro tear damage to the muscle fibers (myofibrils). A form of trauma. This occurs when the Myosin and Actin in the Sarcomeres come under intense pressure as muscles contract while moving heavy resistance.
It is this trauma that will require the myofibrils to be repaired and grow.
Exercise Form and FULL RANGE MOVEMENT
In a leg extension exercise, it is impossible to perform the movement, in a manner that all of the quadricep muscle fibres will be involved at one time in the exercise, (regardless of the amount of weight resistance being used). If the exercise is performed under muscular control, using proper form and sufficient resistance, a higher percentage of the total muscle fibers will be recruited.
Exercises must be performed through the muscles full range of motion from extension to contraction in order to recruit the highest percentage of muscle fibres to contract. The concentric part of the exercise, (from full extension to full contraction) increases the time that the muscles are under tension. With more tension placed on the muscle fibers, more micro tears will occur in the sarcomeres, resulting in greater hypertrophy. Less than full extension and full contraction in each repetition will engage fewer muscle fibres than otherwise possible, which is detrimental to muscular growth.
At the start of the first repetition of the leg extensions, the quadriceps muscles are fresh and strong. However, because the leg is bent at the knee in a starting, stretched position, very few muscle fibres are initially involved. Any cheating, swinging or heaving of the weight, which creates momentum, will reduce the total number of muscle fibers contracting to perform the movement, because adjoining muscles will become involved to create force required to move the weight. This is very dangerous and could injure the knee cartilages and ligaments. Proper form means moving the weight in a slow, controlled speed. It should take 2 to 3 seconds to complete the concentric part of each repetition.
During the concentric part of the exercise, more quadricep muscle fibers will get recruited to complete lifting the weight until the muscle is fully contracted. In the contracted position is where the quadriceps muscles are under the greatest tension. It’s at this point that you are receiving the most benefit from the exercise. Therefore the contracted position should be held for at least 2 seconds. The eccentric part of the exercise is the lowering of the weight back to the start position (where the quadricep muscles lengthen back to their stretched position), should be performed at even a slower speed-3 to 4 seconds. For the purpose taking advantage of the “negative stimulation” portion of the exercise. This will further continue to exhaust the quadriceps muscles. Resulting in greater hypertrophy.
The First Few Repetitions
The first repetition of a Leg Extension (or any exercise) is the most dangerous repetition of a set and should be performed in a very slow, controlled fashion.
During this first repetition, a very small percentage of the quadricep muscle fibres will be involved in completing the full contraction, because the muscle fibres required to move the weight are fresh and strong, therefore fewer number of muscle fibers will be needed. In this case using a weight that in the previous workout, 8 repetitions were completed (with the goal being 12), as little as 2 to 4% of the quadriceps muscle fibres will be used to complete this first repetition.
As you continue to perform a second repetition, the previously used muscle fibers (in the first repetition) will be tired and will not be able to exert the force required to move the weight to the contracted/completed position. Completion of the second repetition is only possible by the recruitment of fresh quadriceps muscle fibers.
With each additional repetition you perform, a greater percentage of quadricep muscle fibres will be recruited to take the place of the exhausted fibers. As you get to the 9th repetition, (the point where you failed in the previous workout) the quadriceps muscle fibers will be under intense the most intense trauma of the set. As the fibers reach exhaustion, they will start burning due to lactic acid buildup. Making the 9th repetition very hard to complete. At this point in the exercise you may have only used 20 to 25% of the total quadriceps muscle fibers and due to discomfort most people will stop performing more repetitions, this clearly is the wrong thing to do, if your goal is to stimulate hypertrophy.
The goal to perform 12 repetitions must be kept in mind. The trauma to the quadriceps, causing the burning feeling due lactic acid buildup, is a signal that the muscle fibers recruited for the completion of the 9th repetition are now exhausted. The fundamental basis of HIT3 Training is that the Hypertrophy stimulating repetitions start at the point where you are pushing beyond this pain barrier. Performing more repetitions will force the quadriceps to recruit more muscle fibers and cause more micro trauma to the quadriceps than any repetition completed. Bare in mind that to get to that 9th repetition and beyond, the first 8 repetitions completed were within the quadricep muscles ability. Therefore, they did not cause the degree of muscle stimulation that the 9th and more repetitions will cause. Simply put, the quadriceps muscles performed the first 8 reps without being overly exhausted. Therefore if the set was stopped at 8 repetitions, there would be no growth stimulation occurring. Because there’s no need for them to grow, they won’t grow.
Continuing the set of Leg Extensions and performing the 10th repetition will cause more quadriceps muscle fibre recruitment, resulting in even more growth stimulation than the 9th repetition caused.
As is the case with the 11th repetition, which will force the quadricep muscles to work much harder than at any time during the previous 10 repetitions.
Again, instead of stopping after the difficulty of the 11th repetition, the set is continued to perform a 12th repetition. This repetition will be the most challenging of all to complete. However, it will stimulate more quadricep muscle fibers more than any of the previous repetitions completed. Therefore the 9th to the 12th repetitions are considered the “growth repetitions.”
How Many Repetitions?
I get asked this question more than any other question. “When a muscle starts burning and each repetition becomes harder to perform, how many more repetitions are required for maximum strength and muscle growth?” The answer I give is “ as many repetitions as humanly possible! Continue with the exercise until the muscle being worked can no longer complete a full repetition. Even at that point not all the muscle fibres have been stimulated. It is only at the point of total muscular failure that you will have recruited and stimulated the highest percentage of muscle fibres as humanly possible, resulting in increased strength and muscle growth.
-Hitting the Wall After barely completing the excruciating 12th repetition, the quadricep muscles will be exhausted to the point that they cannot and will not be able to complete one more full repetition. They have hit the wall.
– achieved muscular failure. But is this the end of the set? For most methods of training, yes. To this point the quadricep muscles have been exhausted in their concentric and eccentric capacities, therefore, what more could one do to stimulate even more hypertrophy? The answer is performing at least two more Isometric repetitions. Where by each repetition is attempted by moving the weight as far as possible and holding that Lee’s than complete contracted position for a count of 10. Then immediately bringing the legs back to the stretched starting position, starting point, and attempting another all out repetition. Even if you can only move to weight several inches to a quarter contracted position, this position must be held for 10 seconds, if possible. At this point in the set of Leg Extensions, the following has happened:
- The first eight repetitions performed equalled the workout performance of the previous workout (using the same weight). -Four more repetitions, the 9th to the 12th, were also completed causing greater muscle stimulation.
- The quadricep muscles were exhausted in their concentric and eccentric capacity.
- The completion of 2 more Isometric repetitions caused muscular failure in the static position.
- The quadricep muscles have failed in your total ability to perform under the most intense force. Mission Accomplished! Hypertrophy has been Stimulated!
In the performance of a HIT3 set of Leg Extensions as described above, it is the 9th to the 12th repetitions that induce hypertrophy. These repetitions may seem impossible to complete, however, with motivation and willpower, they are most important growth producing repetitions of the set. Very few people have the ability to push this hard in a set and perform what I call “truth repetitions”. Watching someone train in this manner is a bit of a scary proposition. The intensity of those last 4 repetitions create a situation where a persons body is shaking, breathing will become heavier, the face will turn red, and their pulse rate increases to more than triple their resting rate.
The whole purpose of exercise is to force our muscles to get stronger. Therefore a set rep goal for each exercise is very important. Once the set rep goal has been achieved, (in the Leg Extension case, 12 repetitions) the weight must be increased by 5 to 10% for the next work out. This increase in weight ensures that you are imposing a higher stress level on the muscles being worked. Resulting in continued stimulation of hypertrophy.
Very few people working out in a gym have ever performed a set of exercise to absolute muscular failure, as they are not aware that this type of intensity is even possible. However, to stimulate the most amount of muscle hypertrophy, that is exactly what is required.
If a person does not experience delayed onset muscle soreness for 24 to 72 hours after the workout, they have not stimulated the muscle to grow. Soreness equates to the hypertrophic affect.
Without the motivation and guidance to workout in a HIT3 manner, it is impossible to achieve premier results.
When I supervise a trainee during a HIT3 workout for the first time, coaching them to focus all their efforts on pushing to total muscular failure, they perform far beyond what they normally do. It is as if they are weight training for the first time. Working out on their own, they have never experienced this type of hi-intensity, and the feeling of a thoroughly growth stimulated muscle part. The muscle soreness they experience will last up to 7 days.
Charting Progress = Motivation
An important requirement of HIT3 training is tracking the performance on each exercise. HIT3 training performance must be measured during each workout. The amount of weight used, the repetition goal and the repetitions performed.
With a repetition goal in mind, the trainee engages the mind on the task at hand, motivating themselves to perform with more determination to achieve the repetition goal. Without a repetition goal and using sufficient weight, it is a pointless set of exercise.
Progressive weight training means that a trainee is aware of the repetition goal of an exercise, and increasing the weight when the repetition goal has been reached. This creates internal motivation in the trainee to work hard to improve their performance at each workout. It is this improvement factor that will drive a trainee to push beyond the pain barrier, to accomplish new strength goals.
That is why I believe that tracking the performance on each exercise, every workout,is crucial to progress. The trainee then is aware of the number of repetitions completed in the previous workout. This creates the motivation for today’s session, to strive to perform more repetitions with the same weight, with the purpose of increasing the weight when the repetition goal has been reached.
It is this factor that will motivate a person to increase their focus, work harder, to push to establish a new record the performance in each workout. Without gaining strength and pushing beyond what the muscle was capable of doing previously, there cannot be any new hypertrophy of muscle fibres or increase in strength.
It is common in gyms to see people training without a workout journal or ever recording their performance on each exercise. It is also very common to see a personal trainers in gyms training clients and not recording or tracking the workout that they are supervising the client to do. Without tracking workout performance, how is a client able to measure progress and stay motivated to work harder each workout?
Most people training today move from exercise to exercise, using only guesswork, without ever keeping track of the weight they are using or the repetitions performed. Without a repetition goal in mind to force a muscle to outperform what was accomplished in a previous workout, there cannot be any muscular growth. That is why most people workout for years, with little in the way of strength gains or hypertrophy.
Charting process is a key factor in how HIT3 Training is the premier method for achieving strength gains and hypertrophy.