If you want muscle growth, it’s time to revamp your workout. High intensity, short duration training makes your muscle cells get thicker fast. Through research and experience I have developed a super-efficient training program I can do with as little as two 40-minute lifting workouts per week, continuously building strength and size. This routine helped me transition from a snowboarding weight of 190 pounds to a rugby weight of over 230 pounds in a period of only a few months, with the weight being mostly lean muscle. It focuses on targeting fast twitch skeletal muscles, the most important for muscle growth. This is not the only way to train. Depending on goals (strength, endurance), this routine is not right for everybody. From my experience, this routine the most efficient way to promote muscle growth.
I have built and evolved this program from several years of personal experience. The research comes from various existing athletic and muscle growth theories. The routine is based on the following hypotheses-
- Intensity is the most important factor for muscle growth (hypertrophy)
- Your workout can optimize and enhance hypertrophy through hormone manipulation
This article is broken into three main sections, each building on the previous-
- The Science of Muscle Growth
- Role and Manipulation of Hormones
- The Workout
The Science of Muscle Growth
In adults, muscles can grow via two mechanisms- by an increase in muscle fiber diameter or muscle fiber length. Muscle growth can only occur by hypertrophy of existing muscle fibers by adding myofibrils to increase the muscle fiber diameter or by adding new sarcomeres to the ends of exiting muscle fibers to increase their length¹.
Here’s a look at why high intensity, short duration training is most effective from the perspective of muscular structure. Short duration exercise (weight training, sprinting) utilizes fast twitch muscle fibers while endurance exercise utilizes slow twitch muscle fibers. Short duration training like resistance exercise leads to an increase in muscle mass while endurance exercise leads to increased oxidative metabolism without muscle growth². Right now, we just need to look at fast twitch, as we are focusing on hypertrophy. Fast twitch can be further broken into two groups Fast Oxidative (FO) fibers and Fast Glycolytic (FG) fibers.
FO fibers are able to use aerobic and anaerobic metabolism for fuel while FG fibers exclusive use anaerobic metabolism (slow twitch fibers use only aerobic). FG are the ones most important for fast, efficient hypertrophy. FG fibers contract very fast, are very powerful and have the largest diameter of the three muscle fiber types. They use strictly an anaerobic metabolic pathway, fatigue very quickly but contain the highest glycogen content, so are efficient using glycolysis for energy³ (more on that in the next section).
For survival instincts, your body wants to conserve energy. Thus, the utilization of muscles occurs in a hierarchy. For any effort, your body will first use your slow twitch muscle fibers. If the workload is too intense for the slow twitch muscle fibers, then the FO fibers are recruited. In order to recruit the large FG fibers, the workload needs to be so intense that the SO and FO fibers can’t handle it. The FG are the last to get called on because they require the most energy. This is why it is important to lift heavy weight (intensely) from the FIRST rep. If the FG fibers aren’t kicking in until your last reps, they aren’t going to be undergoing the anaerobic stress needed for maximum stimulation and growth. FG muscle fibers have a high rate of fatigue, so long, multiset workouts are not going to continuously engage the large FG muscle fibers optimal for hypertrophy.
Muscle contraction (movement) is dependent on the breakdown of adenosine triphosphate (ATP) and the concomitant release of energy⁴. Your body has two types of energy systems for your muscles- aerobic and anaerobic pathways. The aerobic training system can use carbohydrates and fat for fuel and requires the presence of oxygen to do it. Aerobic training is necessary for endurance related activities. Any workout that gets to the aerobic pathway is not good for hypertrophy because you are going to be mostly using slow twitch and fast oxidative muscle fibers, not the fast glycolytic, which use anaerobic respiration. This is why long multiset workouts will lead to aerobic training and hamper maximum muscle growth. In fact, endurance training can decrease resting human growth hormone and cause blunted exercise induced growth hormone response, which will be detrimental to maximum hypertrophy⁵.
To focus on and maximize muscle growth, you must use the anaerobic pathway. The anaerobic pathway can only use glucose and glycogen for fuel and does so in absence of oxygen. The two basic anaerobic energy systems are the phosphagen and glycolysis. The first 5–10 seconds of any muscular contraction use stored adenosine triphosphate (ATP) as fuel. Muscles generally have enough ATP stored to sustain maximal muscle contraction for about 5–6 seconds. Using the phosphagen system, your body can produce ATP for 10–15 seconds, primarily through the creatine kinase reaction by breaking down creatine phosphate (CrP) into its parts — — creatine and phosphate. The energy released from the breaking down of CrP takes an additional adenosine diphosphate (ADP) molecule and attaches to the phosphate, which creates a new ATP molecule. After very exhaustive exercise (like this workout will accomplish) restoration of CrP can take in excess of 15 minutes⁴. Thus, any exercise after depleting CrP in a muscle will be using aerobic pathways, thus not activating the FG muscle fibers.
When exercise continues long enough to deplete the phosphagen system (more than 10–15 seconds), it utilizes glycolysis, another anaerobic metabolic pathway. ATP is derived from blood glucose and glycogen stores³. FO and FG fibers both utilize glycolysis efficiently because of high glycogen stores. Over a 10-second maximal sprint, it is estimated that 53% of energy is from phosphagen, 44% glycolysis, and 3% mitochondrial. By the time a sprint reaches 30-seconds, those numbers shift to 23%, 49%, and 28%, respectively⁴. That means that 28% of your energy is not recruiting the FG muscle fibers, which operate under anaerobic respiration.
This is important to point out that you only have enough ATP for one set max. The aerobic system is responsible for 50% of energy output between 1 to 2 minutes of an exercise and most likely as early as around 75 seconds⁶. This means that if your sets are lasting two minutes, you are reducing anaerobic capacity by more than 50%. Half is going to muscle mass development, half is going towards endurance development. However, if you keep your set duration within the anaerobic timeframe, you could have nearly 100% of training within the anaerobic system.
Role and Manipulation of Hormones
Growth hormone (GH) is a natural hormone that we all have in our bodies. GH is anabolic (promotes muscle growth) but it does a lot more. It influences many other metabolic functions that alter your body composition, including the turnover of muscle, bone and collagen, to the regulation of certain aspects of metabolic function including increased fat metabolism and the maintenance of a healthier body composition in later life. The impact of some of the deleterious effects of ageing could be reduced if exercise focused on GH production⁵. The main activators of GH are sleep and exercise, the latter being the focus here. Importantly, intense exercise will optimize GH production. Research on pulsatile GH release found that GH secretion has a linear relationship to exercise intensity⁷. Simply put, more intensity = more GH. This creates a compounding validation for this type of training and muscle growth. The intensity is simultaneously stimulating the fast-glycolytic muscle fibers while increasing secretion of growth hormone. Constant load exercise (training without increasing intensity) with actually lead to reduced GH release⁸. This is another reason why constantly increasing intensity is so important.
IGF and Lactate
There have been many workouts that advocate intensity for hypertrophy. It’s the foundation of the eponymous and very popular High Intensity Training (HIT) dating back to the 1970’s and Nautilus founder Arthur Jones. The more unique aspect of the workout provided in the next section is adding muscle stretch to each set. This will produce insulin-like growth factor 1 (IGF-1). IGF-1 is a highly anabolic metabolite which can occur as a result of higher GH output. Stretch position isolation exercises have been found to help increase IGF-1 receptors in the muscles more than ordinary isolation exercises⁹.
“Enhanced muscle adaptations to resistance training are concurrent with muscle stretch, which warrants its inclusion within training.” (McMahon G, 2014)
In order to maximize the potential stretch of the exercises, the second half of each superset for each body part in this workout is performed by pausing for 4–6 seconds at the end of each negative rep, at the maximum stretch of the muscle. Doing this will help increase the IGF-1 and stimulate even greater anabolic response by building lactate. Doing this stretch set immediately after a high intensity, heavy set will create an extreme burn. Lactate is a byproduct of glycolysis (the metabolism used by our powerful FG muscle fibers) and has been sown to be beneficial during exercise. Lactate has long been misappropriated to causing muscle burn (caused by acidosis). Lactate production slows down, not causes, acidosis. If the muscle cells did not produce adequate lactate, acidosis and muscle fatigue would occur more quickly, severely impairing muscle performance (Robergs RA, 2004). Lactate is partially responsible for the secretion of GH¹⁰, testosterone¹¹, and insulin¹²
With the right training, anabolic response lasts well beyond the set or even workout. Lactate inducing workouts may amplify the pulsatile release of GH at rest, increasing 24-hour GH secretion⁵. The 24-hour window is a critical part of training frequency. Weight lifting can increase GH and IGF-1 for 24–36 hours. Working a muscle once a week, thus elevating it’s GH for 24 hours a week does not create maximum efficiency. Training up to three times per week will give those peak increases three times for a total of 72 hours a week.
I would recommend starting the first several months of this workout lifting three times per week, with one day in between. It will take this long to realize what maximum intensity is. You need to put more into one set than you ever have before. You need to get to the point where your brain thinks there is absolutely no way to do another rep. Then do 2–3 more because your muscles can do it. When you are doing this, and you are sore for 2–3 days after a workout, training frequency can be dropped to two times per week, and you will still see great increases in strength and mass.
Your muscles won’t grow lifting the same amount of weight no matter how long you lift it. Your muscles with enter the aerobic pathway, which can increase strength and endurance, but won’t produce growth. The goal should be to increase weight or reps EVERY workout. More weight or reps = more intensity = hypertrophy. In the first several months, you should be going up in weights and reps very quickly, simply as you learn how hard you can push yourself when you are putting everything into just one set. Sometimes it may only be one extra rep on one exercise of your superset.
The workout is simple and short. It requires one superset per body part per workout. This should take about 35–45min. For each body part you will do one heavy set followed immediately (<10 seconds) by an exercise that will stretch the muscle. For each set you should aim to do 8–12 heavy reps and 8–12 stretch reps with GOOD FORM. Change your exercises every 9 workouts (3–4 weeks). It could mean changing your heavy exercise, your stretch exercise, or both.
In choosing an order, my typical workout will try to split secondary groups. For example,
Here’s an example of some of the exercises you can use for each body part, for the heavy and the stretch set. This is not a comprehensive list, but could be all you really need. For your heavy set, you want an exercise that mostly isolates the muscle you are working and you can do very heavy with good form. For the stretch exercise, you want something that will stretch the muscle at the bottom of the rep. As you can see below, many exercises do both:
- Squat, Leg Press — Heavy
- Leg Extension — Heavy, Stretch
- Sissy Squats — Stretch
- Stiff Leg Deadlifts, Lying Leg Curls — Heavy, Stretch
- BB/DB/Machine Bench (including Incline, Decline, Flat )— Heavy
- DB/Machine/Cable Fly’s — Stretch
- Pullups, Cable/BB Rows, Pulldowns (Wide, Narrow, Closegrip) — Heavy, Stretch
- BB/DB/Machine Military Press — Heavy, Stretch
- Incline Front Raise — Stretch
- Hammer Curl, BB Curl — Heavy
- Incline Curl Preacher Curl — Stretch
- Close Grip Bench Press, Push Downs — Heavy
- Overhead DB Extension, Overhead Rope Extension — Heavy, Stretch
- Calf Raises on a Box (BB/Machine Standing, Machine Seated), Calf Press — Heavy, Stretch
Here’s what a workout might look like-
Squat 8 x 335lbs, Leg Extension 10 x 240lbs
Stiff Leg Deadlift 11 x 295lbs, Stiff Leg Deadlift 9 x 225lbs
DB Bench 8 x 105lbs, Machine Fly 8 x 150lbs
Weighted Pullups 11 x 15lbs, Wide Grip Pulldowns 9 x 160lbs
DB Military Press 9 x 75lbs, Incline Front Raise 11 x 30lbs
BB Curl 8 x 110lbs, Incline Curl 12 x 30lbs (increase weight next workout)
Overhead DB Extension 9 x 105lbs, Overhead DB Extension 10 x 65lbs
Smith Calf Raise on Box 9 x 385lbs, Smith Calf Raise on Box 9 x 295lbs
Cross-posted on Medium
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² Hickson RC. Interference of strength development by simultaneously training for strength and endurance. Eur J Appl Physiol Occup Physiol. 1980;45(2–3):255–63.
³ James Eldridge, M. (n.d.). CHAPTER 19 — SKELETAL MUSCLE TISSUE. Retrieved from University of Texas of the Permian Basin: http://general.utpb.edu/fac/eldridge_j/KINE3350/chapter_19_Review.htm
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