... NOT the recovery article, but still good ...
Muscle growth depends upon high muscle tension and the length of time that you apply the tension. Scientists are not completely sure how this works, but they have a few ideas.
Weight training damages the muscle fibers, which makes the muscle grow as they repair themselves. Stressed muscles grow important structures called satelite cells that cause the genetic material in the cells to make new muscle tissue.
Not all muscle fibers are alike--some are slow, and some are fast. Your nervous system chooses which fibers to contract according to the load on the muscle and the speed it contracts.
When your body lifts a light load, it chooses small, slow twitch fibers. It calls on the larger fast twitch fibers when called to lift a heavy weight or move quickly. If you want the greatest amount of muscle growth, you will want to build both fast and slow twitch muscle fibers. If you choose to train one way exclusively, you will only train one type of muscle fiber and your muscles will only be a fraction of their potential size.
What's the best way to stress both the fast and slow fibers? The key to muscle growth is tension, and the time tension is applied (often reffered to as time under tension). So, use a reasonably heavy weight for multiple sets. Most research suggests that you should NOT push these sets to failure.
The quality over quantity method that has been explained above works because it trains all the muscle fibers and does not compromise your body's recovery abilities.
Choosing the best combination of sets, reps, load (weight) and intensity is a balancing act at best for any weight-trained athlete.
Low reps/high weight are great for loading the nervous system and causing strength and power gains, but are not as effective at causing muscle growth.
Doing high reps/low weight doesn't overload the large fast twitch muscle fibers enough to promote muscle growth.
So, you have to compromise. Most studies show that the best solution to maximize muscle growth is 3 or more sets of 8 to 10 reps, using a moderate weight that allows you complete all reps in good form using a 2-1-2-1 tempo (2 seconds on the negative portion of the lift, 1 second pause, 2 second postive portion, 1 second pause). Lifting faster than that will allow momentum to come into play, unless you are training for explosive power, which is another article altogether.
Rest and recovery are a major factor if you are looking to build large muscles. Muscles grow after a workout, while you are recovering/resting. The process involves moving amino acids into the cells, whcih your muscles use to make new muscle protein.
Hormones such as testosterone, growth hormone, IGF-1, insulin, and cortisol regulate muscle building. Pushing to failure too often interferes with the growth process -- it slows the movement of amino acids into the cells, depresses tissue building anabolic hormones (testosterone, etc.) and boosts catabolic (tissue-breaking) hormones like cortisol. No good.
A better approach is to use cycle training, also known as periodization. This involves changing your volume and intensity of your workouts from one session to the next. This allows you to recover from hard workouts, which is essential for muscle growth.
Even more important is planned rest days during your training cycle. These days allow you to prepare for your intense training days, which will build larger muscles. You can't train hard if you are still tired from your last workout, right?
A way to put all of this together is to schedule hard, intense days ("red days") once in a while ... choose one bodypart to hit as a "red" once every other week Go hard, hit failure on your lifts. Each time, rotate to a new bodypart.
Before each red day, schedule a rest day. After each "red" day should be a low intensity "green day", during which you use a much lighter weight than usual, but really focus on form, tempo, and range of motion.
The rest of your workouts are "yellow days", which are moderate intensity using weights you can handle for 8 to 10 reps and feels like work, but not hitting failure.
WHAT'S SO WRONG WITH FAILURE?
The problem with doing sets to failure is that if you TRULY hit failure, you won't be able to do too many sets. After the first set, your fibers won't be able to handle the same load again.
For example, let's say you plan to do three sets of bench presses with 205 lbs. You barely complete 10 reps and are laying there in exhaustion. I can guarantee that you will not be able to mimic that effort on the next set ... your muscles will not be aboe to recover that fast. So, the muscles don't reach the high tension of the first set, and in turn will not grow as much. Remember: time under tension.
Also, failure training, when done too often, leads to overtraining, poor technique and overuse injury.
Overtaining is an imbalance between the stress of exercise and recovery. Training to failure makes it very hard to recover adequately. So, you will go into the next workout a little tired amd unable to match the workload of the previous workout.
Overtraining also reduces your testosterone levels and increases your cortisol levels. Studies from UCLA show that muscle growth depends on high levels of testosterone (in men and women). Your muscles won't grow as much when your testosterone tanks are running on empty.
Also, when your body is stressed it pumps out catabolic hormones. These hormones interfere with muscle growth and make training gains nearly impossible. It only takes a few weeks of failur training to send your "test" levels plummeting and yor cortisol levels through the roof.
Failure training also leads to sore joints and tendons. I myself was a huge advocate of failure training for years, and now I have lingering tendinitis in both elbows, and recurring paint in my right shoulder and left wrist. Whenever I step up my training to the point where I am pushing myself to the limits (the occasional falure day), I often get reminded when I am doing too much by one of these little injuries that will come back to the surface.
These tissues heal VERY slowly, and cause alot of pain. Prevention is best, and I am here to tell you that no matter how it looks to the boys in the gym and no matter what it does for your ego, benching another 25 pounds is not worth enduring the pain of elbow tendinitis.
SHOULD YOU ELIMINATE FAILURE TRAINING?
Training to failure CAN be a valuable training method if not overdone.
The human body has a remarkable ability to adapt to stress. When you do exercises such as push-ups, bench pressing, or running, you activate your body's stress management system that causes you to adapt. Your body adapts to exercise stress by improving its fitness--increasing strength, muscle size, endurance, flexibility, etc.
Unfortunately, it will only adapt so much -- the rapid gains that you make at the start of your program come slowly as the months go on. Your body won't respond to the same stress after awhile, so you need to change things. This includes intensity.
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