HackTwat
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[h=2]Insulin-Like Growth Factor[/h]by Charles Poliquin on
Insulin-Like Growth Factors make up the lesser known anabolic hormones, and an understanding of their role in muscle building and breakdown is valuable to get the greatest strength training and body composition results. In fact, insulin-like growth factor-1 (IGF-1), supports growth hormone’s stimulation of protein synthesis, while growth hormone (GH) also triggers IGF-1 secretion from the liver. IGFs include a group of binding proteins, such as the IGF Binding Proteins-1 and -3 (IGFBP-1 and IGFBP-3), which play catabolic and anabolic roles in the body, respectively.
IGFs are also affected by testosterone, probably the most anabolic hormone, indicating the interconnected nature of the different hormones that make up the endocrine system. It is one of the least studied hormones, but there are a number of key training strategies you can use to capitalize on IGFs for the best anabolic response. Here are ten tips you need to know to make the most of IGFs and reach the next level.
1) How Can Raising IGF Levels Make Me Stronger and Bigger?
IGF-1 builds muscle by stimulating muscle protein synthesis because IGF-1 and Mechano Growth Factor (MGF), a related hormone, are released from the overloaded muscle following resistance training. A research review published in the Journal of Strength and Conditioning Research considers IGF-1 “to provide the main anabolic response for the body as a whole” because it increases the rate of protein synthesis—illuminating IGF-1s essential role in muscle and tissue building.
There is significant evidence that resistance training elicits an increase in IGF-1 immediately after each workout. This is likely due to its relationship with GH, which is elevated for a sustained period post-exercise via the surge-like secretions from the pituitary gland. IGF-1 and MGF are thought to “kick start” muscle hypertrophy following lifting, and levels remain elevated for up to 72 hours after a workout.
IGF-1 is also chronically elevated by resistance training, meaning that individuals who were previously untrained who start weight lifting will increase their IGF-1 levels over time. For example, one study compared the effect of resistance training in sedentary individuals over 25 weeks. Participants trained seven exercises using either one set or three sets. After 13 weeks IGF-1 increased by about 20 percent in both groups, indicating that volume doesn’t have a significant role in long-term IGF-1 secretion.
2) Maximize IGF-1 Release with a Hypertrophy-Type Program
Use a hypertrophy-type program with lifts in the 80 percent of the 1RM range for a big bump in IGF levels. A large volume of training hasn’t been shown to be necessary to raise IGF-1 after training, but a relatively heavy weight is. A recent study found that performing four sets of leg press and leg extension at 80 percent of the 1 RM to failure resulted in significant increases in IGF-1 immediately, 30 minutes, two hours, and six hours following training. Rest periods were long—about 2.2 minutes. Researchers note that since IGF-1 data is not extensive, further investigations are necessary to identify the best protocol for IGF-1.
A second study used a slightly larger volume of training (5 sets of 10 leg presses at 75 percent 1RM and 4 sets of 10 squats at 75 percent 1RM with two minutes rest) and also found a significant increase in IGF-1 and MGF. The good news is that this evidence can fit into a protocol that is geared toward maximal testosterone response (heavy weight, large volume, longer rest) or GH (moderately heavy weights, short rest, very large volume). Take note that IGF-1 and MGF were both significantly elevated at 48 hours after training, which researchers note is due to their effectiveness in muscle synthesis and repair.
3) I Want to Get Lean. What Happens to IGF-1 if I Restrict Energy Intake?
Not a good plan! Decreasing your energy intake by as little as 13 percent can result in an unfavorable catabolic state with decreased testosterone and IGF-1 levels. Research on bodybuilders over 11 weeks in preparation for competition found that significantly decreasing energy consumption results in muscle mass loss and a catabolic state despite continued strength training. The bodybuilders had a negative energy balance that started at 200 kcal/day 11-weeks before competition, and reached 950 kcal/day three days before competition. They consumed a diet that averaged 28 percent protein, 60 percent carbohydrate, and 12 percent fat.
Individual muscle mass losses were evident and anabolic muscle building was negatively affected. The bodybuilders had significant decreases in testosterone, insulin, and IGF-1, which indicate a catabolic state. A few possible errors in the bodybuilders programs should be noted: they performed increasing bouts of aerobic training leading up to competition (the study doesn’t include what type of training so we don’t know if it was light, moderate, or high-intensity), and their carbohydrate intake was probably high.
Researchers point to the role of IGF-1 in activating the protein synthesis pathway that cortisol inhibits. It is also involved in the regulation of somatic growth, metabolism, and cellular survival. Plus, energy restriction decreases insulin and when it falls below a certain level, IGF-1 activity is impeded. Low levels of IGF-1 and insulin will be followed by rapid loss of muscle and consumption of more protein may help to counteract the decrease in anabolic pathways.
4) Get Anabolic with Sprint Intervals
Condition with sprint intervals to increase testosterone and IGF Binding Protein-3, an anabolic hormone that increases IGF-1 bioactivity. IGFBP-3 has further benefits because it inhibits the muscle degrading effects of IGFBP-1, which has muscle degrading effects.
Two studies by an Israeli research group found that performing sprint intervals (4 x 250 meters or a varied sprint length of 100, 200, 300, and 400 meter sprints) can trigger IGF-1 and IGFBP-3. The 250 meter sprints triggered IGFBP-3 alone, while the varied length sprints increased levels of IGFBP-3 and IGF-1. Inflammatory cytokines such as IL-6 were also elevated, which can inhibit IGF-1 anabolic activity, meaning that the greater the increase in IGF-1 the better.
Researchers note that to increase IGF-1 and IGFBP-3, you need to perform high-intensity sprints with a decreasing distance protocol (400, 300, 200, 100 meters) because IGF-1 appears to require a higher intensity of conditioning exercise than was used in the longer 250 meter sprints. Additionally, there is a delicate balance to the relationship between these anabolic hormones and inflammatory markers, which they suggest may also play a role in supporting tissue repair after anaerobic exercise.
5) Take Magnesium to Raise IGF-1 Levels
Supplement with magnesium to raise IGF-1 and testosterone levels and improve your anabolic profile and overall health. Magnesium plays a critical role in cardiovascular and neuromuscular function. Low magnesium levels can cause seizures, heart arrhythmias, muscular weakness, and may accelerate the aging process. Plus, in older men, magnesium deficiency has been found to accelerate sarcopenia, or muscle loss, and is related to metabolic syndrome.
A new Italian study found that low magnesium was directly related to low IGF-1 levels. Researchers suggest this is because IGF-1 plays a role in decreasing oxidative stress, which magnesium also impacts. More magnesium means higher concentrations of IGF-1. Additionally, magnesium decreases inflammation and evidence shows that IGF-1 interacts with inflammatory markers, meaning that adequate magnesium allows for higher IGF-1 levels by decreasing chronic inflammation.
Take note that low IGF-1 levels are an independent predictor of mortality in older men, pointing to the essential role of this anabolic hormone on your health. Read about How I Replenish Magnesium Levels in order to get your IGF-1 up to snuff.
6) Raise IGF-1 Levels With Resistance Training for Bone Health
Strength training promotes bones and prevents osteoporosis and one of the reasons is that lifting raises levels of IGF-1. Research shows that in a population of older men (average age over 54) those with significantly lower IGF-1 levels were more likely to have osteoporosis. Resistance training is an excellent option to lower the incidence of bone fractures and promote longevity.
7) Vary Your Tempo and Use Eccentric Pauses to Elevate IGF-1
Use varying tempos when you lift in order to overcome a plateau and shock the muscles into adapting. Tempo training, or changing the rate at which you perform the different parts of a lift, allows you to increase time under tension and maximally stimulate the muscle. Research shows that different tempos can trigger greater hormone responses and adding a pause into a lift will allow IGF-1 to exert a greater anabolic effect.
Think about it: Performing a set of ten reps of squats with 60 kg at a 1-second-up and 1-second-down tempo is quite different from the same weight and reps at a 1-second-up and 4-seconds-down tempo. The difference is the time exposed to tension, and the first variation takes 20 seconds, while the second takes 50! Modifying time under tension provides a new or different stimulus to the muscular system and allows you to train for hypertrophy and strength at the same time.
A recent study compared training with two moderate velocity tempos (2/0/2) vs. (2/0/4) in the bench press and found that IGF-1 was higher following workouts with the 2/0/2 tempo. Also, ratings of perceived exertion were lower than with the 2/0/4 speed. Testosterone response was equal for both speeds. This evidence points to the need to program for tempo and use a variety in your training—not just fast or slow. Plus, adding an isometric pause in the up position of the bench press or stopping the lift during the eccentric motion, is another way to increase intramuscular tension and capitalize on IGF-1 protein synthesis effect.
8) How Can I Apply Tempo Training to Give Me Bigger Arms and More IGF?
So glad you asked! Remember that IGF-1 and MGF kick hypertrophy into high gear and keep muscle synthesis cranking for up to three days after a workout. You will get the greatest anabolic response in the muscle fibers that you have worked and exhausted from your workout. Therefore, in order for IGF-1, MGF, and GH to work their magic on your arms, you need to thoroughly fatigue every last muscle fiber.
Perform my two favorite arm finishers at the end of an arm routine and you’ll increase IGF-1 and get bigger. Try 90-degree Chin-Ups: Use a supinated close grip on the chin-up bar and pull up to 90 degrees of elbow flexion. Hold that position for as long as possible—preferably at least 30 seconds. You can hang weight plates off you if you want to make it harder. Then slowly lower down. If you have anything left in your arms you can do it again.
Another fun arm finisher is Close Grip Pull-Ups for time: Use a 10-15 cm pronated grip. Do a single pull-up for time—slow time that is. The goal is to make the rep last one minute—30 seconds for both the eccentric and concentric contractions.
9) Take Arginine, Ornithine, and Betaine
Add arginine, ornithine, and betaine to your nutrition stack for a greater IGF-1 response after training. All three are amino acids (actually betaine is a derivative of the amino acid glycine) and they can all increase strength with training and make you more anabolic.
A new study found that taking 1.5 grams twice a day of betaine improved participants vertical jump height, bench press throw power, and maximal number of squat reps at a 90 percent load. It also resulted in a significantly greater GH and IGF-1 release than a placebo group. Plus, cortisol release decrease, indicating that betaine creates a potent muscle building environment. Researchers suggest that performance improved because betaine helps support the synthesis of creatine phosphate, the body’s energy source for intense short-term exercise.
Additionally, taking a combination of arginine (3000 mgs) and ornithine (2200 mgs) twice a day has been shown to elevate IGF-1 levels after performing five sets of five squats at 80 percent of the 1RM. Along with increases in IGF-1, GH was significantly higher after supplementing with arginine and ornithine. Researchers point to the interrelated role of IGF-1 and GH in recovery after training by building connective tissue and improving protein synthesis. Get the most out of your hard gym work and get your nutrition in order!
10) Take Phosphatidyl-Choline to Improve IGF-1 Levels and Sleep Better
Phosphatidyl-choline triggers IGF-1 response and it is a great liver detoxifier— IGF-1 is released from the liver, which is one reason this supplement supports an anabolic response.
Additionally, phosphatidyl-choline increases insulin sensitivity and glucose uptake, meaning it helps prevent diabetes and promotes an ideal body composition. It also helps bring down sympathetic nervous system activity and if you take it at night, you’ll sleep better. And better sleep will mean you are setting your body up for a greater GH response because prime time for GH secretion is at night. Good stuff! Remember GH and IGF-1 are interconnected and GH stimulates IGF-1 meaning you can’t go wrong by getting more rest.
Insulin-Like Growth Factors make up the lesser known anabolic hormones, and an understanding of their role in muscle building and breakdown is valuable to get the greatest strength training and body composition results. In fact, insulin-like growth factor-1 (IGF-1), supports growth hormone’s stimulation of protein synthesis, while growth hormone (GH) also triggers IGF-1 secretion from the liver. IGFs include a group of binding proteins, such as the IGF Binding Proteins-1 and -3 (IGFBP-1 and IGFBP-3), which play catabolic and anabolic roles in the body, respectively.
IGFs are also affected by testosterone, probably the most anabolic hormone, indicating the interconnected nature of the different hormones that make up the endocrine system. It is one of the least studied hormones, but there are a number of key training strategies you can use to capitalize on IGFs for the best anabolic response. Here are ten tips you need to know to make the most of IGFs and reach the next level.
1) How Can Raising IGF Levels Make Me Stronger and Bigger?
IGF-1 builds muscle by stimulating muscle protein synthesis because IGF-1 and Mechano Growth Factor (MGF), a related hormone, are released from the overloaded muscle following resistance training. A research review published in the Journal of Strength and Conditioning Research considers IGF-1 “to provide the main anabolic response for the body as a whole” because it increases the rate of protein synthesis—illuminating IGF-1s essential role in muscle and tissue building.
There is significant evidence that resistance training elicits an increase in IGF-1 immediately after each workout. This is likely due to its relationship with GH, which is elevated for a sustained period post-exercise via the surge-like secretions from the pituitary gland. IGF-1 and MGF are thought to “kick start” muscle hypertrophy following lifting, and levels remain elevated for up to 72 hours after a workout.
IGF-1 is also chronically elevated by resistance training, meaning that individuals who were previously untrained who start weight lifting will increase their IGF-1 levels over time. For example, one study compared the effect of resistance training in sedentary individuals over 25 weeks. Participants trained seven exercises using either one set or three sets. After 13 weeks IGF-1 increased by about 20 percent in both groups, indicating that volume doesn’t have a significant role in long-term IGF-1 secretion.
2) Maximize IGF-1 Release with a Hypertrophy-Type Program
Use a hypertrophy-type program with lifts in the 80 percent of the 1RM range for a big bump in IGF levels. A large volume of training hasn’t been shown to be necessary to raise IGF-1 after training, but a relatively heavy weight is. A recent study found that performing four sets of leg press and leg extension at 80 percent of the 1 RM to failure resulted in significant increases in IGF-1 immediately, 30 minutes, two hours, and six hours following training. Rest periods were long—about 2.2 minutes. Researchers note that since IGF-1 data is not extensive, further investigations are necessary to identify the best protocol for IGF-1.
A second study used a slightly larger volume of training (5 sets of 10 leg presses at 75 percent 1RM and 4 sets of 10 squats at 75 percent 1RM with two minutes rest) and also found a significant increase in IGF-1 and MGF. The good news is that this evidence can fit into a protocol that is geared toward maximal testosterone response (heavy weight, large volume, longer rest) or GH (moderately heavy weights, short rest, very large volume). Take note that IGF-1 and MGF were both significantly elevated at 48 hours after training, which researchers note is due to their effectiveness in muscle synthesis and repair.
3) I Want to Get Lean. What Happens to IGF-1 if I Restrict Energy Intake?
Not a good plan! Decreasing your energy intake by as little as 13 percent can result in an unfavorable catabolic state with decreased testosterone and IGF-1 levels. Research on bodybuilders over 11 weeks in preparation for competition found that significantly decreasing energy consumption results in muscle mass loss and a catabolic state despite continued strength training. The bodybuilders had a negative energy balance that started at 200 kcal/day 11-weeks before competition, and reached 950 kcal/day three days before competition. They consumed a diet that averaged 28 percent protein, 60 percent carbohydrate, and 12 percent fat.
Individual muscle mass losses were evident and anabolic muscle building was negatively affected. The bodybuilders had significant decreases in testosterone, insulin, and IGF-1, which indicate a catabolic state. A few possible errors in the bodybuilders programs should be noted: they performed increasing bouts of aerobic training leading up to competition (the study doesn’t include what type of training so we don’t know if it was light, moderate, or high-intensity), and their carbohydrate intake was probably high.
Researchers point to the role of IGF-1 in activating the protein synthesis pathway that cortisol inhibits. It is also involved in the regulation of somatic growth, metabolism, and cellular survival. Plus, energy restriction decreases insulin and when it falls below a certain level, IGF-1 activity is impeded. Low levels of IGF-1 and insulin will be followed by rapid loss of muscle and consumption of more protein may help to counteract the decrease in anabolic pathways.
4) Get Anabolic with Sprint Intervals
Condition with sprint intervals to increase testosterone and IGF Binding Protein-3, an anabolic hormone that increases IGF-1 bioactivity. IGFBP-3 has further benefits because it inhibits the muscle degrading effects of IGFBP-1, which has muscle degrading effects.
Two studies by an Israeli research group found that performing sprint intervals (4 x 250 meters or a varied sprint length of 100, 200, 300, and 400 meter sprints) can trigger IGF-1 and IGFBP-3. The 250 meter sprints triggered IGFBP-3 alone, while the varied length sprints increased levels of IGFBP-3 and IGF-1. Inflammatory cytokines such as IL-6 were also elevated, which can inhibit IGF-1 anabolic activity, meaning that the greater the increase in IGF-1 the better.
Researchers note that to increase IGF-1 and IGFBP-3, you need to perform high-intensity sprints with a decreasing distance protocol (400, 300, 200, 100 meters) because IGF-1 appears to require a higher intensity of conditioning exercise than was used in the longer 250 meter sprints. Additionally, there is a delicate balance to the relationship between these anabolic hormones and inflammatory markers, which they suggest may also play a role in supporting tissue repair after anaerobic exercise.
5) Take Magnesium to Raise IGF-1 Levels
Supplement with magnesium to raise IGF-1 and testosterone levels and improve your anabolic profile and overall health. Magnesium plays a critical role in cardiovascular and neuromuscular function. Low magnesium levels can cause seizures, heart arrhythmias, muscular weakness, and may accelerate the aging process. Plus, in older men, magnesium deficiency has been found to accelerate sarcopenia, or muscle loss, and is related to metabolic syndrome.
A new Italian study found that low magnesium was directly related to low IGF-1 levels. Researchers suggest this is because IGF-1 plays a role in decreasing oxidative stress, which magnesium also impacts. More magnesium means higher concentrations of IGF-1. Additionally, magnesium decreases inflammation and evidence shows that IGF-1 interacts with inflammatory markers, meaning that adequate magnesium allows for higher IGF-1 levels by decreasing chronic inflammation.
Take note that low IGF-1 levels are an independent predictor of mortality in older men, pointing to the essential role of this anabolic hormone on your health. Read about How I Replenish Magnesium Levels in order to get your IGF-1 up to snuff.
6) Raise IGF-1 Levels With Resistance Training for Bone Health
Strength training promotes bones and prevents osteoporosis and one of the reasons is that lifting raises levels of IGF-1. Research shows that in a population of older men (average age over 54) those with significantly lower IGF-1 levels were more likely to have osteoporosis. Resistance training is an excellent option to lower the incidence of bone fractures and promote longevity.
7) Vary Your Tempo and Use Eccentric Pauses to Elevate IGF-1
Use varying tempos when you lift in order to overcome a plateau and shock the muscles into adapting. Tempo training, or changing the rate at which you perform the different parts of a lift, allows you to increase time under tension and maximally stimulate the muscle. Research shows that different tempos can trigger greater hormone responses and adding a pause into a lift will allow IGF-1 to exert a greater anabolic effect.
Think about it: Performing a set of ten reps of squats with 60 kg at a 1-second-up and 1-second-down tempo is quite different from the same weight and reps at a 1-second-up and 4-seconds-down tempo. The difference is the time exposed to tension, and the first variation takes 20 seconds, while the second takes 50! Modifying time under tension provides a new or different stimulus to the muscular system and allows you to train for hypertrophy and strength at the same time.
A recent study compared training with two moderate velocity tempos (2/0/2) vs. (2/0/4) in the bench press and found that IGF-1 was higher following workouts with the 2/0/2 tempo. Also, ratings of perceived exertion were lower than with the 2/0/4 speed. Testosterone response was equal for both speeds. This evidence points to the need to program for tempo and use a variety in your training—not just fast or slow. Plus, adding an isometric pause in the up position of the bench press or stopping the lift during the eccentric motion, is another way to increase intramuscular tension and capitalize on IGF-1 protein synthesis effect.
8) How Can I Apply Tempo Training to Give Me Bigger Arms and More IGF?
So glad you asked! Remember that IGF-1 and MGF kick hypertrophy into high gear and keep muscle synthesis cranking for up to three days after a workout. You will get the greatest anabolic response in the muscle fibers that you have worked and exhausted from your workout. Therefore, in order for IGF-1, MGF, and GH to work their magic on your arms, you need to thoroughly fatigue every last muscle fiber.
Perform my two favorite arm finishers at the end of an arm routine and you’ll increase IGF-1 and get bigger. Try 90-degree Chin-Ups: Use a supinated close grip on the chin-up bar and pull up to 90 degrees of elbow flexion. Hold that position for as long as possible—preferably at least 30 seconds. You can hang weight plates off you if you want to make it harder. Then slowly lower down. If you have anything left in your arms you can do it again.
Another fun arm finisher is Close Grip Pull-Ups for time: Use a 10-15 cm pronated grip. Do a single pull-up for time—slow time that is. The goal is to make the rep last one minute—30 seconds for both the eccentric and concentric contractions.
9) Take Arginine, Ornithine, and Betaine
Add arginine, ornithine, and betaine to your nutrition stack for a greater IGF-1 response after training. All three are amino acids (actually betaine is a derivative of the amino acid glycine) and they can all increase strength with training and make you more anabolic.
A new study found that taking 1.5 grams twice a day of betaine improved participants vertical jump height, bench press throw power, and maximal number of squat reps at a 90 percent load. It also resulted in a significantly greater GH and IGF-1 release than a placebo group. Plus, cortisol release decrease, indicating that betaine creates a potent muscle building environment. Researchers suggest that performance improved because betaine helps support the synthesis of creatine phosphate, the body’s energy source for intense short-term exercise.
Additionally, taking a combination of arginine (3000 mgs) and ornithine (2200 mgs) twice a day has been shown to elevate IGF-1 levels after performing five sets of five squats at 80 percent of the 1RM. Along with increases in IGF-1, GH was significantly higher after supplementing with arginine and ornithine. Researchers point to the interrelated role of IGF-1 and GH in recovery after training by building connective tissue and improving protein synthesis. Get the most out of your hard gym work and get your nutrition in order!
10) Take Phosphatidyl-Choline to Improve IGF-1 Levels and Sleep Better
Phosphatidyl-choline triggers IGF-1 response and it is a great liver detoxifier— IGF-1 is released from the liver, which is one reason this supplement supports an anabolic response.
Additionally, phosphatidyl-choline increases insulin sensitivity and glucose uptake, meaning it helps prevent diabetes and promotes an ideal body composition. It also helps bring down sympathetic nervous system activity and if you take it at night, you’ll sleep better. And better sleep will mean you are setting your body up for a greater GH response because prime time for GH secretion is at night. Good stuff! Remember GH and IGF-1 are interconnected and GH stimulates IGF-1 meaning you can’t go wrong by getting more rest.
