Creatine Super Feature – Part 5

Part 5:
Recent Creatine Research Reviews

The following presents reviews of some of the most recent creatine research conducted between 1999 and 2005 using creatine monohydrate. These reviews cover a wide range of research topics, such as, reconfirmation of creatine supplementation causing increases in muscle strength and building; creatine supplementation effects on young and old athletes and non-athletes; effects on sports performance; and effects on men and women.

As some of the studies measured multiple benefits of creatine, some athletic benefits are also included in this part, in addition to Part 6.

Creatine Monohydrate Supplementation and Muscle and Strength Building

Study Title:
"Mg2 -creatine chelate and a low-dose creatine supplementation regimen improve exercise performance."

Selsby and coworkers (3) conducted a double-blind, placebo study using a Creatine monohydrate taking group (2.5 g of Creatine per day), and a Magnesium Creatine taking group (2.5 g of Creatine per day). Pre-treatment data was collected for the bench press 1 repetition maximum (RM) and maximal work completed during a fatigue set at 70% of the 1RM.

1 Rep Max Calculator

Following 10 days of Creatine supplementation, follow-up tests were completed and data was collected. After 10 days of supplementation, both the Creatine monohydrate and the magnesium Creatine groups had significantly larger increases in maximal work completed during a set of bench presses at 70% of the one repetition maximum, and 1 repetition maximum, both of these experimental groups were similar.

This study provides some evidence that low dosages of creatine monohydrate may be an effective means of enhance muscle strength performance after a period of short-term ingestion. Also, the use of magnesium creatine offered no additional benefits over creatine monohydrate, and compared to higher dosage creatine studies, the improvements were not as big.

Note: one issue I have with using a magnesium-creatine chelate is that in order to take in adequate amounts of creatine, you most likely will be taking in too much magnesium. Creatine monohydrate works best, alone or as an ingredient in sophisticated comprehensive formulas like Explosive Growth Blend.

Study Title:
"Effects of creatine on body composition and strength gains after 4 weeks of resistance training in previously nonresistance-trained humans."

This study by Kilduff and coworkers (4) evaluated the effects of creatine monohydrate supplementation on muscle strength in conjunction with resistance training in nonresistance-trained males. Nineteen nonresistance-trained males underwent 4 weeks of resistance training 3 days per week.

The creatine supplement program they followed was taking 20 grams creatine plus 140 grams glucose per day for a 7 day loading period. This loading period was followed by subjects taking 5 grams creatine and 35 grams glucose per day for a 21 day maintenance period; or a placebo regimen of taking 160 grams glucose per day during the loading period and 40 grams of glucose per day during the maintenance period. Seven of the 9 subjects taking creatine were considered responders based on their increase in strength and body mass.

The results of this Kilduff study indicated that creatine supplementation can increase muscle strength in association with strength training but only in subjects whose estimated creatine uptake and body mass are significantly increased, reporting that the greater the creatine uptake and associated body mass changes, the greater the performance gains.

This study also illustrates that taking glucose with creatine does not guarantee a better uptake of creatine, as 2 of the 9 subjects did not respond to the creatine plus glucose supplement regimen.

Note: based on reviewing 200 studies and working with creatine, my observations and research indicate that the small percentage of people who do not respond in a significantly beneficial way to creatine supplementation, may be due in part to their state of muscle fiber development. That is, they do not have adequate type IIb muscle fiber development to benefit from taking creatine supplements in these short-term studies, usually lasting a few to several weeks. Based on longer studies conducted with strength trained athletes, creatine responsiveness is usually 100%.

Study Title:
"Creatine supplementation enhances anaerobic ATP synthesis during a single 10 sec maximal handgrip exercise."

This research team led by Kurosawa in 2003 (5), examined forearm muscles of twelve healthy male subjects during a 10 second maximal dynamic handgrip exercise before and after ingestion with 30 grams of creatine monohydrate or placebo per day for 14 days.

Creatine supplementation produced an average 11.5% increase in the resting muscle phosphocreatine concentration and a 65.0% increase in the phosphocreatine degradation during exercise, and a 15.1% increase in the mean power output.

The results indicate that creatine supplementation enhanced phosphocreatine degradation during exercise. These results support an improvement in performance during exercise associated with the increased phosphocreatine availability for the synthesis of ATP, from creatine supplementation.

Study Title:
"Effect of creatine loading on anaerobic performance and skeletal muscle volume in NCAA Division I athletes."

In this study Ziegenfuss and coworkers (6) measured the effects of 3 days of creatine monohydrate supplementation on repeated sprint performance and thigh muscle volume in elite power athletes. Ten male and ten female athletes were randomly assigned to a creatine or placebo group.

Subjects completed six maximal 10-second cycle sprints interspersed with 60 seconds of recovery before and after 3 days of creatine supplementation. Creatine supplementation was at the rate of 0.35 grams per kilogram of fat-free mass, or in the placebo group, taking a maltodextrin supplement.

Creatine supplementation resulted in statistically significant increases in body mass, about 0.9 kilograms, increased total work during the first sprint, and peak power during sprints 2 to 6, during the 3 day creatine taking period. Total work and peak power values for males were greater than those for the females during the first sprints. However, the reverse was true during the last three sprints.

Special muscle imaging data showed a 6.6% increase in thigh volume in five of six creatine taking subjects. The researchers concluded that creatine supplementation can increase thigh muscle volume and enhance cycle sprint performance in elite power athletes, and that this effect is greater in females as sprints were repeated.

Note: very impressive results for such a short study period; 3 days.

Study Title:
"Effects of creatine loading and prolonged creatine supplementation on body composition, fuel selection, sprint and endurance performance in humans."

This study conducted by van Loon and coworkers (7) evaluated the effects of both creatine monohydrate loading and prolonged supplementation on muscle creatine content, body composition, muscle and whole-body oxidative capacity, substrate utilization during submaximal exercise, and on repeated supramaximal sprint, as well as endurance-type time-trial performance on a cycle ergometer. For this study twenty subjects participated.

During the 5-day loading period, 20 grams per day of creatine monohydrate was ingested, followed by a 6 weeks period of ingesting 2 grams per day of creatine. Creatine loading increased muscle free creatine, creatine phosphate and total creatine content.

The use of the 2 grams per day maintenance dose, resulted in a decline in both the elevated creatine phosphate and total creatine content and maintenance of the free creatine concentration. Both the short-term and long-term creatine supplementation improved performance during repeated supramaximal sprints on a cycle ergometer.

However, whole-body and muscle oxidative capacity, substrate utilization and time-trial performance were not affected. The increase in body mass following creatine loading was maintained for 6 weeks after supplementation and accounted for by a corresponding increase in fat-free mass.

This study provides evidence that prolonged creatine supplementation in humans does not increase muscle or whole-body oxidative capacity (endurance) and, as such, does not influence substrate utilization or performance during endurance cycling exercise. But, this study reconfirms that creatine supplementation induces an increase in fat-free body mass.

Study Title:
"Differential response of muscle phosphocreatine to creatine supplementation in young and old subjects."

This research study conducted by Rawson and coworkers (8) compared the effects of short-term creatine monohydrate supplementation on muscle phosphocreatine levels, blood and urine creatine levels, and urine creatinine levels in elderly and young subjects. Eight young male subjects average age 24 years, and seven older male subjects average age 70 years.

The subjects ingested 20 grams per day of creatine for 5 days. At the start of the study it was observed that the older subjects had significantly higher baseline plasma creatine levels than young subjects (68.5 versus 34.9 micromol per liter). After the creatine supplementation period, urine creatine increased in both groups. Urine creatinine did not change as a result of creatine supplementation.

The young males showed a significantly greater increase in muscle phosphocreatine compared with the older males; young males 27.6 mmol kg-1 versus old males 25.7 mmol kg-1 ww. There were no differences in blood or urine creatine between groups in response to creatine supplementation.

Study Title:
"Creatine supplementation enhances isometric strength and body composition improvements following strength exercise training in older adults."

Brose and coworkers (9) sought to determine if creatine monohydrate supplementation would enhance the increases in strength and fat-free mass that develop during resistance exercise training in older adults. Twenty-eight healthy men and women over the age of 65 years participated in a whole-body resistance exercise program 3 days per week for 14 weeks.

The study participants were randomly assigned, in a double-blind fashion, to receive either creatine monohydrate at 5 grams per day plus 2 grams of dextrose (14 subjects) or placebo of 7 grams of dextrose (14 subjects).

At the end of the study period, significant increases in all measurements of strength and functional tasks, and muscle fiber area occurred for both the placebo and creatine taking groups. However, the creatine taking group experienced greater increases in fat-free mass and total body mass.

Additionally, the creatine taking group also had a greater increase in isometric knee extension strength in both men and women, and also greater gains in isometric dorsiflexion strength, but in men only. A significant increase in intramuscular total creatine in the creatine taking group was also measured. There were no significant side effects of treatment or exercise training.

This study confirms that heavy resistance exercise training can safely increase muscle strength and functional capacity in older adults, and the addition of creatine supplementation can stimulate increases in total and fat-free mass, and gains muscle strength greater than resistance training alone.

Study Title:
"Creatine supplementation improves muscular performance in older men."

Researcher Gotshalk and coworkers (10) examined the effects of 7 days of creatine supplementation in normally active older men (59-72 yr) by using a double-blind, placebo-controlled design. These subjects were randomly assigned into creatine (10 subjects) and placebo (8 subjects) groups.

The subjects consumed creatine monohydrate supplement at the rate of 0.3 grams per kilogram of body weight. The results indicated that 7 days of creatine supplementation is effective at increasing several indices of muscle performance, including functional tests in older men without adverse side effects. The researchers pointed out that creatine supplementation may be a useful therapeutic strategy for older adults to attenuate loss in muscle strength and performance of functional living tasks.

Study Title:
"Creatine supplementation combined with resistance training in older men."

In this study Chrusch and coworkers (11) determined the effect of creatine supplementation combined with resistance training on muscular performance and body composition in older men.

Sixteen men average age 70.4 years were assigned to the creatine monohydrate supplement taking group, and fourteen men average age 71.1 years were assigned to the placebo taking group, using a double blind study design.

Creatine supplementation for this study consisted of 0.3 grams per kilogram of body weight per day for the first 5 day loading phase, followed by taking creatine consumption at a rate of 0.07 grams per kilogram of body weight per day for the remainder of the study period.

Both groups participated in resistance training, consisting of 36 total sessions, at the frequency of 3 times per week, 3 sets of 10 repetitions, 12 exercises.

Compared With Placebo Taking Subjects, The Creatine Taking Subjects Had Significantly Greater Increases In:

• Lean tissue mass; an increase of 3.3 kilograms in the creatine group versus an increase of 1.3 kilograms in the placebo group.

• Leg press 1-repetition maximum; creatine group increased an average of 50.1 kilograms versus placebo group increasing by 31.3 kg).

• Knee extensions 1 repetition maximum; creatine group increased an average of 14.9 kg versus placebo group increasing by 10.7 kg,

• Leg press repetition endurance; 47 reps average for the creatine taking group versus placebo 32 reps for the placebo group.

Leg (knee) Extensions.

The researchers concluded that creatine supplementation when combined with resistance training, increases lean tissue mass and improves leg strength, endurance, and average power in men of mean age 70 yr.

Study Title:
"Effects of oral creatine and resistance training on myosin heavy chain expression."

Researchers Willoughby and Rosene (12) examined the effects of 12 weeks of creatine monohydrate supplementation and heavy resistance training on muscle strength and myosin heavy chain (MHC) isoform mRNA and protein expression.

In this study, twenty-two untrained male subjects were randomly assigned to either a control group, placebo group , or a creatine supplement - resistance training group in a double-blind fashion. Muscle biopsies were obtained before and after 12 weeks of heavy resistance training.

The placebo and control groups trained three times a week using three sets of 6-8 repetitions at 85-90% 1-repetition maximum on the leg press, knee extension, and knee curl exercises. The creatine - resistance training group ingested 6 grams per day of creatine for 12 weeks.

The Following Is An Overview Of The Results Of This 12 Week Study:

• There were no significant differences for percent body fat between the groups.

• Creatine supplement taking and resistance training produced significant increases in total body mass and fat-free mass, thigh volume, muscle strength, and myofibrillar protein, compared to the other groups.

• Regarding type I, IIa, and IIx muscle fibers, and MHC mRNA expression, the creatine taking and resistance training group experienced significantly greater improvements compared to the other groups.

The researchers concluded that long-term creatine supplementation increases muscle strength and size, possibly as a result of increased myosin heavy chain synthesis.

Study Title:
"Comparison of creatine ingestion and resistance training on energy expenditure and limb blood flow."

This research study conducted by Arciero and coworkers (13) determined the effects of 28 days of oral creatine ingestion. Days 1 to 5, subjects ingested 20 grams creatine monohydrate per day, taken in 5 gram dosages, 4 times daily. During days 6 to 28, 10 grams per day was ingested, taken in 5 grams dosages, twice daily.

Creatine was taken by people who did not resistance train and people who resistance trained about five hours per week. This study used a double-blind, placebo-controlled design, 30 healthy male volunteers (21 /- 3 years; 18 to 30 years) were randomly assigned to 1 of 3 groups; pure creatine monohydrate, no training (10 males), creatine plus resistance training (10 males), or placebo plus resistance training (10 males).

Body composition, body mass, bench and leg press 1 repetition maximum, resting metabolic rate, and forearm and calf limb blood flow were obtained on all 30 subjects on 3 occasions beginning at approximately 6:00 AM following an overnight fast and 24 hours removed from the last training session; baseline (day 0), and 7 days and 29 days following the interventions. No differences existed among groups at baseline for any of the variables measured.

The Following Summarizes The Results:

• Body mass increased significantly in creatine and creatine & resistance training groups, but remained unchanged in the placebo & resistance training group.

• Fat-free mass increased significantly in the creatine & resistance training group (about 1.7 kilograms) and showed a non-significant tendency to increase in the creatine taking group (0.9 kilograms).

• Following the 28-day period, all groups significantly increased bench press: creatine (average 77.3 to 83.2 kilograms; creatine & resistance training (average 76.8 to 90.5 kilograms; placebo & resistance training (average 76.0 to 85.5 kilograms), and leg press; creatine (average 205.5 to 238.6 kg; creatine & resistance training (average 167.7 to 238.6 kg; placebo & resistance training (average 200.5 to 255 kg) in 1 repetition maximum muscular strength testing.

• It was noted that the creatine & resistance training program improved significantly more on the leg press 1RM than the creatine and placebo & resistance training groups, and the bench press 1RM than the creatine group.

• Calf (30%) and forearm (38%) blood flow increased significantly in the creatine & resistance training group, but remained unchanged in the creatine and placebo & resistance training groups.

• Resting metabolic rate increased in the creatine group (average 1,860.1 to 1,907 kcal/day) and in the creatine & resistance training group (average 1,971.4 to 2,085.7 kcal/day), but remained unchanged in the placebo & resistance training group.

• Additionally total cholesterol decreased significantly in creatine & resistance training group (-9.9%; 172 /- 27 to 155 mg/dL) compared with the creatine group (174 to 178 mg/dL) and placebo & resistance training group (162 to 161 mg/dL).

These findings provide more evidence that the addition of creatine supplementation to resistance training significantly increases total and fat-free body mass, muscular strength, peripheral blood flow, and resting energy expenditure and even improves blood cholesterol levels.

Study Title:
"Effect of two and five days of creatine loading on anaerobic working capacity in women."

This study conducted by Eckerson and coworkers (14) measured the effects of 2 and 5 days of creatine monohydrate loading on anaerobic working capacity in women. Ten physically active women randomly received 2 treatments separated by a 5 week washout period:

1.       18 grams dextrose as placebo; or

2.       5.0 grams of creatine monohydrate plus 18 grams of dextrose taken 4 times per day for 5 days.

The creatine supplement increased anaerobic working capacity in the women subjects by 22.1% after 5 days of loading, the placebo did not produce any benefits.

A significant increase in body weight was not observed during this 5 day study. These results show that creatine supplementation is effective for increasing anaerobic working capacity in women following 5 days of loading, but did not produce an associated increase in body weight during this short period of time.

Study Title:
"Short-term creatine supplementation improves maximum quadriceps contraction in women."

In this research study Kambis and coworkers (15) investigated the effects of creatine monohydrate supplementation upon muscle function, thigh circumference, and body weight in women.

Twenty-two college-age women participated in the study. Subjects in the creatine taking group ingested 0.5 grams per kilogram of fat free body mass per day of creatine monohydrate, split in to one fourth dosage, taken four times per day, for five days. Resistance exercise was not permitted during this five day period.

After the five day ingestion phase was completed, measurements that were taken at the start of the study were taken again. Improvements in muscle strength performance were observed in the creatine taking women, but a significant gain in body mass was not observed in this short-term study.

Apparently, the muscle building effects of creatine need longer than a several day phase to exert an effect on women. However, the effects of creatine monohydrate supplementation on strength performance were again impressive, especially within a 5 day period.

Study Title:
"Effect of creatine and weight training on muscle creatine and performance in vegetarians."

The purpose of this study conducted by Burke and coworkers (16) was to compare the change in muscle creatine, muscle fiber morphology, body composition, hydration status, and exercise performance between vegetarians and non-vegetarians with 8 weeks of creatine supplementation and resistance training. Due to the lack of meat consumption among vegetarians, their total creatine levels tend to be lower when compared to meat eating people.

Eighteen Vegetarian & 24 Non-Vegetarian Subjects, Age Range 19-55 Years Old, Were Randomly Assigned (double blind) To Four Groups:

• Ten vegetarians taking creatine.

• Eight vegetarians taking placebo.

• Twelve non-vegetarians taking creatine.

• Twelve non-vegetarians taking placebo.

All of the subjects participated in the same 8 week resistance-training program. Creatine taking subjects took creatine based on their lean tissue mass at the rate of 0.25 grams per kilogram of lean tissue mass per day for 7 days, and 0.0625 grams per kilogram of lean tissue mass per day for 49 days.

Initial biopsy sample results of muscle fiber composition revealed that vegetarian muscle fibers had an initial lower creatine and phosphocreatine content then non-vegetarians (vegetarians were 117 mmol per kilogram and non-vegetarians were 130 mmol per kilogram.

After the study period, creatine taking subjects experienced a greater increase in phosphocreatine muscle levels, total creatine muscle levels, bench-press strength, isokinetic work, Type II fiber area, and whole-body lean tissue compared with subjects taking placebo.

Vegetarians who took creatine had a greater increase in total creatine, phosphocreatine, lean tissue, and total work performance than non-vegetarians. The change in muscle total creatine was significantly correlated with initial muscle total creatine and the change in lean tissue mass and exercise performance.

The findings of this study confirm an ergogenic effect of taking creatine during resistance training and suggest that subjects with initially lower levels of muscle total creatine, like the vegetarians, are more responsive to supplementation.