Can creatine supplements enhance muscle recovery?

Strenua — Mon, 31 Aug 2009 23:49:00 +0000

Creatine has become a popular nutritional supplement among athletes, often taken as supplement by people who want to gain muscle mass, but there is increasingly evidence that it may also help in recovering from exercise induced muscle damage. My previous article suggested there may be a beneficial effect of creatine supplements on inflammation and muscle soreness following prolonged running.

Now a study from Victoria University, Australia has set out to examine the effects of creatine supplementation on the recovery of muscle proteins and force after eccentrically induced muscle damage.

Eccentric contractions are used to decelerate a body part or object, such as when you lower an object gently rather than just letting it drop. Damage caused by eccentric exercise is known to lead to a reduction in muscle force, increased muscle soreness and impaired muscle function.

During the study 14 untrained male subjects consumed either creatine and carbohydrate (Cr-CHO) or only carbohydrate (CHO) for five days before a resistance exercise session. The Cr-CHO group consumed a daily supplement of creatine (0.3 g per kg of body weight) and glucose (1.2 g per kg of body weight); The CHO group took glucose only.

The workout consisted of three exercises: 1) leg press; 2) leg extension and 3) leg curl. For each exercise their concentric 1-RM (repetition maximum) was determined. This is the maximum weight that a single repetition could be performed of a muscle shortening exercise, such as a curl. The resistance exercise session involved 4 sets of 10 eccentric only repetitions at 120% of their maximum concentric 1-RM, lowering the weight by themselves through the entire range of motion over 4 seconds.

Every day for 14 days whilst recovering from the exercises the Cr-CHO group took 0.1 g per kg of body weight of creatine and 0.4 g per kg of body weight of glucose, again the CHO group took glucose only.

The study found isokinetic strength, (where the muscle contracts and shortens at a constant speed), was 10% greater during recovery in the Cr-CHO group compared to the placebo group of CHO alone.

During isometric knee extension (where the muscle length stays the same even though it contracts), it was also found that the creatine supplemented groups had significantly greater strength (21%) during recovery from exercise induced muscle damage.

The paper’s author Matthew Cooke concluded that there is a significant improvement in the rate of recovery of knee extensor muscle function after creatine supplementation following injury. Blood creatine kinase (CK) activity was significantly lower by an average of 84% after 48hrs recovery in the creatine supplement group and peaked at 96hrs. Levels had returned to baseline by 7 days in both groups.

Blood CK levels can be raised from damage of the muscle tissue as a result of intense training, but also due to a number of other factors:

Age – levels decline slightly with age
Gender – at rest CK levels are lower in females than males.
Race – black men usually have higher values than Caucasians.
Climate – standard exercise in cold weather induces higher blood CK levels than the same exercise in warm weather.
Muscle mass and physical activity – at rest CK levels in athletes are higher than in sedentary subjects, this may be due to persistent training which keeps the CK levels elevated.

However, if trained and untrained subjects do the same exercise the CK levels will still be lower in athletes than the untrained. This study published in the Journal of International Society Sports Nutrition did involve untrained subjects which may have resulted in the very high CK levels initially following the exercise.

The major finding of this study was the significantly higher muscle strength after creatine supplementation during recovery from a muscle damaging exercise session; this may be due in part to a faster muscle growth during the recovery period. The study did not report if the subjects gained weight before or after the exercise session as is often reported with taking creatine supplements.

It is not known how creatine may act to increase recovery although it may be that the reduced leakage of creatine kinase from the muscle is an indication of less initial damage to the muscle. There appears to be a large number of studies supporting the use of creatine supplements whether to increase muscle mass or aiding recovery to allow further training. Maybe now scientists need to discover just how creatine supplements work so they can advise athletes on the ideal duration and concentration to use to aid recovery, optimise weight gain and avoid side effects.

Should endurance athletes take creatine supplements?

Strenua — Wed, 26 Aug 2009 12:11:13 +0000

Creatine has become a popular nutritional supplement among athletes and is often taken as supplement by people who want to gain muscle mass, such as for body building, but there is increasingly evidence that it may also help in recovering from exercise induced muscle damage.

Creatine is a natural occurring substance that helps supply energy to muscles. Half of stored creatine comes from food, mainly fresh meat, so as a vegetarian I am likely to have lower levels of muscle creatine. The enzyme creatine kinase (CK) is responsible for the reversible reaction whereby creatine is converted along with ATP to create phosphocreatine and ADP to generate energy.

Whilst creatine has been shown to be beneficial for short high intensity exercises such as weight lifting, it has not shown to have any benefit to endurance activity performance. In fact as creatine is also responsible for weight gain of around 1kg when taking the ‘loading dose’ of 20g a day it may even slow an endurance athlete down without providing any benefit to performance. A study has however, looked at the benefits of creatine on muscle recovery following endurance running

In the study published in Life Sciences journal, subjects were given 4 doses a day of 5g of creatine and 15g of maltodextrine, while the control group received just maltodextrine for 5 days, before a 30km race. The runners were experienced marathon runners with personal best (PB) times of 2.5 -3 hours.

Blood CK levels can be raised from damage of the muscle tissue as a result of intense training and it is often used as a marker of muscle injury. In this study by the University of São Paulo, it was found that athletes from the control group had increased CK levels suggesting a high level of cell injury and inflammation while Creatine supplementation reduced these increases.

In short term studies of less than two weeks there have not been reported side effects of taking creatine supplements. Dr Santos, the papers author reported that ‘the runners finished in times equivalent to their PB, without any side effects such as cramping, dehydration or diarrhoea whilst taking the supplements or during the race.’ However athletes who have taken it long term have reported muscle cramping and kidney damage.

In 2007 International Society of Sports Nutrition published its position on the use of creatine supplementation and exercise. Amongst some of their statements they concluded that ‘there is no scientific evidence that the short- or long-term use of creatine monohydrate has any detrimental effects on otherwise healthy individuals. Creatine monohydrate supplementation is not only safe, but possibly beneficial in regard to preventing injury and/or management of select medical conditions when taken within recommended guidelines.’

Recovering from endurance exercise is important for the long distance runner, but is it worth taking creatine supplements in the days leading up to a marathon to prevent damage and aid recovery. Is it worth possible muscle cramps and other side effects during the race after all you don’t know how your individual body will react?

What’s your view? Are you an endurance athlete who has tried creatine supplements, or do you think we shouldn’t use any type of ergogenic aids? Let us know you experiences or opinions.

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Can creatine supplements enhance muscle recovery?

Should endurance athletes take creatine supplements?