The researchers found certain proteins and carbohydrates found in milk assisted in mitigating exercise-induced muscle damage (EIMD).
Four groups of six healthy males consumed semi-skimmed milk, a milk-based carbohydrate-protein supplement (milk-based CHO-P), water or a sports drink after inducing EIMD.
Delayed-onset muscle soreness (DOMS), isokinetic muscle performance, creatine kinase, and myoglobin were assessed immediately before and 24 and 48 hours after EIMD.
The study found DOMS was not significantly different (p > 0.05) between groups at any time but other measures were in favour of milk and milk-based supplements.
“At 48 hour post-EIMD, milk and milk-based protein–CHO supplementation resulted in the attenuation of decreases in isokinetic muscle performance and increases in creatine kinase and myoglobin,” the researchers wrote.
“This study supports the growing volume of literature which suggests that milk is a powerful post exercise recovery aid,” said Dr Judith Bryans, a registered nutritionist and director of The Dairy Council in the UK.
“Previous research has shown milk to be an effective rehydration solution, while this is the first study to suggest that drinking milk following muscle-damaging exercise may decrease muscle damage.”
EIMD occurs when protein structures break down within the muscle, and reduces muscle performance.
“The results found that, when consumed immediately after resistance-based muscle damaging exercise, both semi-skimmed milk and milk-based CHO-P helped to preserve more muscle than either the sports drink or water,” the Dairy Council said.
The study is not the first to explore the potential benefits of milk consumption. A 2006 study published in the International Journal of Sport Nutrition and Exercise Metabolism assessed a group of cyclists who rode until their muscles were depleted of energy, then rested for four hours before cycling again to exhaustion.
During rest they were given either chocolate milk, which has an optimal ratio of 4:1 for carbohydrates to protein, an isotonic sports drink or a high protein sports drink.
The researchers concluded that the carbohydrates and protein ratio in milk complemented each other, because carbs replace energy while protein rebuilds muscle.
They speculated that chocolate milk is better for recovery than plain milk because of the presence of extra sugars.
Cyclists who had chocolate milk rode about 50 per cent longer than those who drank the protein drink and about as long as those who drank the isotonic preparation.
At the recent Beijing Olympic Games chocolate milk was conspicuous by its presence with high profile athletes such as American multiple gold-medal winning swimmer, Michael Phelps regularly seen drinking it.
Bicarbonate soda was another legal performance enhancer said to have won favour among some athletes. Others included mushrooms, caffeine, cherry juice and honey.
Applied Physiology, Nutrition and Metabolism
Volume 33(4): 775–783 (2008)
‘Acute milk-based protein–CHO supplementation attenuates exercise-induced muscle damage’
Authors: Emma Cockburn, Philip R Hayes, Duncan N French, Emma Stevenson, and Alan St Clair Gibson.