Why is protein important for athletic performance?

In sports where power and strength are important, athletes/individuals need lean muscle mass which occurs through a process called muscle protein synthesis. In short muscle protein synthesis is the remodelling process of skeletal muscle in response to resistance training leading to muscle growth (hypertrophy).

Protein is therefore an important building block for muscle growth and also for nonmuscular structures like tendons and bone. It is thought that adaptations in muscle occur due to a rise in leucine (an amino acid in protein) which triggers off muscle protein synthesis. Resistance training is the main stimulant for muscle protein synthesis, where one bout of resistance training leads to muscle protein synthesis for up to 24 hours.

Types of Protein

There are different types of protein, which commonly come in the form of supplement bars and powders. Many of these products are successful more so through slick marketing than the ingredients involved, with supplement companies usually promoting the more amino acids and secondary compounds the better the product, which is seldomly the case.

The 3 most common types of protein are whey, casein and soy. When these three are compared against each other it is whey protein that is absorbed the fastest and contains the highest leucine content, the most important amino acid for augmenting muscle protein synthesis.

Timing of Protein Ingestion

TThe timing of protein ingestion is extremely important, because if protein ingestion occurs too close together it creates a blunting effect of muscle protein synthesis. As such, protein ingestion needs to occur equally over a 4-5 meals throughout the day with one pre bedtime meal/shake. The pre bedtime intake is important as muscle protein synthesis diminishes throughout the night and a pre bedtime meal can aid to reduce the drop off. As a guide ingesting protein within 2 hours post exercise and every 3-5 hours is a solid approach.

Protein Dosage

Dairy sources of protein appear to be superior to other sources of protein due to the higher leucine content. However, there are reports of increased muscle protein synthesis with lean meat, casein, soy and egg.

For athletic performance, the optimal dosage is .25-.3g per kg. Pre bedtime meals should contain .6g per kg. While the optimal dose for older adults is around 40g per serve. Dosages greater than 40g have not been shown to augment muscle protein synthesis any further, with any excess protein being oxidized (removed).