Important endurance sports nutrition advice

You see them in every gym: those whose primary fitness goal is to build as much muscle as possible. The telltale signs are the heavy free weights they lift and the big protein shakes they guzzle.

Few endurance athletes are interested in building bigger muscles. After all, muscles are heavy, and in most endurance activities, such as half-marathon training, marathon training, or triathlon training, excess body weight is the enemy of performance. And while strength is certainly beneficial to endurance performance, it is possible to get all the strength you need to swim, bike, or run your best from lean, lithe muscles.

Nevertheless, there are some instances when building muscle is a worthy objective for endurance athletes. For example, sometimes I am entirely focused on running, other times on triathlon training. My optimal triathlon racing weight is about 10 pounds greater than my optimal running racing weight. I swim better when I have a little more upper body muscle and cycle better when I have a little more leg muscle than I need for running. Thus, when I transition from a run-focus period to a triathlon-focus period, I make a conscious effort to add muscle to my body.

The Science of Muscle Building

Based on what you see bodybuilders doing at the gym, you might assume that, at those times when I am trying to build muscle, I lift heavy weights and consume large amounts of protein. But research has shown that, while lifting heavy weights is an absolute requirement for building muscle, eating lots of protein is not.

In a new study from the University of Texas Medical Branch at Galveston, researchers fed 4-oz and 12-oz portions of meat to adult volunteers and measured subsequent rates of muscle protein synthesis. They found that the rate of muscle protein synthesis was no higher after the 12-oz portion was eaten than after the 4-oz portion was eaten. In case you don’t know, a 4-oz portion of meat is probably smaller than what most of us normally eat for dinner.

This study did not involve any weightlifting. Perhaps weightlifting increases protein requirements and makes those protein shakes necessary. Or maybe not. Research by Mike Rennie, one of the world’s foremost researchers in this area, determined that whole-body protein synthesis achieves its maximum rate at a protein intake level of 1.4 g/kg body weight daily in weightlifters. This is higher than the government’s recommended daily allowance—but not higher than the protein intake level of the average American. Other research by Rennie showed that a single dose of 10 g of essential amino acids is sufficient to maximize acute muscle protein synthesis. That’s the amount of essential amino acids in a glass of skim milk.

Forget the Protein Powders

Based on such studies, protein researcher Stuart Phillips of McMaster University in Canada concluded, “At present there is no evidence to suggest that supplements are required for optimal muscle growth or strength gain. Strength-trained athletes should consume protein consistent with general population guidelines, or 12% to 15% of energy from protein.”

The average American already gets roughly 18 percent of calories from protein. So if you should ever decide to add a little muscle to your body, start lifting heavy weights and just keep eating the way you’re eating.