To fuel strength training, the body primarily uses carbohydrates. In the form of glycogen and blood glucose, carbohydrates power intense bursts of activity. But that activity also significantly depletes muscle glycogen stores, requiring the body to restore them through glycogen synthesis. Research has shown that carbohydrates speed this process. While cutting carbs can give strength athletes that ripped look, doing so during training actually slows the progress of building muscle. Looking and performing one's best is not as simple as reducing all carbohydrates indiscriminately. Strength athletes need to be mindful of what kind of carbs they're eating and when. If they are, they'll be able to bolster their systems and bulk up even faster.
Common Misconceptions
Strength training doesn't deplete much muscle glycogen. The post-workout window is a myth. Taking advantage of the post-workout window will give faster glycogen recovery, but not more glycogen storage. Resistance athletes can't benefit from increased glycogen restoration.
All of these are misconceptions about the role of carbohydrates in strength training.
The truth is much more complex. Studies have shown that strength training does deplete muscle glycogen. As one study put it: "resistance exercise results in significantly decreased muscle glycogen". When muscle glycogen is depleted, the body works to replace it. Since glycogen is depleted during a workout, the post-workout period is when the important work of rebuilding energy stores occurs. From this comes the mythology of the post-workout window, but it does have some truth to it.
Post-workout Window
The post-workout window - the period immediately after finishing one's workout - is incredibly important for the restoration of muscle glycogen. As one study found, "When carbohydrates are given immediately after and 1 hour after resistance exercise, the muscle glycogen content of the vastus lateralis is returned to 91% of resting values compared with 75% of pre-exercise values in 6 hours when only water is given". More startling was this finding: "relatively little glycogen resynthesis occurs when no carbohydrates are consumed after exercise". Immediately following a workout, the body needs carbs to start rebuilding glycogen stores for future workouts. Abstaining from carbohydrates drastically decreases the amount of glycogen the body synthesizes, causing longer recovery times. As that study goes on to say, "The amount of muscle glycogen synthesis in the 24-hour period postexercise is also directly correlated to the amount of carbohydrate ingested and the timing of that ingestion".
Other studies have shown similar results, as with the study that proclaimed, "as muscle glycogen content can be reduced by 30-40% following a single session of resistance-type exercise, carbohydrate coingestion would be preferred when trying to accelerate muscle glycogen repletion". Another study concluded that "carbohydrate ingestion following resistance exercise has been shown to enhance muscle glycogen resynthesis. This may decrease recovery time following resistance exercise and enable an increase in training volume which may enhance physiological adaptations". While research can sometimes be confusing or contradictory, many different studies have shown the link between strength training and muscle glycogen stores, so strength athletes should pay attention.
Carbohydrate Supplementation's Far-reaching Effects
Carbohydrate supplementation helps muscle glycogen stores, but it doesn't end there. Studies have also found that carbs might actually enhance the overall effects of strength training: "it appears that the inclusion of a carbohydrate supplementation regime may enhance protein synthesis or decrease muscle breakdown and ultimately enhance the effects of resistance training. This may be of particular importance to the strength athlete who is attempting to promote muscle growth and possibly enhance overall muscular strength".
Not only does carbohydrate supplementation in the post-workout period restore muscles' energy stores, it enhances the other processes of building muscle. Carbohydrate supplementation results in "increases in work output during training, increases in rates of recovery between training sessions, increases in protein synthesis rates, maintenance of muscle glycogen stores, and creation of an anabolic hormonal environment. All of these benefits could ultimately result in enhanced muscular strength and hypertrophy, which are of particular importance to athletes who compete in sports that require enhanced strength and size". Another study notes that "carbohydrate ingestion during or immediately after resistance exercise has been shown to increase postexercise insulin and growth hormone levels, which may lead to increased protein synthesis and hypertrophy". With its effects on insulin levels and hormonal balance, research is showing that carbs have a much larger role than simply restoring muscle glycogen, as important as that is.
Eating for Strength
Such an academic discussion may seem irrelevant to strength athletes' day-to-day life, but these studies offer a guide to what they should be doing and when. Generally, strength athletes should eat between five and seven grams of carbohydrate per kg of body weight per day. It's recommended that strength athletes consume one gram per kg of body weight immediately following a workout. Another equal amount an hour later may fully restore muscle glycogen levels.
But the type of carbohydrate also matters. Traditionally carbs have been separated into sub-groups of simple and complex carbohydrates, which isn't particularly useful. A better way to consider carbs is to analyze them based on their glycemic index (GI). This measures every food's impact on blood sugar against a pure glucose value of 100. High GI foods cause rapid rises in blood sugar whereas low GI foods offer a steadier, slower rise.
Strength athletes should focus on "consuming liquid carbohydrates prior to, during, and immediately after the resistance-training session, whereas the remainder of the carbohydrate consumption, from the healthy diet, should focus on low-glycemic carbohydrate sources (fruits, vegetables, and grains)". A low GI diet encourages steadier blood glucose and insulin levels, making it easier for the muscles to replenish glycogen stores. It also reduces the amount of blood glucose being stored as fat.
Far from being an impediment, if strength athletes get the right kinds of carbs at the right times, they'll find they're able to achieve their goals more quickly and more efficiently. And who wouldn't want that?
