Serious endurance athletes are always looking for that extra edge, but sometimes it isn’t the latest bike or shoe technology that delivers that marginal performance gain.
Most athletes already understand the importance of protein in their post-exercise nutrition and supplement regimens because the repair and recovery benefits are backed by numerous scientific studies.
But few realise that including protein or amino acids in your energy drink bottle during training and racing can also significantly improve your performance and recovery.
Including protein in endurance drinks is not a new concept but more supplement manufacturers now realise the benefits.
The result is a wide range of supplements produced for use during training and racing, such as Biogen Cytogen Race Mix, Pepto Sport, 32Gi Race Pro, USN Pro Enduro and Hammer Perpetuem, among many others.
The products not only provide an immediate source of useable energy but also help to limit tissue damage and preserve muscle.
The end result, in a nutshell, is minimised recovery demands, which lets athletes get back to training sooner. And with less time off between hard sessions, progress tends to ramp up faster compared to those who aren’t as fastidious about their protein intake.
The idea behind the importance of protein in endurance supplements stems from a pioneering study conducted in 2000 by John Ivy, Ph.D.
In the study conducted at the Department of Kinesiology and Health Education at the College of Education, University of Texas in Austin, cyclists improved their endurance by 57% (compared with water) when drinking a carbohydrate and protein blend in a 4:1 ratio, and a still impressive 24% when compared with a carbohydrate-only drink.
Once the team released these results, people were quick to conclude that, because muscle breakdown occurs faster during exercise, consuming a supplement that includes protein delivers an additional source of energy to working muscles through a metabolic process known as gluconeogensis (GNG).
This process has the ability to generate glucose from non-carbohydrate sources within the body, including amino acids derived from either muscle tissue or digested protein.
The energy conundrum
However, the real reason behind these performance benefits seems to transcend energy production.
Ian Craig, BSc MSc CSCS, an Exercise Physiologist, Nutritional Therapist and sports coach, explains that most research studies looked at the effects of carb-protein drinks used during exercise durations of around 60 minutes to three hours.
“That’s not long enough to make a determination on whether protein aids performance, to be honest. You can do a three-hour cycle race or a half marathon on glycogen alone. If you added amino acids to a supplement for these events then you wouldn’t get much additional benefit.”
Andrew Bosch, Associate Professor of Exercise Science at the University of Cape Town (UCT), supports this statement, saying that “in UCT lab tests that utilised three hours of cycling, there was no involvement of protein in the energy production pathways. However, it has previously been shown that approximately 10% of total energy requirements can be derived from muscle protein over a very prolonged event.”
Bosch does point out that this would vary, particularly when carb intake is sub-optimal, as protein may be more likely to contribute to energy production and that lesser-trained individuals may get more of a benefit than elite athletes.
Craig continues: “What hasn’t really been studied is what happens during an eight-hour ultra-endurance event or a multi-day stage race.”
The recovery link
According to Craig, there is stronger evidence regarding the benefits of protein in endurance drinks for recovery.
“Numerous studies have shown that a carbohydrate-protein drink can positively influence various physiological aspects that pertain to optimal recovery, including the degree of muscle damage that occurs, the mediation of the inflammatory response, and a reduction in delayed onset muscle soreness (DOMS).
“This obviously has a positive, albeit indirect, effect on performance during subsequent bouts of exercise,” states Craig.
Basically, when taken during exercise, a carb-protein supplement ensures that the recovery process starts early, while athletes are still exercising.
Independent research conducted by UCT researchers on the Springbok Sevens squad prior to the IRB Sevens World Cup in 2009 backs this claim.
The study used Pepto Sport to determine the effect that a carb-protein supplement would have at a 2:1 carb-to-protein macronutrient ratio. In the study, half the group took the carb-protein drink, while the other half took an equi-caloric carb placebo.
Researchers specifically looked at DOMS reduction and next-day soreness over a number of weeks. During the first two weeks, there was no significant difference in perceived soreness due to the conditioning of the athletes.
However, after 18 days there were differences in reported muscle soreness, with those using the protein-containing recovery drink reporting less DOMS. This showed that even among elite athletes, the inclusion of protein – in this instance DSM hydrolysates – could improve post-training recovery.
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Link to inflammation
Both Craig and Bosch state that one component of this modulating effect may be the influence a carb-protein drink can have on the inflammatory response.
“Inflammation is a key element of recovery. It is therefore plausible that if you get your nutrition right during exercise, you can reduce the inflammatory response afterwards. This could limit damage and boost recovery between consecutive days of intense exercise, be it a stage race or heavy training cycle,” explains Craig.
“However, there is only a small body of scientific evidence that points to the beneficial effects on inflammation that protein can have when ingested during exercise,” explains Bosch.
Where, then, do endurance athletes derive the greatest value from a combination of carbs and protein ingested during exercise?
It seems the greatest benefit comes from reduced muscle damage. In Dr Ivy’s University of Texas study, researchers stated that in addition to “significant improvements in cycling time to fatigue”, the administration of a carbohydrate beverage with additional protein calories reduced “post-exercise muscle damage in comparison with a carbohydrate-only beverage”.
According to Craig, less muscle damage equates to lowered recovery demands after exercise.
“Our bodies don’t really want to lose protein as it is such an important element. However, research shows that up to 5-10% of our energy requirements will be derived from protein during high-intensity endurance exercise.”
If there are no free-form amino acids in circulation, then your body will ‘digest’ muscle protein through the GNG process.
“However, ingesting protein during such an event, or a long duration event, our body would preferentially use the free form amino acids for energy, and therefore spare muscle tissue. This would significantly boost an athlete’s recovery potential.”
Research also backs this claim. A study done at the Institute of Human Physiology in Verona, Italy, found that conditioned athletes that were trekking through a mountainous area, at an average altitude of 10,000 feet, for 21 days lost no muscle mass when taking a BCAA supplement – in fact, they actually gained muscle.
This finding was in stark contrast to the norm, where the athletes would normally lose significant body mass, particularly from muscle, due to the extreme physical exertion and hypoxia (lack of oxygen). This suggests that protein’s ultimate benefit in a carb-protein supplement is its muscle-sparing effect.