Rugby World

I featured in a short Q&A in Rugby World magazine recently with client Sam Warburton on behalf of MSC Nutrition. The key messages have been highlighted below.

What you will learn:

  • The basic role of nutrition in athletic performance
  • Both mine & Sam’s biggest nutritional challenges
  • An insight into Sam’s supplement strategy

Who this is applicable to:

  • Anyone with an interest in performance nutrition
  • Aspiring rugby players
  • Current rugby players

Who should not read this:

  • People not interested in nutrition?

Enjoy, and please leave feedback. I am open to critique, it is the only way I will ever improve as a practitioner, coach, and as a person.


  • What role do you feel nutrition plays in your performance?

I realise that nutrition plays a fundamental role in not only body composition or performance, but in health too. Nutrition stems well beyond simply providing energy and creating new cells, nutrition plays a vital role in the prevention of certain diseases, cell signalling and even the rate of bone metabolism. As a nutritionist it is my role to convince individuals of its importance. From an athletic performance perspective nutrition plays a fundamental role in the provision of energy before and during, ensuring cells are adequately hydrated throughout and sufficient energy and amino acids are available to aid and enhance recovery following an exercise bout.

  • What are the greatest challenges you face from a nutritional perspective?

The biggest challenge I face on a daily basis is hitting my elevated protein requirements. Research has demonstrated that current government guidelines for protein intake have been significantly underestimated, with the most recent research suggesting that resistance trained, athletic individuals could require upwards of 2.5 g/kg body mass to increase or maintain muscle mass throughout a season. Consuming this amount of protein in a day, especially when away from home is difficult, with most restaurants and eateries generally offering carbohydrate and fat dominant meals; that’s where supplemental protein such as MSC probiotic whey is extremely handy.

  • What supplements currently feature in your programme?

At the moment my supplement strategy is pretty basic as my training volume is fairly low, I currently use the MSC immune support which is essentially a multivitamin, omega-3 – fish oil, whey and creatine monohydrate. Sometimes regenerate when I can’t access food.

  • What one piece of nutrition advice would you offer to an aspiring rugby player?

I would advise all players to focus on developing an in depth knowledge of the nutrition basics and how to apply them; the basics being your individual requirement for energy (kcal’s), the macronutrients, protein, carbohydrate and fat and also the micronutrients. Calculate your requirements and then hit them daily. Track your nutritional intake daily using either a spreadsheet or an online application such as myfitnesspal. Well-applied basics are going to have the greatest performance enhancing effect especially in younger athletes. Young players often focus on the more intricate aspects of nutrition and are often mislead by the supplement industry and their often-overhyped claims, and they overlook the fundamental components of nutrition. Supplements have their place, especially high quality, evidence-based products such as MSC, but focussing on supplemental nutrition prior to developing an understanding of the basics is a big issue. If you struggle then seek the help of a professional nutritionist.

Carbohydrate sports drinks

Q. I’m a triathlete; do I need to consume sports drinks? If so, which ones are suitable?

Firstly, we must look at physiological demands of the sport of triathlon in order to gain an understanding of the nutritional requirements.

Matt_Jones

The sport of triathlon requires athletes to sequentially swim, cycle and run over various distances, therefore the physiological demands and nutritional challenges differ greatly from race to race. A case study revealed carbohydrate energy expenditure was 15,762 kJ during the Grand Columbian half Ironman triathlon, and muscle glycogen concentrations were reduced to 36.6 mmol/kg wet wt -1/hr-1 from an initial 227.1 mmol/kg wet wt -1/hr-1 (1). Similarly, Noakes (2000) demonstrated near complete glycogen depletion following the 4.5-hour cycling stage of a simulated ironman triathlon, where elite male triathletes exercised at an intensity of 71% vo2max. It was interesting to note that following the 180km cycle, glycogen stores were almost completely depleted, although the triathletes were able to maintain running speeds of 16km/h for the remaining 160-minutes, at an intensity of ~66% vo2max, possibly due to the increased rate of intramuscular triglyceride oxidation of the elite participants (3). This study, among others clearly demonstrates the elevated energy and carbohydrate requirements of triathletes, in that regards the ingestion of carbohydrate during exercise will be ergogenic.

The sports drink industry is projected to reach $2bn by 2016, this phenomenal figure highlights the rapid rise in popularity of such drinks, designed to delay the onset of fatigue and enhance athletic performance through the delivery of carbohydrate and fluid simultaneously. When an industry is this financially powerful it is necessary to critique it thoroughly and analyse the efficacy of its product, so in the following article we will do exactly that. Initially we will look at the carbohydrate content, and examine which drinks are most suitable from this perspective, in the second section we will go on to explore the efficacy of the additional ingredients in modern sports drinks.

Fatigue is generally defined as a decrease in force production (4); although the precise cause of fatigue during endurance exercise of moderate intensity (65 – 75% vo2max) remains unknown (5) several factors are thought to be responsible, predominantly the depletion of glycogen stores, reduced blood glucose concentrations and hypoglycaemia.

Existing evidence suggests that the ingestion of carbohydrate during a prolonged exercise task is effective in increasing endurance and athletic performance through improved maintenance of blood glucose concentrations, increased rates of carbohydrate oxidation and sparing on endogenous carbohydrate stores.

Carbohydrate oxidation refers to the energy obtained from the metabolism (breakdown) of carbohydrate, obviously important during exercise.

A systematic review with meta-analysis of the existing carbohydrate during exercise (time trial) data concluded that the consumption of 30 – 60 g/hr carbohydrate in a 6 – 8% glucose concentrations during exercise greater than 1-hour maintains blood glucose concentrations and high carbohydrate oxidation rates, and may improve time trial performance by ~2% (6). An improvement of 2% in sport of any kind is significant, an improvement of 2% in the 2013 ITU World Triathlon Grand Final in London was the difference between 1st and 26th place (International Triathlon Union, 2012), so fairly significant!

Such carbohydrate intakes achieve the maximal 1 – 1.1 g/min-1 oxidation rates, with higher intakes associated with increased incidence of gastrointestinal symptoms and little additional effect. Carbohydrate oxidation from single source glucose appears to be limited to rates of 1 – 1.1 g/min-1 owing to the fact that the sodium-dependant glucose transporter (SGLT1) becomes saturated at rates of 1 g/min (7, 8). More recent data however has illustrated a role for multiple-transportable carbohydrates, where multiple transport mechanisms can be utilised at the same time. Fructose utilises the transporter GLUT5, so saturating SGLT1 through glucose ingestion with the addition of fructose will allow for the delivery and oxidation of more carbohydrate. Research has confirmed this, with observed carbohydrate oxidation rates around 65% greater than previously thought to be maximal (1 – 1.1 g/min from a single source). Such blends often utilise a 2:1 ratio glucose:fructose or maltodextrin:fructose, and can result in exogenous carbohydrate oxidation rates of 1.75 g/min.

These multiple-transportable carbohydrate formulations also offer the advantage of enhancing fluid delivery and improving oxidation efficiency, and reducing the likelihood of gastrointestinal distress (9). The increased rates of carbohydrate oxidation with multiple-transportable carbohydrates do result in improved time trial performance too, one study concluded the ingestion of a glucose:fructose (2:1 ratio) beverage resulted in an 8% improvement in time trial performance compared to the ingestion of a glucose only beverage, both beverages delivered carbohydrate at equal rates of 1.8 g/min (10). So sports drinks that contain both glucose and fructose ingested at high rates may be more beneficial than those that contain glucose alone (11).

To achieve such high oxidation rates, large dosages of carbohydrate are required; such large doses may not be practical or even possible during competition. Therefore, for triathlon performance the ingestion of carbohydrate at rates of 90 g/hour is recommended. The optimal carbohydrate mixture would be a combination of glucose and fructose, maltodextrin and fructose, or glucose, sucrose and fructose.

Existing sports drinks offer such formulations, lets look at some of the options:

Product Carbohydrate formulation Carbohydrate per product Required rate of ingestion
High5 EnergySource Maltodextrin & fructose (2:1 ratio) 45g / 50g sachet Up to 2 sachets per hour
Gatorade Perform Glucose & sucrose (glucose & fructose)* 33g / 36g sachet Up to 2.7 sachets or 3 bottles per hour
Lucozade Sport Elite Glucose & fructose (2:1 ratio) 45.5g / 500ml bottle Up to 2 bottles per hour
Coca cola (flat) Sucrose (glucose & fructose)* 53g / 500ml bottle Up to 1.7 500ml bottles
DIY formulation Maltodextrin (60g) & fructose (30g) N/A N/A

* ratio not stated.

Based on the existing products on the market, my recommendation would be High5 EnergySource, this appears to be optimal in regards carbohydrate formulation, and would probably be the most practical. High5 also offer an EnergySource plus option that contains additional caffeine, we will go on to examine the beneficial effects of caffeine in the second section of this post. You will also notice that coca cola is included on the above list, a number of world leading endurance sports athletes now utilse coca cola during exercise as an ergogenic aid owing to its carbohydrate content, it also contains caffeine (although only in small doses (32mg/330ml)) and offers the obvious advantage of being the tastiest option. Flat coca cola is being used by leading tour de France teams and the Australian Institute of Sport actually create a coca cola slush (ice) drink for their athletes. Obviously flat coca cola will reduce the gastrointestinal issues that accompany the ingestion of carbonated drinks, which could otherwise impair athletic performance.

Please note that some carbohydrate sports gels are promoted during endurance exercise, but owing to the reduced carbohydrate concentrations you would be required to consume around 4 – 5 of these gels every hour, which offers obvious disadvantages. Firstly, you’d need to carry a small back pack to transport them in and also you’d have to spend a couple of seconds 4 – 5 times each hour opening and consuming the gels. So for the longer endurance events, over 1-hour I would suggest drinks as opposed to gels be consumed. Gels are advantageous during shorter endurance events, or when training to maintain blood glucose concentrations and provide lower doses of single source glucose for oxidation. I’m not aware of any gel that contains the optimal 2:1 ratio of glucose:fructose, any such formulation is likely to be extremely sweet, sticky, sickly and not suitable for consumption during an endurance event.

In answer to the question, yes, as a triathlete you will require carbohydrate supplementation during exercise. I have provided a recommendation for a product based on the carbohydrate content alone, in the second section I will go on to advise which additional ingredients will be of benefit to your performance and again provide recommended products/strategies.

If you enjoyed this blog post please share it with your friends, and if you have any questions I’m currently running a bi-monthly Q&A blog post where I will answer any of your nutrition related questions in a full blog post, two questions answered each month. So please get in contact with your nutrition related questions!

References:

  1. Gillum, T, L., Dumke, C, L., & Ruby, B, C. (2006). Muscle glycogenolysis and resynthesis in response to a half Ironman triathlon: a case study. International Journal of Sports Physiology & Performance, 1, 408-413.
  2. Noakes, T, D. (2000). Physiological models to understand causes of fatigue and the adaptations that predict or enhance athletic performance. Scandinavian Journal of Medicine & Science in Sports, 10, 123-145.
  3. Phillips, S, M., Green, H, J., Tarnopolsky, M, A., Heigenhauser, G, J., & Grant, S, M. (1996). Progressive effect of endurance training on metabolic adaptations in working skeletal muscle. American Journal of Physiology Endocrinology & Metabolism, 270, 265-272.
  4. Burke, L., & Deakin V. (2006). Clinical Sports Nutrition. (3rd edition). Australia. McGraw-Hill Australia Pty Ltd.
  5. Allen, D, G., Lamb, G, D., & Westerblad, H. (2008). Skeletal muscle fatigue: cellular mechanisms. Physiology Reviews, 88, 287-332.
  6. Temesi, J., Johnson, N., Raymond, J., Burdon, C., & O’Connor, H. (2011). Carbohydrate ingestion during endurance exercise improves performance in adults. Journal of Nutrition, 141, 890 – 897.
  7. Jeukendrup, A, E., Wagenmakers, A, J., Stegen, J, H., Gijsen, A, P., Brouns, F., & Saris, W, H. (1999). Carbohydrate ingestion can completely suppress endogenous glucose production during exercise. American Journal of Physiology, 276, 672-683.
  8. Wright, D, A., Sherman, W, M., & Dernbach, A. (1991). Carbohydrate feedings before, during, or in combination improve cycling endurance performance. Journal of Applied Physiology, 71, 1082–1088.
  9. Jeukendrup, A. (2010). Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Current Opinion in Clinical Nutrition & Metabolic Care, 13, 452 – 457.
  10. Currell, K., & Jeukendrup, A. (2008). Superior endurance performance with ingestion of multiple transportable carbohydrates. Medicine & Science in Sports & Exercise, 40, 275 – 281.
  11. Jentjens, R., Achten, J., & Jeukendrup, A, E. (2004). High rates of exogenous carbohydrate oxidation from multiple transportable carbohydrates ingested during prolonged exercise. Medicine & Science in Sports & Exercise, 36, 1551-1558.

References:

1. Gillum, T, L., Dumke, C, L., & Ruby, B, C. (2006). Muscle glycogenolysis and resynthesis in response to a half Ironman triathlon: a case study. International Journal of Sports Physiology & Performance, 1, 408-413.
2. Noakes, T, D. (2000). Physiological models to understand causes of fatigue and the adaptations that predict or enhance athletic performance. Scandinavian Journal of Medicine & Science in Sports, 10, 123-145.
3. Phillips, S, M., Green, H, J., Tarnopolsky, M, A., Heigenhauser, G, J., & Grant, S, M. (1996). Progressive effect of endurance training on metabolic adaptations in working skeletal muscle. American Journal of Physiology Endocrinology & Metabolism, 270, 265-272.
4. Burke, L., & Deakin V. (2006). Clinical Sports Nutrition. (3rd edition). Australia. McGraw-Hill Australia Pty Ltd.
5. Allen, D, G., Lamb, G, D., & Westerblad, H. (2008). Skeletal muscle fatigue: cellular mechanisms. Physiology Reviews, 88, 287-332.
6. Temesi, J., Johnson, N., Raymond, J., Burdon, C., & O’Connor, H. (2011). Carbohydrate ingestion during endurance exercise improves performance in adults. Journal of Nutrition, 141, 890 – 897.
7. Jeukendrup, A, E., Wagenmakers, A, J., Stegen, J, H., Gijsen, A, P., Brouns, F., & Saris, W, H. (1999). Carbohydrate ingestion can completely suppress endogenous glucose production during exercise. American Journal of Physiology, 276, 672-683.
8. Wright, D, A., Sherman, W, M., & Dernbach, A. (1991). Carbohydrate feedings before, during, or in combination improve cycling endurance performance. Journal of Applied Physiology, 71, 1082–1088.
9. Jeukendrup, A. (2010). Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Current Opinion in Clinical Nutrition & Metabolic Care, 13, 452 – 457.
10. Currell, K., & Jeukendrup, A. (2008). Superior endurance performance with ingestion of multiple transportable carbohydrates. Medicine & Science in Sports & Exercise, 40, 275 – 281.
11. Jentjens, R., Achten, J., & Jeukendrup, A, E. (2004). High rates of exogenous carbohydrate oxidation from multiple transportable carbohydrates ingested during prolonged exercise. Medicine & Science in Sports & Exercise, 36, 1551-1558.