October 17th, 2011
Introduction
While the thought of it ain’t too pleasant, drinking beetroot juice has recently been shown to improve cycling time trial performance over 4 km and 16.1 km. Why might that be? Well, it looks like the nitrate-rich beetroot juice enhances blood flow by increasing the diameter of blood vessels and thus enhancing oxygen delivery as well as making energy metabolism more efficient during high intensity endurance exercise.
The Research
Nine young competitive male cyclists (21 ± 4 years; 79.6 ± 9.7 kg; VO2max 56.0 ± 5.7 ml/kg/min) completed four time trials (TT) in a random order using a Computrainer system with each test separated by 48-72 hours:
- 4 km TT with the beetroot juice containing nitrate
- 4 km TT with the beetroot juice with the nitrate removed (placebo)
- 16.1 km TT with the beetroot juice containing nitrate
- 16.1 km TT with the beetroot juice with the nitrate removed (placebo)
The beetroot juice used was an organic commercial product produced in the UK but available here in Oz for a reasonable price – 750 ml bottle RRP is $5.50 and the 250 ml bottle $3.00. The cyclists turned up to the lab fresh having done no hard training in the previous 24 hours and eaten the same food and fluids leading up to drinking the juices before each TT in the lab. When they turned up at the lab and after drinking the juice, they had their blood levels of nitrite measured (the nitrate in the juice turns to nitrite that then becomes nitrous oxide (laughing gas) – a blood vessel dilator that makes the blood vessel wider and thus enhances blood flow). Over a period of 15 minutes, the cyclists drank 500 ml of the beetroot juice 2.5-2.75 hrs before doing each of the four TTs on four separate days at least two days apart. During the time between drinking of the juice and the TT, they drank only water and did no exercise. During each TT, power output (watts) and oxygen use were measured continuously.
The Results
The beetroot juice significantly increased average power output during the 4-km TT by 2.8 % (292 ± 44 watts) compared to the placebo drink of beetroot juice with the nitrate removed chemically (279 ± 51 watts). During the 16.1-km TT, the beetroot juice with nitrate improved power output by 2.7% (247 ± 44 versus 233 ± 43). Each of the nine riders improved in both the TTs after taking the juice with nitrate in it – the normal beetroot juice!
The So What?
This British study strongly suggests the commercially-available beetroot juice improves TT performance in club level, sub-elite cyclists. They cautiously say that the study was done on club-level riders and the same effect may not be seen in high-performance riders. However, my feeling is why not give it a go. The word on the street is that Geelong Football Club )Premiers) and the Wallabies have used it!! Be warned though, your pee goes pink!!
Source: Lansley, K.E. and others. (2011). Acute dietary nitrate supplementation improves cycling time trial performance. Medicine and Science in Sports and Exercise. 43(6): 1125-1131.
Browse related items: endurance performance, fruit and vegetables, nutrition, supplements
September 7th, 2011
Introduction
Most masters endurance athletes are aware that carbohydrate loading before an endurance event is crucial to last an event longer than 90 minutes. We know that the last three days before a triathlon, marathon or half-marathon, road race, regatta or carnival is the time to load up on the rice, the pasta, and the sports drinks. Here is some research that highlights that it’s the amount of carb taken the very day before the event may be equally critical. More importantly, this research was conducted on mongrels like us – older athletes. The researchers concluded that marathon pace was faster and better-maintained in runners who consumed greater than 7 grams of carbs per kilogram of body weight the day before the run.
The Research
An internet-based data collection tool allowed 257 competitors in the 2009 London Marathon (39±8 years, finish time: 273.8±59.5 min) to record a range of anthropometric (body measures such as weight, height), training and nutritional predictors of performance. The English sports scientists used complex multivariate statistical methods to quantify the change in running speed and estimate which of the predictors contributed to performance differences.
The Results
Gender, body mass index, training distance, and the amount of carbohydrate consumed the day before the race were significant predictors of the variability in running speed. The analysis also revealed that those competitors who consumed carbohydrate the day before the race at a quantity of >7 g/kg body mass had significantly faster overall race speeds and maintained their running speed during the race to a greater extent than with those who consumed <7 g/kg body mass.
So What?
This reseach strongly supports the importance of high carbohydrate intakes for any masters athlete competing in any endurance event, especially marathoners and athletes involved with endurance events including team sports and masters athletes competing in many events in one day or day after day such as at masters games or championships. The table below gives examples of common foods and their carbohydrate content. It is taken from Chapter 16 (Nutrition for the Masters Athlete) of my book The Masters Athlete, the most definitive chapter related to sports nutrition for older athletes that you will ever read – biased as I am! The table below from my book will enable you to calculate how much carbohydrate you should eat the day(s) leading into an event to ensure you get the greater than 7 grams / kilogram of body weight you need to maximize your chances of PBs. Each of these serving sizes gives 50 grams of carbohydrate.
Table 1: Common foods that give 50 grams of carbohydrate per serving.
Food
|
Serving |
Food |
Serving |
Cereals
|
|
Fruit
|
|
| Cornflakes/Wheaties |
60 gm (2 cups) |
Canned fruit – light |
360 gm (1.5 cups) |
| Muesli |
65 gm (1-1.5 cups) |
Canned fruit – heavy |
240 gm (1 cup) |
| Toasted Muesli |
90 gm (1 cup) |
Fresh fruit salad |
500 gm (2.5 cups) |
| Porridge – milk |
350 gm (1.3 cups) |
Bananas |
2 medium-large |
| Porridge – water |
410 gm (2 cups) |
Mangoes, pears, grapefruit |
2-3 |
| Muesli bar |
2.5 |
Oranges, apples |
3-5 |
| Rice cakes |
6 thick/10 thin |
Nectarines, apricots |
12 |
| Rice boiled |
180 gm (1 cup) |
Grapes |
470 gm (2 cups) |
| Pasta/noodles boiled |
200 gm (1.3 cups) |
Melons |
900 gm (5 cups) |
| Canned spaghetti |
440 gm (large tin) |
Strawberries |
760 (5 cups) |
| Crispbreads/dry biscuits |
6 large, 15 small |
Sultanas, raisins |
70 gm (4 tbsp) |
| Plain sweet biscuits |
8-10 |
Dried apricots |
115 gm (22 halves) |
| Bread |
110 gm (4 slices white, 3 thick grain) |
Vegetables/Legumes
|
|
| Bread rolls |
110 gm (1 large) |
Potatoes |
350 gm (1 large, 3 medium |
| Pita bread |
100 gm (2 pitas) |
Sweet potatoes |
350 gm (2.5 cups) |
| Muffin |
120 gm (2) |
Corn |
300 gm (1.2 cups creamed or 2 cobs) |
| Crumpet |
2.5 |
Green beans |
750 gm (7 cups) |
| Pancake |
150 gm (2 medium) |
Baked beans |
440 gm (1 large can) |
| Scone |
125 gm (3 medium) |
Soy/kidney beans |
500 gm (3 cups) |
| Iced fruit bun |
105 gm (1.5) |
Pumpkin or peas |
800 gm (4 cups) |
Dairy Products
|
|
Sugars/Confectionery
|
|
| Milk |
1 litre |
Sugar |
50 gm |
| Flavoured milk |
560 ml |
Jam |
3 tbsp |
| Custard |
300 gm (1.3 cups) |
Syrups |
4 tbsp |
| Natural or diet yoghurt |
800 gm (4-5 tubs) |
Honey |
3 tbsp |
| Fruit yoghurt – non-fat |
350 gm (2 tubs) |
Chocolate |
80 gm |
| Ice cream |
250 gm (10 tbsp) |
Jelly beans |
60 gm |
Drinks
|
|
Sports Foods
|
|
| Unsweetened fruit juice |
600 ml |
Sports drink |
700 ml |
| Sweetened fruit juice |
500 ml |
Meal supplement |
250 ml |
| Cordial |
800 ml |
Sports bar |
1-1.5 bars |
| Soft drinks |
500 ml |
Sports gels |
2 sachets |
Source: Atkinson, G. and others (2011). Pre-race dietary carbohydrate intake can independently influence sub-elite marathon running performance. International Journal of Sports Medicine, 32(7): 611-617.
Browse related items: endurance performance, fruit and vegetables, nutrition, team sports