Distance Running

by Andrea Brakhuis

2008

Characteristics of the Sport
Overview

Distance runners compete over a variety of race lengths most commonly 10 km, 15 km, half marathon (21.1 km) and the marathon (42.2 km). While there is a 10 000 m track event, most distance running is done as road races or cross-country runs. 'Fun runs' of various lengths attract community participation, recreational runners joining with elite and club-level runners.  Ultra-distance races such as 50 mile, 100 km, 100 mile and 24 hour races also exist.

Distance runners mature with age, requiring years of base training to build up to the program of an elite runner. Consequently, most elite competitors are aged from their mid-twenties to late thirties. At a recreational level, running is a great social leveller, and you can find both teenagers and seventy-year-olds competing in the same fun run.

 
Training

Recreational runners train primarily for fitness or health, and compete in a number of fun runs, and perhaps a marathon each year. Daily training sessions might add up to a weekly distance of 50km, perhaps peaking at 80-100km before a marathon. Elite distance runners typically do more training than this and include track sessions, water running, weight sessions and long runs.
 
Competition

The elite runner may compete in a number of races of varying distances each year, with a few key races being chosen for full preparation and peaking. Many elite and recreational runners will compete weekly over a season of road races (summer), or cross-country runs (winter), treating each race as a hard training session. Marathon runners are unlikely to compete more than once or twice in a year over this distance. Recreational runners are more likely to train towards a fun run or club race without a long-term plan in mind.

Distance running is predominantly an aerobic activity, with elite male athletes running from under 30 minutes for 10 km, to just over two hours for the marathon. Recreational runners will take longer to complete these distances.
 
Physical Characteristics

Distance runners typically carry low body-fat levels, an advantage when you have to carry your body weight over many kilometres. Many elite runners have low total body weights, being small in stature and lightly muscled, particularly in the upper body.
Common Nutrition Issues
Recovery and Carbohydrate

Daily and twice daily training sessions call for recovery strategies, especially when two hard sessions are held back to back. Most runners will find that the typical western diet does not provide sufficient fuel for marathon training. In fact the first time many runners hit the wall is during their first weeks of big training mileage, due to a gradual process of failing to restore muscle glycogen levels.

The timing of carbohydrate is crucial for recovery after long, hard training sessions or races. Not only are your muscles depleted of carbohydrate, but also running causes some damage to muscle fibres, which will delay glycogen recovery. Carbohydrate intake soon after the session or race will ensure you meet your carbohydrate needs before the next training session.
 
Low Body Fat Levels

The low body fat levels of elite distance runners are typically a result of well-chosen parents and high volume training. However, some runners, both elite and recreational, need additional help to reduce body fat levels. The first step is to set a realistic target - a body fat level that is part of good health as well as good performance, and a body fat level that can be achieved and maintained with a healthy diet and a sensible workload.
 
Iron Deficiency

Distance runners, particularly females, are at a high risk of low iron status. There are a number of reasons for this, including iron losses in sweat, gastrointestinal bleeding, loss of red blood cell damage, low iron intake and menstruation in females. On paper, many runners look like they eat adequate dietary iron but on closer examination, this can be mostly plant based iron foods that are not well absorbed. A sports physician can help an athlete determine whether a runner has low iron stores.
 
Gastrointestinal Problems

Many runners report gastrointestinal problems during hard runs, particularly races. It's hard to do a PB when you are suffering stomach cramps or pain, diarrhoea or wind. Some runners experience problems at the top end, with burping and heartburn, and a few even find that they pass blood during races. The cause of these problems is unknown, but it seems to be related to the intensity of the running, the stress of competition and perhaps, dehydration or over hydration. Some runners are able to pinpoint certain foods that cause problems, but this is an individual matter. Probably the best general guide is to experiment with the type and timing of food that you consume before running. Often, it is best to run on an empty stomach, with the pre-race or pre-training meals eaten well in advance. Liquid meal supplements such as PowerBar Protein Plus powder or Sustagen Sport make a good, low bulk, pre-exercise meal.

If problems persist, for important races you might need to achieve an empty gut by switching to low fibre foods and/or replacing meals with liquid meal supplements over the last 24 hours.

 
The Pre-Event Meal

With early morning races, it is tempting to sleep in for as long as possible and skip breakfast. Other runners worry about gastrointestinal upsets if they eat a big breakfast before a race. However, the pre-event meal should not be sacrificed. It is the last opportunity to top up glycogen stores, particularly liver stores, and to top up fluid levels.

In many cases, a light snack, even a couple of pieces of toast and a drink, might be the best menu. If your race starts later in the day there might be time for a larger meal three to four hours pre-race. Don't forget fluids, especially if the day is hot. Liquid meal supplements provide a compact and quickly digested alternative to solid food in situations where time is scarce or pre-race nerves are a problem.
 
Race Fluids and Fuel

For events up to the half marathon, you should have all your fuel needs on board. Race nutrition strategies need only focus on issues relating to fluid balance, namely the prevention of severe dehydration. In races of this distance, the major threat of overheating comes from the pace which you are running- the faster you run, the more metabolic heat you produce. But severe dehydration will add to the problem. So, it’s important to know your sweat losses and drink fluids accordingly.

In races of less than 10-15 km in cool conditions, there may not be any need to drink during the event, and runners may not want to sacrifice any time. As the distance increases and/or temperature rises, however, it’s important to consume fluids from aid stations along the route. Make use of fluids available at aide stations in order to replace fluid lost from sweat. If you are running for more than an hour, it maybe best to use a mix of fluids including water, sports and coca cola.  Sports drinks and coca cola provide a source of carbohydrate in addition to fluid.  In longer races, some athletes may use sports gels and even foods such as sports bars to increase their hourly intake of carbohydrate.
Case Study

Don, a 'run for fitness' man, decided six months ago he would train for a marathon. His training had been progressing well, but in the last month he felt he had been tired all the time, despite plenty of sleep, and he didn't feel as if he was recovering between training sessions. His running program was gradually increasing in mileage as suggested by the magazine article he was following, and he was keeping on top of the niggling knee pain with a supply of anti-inflammatory drugs from a friend. Don thought he needed more carbohydrate in his diet and decided to see a Sports Dietitian.

The Sports Dietitian questioned him about his symptoms, his training and his diet. Don described his daily meal routine, pointing out that he had put it together from the article in the running magazine. Not being a terrific cook, he had kept things simple - this included eating either rice or pasta each night. In addition to this, he often didn't eat meat, as he believed it was too fatty for a runner. He didn't eat packaged breakfast cereals, but made his own muesli from rolled oats and added bran. As for legumes, silverbeet and spinach, he rarely ventured outside the conventional vegetables his mother had cooked for him at home. Dried fruit? - a little in muesli. Eggs?  - too high in cholesterol. Vitamin or mineral supplements were not taken.

The Sports Dietitian suggested that iron deficiency, rather than carbohydrate deficiency, might be the root of his fatigue problem. Don’s major source of dietary iron came from foods such as wholegrain bread, rice, pasta and oats, which is the form of iron that is least well absorbed. Additionally, Don's iron requirements were increased above normal. The increased training mileage, all on hard surfaces wearing his well-worn shoes, could be causing additional damage to red blood cells. And it was probable that the chronic use of anti-inflammatory drugs was causing a small but consistent loss of blood through gastrointestinal bleeding.

The Sports Dietitian organised for Don to see a sports doctor to discuss the appropriate use of anti-inflammatory drugs, and to order a blood test to determine his iron status. The results came back a few days later, the haemoglobin level normal, but at the low end of the range, and the ferritin level (a storage form of iron) quite low at 12 ng/ml. This suggested that Don was in the first stages of iron deficiency.

Don was put on high iron supplements for six weeks, to boost iron stores while he reorganised his dietary intake. Once his stores were topped up, Don would support his iron needs with iron from his food. The following plan was suggested:

    * Continue with high carbohydrate foods at each meal, but add a small portion of lean red meat, chicken, liver pate or shellfish to the menu. The principle of a low fat intake could still be preserved.
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    * Add some iron fortified breakfast cereal to his homemade muesli mix.
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    * Expand food choices by trying legumes, green leafy vegetables, and low fat egg dishes.
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    * Add some vitamin C foods such as orange juice, to any meal in which non-haem (plant-based foods) iron was the prominent source of iron.
    *  
    * Don was given some recipes and began to experiment with cooking, adding in variety and iron rich foods.

At the end of six weeks, Don reported feeling more energetic and more adept in the kitchen. His ferritin levels had increased to greater than 50 ng/ml, so it was agreed to stop the supplement and retest in another six months. At the last report, he was confidently counting the days until the big event.

Department of Sports Nutrition, AIS, Australian Sports Commission