(The information in this article was taken or adapted from the High Performance Coaching Program Study Guide.)
Beyond attempting to regularly consuming a healthy, varied and well-balanced diet, players should particularly focus their efforts on adequate and appropriate consumption of three primary nutrients – water, electrolytes, and carbohydrates. These nutrients have the immediate effect on performance. Some key take home points and recommendations are listed below.
- Many players begin matches or practice dehydrated to some degree.
- During training or competition, sweat losses can be extensive – 1-2.5 liters per hour or more!
- Any water deficit can have a negative effect on a player’s performance and well-being. A progressive water deficit (from sweating and inadequate fluid intake) can cause
-- Increased cardiovascular strain
-- Decreased temperature regulation capacity
-- Decreased strength, endurance and mental capacity
- Many players do not rehydrate adequately after training or competition.
- Drink plenty of fluids (e.g., water, juice, milk, sport drinks) throughout the day.
- Drink regularly during training and competition – typically, older adolescents and adults can comfortably consume up to 48 ounces (~1.4 liters) or so per hour.
- After a match or training session, drink about 150% of any remaining fluid deficit.
- Players lose far more sodium and chloride (salt) from sweating than any other electrolyte.
- Sodium and chloride losses are greater with higher sweating rates.
- Sodium and chloride losses (via sweating) tend to be less when a player is acclimatized to the heat.
- Sodium deficits can lead to incomplete rehydration and muscle cramps.
- To completely rehydrate, a player must replace the sodium and chloride that was lost through sweating.
- Excessive rapid water consumption, combined with a large sweat-induced sodium deficit, can lead to hyponatremia
- When a player competes or trains in a hot environment, adding salt to the diet (or eating high-salt foods) can help to prevent a sodium deficit and maintain/restore hydration. Good sodium and chloride sources include:
-- Salt: ¼ teaspoon (or 1.5 grams) has 590 mg of sodium.
-- Salted pretzels
-- Tomato juice
-- Salted sport drinks (or PedialyteÒ)
-- Soup, cheese, tomato sauce, pizza, and many processed foods.
- Adequate carbohydrate intake is crucial to optimal performance in tennis.
- Carbohydrate utilization is greater as intensity of play increases and when a player competes or trains in the heat.
- Even if a player eats well before competition, after 60 to 90 minutes of intense singles, carbohydrate stores will likely be significantly decreased and the ability to maintain blood glucose and meet the muscles’ demand for energy may be seriously challenged, which could rapidly lead to fatigue.
- Generally, 3.0-5.0 grams of carbohydrate per pound of body weight (465-775 grams per day for a 155-lb player) is appropriate for periods of intense training or competition.
- Athletes should consume about 30-60 grams of carbohydrate per hour during play and practice.
- Foods and sport drinks with a high glycemic index can be particularly effective for providing rapid carbohydrate energy or restoration during and after play or practice.
All players differ in what foods and which nutritional strategies they can tolerate and perform well with. New foods, drinks, or other dietary protocols should be experimented with well before any important match or tournament.