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  1. #21

    Ngày tham gia
    Nov 2013
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    Trích dẫn Gửi bởi Cường Ken
    Nutrition: Playing Tennis in the Heat: How to Manage Water and Electrolyte Losses
    By Michael F. Bergeron, Ph.D.

    Your body produces heat during tennis -- lots of it! And as intensity and duration of play increase, you face an growing challenge to eliminate the accumulating heat, especially in hot weather. The best way for a tennis player to get rid of internal body heat during play is by sweating. But if it’s hot and humid, even sweating doesn’t eliminate heat effectively.

  2. #22

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    Sep 2013
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    Cường Ken;766859]Nutrition: Playing Tennis in the Heat: How to Manage Water and Electrolyte Losses[/QUOTE]

    In warm to hot conditions, most adult tennis players will lose between 1.0 and 2.5 liters of water during each hour of competitive singles, although sweat rates of 3.5 liters per hour have been observed during play in very hot (above 95° F) conditions. Sweat rate increases as:

    1. the environment gets hotter and more humid,

    2. as intensity of play increases, and

    3. as a player becomes more aerobically fit and acclimatizes to the heat.

  3. #23

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    Nov 2013
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    Trích dẫn Gửi bởi Cường Ken
    Cường Ken;766859]Nutrition: Playing Tennis in the Heat: How to Manage Water and Electrolyte Losses
    And although women generally sweat less than men, this is not always the case.

  4. #24
    Trích dẫn Gửi bởi Cường Ken
    And although women generally sweat less than men, this is not always the case.
    Sweat is mostly water, but it contains a fair amount of sodium (Na ) and chloride (Cl-). In contrast, there is usually very little potassium (K ) in sweat. Furthermore, contrary to what many tennis players and coaches have heard, clinical evidence clearly supports a relationship between heat-related muscle cramps and a high sodium loss, not potassium. Players will generally lose 3-10 times as much sodium as potassium during play.

  5. #25

    Ngày tham gia
    Jan 2014
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    Trích dẫn Gửi bởi Cường Ken
    Sweat is mostly water, but it contains a fair amount of sodium (Na ) and chloride (Cl-). In contrast, there is usually very little potassium (K ) in sweat. Furthermore, contrary to what many tennis players and coaches have heard, clinical evidence clearly supports a relationship between heat-related muscle cramps and a high sodium loss, not potassium. Players will generally lose 3-10 times as much sodium as potassium during play.
    And without adequate sodium replacement, the cumulative effect of such losses can lead to a progressive sodium deficit after several days of playing or training in the heat. The effects of inadequate sodium replacement may include incomplete rehydration between matches (from a decreased retention of fluid) as well as muscle cramps or increased heat exhaustion during subsequent play. Again, regarding electrolytes, players should be more concerned about replacing sodium losses after a match, not potassium losses. And notably, bananas will not resolve or prevent heat-related muscle cramps; although appropriate salt and fluid intake often will.

  6. #26

    Ngày tham gia
    Jun 2013
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    Trích dẫn Gửi bởi Cường Ken
    And without adequate sodium replacement, the cumulative effect of such losses can lead to a progressive sodium deficit after several days of playing or training in the heat. The effects of inadequate sodium replacement may include incomplete rehydration between matches (from a decreased retention of fluid) as well as muscle cramps or increased heat exhaustion during subsequent play. Again, regarding electrolytes, players should be more concerned about replacing sodium losses after a match, not potassium losses. And notably, bananas will not resolve or prevent heat-related muscle cramps; although appropriate salt and fluid intake often will.
    Even with relatively short matches, it’s not uncommon for tennis players to finish play with water deficits equal to or greater than 2% of their respective pre-match body weights. So, why don’t these players drink more during play? One reason that tennis players don’t always offset sweat losses with fluid intake is that, during a match, thirst is usually not a rapid enough indicator of body water losses.

  7. #27

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    Sep 2013
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    Trích dẫn Gửi bởi Cường Ken
    Even with relatively short matches, it’s not uncommon for tennis players to finish play with water deficits equal to or greater than 2% of their respective pre-match body weights. So, why don’t these players drink more during play? One reason that tennis players don’t always offset sweat losses with fluid intake is that, during a match, thirst is usually not a rapid enough indicator of body water losses.
    Consequently, players don’t always feel the need to drink as much as they should. Therefore, tennis players should follow a predetermined hydration plan, whether they are thirsty or not. But, is a 2-3% body weight deficit a big deal? After all most players drink enough to avoid serious heat disorders. Well, very little research has specifically examined varying levels of a body water deficit on tennis performance.

  8. #28

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    May 2013
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    Trích dẫn Gửi bởi Cường Ken
    Consequently, players don’t always feel the need to drink as much as they should. Therefore, tennis players should follow a predetermined hydration plan, whether they are thirsty or not. But, is a 2-3% body weight deficit a big deal? After all most players drink enough to avoid serious heat disorders. Well, very little research has specifically examined varying levels of a body water deficit on tennis performance.
    However, other research studies have shown significant decreases in muscular strength, muscular endurance, physical work capacity, and even mental performance, with only marginal to moderate body water losses. Further, current research shows that fluid ingestion reduces internal body temperature, as well as muscle glycogen use, during prolonged exercise; these factors can clearly contribute to improved performance.

  9. #29
    Trích dẫn Gửi bởi Cường Ken
    However, other research studies have shown significant decreases in muscular strength, muscular endurance, physical work capacity, and even mental performance, with only marginal to moderate body water losses. Further, current research shows that fluid ingestion reduces internal body temperature, as well as muscle glycogen use, during prolonged exercise; these factors can clearly contribute to improved performance.
    So what should you do? First of all, recommendations for managing fluid and electrolyte losses should be individual specific. However, several general recommendations can be made;

  10. #30

    Ngày tham gia
    Dec 2013
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    Prior to playing in a hot environment, make sure that you are acclimatized to the heat. This can be accomplished in 7-10 days, so long as you exercise for 1-2 hours each day in the same heat.

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