NUTRITION - composition and timing of nutrient and fluid intake before, during, and after exercise or sport event

Question 1

Nutritional modifications BEFORE aerobic endurance, Strength/Power, and HIIT sports
4+ hours
2 hours
1 hour

Answer 1

Prehydrate several hours before exercise to allow fluid absorption and urine output (USG should be <1.020).
4+ hours before: 1g-4g of carbs per kg/BW and 0.15g-0.25g protein per kg/BW – 5-7 ml of fluid per kg/BW

2 hours before: 1g of carbs per kg/BW – 3-5ml per kg/BW

> /=1 hour before: 0.5g carbs per kg/BW – ~8 oz of fluid. Meals should be smaller. Liquid sources of carbs are best when

Question 2

Amount of glycogen stored in liver and muscle

Answer 2

15 g per kg of bodyweight

ex. 80 kg man can store 1,200 calories of glycogen.

Question 3

Pre-competition meals and drinks should be:

Answer 3

Familiar to athlete.
Low in fat and fiber.
Moderate in protein.

Question 4

Nutritional mods DURING aerobic endurance sports

Answer 4

Carb intake of 28g - 144g per hour during aerobic activity can decrease reliance on limited glycogen stores, extended time to exhaustion, and improve performance by proving a steady stream of carbs.
Each carb has a different rate oxidation: Glucose, sucrose, maltose, maltodextrin, and amylopectin are oxidized quickly. Fructose, galactose, and amylose are 25%-50% slower.
Aerobic athletes should consume 30-90g of multiple carb types together (i.e. sucrose, fructose, and glucose, or maltodextrin) each 1 hour during prolonged activity.
Include protein to reduce muscle damage (increased CK makes this apparent).

Question 5

Nutritional mods DURING high intensity intermittent activity

Answer 5

Tennis players (matches can last 3+ hours and they cannot continuously drink): recommended to consume 200-400 ml (some should be sports drink) per changeover. Carb intake may not affect perceived exertion, but improves stroke quality (velocity, precision, error rate, etc.).
Consuming 2ml - 5ml per kg/BW of a fluid/carb-sports drink solution in intervals (i.e. every 15 minutes) is advantageous during intermittent sports activity.

Question 6

Nutritional mods BEFORE and DURING strength/power activity

Answer 6

Strength and power athletes can maintain their glycogen stores, which may decrease muscular fatigue in slow-twitch fibers and possibly lead to better performance, by supplementing carbs before and during competition.

Question 7

Nutritional mods AFTER aerobic activity

Answer 7

During strenuous aerobic activity, even after recommended 1.0-1.85g kgBW/hour of high carb intake, glycogen resynthesis my be delayed due to either metabolic disturbance or mechanical damage to muscle cells
Best to consume 0.2g-0.5g kg/BW protein in post activity meal to build and repair muscle, possibly reducing soreness. Ingesting a protein-carb supplement improves performance and reduces markers of muscle breakdown.

Question 8

Carb requirements for rapid glycogen synthesis post exercise

Answer 8

1.0g-1.85g per kg/BW/hr consumed immediately after activity at regular intervals every 15-60minutes for up to 5 hours.
Athletes that have more than 24 hours can wait before eating after exercise and replace their glycogen over the next 24 hours as long as they consume adequate amount of carbs during that time.

Question 9

Nutritional mods AFTER HIIT activity

Answer 9

Immediate recovery after activity if there is little time between next activity (i.e. tournaments).
Carbs should be included immediately in post activity meals when there’s less than 24 hours recovery time.
Protein: Research unclear on amount. Should follow strength and power recommendation of consuming minimum 20-25g of fast, high-quality, leucine-rich (2-3g leucine) protein.

Question 10

Nutritional mods AFTER Strength and Power activity

Answer 10

Should consume high-glycemic carbs immediately post exercise if competing or training again over course of 24 hours.
20-25g of fast (egg or whey), high-quality, leucine-rich (2-g or 0.5g per kg/BW) protein.

Question 11

Challenge for women w/ carb loading

Answer 11

Lower daily calorie intake.
Women that normally consume <2400 cals/day may find it hard to consume grater amount of carbs.
Thus, women should increase total daily energy intake above 2400 cals in addition to consuming a higher carb diet in order to increase glycogen stores.

Question 12

Carb loading for high-intensity athletes

Answer 12

results vary upon athletes response to carb loading

Question 13

Optimal carb intake during carb loading

Answer 13

8-10g of carbs per kg of BW per day

Question 14

Carb loading for resistance training

Answer 14

no significant increase in power when intaking 4.4-6.5g of carbs.

Question 15

Amount of carbs kgBW/day up to 3 days before event? The 2 days before and event?

Answer 15

> /= 3days: 8-10g

2 days: 10-12g

Question 16

Phases of glycogen synthesis post exercise

Answer 16

Phase 1: independent of insulin and lasts 30-60 min., and glycogen synthesis is rapid
Phase 2: lasts several hours, and glycogen synthesis occurs much slower.

Question 17

Amount of carbs for rapid glycogen resynthesis AFTER exercise

Answer 17

1.0-1.85g per kgBW/hour every 15-60 min. for up to 5 hours.