Practice exam

Question 1

Fatigue is ‘the inability to maintain power output… leading to a loss of performance’ Both peripheral and central factors are thought to be involved in fatigue.
a) Describe the 2 most important local factors involved in fatigue in sprinting exercise

Answer 1

• Acidification (H+: lactate accumulation)
• PCr depletion

Question 2

Acidification is an important issue for middle-distance athletes.
b) Describe how the body tries to prevent this acidification.

Answer 2

The body tries to ‘mop up’ the protons with the help of bicarbonate and carnosine (buffering capacity)

Question 3

c) How does acidification result in fatigue (2 mechanisms)?

Answer 3

H+ accumulation, which leads to decreased muscle contraction
It also inhibits PFK, and thus slows down glycolysis and ATP re-synthesis

Question 4

Repeated endurance exercise training increases mitochondrial biogenesis, contributing to an increased aerobic capacity.
a) Describe a molecular sequence of events that links aerobic exercise to mitochondrial biogenesis

Answer 4

Aerobic exercise (Ca2+ increase, ROS increase) -> increase of AMPK and MAPK P38y -> increase of PGC-1alfa (and NRF-1) -> increase TFAM -> mitochondrial biogenesis

Question 5

b) Name another adaptation in the skeletal muscle to endurance exercise, that occurs through largely the same molecular pathway

Answer 5

Angiogenesis

Question 6

In a group of strength athletes (e.g. weight lifters) body composition is measured by underwater weighing (two component model based on the measurement of body volume and body weight), and by the “golden standard” (four component model based on the measurement of body volume, osseous mineral, total body water and body weight). Fat percentage as measured by underwater weighing was on average 21% and fat percentage using the four component model was on average 18%.

a) Are the higher values reported for the two component model in agreement with your expectations? Explain your answer!

Answer 6

Strength athletes -> increased muscle tissue. Assumption = FFM density = 1.1g/cm3 in underwaterweighing, usually correct for the general population.
Ratio muscle mass/bone is higher, resulting in a lower density of FFM. With increased muscle tissue, you expect an overestimation of fat%. The lower % in the four component model is therefore expected.

Question 7

b) Which two assumptions underlying the two component model are dealt with in the four component model?

Answer 7

Hydration coefficient of FFM (73.5%) and the assumption of a fixed amount of bone minerals. Deviations from these assumption can lead to incorrect use of the
FFM density. So to overcome this, it is better to measure the actual amount of water and to measure the actual amount of bone minerals. The 4CM does take this into account, by
measuring water using stable isotopes of water and by measuring bone minerals using DEXA.

Question 8

Energy expenditure can be assessed with formulas using - an estimation of - basal metabolic rate (BMR) and physical activity (level).
a) Give the method which is often used in practice in athletes, and explain the components.

Answer 8

Method which is often used in practice in athletes = TEE = general EE + Exercise EE
General EE = BMR * PAL * h/24 and Exercise EE = BW * MET * h

Question 9

b) What is the difference between energy balance and energy availability; and which one is the preferred estimation in Sports

Answer 9

Energy balance = EI- EE
Energy availability = EI – EEE -> Amount of energy remaining for body functions after accounting for
energy expended from physical activity
With energy balance, it is possible that the athlete is ‘in balance’, even though there is not a sufficient energy intake for the expenditure. This is because the body will try to compensate for the energy losses by lowering the energy used for the BMR.
With energy availability, you look at the energy that is left for the basal metabolism, which can then be categorized and is much more linked to an athlete’s health.

Question 10

a) How much should an athlete drink? And how does an athlete know that he/she is rehydrated?

Answer 10

150% of the post-exercise sweat loss (BW loss) rehydration: bodyweight or urine color

Question 11

It is advised to add sodium to the drinks; the ideal amount however is in practice not really possible.
b) Give the explanation for this advice.

Answer 11

More sodium= increases uptake of water , keeps thirst signal intact compared to water and optimizes water retention (no plasma dilution)

Question 12

c) How much sodium should this be added ideally? Why is this in practice not a real option, and which alternative strategies could an athlete consider?

Answer 12

60-80 mmol/L (ORS)
It is not a real option, because the taste will be very bad. Instead, take sports drinks with a little less salt and eat salty snacks

Question 13

d) Can caffeine and alcohol be part of an athlete’s post exercise rehydration strategy? Explain.

Answer 13

Both can induce diuresis; but effect caffeine is small – and not really an issue. For alcohol
it is, although low alcoholic beverages seems to have no impact after exercise-induced
dehydration. However , for more reasons alcohol is not recommended

Question 14

a) What are the normal recommendations for protein?

Answer 14

0.8 gr/kg/day per meal

Question 15

b) What is the recommended intake for physical active individuals, e.g. strength athletes?

Answer 15

1.2-1.7 gr/kg/day, with endurance athletes at the lower end of this range and resistance
athletes at higher end

Question 16

c) Explain what the effect is of 30 G CHO ingestion post exercise on skeletal muscle protein balance, and what the effect is of 20 gram whey protein post exercise on skeletal muscle protein balance

Answer 16

When CHO are ingested, insulin will be produced by the body which will inhibit protein breakdown. Without protein, there is no effect on protein synthesis. The total effect will be that there is a net negative protein balance It is however less negative when compared to no consumption of food.
20 gr whey protein = increase in protein synthesis and slightly suppress MPB (insulin). and in the end, a net positive protein balance.

Question 17

The ergogenic category of the stimulants consists of a rather heterogeneous group of compounds that include amphetamine, caffeine, ephedrine and methylphenidate (= Ritalin®).
Please answer the following questions regarding this group of compounds.

a) For which alleged purpose(s) are compounds belonging to this class being used?

Answer 17

Increase energy and endurance, reduce mental fatigue, increase lipolysis.
Hence, these compounds will be mainly attractive in endurance sports including team sports that require physical activity for longer periods of time. To some extent the compounds will also increase alertness.

Question 18

b) Which of the compounds mentioned above is/are presently allowed for use in food supplements? ( amphetamine, caffeine, ephedrine and methylphenidate (= Ritalin®). )

Answer 18

caffeine

Question 19

c) What are the potential side-effect and risks of compounds belonging to this class?

Answer 19

Tremor, increased hart rate, agitation, insomnia
More severe side-effects: overstimulation and decreased ability to respond to physiological feed-back signals that normally limit performance and overstimulation. Overconfidence: overstimulation, heat-stress,
to even stroke, shock etc.

Question 20

Strenuous exercise can (temporarily) reduce immune function, increasing the risk of infection in athletes. Nutrition could play a role in reducing the immune response
Which nutritional strategies are proven effective? Explain how they can affect the post exercise immune response.

Answer 20

Energy, CHO and/or fluid supplementation will reduce exercise stress (cortisol) and attenuate the effect of exercise on immune function.
There is some evidence that also vit C can do the same