Date | November 2019 | Marks available | 5 | Reference code | 19N.2.HL:.tz0.5 |
Level | Higher Level | Paper | Paper 2 | Time zone | time zone 0 |
Command term | Explain | Question number | 5 | Adapted from | N/A |
Question
Distinguish between health-related and performance-related fitness.
Apply two health-related components of fitness to a marathon runner.
Describe the exchange of carbon dioxide from the bloodstream during exercise.
Explain the reason for elevated breathing in the first minutes after a swimming sprint.
Outline two types of drag that can occur in swimming.
Suggest how a triathlete (swimming, cycling, running) can overcome drag.
Markscheme
performance-related fitness is based on attributes such as agility/balance/coordination/power/reaction time/speed, whereas health-related fitness is related to body composition/cardio-respiratory fitness (aerobic capacity)/flexibility/muscular endurance/strength ✔
Aerobic capacity:
capacity of the runner to take in, transport and use oxygen system to sustain movement or effort over a period of time ✔
Muscular endurance:
the capacity of legs to repeat movements over a period of time without undue fatigue ✔
Body composition:
a low percentage of fat reduces amount of work required by leg muscles ✔
Flexibility:
can increase stride length ✔
Strength:
enables athlete to maintain speed up hill ✔
Accept other acceptable examples of application to a marathon runner.
there are increasing levels of CO2 during exercise ✔
diffusion gradient / rate of exchange is increased ✔
gases move from an area of high concentration to an area of low concentration ✔
CO2 is carried in the blood as bicarbonate (ions) dissolved in plasma (bound to hemoglobin)
OR
CO2 is carried in the form of bicarbonate ✔
CO2 <dissolved in plasma> diffuses from <pulmonary> capillaries into the alveoli and exhaled ✔
(when blood enters the lungs) carbonic acid dissociates into CO2 and H2O ✔
CO2 is released from hemoglobin (carbaminohemoglobin) in the lungs and into the alveoli and exhaled ✔
the greater the intensity of the exercise, the greater the EPOC ✔
initial stages of exercise, oxygen demand cannot be met by the aerobic system <oxygen deficit>
OR
initial stages are met by anaerobic processes ✔
oxygen deficit is paid back after exercise/oxygen debt ✔
alactic/fast component is replenished with <3–4 litres of> oxygen ✔
ATP and CP/PC stores are replenished ✔
myoglobin oxygen levels are replenished ✔
aerobically metabolize lactic acid ✔
resynthesize lactate to glycogen ✔
replacement of muscle / liver glycogen stores ✔
Surface drag:
<sum of> friction forces between fluid molecules and the object. ✔
as a body moves through a fluid, its outer surface catches a layer of the fluid nearby, slowing it down ✔
this can be minimized by changing the surface to reduce the interaction between surface and fluid ✔
Form drag:
as a body pushes against a fluid, the fluid pushes back (action and reaction) ✔
the greater the surface area the greater the drag ✔
Wave drag:
acts where there is a reaction between two types of fluids ✔
when a body moves along the surface of a fluid, some fluid is displaced to form a wave that can oppose motion ✔
by wearing closer-fitting, smoothing clothing/head gear ✔
through shaving down body hair ✔
swimming underwater as much as possible ✔
swimming in a deck level pool/ using specialized wave limiting lane ropes✔
streamlining their body position ✔
use of drafting behind another swimmer/cyclist ✔
modifications to bicycle to make it more aerodynamic ✔