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Foundations in Sports Coaching
7 Anatomy and physiology for coaches
Case study recommended answers
1 Discuss the joint movements involved in front crawl swimming
As a minimum your answer should discuss the major joints including the glenohumural
joint, hip, knee and ankle joint.
Glenohumeral joint - During front crawl swimming the shoulder joint involves a combination
of movements for example including extension, abduction, flexion, adduction.
Hip joint – During front crawl swimming the hip joint involves a combination of flexion and
extension.
Knee joint – During front crawl swimming the knee joint involves a combination of flexion
and extension.
Ankle joint – During front crawl swimming the knee joint involves a combination of flexion
and extension.
2 Discuss the muscles responsible for the movements identified in front crawl
swimming.
Glenohumeral joint
Extension – Latissimus dorsi, deltoid (posterior), pectoralis major (sternla head), teres
major triceps brachii (long head).
Abduction – deltoid (lateral and anterior), supraspinatus, pectorlis major (sternal head).
Flexion - Deltoid (anterior and lateral), pectoralis major (clavicular head), coracobrachialis,
biceps brachii (short head).
Adduction – latissumus dorsi, pectoralis major (sterna head), pectoralis major (clavicular
head), teres major, coracobrachialis, triceps brachii (long head).
Hip joint
Flexion – Illipsoas, tensor fasciae latae, rectus femoris, Sartorius, adductor longus,
adductor brevis, pectineus.
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Foundations in Sports Coaching
Extension – Gluteus maximus, semitendinosus, semimembranosus, biceps femoris long
head), adductor magnus (ischial fibers).
Knee joint
Flexion – Hamstrings, gracilis, Sartorius, popliteus, gastrocnemius.
Extension – quadriceps femoris.
Ankle joint
Plantar flexion – gastrocnemius, soleus, plantaris, tibialis posterior, flexor hallucis
posterior, flexor digitorium longus.
Dorsi flexion – tibialis anterior, extensor digitorium longus, extensor hallucis longus,
peroneus tertius
3 Describe the muscle fibre types required during cycling and spinning.
Spinning is a popular indoor cycling activity which is used by many cyclists and triathletes
to complete their training, particularly if weather conditions are not conducive to outdoor
cycling. On average a spin session duration is 45-60 minutes. Predominantly type 1
muscle fibres will be recruited. However, during short sharp intensity sprints on the bike,
type 2a muscle fibres will be recruited. Type 2b fibres are far less likely to be recruited and
only in times of the most powerful contractions.
Type 1 muscle fibres – as their name ‘slow twitch’ denotes, they contract slowly. Muscle
fibres are smallest in diameter therefore produce a low level of force, fatigue resistance
and are able to produce contractions for long periods of time. The fibres appear as dark
red due to large amounts of blood capillaries and myoglobin, accompanied with many
mitochondria required to sustain aerobic cellular respiration. The fibres are therefore
recruited for aerobic endurance activities such as long distance running and cycling and
swimming, these activities are lower in intensity as they need to be sustained over a longer
period of time.
Type 2a (FOG) muscle fibres – muscle fibres are intermediate in size. They also appear as
dark red due to the large content of blood capillaries and myoglobin, and are fairly
resistant to fatigue, therefore recruited for aerobic exercise. These fibres differ from slow
twitch as they also contain a high level of intracellular glycogen, allowing generation of
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Foundations in Sports Coaching
energy and force via anaerobic respiration, resulting in faster contractions than slow twitch
fibres, with peak contraction reached earlier, although for a shorter duration. These fibres
are suited to events such as middle distance running e.g. 800m or 1500m and walking
activities.
Type 2b (FG) muscle fibres – muscle fibres are largest in size producing the most powerful
contractions due to the high number of myofibrils. The fibres appear white in character
due to low levels of blood capillaries, myoglobin and mitochondria. They have the capacity
to contain large amounts of glycogen, and contract quickly and strongly, however fatigue
quickly. They are completly dependant on anaerobic respiration. These fibres are suitable
for high intensity, short duration activities such as sprinting, weight lifting, jumping e.g. high
jump or long jump and throwing events such as javelin or shot putt.
4 Describe the process of internal and external respiration.
Pulmonary ventilation (breathing) is the mechanical process of air flowing from the
atmosphere into the lungs, more specifically the alveoli. This is possible due to the
alternating pressure differences created by contraction and relaxation of the respiratory
muscles such as the intercostals muscles.
External respiration is the exchange of gases between the alveoli and the capillaries.
Oxygen diffuses from the alveoli which is at higher pressure, moving to lower pressure in
the capillaries, while carbon dioxide diffuses from high pressure in the capillary to lower
pressure in the alveoli.
Internal respiration is the exchange of gases during systemic circulation, the exchange of
gases from the capillaries to the tissue cells and vice versa.
Pressure changes during pulmonary ventilation are caused by inhalation (also known as
inspiration, breathing in) and exhalation (also known as expiration, breathing out). Air
moves into the lungs when the pressure inside the lungs is less than the pressure outside
the lungs; this pressure is created during inhalation. Air moves out of the lungs when the
pressure inside the lungs is greater than the pressure in the atmosphere created during
exhalation.
Inhalation – the intercostals muscles contract lifting the ribs up and outwards, the
diaphragm forced downwards with the sternum pushed forwards, increasing the volume of
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Foundations in Sports Coaching
the chest cavity. The pressure inside the lungs is lower than that of the atmosphere,
drawing air into the lungs. Consequently, oxygen diffuses into the capillaries and carbon
dioxide into the alveoli.
Exhalation – the intercostals muscles relaxing, ribs are drawn in and downwards, sternum
moves inwards and the diaphragm is drawn upwards decreasing the volume of the chest
cavity. The pressure inside the lungs is higher than that of the atmosphere, expelling air
into the atmosphere.
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