Muscular System

Question 1

Explain the difference between the flexion & extension during a recognised sporting movement.

Answer 1

Flexion = decreasing angle between bones of a joint. E.g. bending elbow during upward phase of bicep curl
Extension = increasing angle between bones of joint up to 180 degrees. E.g. straightening elbow on throwing phase when releasing javelin

Question 2

Explain the difference between plantarflexion & dorsiflexion during a recognised sporting movement.

Answer 2

Plantar Flexion = action of pointing toes, increasing angle between tibia & tarsals - brought about through contraction of gastrocnemius muscle. E.g. punt kicking phase in Gaelic football
Dorsiflexion = action of pulling toes up to shin, caused by tibialis anterior, found in front of lower leg. E.g. during recovery phase when running, as athlete recovers foot is bent as in dorsiflexion

Question 3

State the main muscle fibre type used during an endurance activity and identify two characteristics of this fibre type

Answer 3

Slow twitch muscle fibre (slow oxidative fibre)
These fibres contract more slowly & don’t produce as much force as fast twitch fibres

Support sub-maximal contractions, e.g. endurance based athletes, runners, cyclist, long distance swimmers
Aerobic in nature
Resistant to fatigue

Question 4

Explain how wave summation and spatial summation facilitate the control of muscular contractions

Answer 4

Wave:
Strength of muscle contraction can be increased
Wave summation = freq with which impulses arrive at motor unit
Time intervals can increase or decrease depending on strength of contraction needed

Spatial:
Different motor units being stimulated across whole muscle to produce contraction
Allows use of stores of ATP to be shared around whole muscle, thus reducing fatigue
Strength of muscle contraction can be increased by recruiting more motor units

Question 5

Prolonged exposure to training causes structural and physiological adaptations to occur which allow endurance athletes to perform better.
Identify and describe two adaptations to muscular systems resulting from endurance training

Answer 5

Increased production of myoglobin
Increased size & density of mitochrondria
Reduction in body fat/increase in lean muscle mass

Question 6

Identify disadvantages of altitude training experienced by some elite athletes

Answer 6

Athletes may experience altitude sickness, dizziness, headaches, nausea
Detraining effect is possible - decreased availability of O2 makes training harder - difficult to train at same intensity, which could lead to loss of fitness level
Benefits may be lost quicker than anticipated when athlete returns back to sea level
Altitude training = expensive method of training for some athletes

Question 7

Discuss the reasons why altitude training is considered to be an effective method of training for endurance athletes

Answer 7

Athletes from many sports have used altitude training to prepare for high profile matches & events
Atmospheric pressure decreases as altitude increases - significant implications for athletes as fall in partial pressure leads to shortage of oxygen (hypoxia). Every breath at high altitude delivers less of what working muscles require
Body produces extra blood cells - increased number & concentration of RBC, thus increased concentration of haemoglobin & myoglobin. Will experience increased tolerance to lactic acid/delayed OBLA