Muscular System
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Explain the difference between the flexion & extension during a recognised sporting movement.
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
Explain the difference between plantarflexion & dorsiflexion during a recognised sporting movement.
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
State the main muscle fibre type used during an endurance activity and identify two characteristics of this fibre type
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
Explain how wave summation and spatial summation facilitate the control of muscular contractions
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
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
Increased production of myoglobin Increased size & density of mitochrondria Reduction in body fat/increase in lean muscle mass
Identify disadvantages of altitude training experienced by some elite athletes
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
Discuss the reasons why altitude training is considered to be an effective method of training for endurance athletes
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