lecture 5-6 Flashcards by Jessica Walsh

Physiological demands of sport: considerations

Considerations
 Duration of the event
 Rest periods
 Rotations/substitution
 Closed or open environment
 Environmental conditions

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Physiological demands of sport- team sport

Time motion analysis
 Repeated sprints
 Endurance

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Physiological demands of sport- individual sport

 Individual demands
○ Power lifting
○ Tennis
○ Running – speed or endurance

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how does ATP contract a muscle

ATP is the energy currency of the body
regardless of the activity undertaken
 Power or endurance
 It is all about muscle contraction
 Energy is released when a phosphate
molecule is cleaved from ATP to form
ADP + Pi + Energy

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how is ATP replenished

 ATP is recycled
 ADP + Pi + energy = ATP
 But where does this energy come from?
 Via breakdown of macronutrients in the food we eat
 Carbohydrate
 Fat
 Protein

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what are the 3 main pathways to replenish ATP

ATP-PCr
 Lactic acid system
 Aerobic energy system

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ATP-PCr system

 PCr splits releasing energy which can then be used to recycle ATP
Like ATP, PCr is also in limited supply
 ~300-600g
 Enough stored for 3-15 s of high intensity exercise
 Thus is the main source of energy in activities such as sprinting

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Lactic Energy System

 Anaerobic glycolysis
 Does not require oxygen
 Break down of CHO to produce energy
for ATP production
 The by-product of this process is Lactate lasting 30-60 s

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Aerobic Energy System

Requires Oxygen to ‘burn’ fuel to produce ATP
 Is the most economical energy system producing large amounts ATP,
 although it is not as rapid as the anaerobic pathways

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What limits the energy system?

- Fuel availability
 Oxygen availability
 Removal of waste products
 Cardiac output
 Mitochondria
 Buffering capacity

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Adaptation to Anaerobic training

Muscle fibre type changes
 Increased levels of anaerobic substrates
 Enzymatic changes that enhance
glycolysis
 Increased capacity to generate high
levels of Lactate

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Aerobic training methods

Continuous aerobic training
 Fartlek
 Interval
 Usually >30 min at an intensity below the LT
 In athletes, the duration is generally greater than the performance time
○ Exceptions may be marathons or prolonged team games
 During these sessions there is no significant accumulation of Lactic acid

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measuring energy systems

VO2max
 Beep test
 Yo-Yo
 Timed run (1600m – 5000m)

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What is VO2max?

 The highest rate at which oxygen can be taken up and utilised by the body during severe exercise

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What are the Rate Limiting

Factors of VO2max?

Cardiac Output
- Improved with training
Oxygen Delivery
- Hbmass increased with training
Oxygen Extraction
- Increased capillary and mitochondrial function
Metabolic waste removal?

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Strength

The amount of force a muscle group can exert against a resistance in one maximal effort

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Strength Endurance

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When a load has to be resisted for a period of time, this capacity is known as strength endurance
 A stronger muscle will have greater strength endurance than a weaker one, as at a given resistance, it will use a smaller percentage of its
maximal strength

Why strength is important

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speed athletes
power events
stability events
muscle endurance

Speed

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Tendency to think of this capacity in terms of just running speed, but it really relates to all forms of human movement
 Speed of movement is important in all power sports, including throwing & striking
skills as well as running & kicking performances

Power

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 The performance of work per unit of time
 The ability to propel an object or project our
body against gravity is dependant upon the
amount of power we can generate

Power depends on

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The strength of the muscular contraction

 Speed of contraction – how quickly one can generate maximum force or rate of force development

Factors influencing strength,

power & speed

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General
 Age
 Gender
 Psychological
 Environmental
Anatomical /
Biomechanical
 Fibre type
 Tendon insertion
 Lever length
 Posture
 Body type
 Flexibility

Age & Strength

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Strength develops with normal growth
 The best developmental period is late adolescence
 PA stages 3-5
 Just after PHV
 Strength increases are max even without training
Strength generally decreases with age
 >40 males
 >30 females

Gender differences

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 In terms of absolute strength, women are
generally not as strong as men due to lower quantity of muscle
 However, relative to muscle cross-sectional area, no differences exist between the sexes, indicating muscle quality is not sex specific
- Females can develop strength in the same
manner as males, but may not experience the same rate of gain due to the catabolic action of oestrogen
 This is also why females tend to experience less hypertrophy than males

Factors affecting strength & | power

``` General  Age  Gender  Psychological  Environmental Anatomical/Biomech  Fibre type  Tendon insertion  Lever length  Posture  Body type  Flexibility ```

positives and negatives of Longer segment length

``` Disadvantage  Increase resistance to Torque  Require greater muscle force to move load Advantage  Able to generate greater speed ```

Tendon insertion

``` The points at which tendons are attached to bone.  Further from the joint centre results in the ability to lift heavier weights  But results in a loss of maximum speed ```

Muscle contractions

``` Concentric: tension > resistance  shortening Eccentric: tension < resistance  lengthening Isometric: tension = resistance  no change ```

Power – Load relationship

 Inverse relationship between force | development & velocity of movement

Determining muscle fibre type

Muscle biopsy technique |  Histological staining

principles of training

``` - Principle of progressive overload  Principle of individuality  Principle of specificity  Principle of variations  Principle of recovery ```

Mechanisms of Strength | Development

 Neural mechanisms  Inter muscular coordination 0-2 weeks  Intra muscular coordination 1-8 weeks  Hypertrophy

Hypertrophic development

```  High volume of work  Via number of sets & exercises  Moderate to high loads  65-85% of 1RM  Many exercises per muscle group  3-6 sets x 6-12 reps per exercise  3-4 exercises per muscle group  2-3 times per week ```

Plyometric training

```  The essential elements for successful plyometric exercises are:  RATE OF STRETCH is more important than amount of stretch  CONCENTRIC CONTRACTION PHASE should occur immediately after the eccentric contraction ```

improvements made through Plyometric training

An ability to train the muscle group through its full ROM;  An ability to invoke the stretch reflex to augment the concentric contraction;  The pre-stretch phase also allows elastic energy to be stored in the muscle & tendon connective tissue  This also augments the concentric contraction.

Determinants of speed

1. Muscle fibre type 2. Skill (neuromuscular coordination) 3. Lever length 4. Posture

Improving speed

1. Increasing the + ve forces - improved strength - improved power 2. Decreasing the - ve forces - improved flexibility (less resistance) - improved skill (decreased co-activation of antagonists) - Speed resisted training Improving the muscle strength & power

Progressive overload

``` The muscle will only develop when work loads are above those usually encountered. Variables:  Intensity  Duration  Frequency ```

Principle of Individuality

``` Tolerance of training loads Responsiveness to training load Recovery from training Training needs Environmental tolerance Physical characteristics Life-style variations Preference ```

Principle of Specificity

 The adaptations which occur are specific to the type of training performed  The best gains in performance are achieved when the training is performed in a manner very specific to the competitive action

Principle of Variation

 If a training stimulus is consistently applied in exactly the same manner  its effectiveness will diminish,  the athlete will become stale & training gains will be reduced.

Principle of recovery

 For maximum training benefits, complete recovery from previous training stimulus must occur before reintroduce the stimulus.  Muscle growth and adaptation occurs BETWEEN training sessions and therefore, an adequate recovery is essential.

lecture 5-6 Flashcards

(42 cards)