lecture 5-6 Flashcards
Physiological demands of sport: considerations
Considerations Duration of the event Rest periods Rotations/substitution Closed or open environment Environmental conditions
Physiological demands of sport- team sport
- Time motion analysis
Repeated sprints
Endurance
Physiological demands of sport- individual sport
Individual demands
○ Power lifting
○ Tennis
○ Running – speed or endurance
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
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
what are the 3 main pathways to replenish ATP
- ATP-PCr
Lactic acid system
Aerobic energy system
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
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
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
What limits the energy system?
- Fuel availability Oxygen availability Removal of waste products Cardiac output Mitochondria Buffering capacity
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
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
measuring energy systems
- VO2max
Beep test
Yo-Yo
Timed run (1600m – 5000m)
What is VO2max?
The highest rate at which oxygen can be taken up and utilised by the body during severe exercise
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?
Strength
The amount of force a muscle group can exert against a resistance in one maximal effort
Strength Endurance
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
- speed athletes
- power events
- stability events
- muscle endurance
Speed
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
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
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
General Age Gender Psychological Environmental Anatomical / Biomechanical Fibre type Tendon insertion Lever length Posture Body type Flexibility
Age & Strength
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
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
- Muscle fibre type
- Skill (neuromuscular coordination)
- Lever length
- Posture
Improving speed
- Increasing the + ve forces
- improved strength
- improved power - 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.
