Measuring Movement and Exercise Flashcards
Why classify types of movement?
For:
- coaching/training
- clinical purposes
- skill acquisition
- to study performance
When do you use functional movement screening?
- Infants and children
- Medical students
- Army recruits
- Professional athletes
- Rehabilitating patients
What is a motor skill?
An act or task requiring movement for successful completion
Movement scientists classify skills to help explain which common features?
- Perception
- Power
- Endurance
- Adaptability
- Efficiency
What are 4 ways to classify skills?
- Physical vs cognitive
- Timing and types of muscle contraction
- Energy system/s utilised
- Precision and stability: gross vs fine, speed vs accuracy
What is the timing of muscle activity in in-phase movements?
Bilateral homologous muscle groups contract synchronously eg. diving into a pool, breast-stroke
What is the timing of muscle activity in anti-phase movements?
Muscles contract in alternating fashion eg. front crawl, gait
What is the timing of muscle activity in co-activation of muscles about joint/s?
Multiple muscles contracting together (synergy)
What is resistance training?
Involves moving weight eg. lifting body weight
What is endurance training?
Involves sustained effort, tolerate exercise
How do you classify whether training is resistance or endurance?
Usually based on what energy system/s is used (ATP-CP, Glycolytic, Oxidative)
What is plyometric training?
Rapid, explosive powerful movement
What are open skills?
Performed in a changing environment. Movements are continuously adapted accordingly to surrounding context. eg. surfing, football
What are closed skills?
Performed in predictable environment. Movements can be planned ahead and self-paced eg. long jump, gym exercise, biathlon
What is open kinetic chain skill/exercise?
- The distal segment can move freely (hands are free to move).
- Segments isolated eg. dumbbell bicep curl, low joint stability shear forces
What is closed kinetic chain skill/exercise?
- Distal and proximal segments are fixed (the joints responsible for that movement are engaged and hands are fixed on the floor).
- Functional, increases muscle recruitment eg. press-up, high muscle co-contraction
What is the speed-accuracy trade-off?
- The faster you move, the less accurately you move
- It is trainable ie. table tennis
How can you change the state of motion of an object or body?
Need to apply a force.
What is a force?
A push or pull applied to an object
What factors determine muscle force?
- Anatomical (muscle size/shape)
- Physiological (muscle fibre type, level of fibre recruitment)
- Mechanical (muscle moment arm, length and contraction velocity)
How is force generated?
By contraction of muscle as needed
What is the length-tension relationship?
Force related to muscle length
What is muscle redundancy?
More muscles doing the same task but they don’t have the same attachment sites. Different muscles have different advantageous angles
Whats the benefit of an angled muscle?
Can squeeze more muscle fibres in and muscles with more muscle fibres are able to generate more force
What happens to our force/muscle fibres when there is a light load?
Light load means we can go for a long time and don’t require many muscle fibres
What happens to our force/muscle fibres when there is an increase in stimulus?
Increased stimulus means increased muscle fibres which decreases the speed of contraction. We can produce more force if needed, but the number of times and speed we do it is the cost.
Whats an example of when force is greater or less than the external load?
Squat Example:
- When you move downward the force produced is less than the load because gravity is doing the work for you
- Moving back up means that force production goes much higher than the load because you have to move the load of the bar and the force of gravity.
How does muscle grow?
The way muscle grows is not uniform, some parts of the muscle will grow more than others and that depends on the way you move the muscle
Relationship between ROM and muscles
The greater the range of motion of the exercise the more muscles you will engage
Whats the best way to increase muscle strength?
Use high weight, low velocity exercise to engage many muscle fibres and increase muscle strength
What are direct methods of measuring force?
Buckle transducer, fibre-optic transducer
How can we measure the effect of a push/pull?
- Ground reaction force plate: F = ma
- Dynamometry - functional strength eg. flexion, extension
What are 4 constraints to force generated by a muscle?
- Muscle architecture/morphology
- Muscle length
- Moment arm of muscle
- Contraction velocity
What is our ultimate limitation to velocity?
The time it takes to bind the myosin head to the actin protein (we can’t speed this process up). Also the relaxation
How do you measure work?
W = F x S (displacement)
What is power and how do you measure it?
- Power measures the rate at which we do work. (P = w/t)
- Power is the ability to apply high force in the shortest amount of time
What is the time to produce maximum force?
0.3-0.4s or 300-400ms
What is the time to perform sports related task?
0.08-0.18s or 80-180ms
What is the constraint to power?
The rate of force development
What is the effect of biking up and down hill on power?
- Uphill: Big force, small displacement = not the best power
- Downhill: Small force, large displacement = not the best power
What is the maximal power?
- 1/3 Vmax and 15-30% of Fmax
- Optimal power is in the middle of the curve P=Fv
What are the 3 ways to train power?
- Stimulate many muscle fibres at one time - training
- Stimulate the nervous system by moving quickly - speed up the time it takes for a muscle to communicate with our brain
- Use functional exercises - need to train them in a way that translates as closely to what they do as possible
What are the 3 ways to measure power?
- Displacement
- Time
- Body mass
But we can also measure power in the field through the vertical jump
What is endurance?
The ability to sustain power
Factors that affect the need for short, intense power demand?
- Aerobic fitness
- Anaerobic fitness
- Strength
- Economy of movement (technique, equipment)
- Psych factors (motivation, mental resilience)
Factors that affect the need for very prolonged, power demand?
- Aerobic fitness
- Energy availability
- Strength
- Physical resilience
- Equipment
- Psych factors
What is endurance fitness?
Attributes that allow one to complete endurance tasks
List 4 key physical, physiological and psychological attributes for swimming in the ocean?
- Thermoregulation
- Aerobic Fitness (for swimming)
- Enough thermal mass (skinfold mass)
- Motivation and resilience
List 4 key physical, physiological and psychological attributes for track cylcing?
- Aerobic fitness
- Technique
- Strength
- Anaerobic capacity
List 4 key physical, physiological and psychological attributes for tramping?
- Aerobic fitness
- Thermoregulation
- Motivation
- Economy of movement
What are 3 ways to measure endurance fitness?
- Performance itself
- A surrogate performance (eg. 10km to predict marathon)
- 3 key performance factors/determinants: VO2 max, max sustainable threshold, economy of movement
How much does genetics account for one’s aerobic fitness?
~75%
What are the 2 things that most determine aerobic power and threshold?
- Capability to deliver oxygen to muscles
- Capability to use oxygen and energy in muscle
Why measure max aerobic power (VO2 max)?
- It’s a major determinant (and therefore also predictor) of endurance performance in many contexts
- Prognostic value for tolerance of many novel stressors
- Sets the upper limit for producing ATP aerobically
Why is VO2 max so insightful?
Stresses most homeostatic variables
How does the cardiovascular system respond to increasing exercise intensity?
- Mostly linear response
- eg. heart rate - as you speed up exercise, you get a linear increase in HR
- Except, the amount of oxygen in your blood is not linear
How does the respiratory system respond to increasing exercise intensity?
- Mostly non linear response
- eg. ventilation, blood and muscle lactate and pH
How does the neuromuscular system respond to increasing exercise intensity?
Mostly non linear response
What is an indirect method for measuring VO2max through submaximal effort and what is an issue with this?
- increase fitness will allow increase pace and/or decrease HR
- eg. test: rockport 1 mile walk
- Issue: doubly-indirect, so decreased validity
What is an indirect method for measuring VO2max through maximal effort and what is an issue with this?
- increase fitness will allow increase endurance in (usually incremental) test
- eg. test: beep, yoyo, ~4min power
- Issue: Surface and learning issues
What is a direct method for measuring VO2max through submaximal effort and what is an issue with this?
- Measure VO2max and HR at diff intensities, predict VO2max from linear relation of VO2 with HR
- eg. test: bruce test, astrand test
- Issue: Usually relies on predicted HRmax
What is a direct method for measuring VO2max through maximal effort and what is an issue with this?
- Measure VO2max throughout max-effort test
- eg. test: incremental bike, run, row test
- Issue: Validity + reliability (3%)
What is metabolism?
Total of chemical reactions occurring in the body
- Anabolic reactions: synthesis of molecules
- Catabolic reactions: breakdown of molecules
What is the metabolic pathway?
Series of reactions, forming an end-product
What is bioenergetics?
The study of energy transfer in chemical reactions within living tissue
What usually drives anabolism?
The energy from catabolism
What is resting metabolic rate (RMR)?
60-75% of total daily energy use
What percent of RMR can elite athletes sustain?
> 15 x RMR
What is work rate limited by?
The rate that ATP can be:
- Used/metabolised (limiting factor in explosive exercise)
- Re-synthesised (if >2seconds)
What are the 3 forms of biological work that ATP drives?
- Mechanical work (muscle contraction)
- Chemical work (biosynthesis)
- Transport work (concentrates molecules inside or outside cell)
What does maximum sustainable exercise depend on?
Factors limiting energy transfer eg.
- Enzymes
- Amount of substrate and relative to amount of end-product
- Temperature
- pH
What are the 3 energy systems?
- ATP-CP system
- Anaerobic glycolytic system
- Aerobic oxidative system
How do the energy systems operate?
They operate as a continuum - relative contribution of each to ATP resynthesises depends mostly on exercise intensity and duration
What are the advantages and disadvantages of the ATP-CP energy system?
ADVANTAGES:
- extremely fast, immediately
DISADVANTAGES:
- tiny store of ATP and PCr in muscle
- makes limited amount of ATP
- PCr depletes rapidly during exercise
What are the advantages and disadvantages of the glycolytic energy system?
ADVANTAGES:
- fast
DISADVANTAGES:
- wasteful of valuable carbohydrates
What are the 6 benefits of lactic acid?
- Produced from pyruvate; allows glycolysis to continue
- Accepts H+ ions, so an important buffer within muscle
- Valuable fuel, especially for heart and brain
- Increased excitability of motor cortex
- Signalling; stimulates adaptation eg. of mitochondria, of gut microbiota
- Marker of exercise intensity (sustainability)
In the oxidative system, what are the two series of reactions that occur in the mitochondria?
- Kerbs cycle: Breaks C-H bonds, producing CO2, electrons and H+
- Electron Transport Chain: Series of enzymes; combine electrons, H+ and O2 to produce water
Whats the difference in protein, fat and carb used for fuel during exercise?
- Protein: provide the smallest energy contribution (<10%) for exercise
- Fats and CHO: contribute to similar extent at rest and low intensity
- Fatty acids: become major contributor if long duration or low glycogen
- CHO: major contributor if higher intensity esp. >~65% VO2 max
What percent of daily energy use does exercise contribute to?
10-30% of daily energy use
What is RMR in relation to BMR?
~50% > BMR
What is sleep in relation to BMR?
~5% < BMR
Why is it unlikely to work off a big mac combo?
- Would need to walk about 28km and:
- Can’t sustain intensity
- Can’t sustain duration
- Don’t have enough time or physical resilience to do that
What provides the most accurate estimate of energy use?
Oxygen consumption measurements
What provides the least accurate estimate of energy use?
Physical Activity recall questionnaires
How do you work out the efficiency in converting food energy into mechanical power output?
Efficiency = work rate / metabolic rate x 100
How much energy is lost as heat?
~2/3 of energy lost as heat just producing ATP aerobically
How to measure energy usage in exercise?
Metabolic rate = aerobic (VO2max) + anaerobic
How to predict energy usage (metabolic rate) from work rate?
- Because metabolic rate is linearly related to work rate
- Roughly: MR = WR x 5 + RMR
How to predict energy usage (MR) from heart rate?
When in steady state,
- MR linearly related to WR and HR is linearly related to WR
- So therefore can estimate MR from HR
Reasons that the HR vs WR (or MR) relations differ?
- Between people
- Between modes of exercise
- With other factors: your state and environment
How to estimate energy usage form smart apps/combined sensor technologies?
- Usually a combination of physiological sensors and physical sensors
- Much improved validity
- Proprietary algorithms so very difficult to scrutinise
- More serious issues emerging
What is Movement capability?
Movement capability changes markedly throughout the lifespan so monitoring and screening movement capability is important
What is physical literacy?
A combination of a person’s motivation, confidence and competence to be active, along with their knowledge and understanding of how being active contributes to their life
What are important considerations when preparing any motor response?
- Sensory information
- Reaction time
- Arousal
- Attention
What are 4 movement factors?
- Preparation
- Postural control
- Force and timing
- Coordination and laterality
How does using our body’s lateral symmetry help use our opposing limbs?
- Maintain CoM over base of support
- Control and optimise force application
- Modify mechanical advantage of levers
What are currently accepted as the most valid and reliable tools to assess children’s movement competency?
Movement assessment batteries eg. Movement-ABC, test of gross motor development-2
What is Movement ABC-2?
- 20-30mins, trained operators
- 30 items, 6 scales,
3 sub-scales: - Balance eg. stork balance, walk backwards
- Ball skills eg. catching, throwing
- Manual dexterity eg. shifting pegs by row
What are 6 examples of functional movement tests for older people?
- Timed up and go
- 4 stage balance test
- Sit to stand
- Grip strength
- 6 minute walk test or 2 minute step test (marching in place)
- Short physical performance battery
