Weeks 5-9 Flashcards
What is subjective/self-reporting fatigue?
Perception
Subjective lack of physical or mental energy (or both) that is perceived by the individual to interfere with usual and desired activities
What is objective/performance fatigue?
Difficulty maintaining force output or muscular control
What can neuromuscular fatigue be due to? (2) Which is common in healthy and disease people?
- Altered neural activation (commonly with disease) OR
- Altered muscle metabolism (commonly with healthy)
What potential locations of sources of fatigue? (4)
- CNS (brain, spinal cord)
- PNS
- N-M Junction
- Muscle fibre (membrane, SR, actin-myosin)
What are peripheral factors of fatigue? (6)
- NM transmission
- Excitation contraction
- Decreased energy stores
- Increased metabolites
- Electrolyte gradients
- SNS
What are central factors of fatigue? (6)
- CNS motor drive
- Feedback from muscle
- Motivation
- Discomfort
- Sleep disorders MS
- Endocrine abnormalities
What is acute neuromuscular fatigue? What is it mostly associated with?
Local contractile failure in muscle. Mostly associated with energy production (energy supply fatigue)
What contributes to acute neuromuscular fatigue? (5)
- Lack of blood flow
- Lack of oxygen
- Nutrient fatigue or substrate depletion (creatine phosphate or glycogen depletion)
- Increased metabolites
- Altered Ca2+ signalling
What are the three types of muscle soreness?
- Acute (during activity)
- Delayed onset (24-72 hours after activity)
- Sustained (injury related)
What are characteristics of acute muscle soreness? (6)
- Occurs during physical activity
- Not usually associated with tissue damage
- Associated with lactic acid production (more in high intensity)
- May produce a burning sensation
- Recovery rapid after stopping activity
- Fastest recovery from low intensity dynamic activity
What are characteristics of DOMS? (8)
- 24-72 hours post unaccustomed physical activity
- Common when starting a new exercise program, first day of a new job or a change of job tasks
- Associated with eccentric muscle contractions (walking downhill, unloading)
- Associated with damage to muscle fibres and inflammation (mild strain injury)
- Muscles are often swollen and stiff
- Usually resolves in 2-3 days
- Provides protection for ~6 weeks
- Soreness can be severe
a) How to minimise DOMS when starting an exercise program? (2) b) In what population is this particularly important?
a)
- Use modest loads (especially eccentrically)
- Limit downhill running and increase slowly
b) The elderly
How could you minimise DOMS in the workplace for new employees?
Limit their exposure to tasks that are likely to instigate DOMS, in their first few days of work to allow for adaptation
What are characteristics of muscle soreness due to strain injury? (6)
- Muscle or associated tissue injured
- May involve fibres and/or connective tissues
- Often due to over exertion or poor mechanics
- May feel soreness immediately
- May take time to heal
- Requires rest time for recovery
What is the difference between a sprain and a strain?
Sprain - ligament or joint capsule
Strain - muscle and/or tendon
What are some causes of skeletal muscle injuries? (5)
- Damage to muscle fibres
- Damage to tendons
- Damage to myotendinous junction
- Damage to tendon attachment to bone
- Spasm (sustained contraction) due to nerve activation or irritation
What are satellite cells? When are they stimulated?
- Type of muscle stem cells that sit between the basal lamina and sarcolemma
- Stimulated and proliferate when cells are substantially damaged - when not in contact with sarcolemma
What are the steps in muscle regeneration? (5)
How long may this process take?
- Muscle fibres damaged
- Cell infiltration and inflammation
- Degenerative dismantling of damaged cell
- Proliferation of satellite cells
- Form myotubes then filled with new myofibrils
- Process may take 6 months
What muscle changes occur with disuse? What is this due to?
- Atrophy - decreased muscle fibre size (cross-sectional area)
- Weakness/loss of force
- Usually due to loss of mechanical loading rather than loss of neural activation
What are the effects of bed rest? (microgravity) (2)
- Greater atrophy in antigravity muscles
- Greater atrophy in fast twitch fibres
What are some circumstances that may induce disuse adaptations? (5)
- Sedentary behaviour
- Immobilisation of body segments
- Bed rest
- Ageing
- Denervation
What is the cause of muscle cramps?
- Triggered by nerve activity
- Not fully known
What makes muscles more susceptible to cramps and what is a strategy to overcome that?
- Water intake after dehydration makes muscles more susceptible to cramps; ? dilution of electrolytes
- Can be managed with intake of electrolytes
What factors put someone at greater risk of muscle cramps? (6)
- Fatigue
- Dehydration/electrolyte imbalance
- Reduced blood flow
- Hypothyroidism
- Pregnancy
- Genetics
What position are muscles in to cramp?
Shortened position
What is the acute treatment for muscle cramps?
- Stretch muscle (put in lengthened position)
- Increase blood flow (heat or massage)
What does ETAP stand for? (Stitch)
Exercise-induced Transient Abdominal Pain
What are signs and symptoms of ETAP?
- Somatic pain (not visceral)
- Area of sensation
- Referred pain to shoulder tip
- Aggravated by GIT loading
- Exercise may alter lymphatic flow influencing peritoneal fluid content
Characteristics of ETAP are consistent with…?
…irritation of parietal perineum
What are some ways to prevent ETAP? (4)
- Don’t eat or drink shortly before exercise if prone to ETAP
- Limit fluid intake volume during exercise
- Consider tonicity of fluids
- Age - decreases with age
What is the role of cool down? (3)
- Prevent sudden decrease in venous return
- Provide good blood flow for reduction/removal of muscle metabolites
- Provide some restoration of muscle energy stores
What are some recovery strategies? (11)
- Passive rest
- Active recovery
- Stretching
- Myofascial release
- Electrostimulation
- Compression garments
- Immersion
- Contrast water therapy
- Cryotherapy
- Hyperbaric therapy
- Nutrition
What are neuromuscular goals of training? (3)
- Enhance musculoskeletal health
- Improve sports performance
- Change body aesthetics
What are the benefits of good muscular health? (4)
- Have the right muscle mass for functional activities
- Have the right muscle mass for metabolic health
- To countermeasure muscle atrophy and weakness
- To enhance muscle metabolism
What can be improved to increase overall muscle performance? (6)
- Strength
- Muscle endurance
- Muscle power
- Flexibility
- Posture
- Running/movement efficiency
What factors affect someones neuromuscular adaptations from exercise training? (3)
- Initial fitness level
- Genes
- Training program characteristics
What are some resistance training equipment? (5)
- Free weights/barbells
- Pulley systems
- Isokinetic devices
- Resistance bands
- Body weight
What is the typical strength increase with resistance training? (%)
25-30%
What population has larger increases in strength with resistance training?
The elderly
What training program has the greatest strength increase? What is the second and third greatest?
- Most - resistance
- Modest - circuit
- Least - endurance
What key components of resistance training give the greatest strength increase? (2)
- Heavy loads
- Fewer reps
When do neural and morphological changes occur in strength training?
- Neural early in the program
- Morphological later in the program
What neural changes occur in strength training?
- Increased strength
- Dynamic strength greater increase than isometric
- Crossover effects
- Imaginary training
How do neural effects of training contribute to changes in muscle force? (3)
- Change in motor unit recruitment patterns
- Change motor unit synchronisation
- Decrease central inhibition for voluntary efforts
What is the main morphological change in strength training?
Increased muscle size = increased muscle force
a) How long of training does it take for an increase in muscle size and strength?
b) Does it eventually limit?
a) ~ 8 weeks
b) Yes. Eventually a limit to further increases
What affects the extent of muscle size changes? (3)
- Muscle group (upper limbs>lower limb)
- Selective area of muscle (different muscle loading, adaptations to specific loading)
- Fibre type (Type II fibres more capacity to change in size)
- Age (older adults can increase muscle size)
- Sex (M=F lower limb, M>F in upper limbs)
Is there more evidence of hypertrophy or hyperplasia as a result of strength training?
Hypertrophy
What does hypertrophy increase in strength training? (4)
- Size of fibres
- Myofibril size and number
- Myofibril proliferation
- Protein synthesis
How could someone improve their flexibility/lack of length in muscle? (2)
- Insertion of more sarcomeres in fusiform muscles to increase muscle length
- Training strategies such as stretching and eccentric training
What can contribute to reduced flexibility? (2)
- Ageing
- Disuse or limited use
What is the relationship between fibre myofibril content and myonuclei?
- Fibre myofibril content is proportional to myonuclei
What are myonuclei produced from?
Satellite cells which undergo mitosis
What morphological changes occur to tendons during strength training? (2)
- Tendon stiffness
- Tendon hypertrophy
Define physical fitness (WHO)
Ability to perform muscular work satisfactorily
What are the three types of physical fitness?
- Health
- Occupation
- Sport-specific
What does cardio-respiratory fitness (aerobic fitness) represent clinically?
The capacity of the body to deliver oxygen to tissues for ATP production (VO2) and remove metabolites (CO2)
What may CRF be compromised by? (2)
- CV disease
- Inability to activate skeletal muscle
What comprises musculoskeletal fitness? (4)
- Power
- Strength
- Endurance
- Flexibility
What are some body composition complications that may affect CRF? (3)
- Excess fat
- Lack of muscle mass
- Low bone density
Why would you use physical fitness testing? (9)
- Assess current health status
- Monitor rehabilitation
- Assess for sports needs
- Assess fitness for work or employment
- Identify strengths and weaknesses
- Assist in setting training goals
- Influence training program design
- Provide motivation for exercise
- Monitor training program effects
What are the four requirements for good fitness testing?
- Specificity
- Validity
- Objectivity
- Reliability
What are some considerations when doing fitness testing? (9)
- Does it only test one thing?
- Does the participant know what to do?
- Is technical competence required?
- Is the test well standardised?
- Time of day
- Environmental conditions
- Sensitivity (changes in training and fitness)
- Nutrition and hydration
- Medications
What fitness tests are commonly used for the general population? (4)
- Submaximal CRF tests
- Strength endurance tests
- Sit and reach for flexibility
- Body composition
What fitness test types are commonly used for the sports population? (3)
- Wide variation - depending on sport
- Max strength and power tests
- Anaerobic, speed and agility
What fitness tests are commonly used for kids? (5)
- Beep test for CRF
- Strength endurance
- Sit and reach for flexibility
- Stork stand for balance
- Body composition (new)
What fitness tests are commonly used for the elderly (6)
- 6 minute walk test
- 10 metre walk speed
- Sit-to-stand
- Timed up and go
- Chair sit and reach
- Berg balance test
What are some safety factors for fitness testing?
- Genetics and medical history
- Higher risk in sedentary population
- Max effort is greater risk than submax
- High risk in environmental extremes
- Risk of injury - blisters
What can be assessed to determine muscular fitness? (6)
- Strength
- Power
- Strength endurance
- Flexibility
- Posture
- Balance
What is strength?
The maximum capacity to generate force
What is power?
The rate of performing work
What is strength endurance?
The capacity to sustain repeated submaximal muscle contractions or a single static (isometric) contraction
What are three types of strength testing? (Iso…)
- Isometrically - joint ad muscle length don’t change during contraction
- Isokinetically (isovelocity) - velocity of movement is constant but force varies
- Isotonically - tension in the muscle starts the same despite changes in muscle length
What are the two types of muscle contractions?
- Concentric - shortening
- Eccentric - lengthening
What are some considerations when assessing muscle performance?
- Muscle specific
- Joint angle specific
- Velocity dependent
- Warm up, also standardised
- Number of trials and rest intervals (usually 3 trials with 3 minutes rest in-between)
- Good to have an idea of the athlete’s performance before testing
What are advantages of isometric strength testing? (4)
- Commonly used
- Reliable
- Good indicator of max force - more in an isometric contraction than concentric
- Safe
What are limitations of isometric strength testing? (2)
- Measuring force of one angle joint only
- Poor relationship with sports performance and training effects
What are advantages of isokinetic strength testing? (4)
- Can standardise test
- Reliable at lower velocities
- Record force through full ROM
- Can compare L and R lim forces, con vs eccentric movements, agonist and antagonist muscles
What are advantages of isotonic strength testing? (1)
Good reliability with experienced people
What are limitations of isotonic strength testing? (2)
- If inexperienced subjects, difficult, less reliable, may not be able to perform the skill properly
- Safety considerations of spotters, form, good instructions
What does isometric strength testing involve?
Max effort over 3-4 seconds
e.g. cable tensiometer
What does isokinetic strength testing involve?
Person exerts a force against a lever arm which keeps velocity constant
What does isotonic strength testing involve?
Constant load, con and eccentric movement, often looking for 1RM
e.g. bench press
Power = ?
Power = (force x distance) / time
What is power testing and what are some examples?
- Short-duration explosive effort tests, indicative of anaerobic energy systems
- E.g vertical jump, standing long jump
What effect does strength endurance have on performing work?
Stronger muscles perform activities at lower percent of max capacity
What is strength-endurance testing and what are some examples?
- Ability to maintain force without fatigue
- E.g sustained isometric force - wallsit
- E.g. reps of a single action - push-ups, stand-ups
What is the difference between absolute and relative endurance tests?
Absolute - number of reps with a set load
- relative - number of rests at a set % of a person’s 1RM
What factors may affect flexibility? (8)
- Joint structure
- Length and distensibility of muscles, tendons and ligaments
- Soft tissue impediments
- PA level
- Environmental conditions
- Ability to relax muscles
- Muscle soreness and stiffness
- Pain tolerance
How to assess flexibility? (2)
- Visual - against a diagram
- Measured ROM e.g. sit and reach
What would balance tests be used for and what are some examples?
- Part of assessment for dizziness/vestibular disorders
- E.g single limb stance, stork stand, wobble board
