Wk 9 - factors affecting performance, training for performance and training for specific populations Flashcards
1
Q
Name the factors which affect performance:
A
- Factors depend on the performance itself e.g. 400m v marathon
- Performance required strength and skill
- Energy demands will depend on the needs – seconds v hours and mix of anaerobic and aerobic energy sources
- Environment and/or diet can influence – heat and altitude and carbohydrate and water intake
- Psychological component
2
Q
What are the sites of central and peripheral fatigue?
A
- Fatigue – inability to maintain power output or force during repeated muscle contractions, which is reversible with rest
- Central fatigue – central nervous system
- Peripheral fatigue – neural factors, mechanical factors and energetics of contraction
- Uncertainty about exact causes of fatigue – due to difference in research methods
3
Q
What are the 4 approaches to study muscle fatigue?
A
-Muscle in vivo
-Isolated muscle
-Isolated single fiber
-Skinned fibre
4
Q
Advantages and disadvantages of muscle in vivo:
A
+ Fatigue can be central or peripheral
+ All types of fatigue can be studied
- Mixture of fibre type
- Complex activation patterns
5
Q
Advantages and disadvantages of isolated muscle
A
+ Central fatigue eliminated
+ Dissection simple
- Mixture of fibre types
- Drugs cannot be applied rapidly because of diffusion gradients
6
Q
Advantages and disadvantages of isolated single fiber
A
+ Only one fiber type present
+ Force and other changes can be unequivocally correlated
- Environment different to in vivo
- Small size makes analysis of metabolites different
7
Q
Advantages and disadvantages of skinned fiber
A
+ Precise solutions can be applied
+ Metabolic and ionic changes associated with fatigue can be studied in isolation
- Relevance to fatigue can be questionable
- May lose important intracellular constituents
8
Q
What is central fatigue?
A
- Central fatigue characterized by reductions in – motor units activated and motor unit firing frequency
- CNS arousal can alter the state of fatigue – by facilitating motor unit recruitment: increasing motivation and physical or mental diversion
- Excessive endurance training (overtraining) – reduced performance, prolonged fatigue, etc and related to brain serotonin activity (and its ratio to dopamine)
- ‘Central governor’ model (Noakes) – conscious and subconscious brain, not spinal cord or motor unit
- Other models of fatigue exist: e.g. psycho-biological model (Marcora) – fatigue is a conscious process and exercise will persist if the motivation is greater than the perceived exertion
9
Q
What are the peripheral fatigue neural factors?
A
- Neuromuscular junction – not the site of fatigue
- Sarcolemma and transverse tubules – altered muscle membrane to conduction and action potentials (inability of Na+/K+ pump to maintain action potential amplitude and frequency – can be improved by training) and an action potential block in the T-tubules (reduced sarcoplasmic reticulum Ca2+ release)
10
Q
What are the peripheral fatigue mechanical factors?
A
- Cross-bridge cycling and tension development depends on – arrangement of actin and myosin, Ca2+ binding to troponin and ATP availability
- High H+ concentration may contribute to fatigue – reduce the force per cross-bridge, reduce the force generated at a given Ca2+ concentration and inhibit Ca2+ release from SR
- End result is longer ‘relaxation time’, one sign of fatigue – due to slower cross-bridge cycling – important in fast twitch fibres
11
Q
What are peripheral fatigue energetics of contraction?
A
- Imbalance between ATP requirements and ATP generating capacity – accumulation of Pi – inhibits maximal force, reduces cross-bridge binding to actin and inhibits Ca2+ release from SR
- Rate of ATP utilization is slowed faster than rate of ATP generation – maintains ATP concentration and the cell does not run out of ATP
- Muscle fibre recruitment in increasing intensities of exercise
- Type 1 -> Type 2a -> Type 2x
- Up to 40% VO2 max type 1 fibres recruited
- Type 2a fibres recruited at 40 to 75% VO2 max
- Exercise >75% VO2 max required 2X fibres – results in increased lactate and H+ production
12
Q
What is radical production during exercise which contributes to muscle fatigue during prolonged exercise?
A
- Exercise promotes muscle free radical production – radicals are molecules with an unpaired outer orbital electron and capable of damaging proteins and lipids in muscle
- Can contribute to fatigue during exercise >30 min – damage contractile proteins (myosin and troponin) (limits the number of cross-bridges in strong binding state) and depress sodium/potassium pump activity (disruption of potassium homeostasis)
- Antioxidant supplements do not prevent fatigue – high anti oxidant does can impair muscle performance, N-acetyl-cysteine only delays exercise-induced muscle fatigue and high antioxidant doses may depress training-induced adaptations in skeletal muscle
13
Q
What is ultra-short performance?
A
- Events >10 seconds (high power events)
- Dependent on recruitment of type 2 muscle fibres – generate greater forces that are needed
- Motivation, skill and arousal are important
- Primary energy source is anaerobic – ATP-PC system and glycolysis (creatine supplementation may improve performance)
14
Q
What factors affect ultra-short events?
A
-Practice
-Skill and technique
-Muscular power
-Fiber type distribution and recruitment
15
Q
What are short term performances?
A
- Events lasting 10 to 180 seconds
- Shift from anaerobic to aerobic metabolism – 70% energy supplies anaerobically at 10 seconds and 60% supplied aerobically at 180 seconds
- Fuelled primarily by anaerobic glycolysis – results in elevated lactate and H+ levels (interferes with Ca2+ binding with troponin and interferes with glycolytic ATP production)
- Ingestion of buffers may improve performance
16
Q
What are moderate-duration performances?
A
- Events lasting 3 to 20 minutes – 60% ATP generated aerobically at 3 minutes and 90% ATP supplied aerobically at 20 minutes
- A high VO2 max is advantageous – high maximal stroke volume and high arterial oxygen content (hemoglobin content and inspired oxygen)
- Requires energy expenditure near VO2 max – type 2x fibres recruited and high levels of lactate and H+ accumulation
17
Q
What factors affect moderate duration performances?
A
-Fiber type
-Genetics
-Mitochondrial and capillary density
-Training
18
Q
What are immediate duration performances?
A
- Events lasting 21 to 60 minutes
- Predominantly aerobic – usually conducted at <90% VO2 max and high VO2 max is important
- Other important factors – running economy or exercise efficiency, environmental factors, state of hydration and lactate threshold
19
Q
What factors affect immediate-duration performances?
A
-Bioenergetics
-Biomechanics
-Running economy
-Steady state VO2
20
Q
What are long term performances?
A
- Events lasting 1 to 4 hours
- Environmental factors more important
- Maintaining rate of carbohydrate utilization – muscle and liver glycogen stores decline, ingestion of carbohydrate (maintain carbohydrate oxidation by the muscle)
- Consumption of fluids and electrolytes
- Diet also influences performance
21
Q
What factors affect long term performance?
A
-Heat load
-Dehydration
-% of VO2 max
-Liver and muscle glycogen stores
-% of type 1 fibers
22
Q
What factors influence ultra-endurance events?
A
- VO2 max
- % of VO2 max that can be sustained
- Metabolic responses – marked increases in fat oxidation which is consistent with exercise at <60% VO2 max and ~50% reduction in muscle glycogen stores
- Potential for hyponatremia – only affects 4% of athletes
- Non-physiological factors can affect performance as well – e.g. foot management
23
Q
What are training principles?
A
Training program should match the anaerobic and aerobic demands of the sport
24
Q
Describe the training principles:
A
- Specificity – specific muscles involved and specific energy systems that are utilized
- Overload – increased capacity of a system in response to training above the level to which is it accustomed. Too much leads to overtraining and overreaching.
- Rest – important to manage recovery time to optimise adaptive response and avoid overtraining
- Reversibility – training effect quickly lost
-Different sports require different contributions of aerobic and anaerobic energy systems
25
Describe the influence of sex and initial fitness level:
* Males and females respond similarly to training programs – exercise prescriptions should be individualized for all (most studies involve 70kg men and so data cannot be generalised)
* Training improvement is always greater in individuals with lower initial fitness -> 50% increase in VO2 max in sedentary adults. 10-20% improvement in normal, active subjects. 3-5% improvement in trained athletes.
26
What influence do genetics have?
* Genetics plays an important role in how an individual responds to training
* Anaerobic capacity is more genetically determined than aerobic capacity – training can only improve anaerobic performance to a small degree – dependent largely on fast fibres
* Three key elements contribute to aerobic performance – a high VO2 max, superior exercise economy/ efficiency and a high lactate threshold and critical power. (genetics are important in determining VO2 max)
27
What are the influences of genetics on training-induced changes in VO2 max?
- Low responders -> Possess a relatively low untrained VO2 max. Often exhibit limited exercise training response, as VO2 max improves by 5% or less
- High responders -> Individuals with the ideal genetic makeup required for champion endurance athletes. Possess a relatively high trained VO2 max. Often increase VO2 max by 50% with training.
28
Describe a warm up, workout and cool down:
-Warm up -> increased CO and blood flow to skeletal muscle, increases muscle temperature and enzyme activity and can reduce risk of exercise-induced muscle injury
-Workout -> Training session (aerobic power, anaerobic power or muscular strength)
-Cool-down -> return blood ‘pooled’ in muscles to central circulation
29
How do you train to improve aerobic power?
Three primary training methods – interval training, long slow distance and high-intensity continuous exercise. Training is designed to improve: VO2 max, lactate threshold and running economy.
30
What are the laboratory tests used to quantity endurance exercise potential?
-> VO2 max training approaches are founded on a few key laboratory tests:
1. Lactate threshold – incremental intensity test with blood samples for lactate and ‘breakpoint’ for lactate accumulation identified
2. Ventilatory threshold – ventilatory response to incremental work produces increased slope – ventilatory ‘breakpoint’ identified
3. Critical power – a submaximal power output that can be maintained for indefinite periods
4. Exercise economy – metabolic and mechanical factors influencing movement economy
31
What is the measurement of peak running velocity for improved performance?
* Peak running velocity – highest speed that can be maintained for 5+ seconds, 60 seconds etc
* Peak running velocity is inversely correlated to endurance race finish times – running velocity in training accounts for 40% to 80% of race performance improvements (40% marathon and 80% shorter distances e.g. 5km)
32
Describe interval training (HIIT)?
-> Originally popularised 70+ years ago. HIIT characterized by: repeated high intensity exercise bouts, separated by brief recovery periods, work interval, rest interval, set and repetitions. Training outcomes of HIIT – improved VO2 max, running economy, and lactate threshold better than low-intensity intervals. As little as 30s of HIIT exercise promotes adaptations e.g. increases mitochondria volume.
33
Describe long, slow distance:
-> Low-intensity exercise (50-65% VO2 max or 6-70% HRmax. Training duration is greater than event or competition duration. Training improvement are based on volume of training. Targets the aerobic base, however short term intensity training is better for improving VO2 max.
34
Describe high intensity, continuous exercise:
-> Excellent method of increasing VO2 max and lactate threshold. High-intensity exercise (at or slightly above lactate threshold and 80-100% VO2 max for most athletes). Monitor intensity using HR.
35
Draw the HR intensity zones for training:
-Found in training for performance notes
36
What are injuries and over training?
* Most injuries are a result of overtraining – short term, high intensity exercise and prolonged, low intensity exercise
* The 10% rule for increasing training load – increase intensity or duration <10% per week
* Other injury factors – strength and flexibility balance, footwear problems, malalignment, poor running surface and disease (arthritis)
37
How do you train to improve anaerobic power?
* ATP-PC system – short (5-10 seconds), high intensity work intervals. 30 to 60 second rest interval – little lactic acid is produced, so recovery is rapid
* Glycolytic system - short (20-60 seconds), high intensity work intervals. May deplete muscle glycogen levels
38
Describe strength training:
-Types of strength training exercises -> isometric or static (application of force without joint movement), dynamic (includes variable resistance exercise) and isokinetic (exertion of force at constant speed)
-Strength training adaptations -> increase muscle force production and increased muscle mass (hypertrophy and hyperplasia)
39
What is the basis for most resistance training programmes?
-Intensity -> based on % of 1-RM
-Volume -> number of repetitions and number of sets
40
What is strength and power?
-Strength -> ability to exert force in order to overcoming resistance
-Power -> ability to exert force with respect to time i.e. rate at which force can be applied
41
What are the general strength training principles?
* Improvements in strength via progressive overload – periodically increasing resistance (weight lifted) to continue to overload the muscle
* Intensity – 8 to 12 RM
* Number of sets for maximal strength gains – 2+ sets result in greater strength gains and hypertrophy. >10 sets not recommended for optimal strength gains
* Frequency – 2-4 days per week to incorporate rest days. 4-6 days per week if using ‘split’ routines
* Specificity – should involve muscles used in competition and speed of muscle shortening similar to speeds used in events
42
Draw the resistance training guidelines for strength gains and muscular endurance
-Notes in training for performance
43
What are the sex differences in response to strength training?
* Untrained males have greater absolute strength than untrained females – upper body 50% stronger and lower body 30% stronger
* Strength/ cross sectional area of muscle is similar between males and females – 3-4kg of force per cm2 of muscle in both
* There are no sex differences in response to short-term strength training – however, men exhibit greater hypertrophy as a result of long term training due to higher testosterone levels
44
Describe combining strength and endurance training programmes:
-> Combined strength and endurance training may limit strength gains vs strength training alone – depends on:
* Training state of individual
* Volume and frequency of training
* Way the two methods are integrated
Suggested recommendations – perform strength and endurance training on alternate days to optimal strength gains and athletes who’s sport requires maximal strength should avoid concurrent training
45
Describe protein availability and muscle protein synthesis:
Ingesting protein increases rate of protein synthesis post-training. Important for both endurance and resistance training and need to plan protein intake around workouts (both protein amount and timing (and type))
46
What is supplementation with mega doses of antioxidants:
Antioxidant supplements may prevent damage and fatigue induced from free radical production. However, high doses of antioxidants may block training adaptations. Free radicals activate signalling involved in muscle adaptation to training.
47
Describe DOMS:
* Appears 24 to 48 hours after strenuous exercise
* Due to microscopic tears in muscle fibres or connective tissue – results in cellular degradation and inflammatory response (not due to lactic acid)
* Eccentric exercise causes more damage that concentric exercise
* Slowly begin a specific exercise over 5 to 10 training sessions to avoid DOMS
* Common treatments include: RICE along with nonsteroidal anti-inflammatory drugs
48
How to train to improve flexibility:
-Stretching exercise improve flexibility
-Static stretching -> continuously holding a stretch position for 10 to 60 seconds, repeat each stretch 3 to 5 times
-Dynamic stretching -> ballistic stretching movements
-Proprioceptive neuromuscular facilitation (PNF) -> preceding a static stretch with isometric contraction of muscle being stretched and requires a training partner
49
What is tapering?
-> Is the short term reduction in training load prior to competition. Improves performance in both strength and endurance events. Allows muscle to resynthesize glycogen and heal from training-induced damage.
50
What is training periodisation?
* Macrocycle – entire season/ year
* Mesocycle – 2-6 weeks – target specific training goals
* Microcycle - ~7 days – a focus block of training
51
Why is planning for peak performance during the year crucial?
* Structure training across the year to target difference performance demands
* Timing to develop aspects of endurance, strength, speed and skills will need to be different/ focused
52
What are common training mistakes?
-Overtraining -> Workouts that are too long or too strenuous. Greater problem that undertraining.
-Undertraining
-Performing non-specific exercises -> Do not enhance energy capacities used in competition
-A lack of a long-term training plan -> Misuse of training time
-Failure to taper before a performance -> Inadequate rest; compromises performance
52
What are symptoms of overtraining?
-Decrease in performance
-Loss of body weight
-Chronic fatigue
-Increased number of infections
-Psychological stress
53
Describe females in sport:
-Females’ responses to training are similar to males -> Thermoregulation impaired during luteal phase of menstrual cycle
-Key concerns for female athletes -> Exercise and the menstrual cycle, eating disorders and bone mineral density
53
What are menstrual disorders with exercise?
* ‘Athletic’ amenorrhea – Cessation of menstruation, due to disruptions in the normal hormonal signalling process between the hypothalamus and the pituitary gland
* Incidence – 12-69% of female athletes versus 3% in the general population
* Causes – Amount of training (i.e. overtraining), increased psychological stress and low energy availability (increased energy expenditure and/or restricted nutrient intake)
-Follicular phase -> Peak in oestrogen at the end of the stage
54
Describe training and menstruation?
How these phases of the 28-day menstrual cycle, and the associated hormonal fluctuation, impact exercise adaptations are not fully understood. Little reason to avoid training or competition during menstruation. Dysmenorrhea is prevalent in athletes – painful menstruation due to prostaglandins, which are releases prior to the onset of menstrual flow and causes smooth muscle in the uterus to contract, causing ischemia (reduced blood flow)
54
Describe anorexia nervosa:
-Extreme steps to reduce body weight
-Techniques -> starvation, excessive exercise and laxative use
-Effects -> excessive weight loss, amenorrhea, death
-Treatment -> psychological counselling and nutritional guidance
-Warning signs -> rapid weight loss and excessive exercise
55
Describe bulimia:
-Pattern of overeating followed by vomiting
-Effects -> damage to teeth and esophagus due to vomiting of stomach acids
-Treatment -> requires professional support
-Warning signs -> noticeable weight loss and depressive moods
56
Describe osteoporosis as a female athlete bone mineral disorder:
-> Osteoporosis – loss of bone mineral content. Major causes – estrogen deficiency due to amenorrhea and inadequate calcium intake due to eating disorders. While training has been shown to reduce the rate of bone loss, exercise cannot completely reverse the process. Population at risk – females in the military due to rationing of food but lots of exercise done.
57
What is the female athlete triad?
Is a medical problem commonly observed in physically active young girls and women. Now commonly referred to as relative energy deficiency in sport (RED-S) – captures additional complexity – male athletes can also be affected and it impacts other physiological functions (e.g. immunity, metabolism and CV health). Associated with serious health consequences – amenorrhea and osteoporosis. The cause is low energy intake – leads to health problems due to lack of energy required for maintaining cellular homeostasis.
58
Describe competitive training for people with diabetes:
-People with type 1 diabetics can train vigorously provided they -> Are free from diabetic/ medical complications and can obtain the same benefits as nondiabetics
-Safe participation involved avoiding hypoglycaemia -> Combination of exercise, diet, and insulin for optimal blood glucose control. Have carbohydrate snack or drink available during exercise
-Insulin injection site -> Should be away from working muscle to prevent increased rate of uptake and hypoglycaemia
59
Describe sarcopenia as an age related change in skeletal muscle:
Sarcopenia – age-related loss of muscle mass. Due to – decrease in muscle fibre size and number of fibres (responsible for majority of loss of muscle mass). Contributing factors – inactivity, oxidative stress to muscle fibres, inflammation and decrease in anabolic hormones such as testosterone. Exercise can reduce this loss – resistance training is most effective, and some activity is better than no exercise.
60
When does endurance performance decline?
After 60
61
What are mechanisms for age-related decline in endurance exercise performance?
Age-related decay in maximal oxygen extraction is due to a decrease in capillary density and mitochondrial volume. Ageing depresses the spontaneous electrical activity of the SA node and reduced chronotropic responsiveness
62
What are the training guidelines for masters athletes?
* Medical clearance must be obtained – Physical exam and exercise stress test
* Training principles similar to young athletes – Be aware of overtraining symptoms e.g. excessive feeling of fatigue at rets, reduced ability to perform a workout, higher resting HR and disrupted sleep
* Training program should be individualized – Considering age, training status and competitive schedules
* Avoid overuse injuries – Rest days between challenging workouts
63
What are the medical issues with affect para-athletes and the consequences of neurological injury?
* Neurogenic bladder – Predisposed to UTI due to incomplete voiding, elevated intravesical pressures, and/or catheter use. UTIs are frequent and can cause pain, fever, increased muscle spasticity and autonomic dysreflexia. At London 2012 Paralympic Games, this illness affected 8.5% of athletes
* Neurogenic bowel – Regular and time-consuming bowel programmes. Fear of bowel accidents. Difficulty with bowel evacuation might have a negative impact on athletes preparation for competition.
* (Autonomic dysfunctions and exercise) Diminished supra-spinal sympathetic control to the heart and blood vessels – ‘CV blunting’; HR peak <130bpm. Decreased circulating catecholamines and cardiac contractility. Low BP. Orthostatic and post-exercise hypotension. Impaired blood flow redistribution. Reduced capacity of the venous muscle pump. Restricted SV. Premature fatigue and low aerobic capacity.
* Autonomic dysreflexia – Symptoms include: pounding headache, blurred vision, facial flushing, nasal congestion or stuffiness.
* Autonomic dysreflexia (boosting) – Boosting (purposeful triggering of AD) can result in performance benefits of approximately 7-10%, which are substantial in elite sporting competitions. Banned by the IP. If athletes susceptible to AD have a systolic blood pressure >160mmHG, they are disqualified.
64
What is thermoregulatory impairment in athletes with a spinal cord injury?
-> A spinal cord injury (SCI) can result in: no sweating response, decreased sweating response and decreased blood flow control. The core temperature of athletes with tetraplegia rises rapidly during exercise (in a 19-20C environment) causing an overheating risk and potential performance decrements. Practical solutions – ice vest before exercise and water sprays during breaks in play.
65
What are other para-athlete considerations?
Athletes with SCI experience osteoporosis below the neurological level of injury, ultimately leading to an increased risk of fractures. Calcium supplements or functional electrical stimulation. Skin breakdown and pressure sores are significant problems for athletes with sensory loss.
66
What is cerebral palsy?
-Disorders of speech, hearing and vision which affect communication
-Increased muscle tone, decreased range of motion and altering patterns of normal joint alignment
-Botox can be used to manage spasticity
67
What are amputees?
-The residual limb and prosthetic device form an interface with unique biochemical loads
-Overuse injuries to the contralateral limbs
-Skin breakdown over the distal residual limb at the prosthetic interface
