Body composition and performance Flashcards
what is heavier - adipose tissue or muscle? Why?
Muscle - it’s denser
What are some of the limitations of height/weight tables?
- Developed from data derived primarily from white populations
- Provide no assessment of body composition
Define overweight, overfat and obese
Overweight: body weight that exceeds some average for stature, and perhaps age. Frequently accompanies increase in body fat (not always).
Overfat: when body fat exceeds an age- and/or gender-appropriate average
Obesity: the overfat condition that accompanies a constellation of comorbidities
How do you calculate BMI (body mass index)?
Weight divided by height
Give a limitation of BMI as a body measurement?
- doesn’t give any indication of body composition or body fat distribution
- doesn’t take into account differences in race/ age/ gender etc
- numerator of the BMI equation can be affected by factors other than excess body fat, such as bone, muscle mass, and increased plasma volume induced by exercise training
- certain athletes can be mistakenly classified as overweight
Explain what essential and storage fat are
- Essential fat is necessary for normal bodily functioning
- It’s found in bone marrow, in heart, lungs, liver, spleen, kidneys, intestines, muscles, and throughout central nervous system
- Storage fat accumulates in adipose tissue or between the abdominal organs
Difference between fat free mass and lean body mass?
Lean body mass is the weight of muscles, bones, ligaments, tendons and internal organs. Since there is some essential fat in the marrow of your bones and internal organs, lean body mass includes a small percentage of essential fat.
Fat free mass is weight devoid of all fat.
What percentage essential and storage fat are the standard reference woman and man?
- Reference woman: 15% storage fat and 12% essential fat (approx 27% total)
- Reference man: 12% storage fat and 3% essential fat (15% total)
Advantage and disadvantages of bioelectrical impedance body composition testing?
Ads: simple; quick; inexpensive
Dis: variability in measurement; dependence on the hydration level of the patient. can’t use with pacemaker
Advantages and disadvantages of densitometry/ hydrostatic weighing?
- More accurate than skin fold calipers or electronic devices
- For those with pacemakers, hydrostatic testing is an alternative to electrical impedance devices
- For athletes, hydrostatic testing could underestimate real body fat percentages
- have to exhale and hold very still under water multiple times
- expensive
When thinking about body composition of athletes, what can you say about fat free mass?
- Includes muscle
– more = good for power, strength, muscle endurance
– more = bad for aerobic endurance (more mass to carry)
When thinking about body composition of athletes, what can you say about relative body fat?
- Fat: dead weight but useful energy store
- Less fat usually = better performance
- Exceptions: sumo wrestler, swimmer, weightlifter
What are four key risks of severe weight loss when athletes are trying to ‘make weight’ for competition?
- Dehydration
- Chronic fatigue
- Eating disorders
- Menstrual dysfunction
What is the ‘female athlete triad’, when referring to body composition?
- Bone mineral disorders
- Eating disorders
- Menstrual disorders
What types of muscle fibres do humans have?
Type 1 (slow oxidative): slow twitch (endurance fibres) - low levels of force but good fatigue resistance
Type 2: fast twitch
2a (fast oxidative) - good levels of force and moderate fatigue resistance
2x (fast glycolitic) - highest levels of force BUT rapidly fatigued
Name 3 types of muscle?
Skeletal; cardiac; smooth (inc blood vessels)
What can you say about type 1 muscle fibres?
- ‘slow oxidative’
- fatigue resistant – they are the endurance fibres
- rich blood supply – dense, rich supply of capillaries
- more mitochondria
- contain fat droplets
What can you say about type 2 muscle fibres?
- proportionally lower supply of blood cf type 1, although in highly trained people this can change
- good at storing fat – cf the droplets in type 1, type 2 has rich supplies of glycogen
- type 2a and type 2x. 2x is very fast and very quick to fatigue. 2a expresses some high speed properties and some fatigue resistance (humans don’t have type 2b)
Are your number of type 1 and 2 fibres fixed?
No. They can convert between types depending on use. So endurance athletes might develop more type 1
What is the unit of contraction in a muscle cell?
Sarcomere
What protein filaments do sarcomeres contain?
Myosin and actin
When thinking about sarcomeres, what is the Z-line?
The boundary between successive sarcomeres
How do muscles contract?
During contraction the overlap between actin and myosin filaments increase and so sarcomere shortens
Why are we weaker at either end of ROM?
Either the filaments have maximally overlapped so muscle can’t concentrically contract any more, or the filaments are so teased apart that it is hard for them to start overlapping more
Muscles can change shape by getting longer or thicker. How does this happen (in relation to sarcomeres)?
If you do lots of stretching more sarcomeres are laid down at the tendon end so muscles get a longer resting length. Called being laid down in series. If you do lots of concentric contractions the sarcomeres will get laid down width wise or ‘in parallel’.
Is intense stretching good for warming up?
No! Intense stretching decreases blood flow – we want to increase blood flow before activity!]
What do ATP and PCr stand for?
Adenosine triphosphate and creatine phosphate
How might an endurance runner’s muscle fibre types differ from a weightlifter?
- Endurance runner will develop more slow twitch type 1. These have a richer blood supply
- Weightlifter will develop more fast twitch type 2, which will contain more glycogen for short, intense anaerobic effort
what are the standard recommendations for weight training for strength cf for hypertrophy?
- Strength = very heavy weight and very few reps
- Hypertrophy = about 8-12 reps is the classic advice, but now more modern thinking is do lots of whatever you like. Hypertrophy isn’t just about strength and neuro changes, it’s also about increased blood vessels
Explain the terms hypertrophy and hyperplasia
Growth of a muscle could result from one or both of the following:
- Fibre hypertrophy (increase in size of muscle fibres)
- Fibre hyperplasia (increase in number of muscle fibres)
Fibre hyperplasia may contribute a small proportion (5-10%) to muscle growth
Name 2 body water compartments?
intracellular and extracellular (eg sweat, plasma, tears)
Is sodium higher inside or outside cells?
Outside. Sodium has highest concentration by far of the minerals we see in our body fluids
What are proteins made of… and how many?
Proteins are made up of amino acids. Humans have 20 amino acids; we’ve named 21 but 1 of them humans don’t use
Which form of sugar can be used by all cells?
Glucose
What is the name of the aerobic mitochondrial process that allows generation of energy?
Krebs cycle
About how many calories of energy do you have stored with you?
2000 (2012 more precisely, or 503g)
KEY Where are those 2012 calories within you stored?
- Muscle glycogen 1600 kcal / 400g
- Liver glycogen 400 kcal / 100g
- Plasma glucose 12kcal / 3g
KEY how much CHO/ carbohydrate should athletes be taking on during recovery; during moderate exercise; and during intense exercise?
- During recovery 1.0-1.2g per kg per hr
- Moderate exercise 5-7g.kg-1.h-1
- Intense exercise 7-12g.kg-1.h-1
how much fluid might someone lose per hour from moderate exercise, and how much from intensive/ in heat?
- 600ml per hour for someone exercising moderately
- 2l per hour intensive and/ or in hot environment
How long could someone high intensity run using their CHO energy stores, and how long using their fat reserves?
- CHO about 1.6 hours
- fat about 120 hours
What is supercompensation?
Immediately following a training session capacity to perform may be reduced or increased degradation is evident.
The decrease may be followed by a “rebound” (recovery) above pre -training levels in the days following a training session - referred to as ‘supercompensation’
What is validity; internal validity; and external validity?
A test that measures exactly what it sets out to measure
Internal validity – can the results of the study be attributed to the study intervention?
External validity – can the results of the study be applied to the real world?
What is reliability?
Relates to consistency and repeatability. Eg Keeping factors like temperature/ humidity/ barometric pressure/ had your athlete eaten recently etc the same will increase reliability
What is periodisation and what is it for?
using a periodic shift in emphasis in your training programme to try and have athlete peak around competition time and minimise risk of injury
Why would you use periodisation?
- To allow physiological adaptations and performance improvements to occur due to appropriate periods of heavy, light and moderate training and rest
- To reduce risk of
injury, illness and negative psychological changes due to overtraining - To enable athlete to peak at
appropriate time (competition / trials etc)
What are overload and regeneration?
overload = you produce a training stimulus that makes you worse temporarily. But the recovery period produces adaptation in muscular, cardiac, respiratory etc systems.
What is negative adaptation?
Result of incorrect balance between stress and regeneration.
ie too frequent / infrequent
What are 3 types of training in periodisation terminology?
General training – concentrates on endurance, general strength and mobility
Specific training - technique, resisted movements ie. Towing, overweight implements, medicine ball
Competition training- tactics, set pieces
How do recovery and super compensation relate to each other?
Athlete needs time to recover after overload to allow for adaptations/ super compensation. Without recovery, supercompensation can be delayed or compromised
As well as Olympic or annual cycles, what other periods of time might you work with in your programming?
Macrocycle = 2-4 mesocycles.
Mesocycles = 4 weeks / microcycles.
Microcycles = days / 7 or more units.
What is fatigue?
a gradual decline on the ability of muscles’ capacity to generate force due to physical activity
Where might fatigue be? give 3
- Peripheral fatigue: decrease in the contractile strength of muscle fibres produced by changes at or distal to the neuromuscular junction
- Central fatigue
originates at the central nervous system (CNS), which decreases the neural drive to the muscle - Mental fatigue
Limits exercise tolerance through higher perception of effort
