Which three muscle types are found in the body?
Cardiac, skeletal, and smooth muscle.
Which muscle types are involuntary?
Cardiac and smooth muscle.
Where is cardiac muscle located?
In the walls of the heart chambers.
What is cardiac muscle’s fatigue behavior in a healthy heart?
It does not fatigue.
What do skeletal muscles attach to?
Bones.
What do skeletal muscles generate to help maintain body temperature?
Heat.
Where do smooth muscles work involuntarily?
In and around organs such as the intestines and blood vessels.
Which major skeletal muscles are named in the course?
Deltoids, biceps, triceps, wrist flexors, wrist extensors, supinators, pronators, pectorals, abdominals, obliques, quadriceps, hip flexors, tibialis anterior, erector spinae, trapezius, latissimus dorsi, gluteals, hamstrings, gastrocnemius, and soleus.
What is an agonist in a movement?
The prime mover responsible for the movement.
What can an agonist do during a controlled lowering phase?
Lengthen while controlling the movement.
What does an antagonist do relative to the agonist?
It relaxes and produces the opposite movement.
Where are antagonistic partners located relative to a joint or bone?
On opposite sides.
In an antagonistic pair, how do the muscles act to reverse movement?
They swap which muscle contracts and which relaxes.
What happens to muscle length during a concentric contraction?
The muscle shortens while generating force.
What happens to muscle length during an eccentric contraction?
The muscle lengthens while generating force.
What happens to muscle length during an isometric contraction?
The muscle remains the same length while generating force.
How are skeletal muscle fibres broadly classified?
Type I slow-twitch and Type II fast-twitch fibres.
How do Type I fibres contract and resist fatigue?
They contract slowly, produce less force, and resist fatigue.
What aerobic capacity do Type I fibres have?
High aerobic capacity.
How do Type IIa fibres compare with Type IIx in fatigue resistance?
They resist fatigue more than Type IIx fibres.
Which activities suit Type IIa fibres?
Speed, power, and strength activities.
When do acute muscular responses occur compared with chronic responses?
Acute responses occur during or immediately after one exercise session; chronic responses develop over a longer period.
How does exercise meet working muscles’ increased metabolic and oxygen-glucose demands?
By increasing blood supply to working muscles.
What can resistance-training stress cause in muscle fibres?
Microtears that produce tissue swelling and pain.
What causes muscle hypertrophy after regular overloaded resistance training?
Muscle fibres enlarge as their muscle-cell protein content increases.
How can increased mitochondrial number and size affect aerobic performance?
They improve aerobic energy production and can improve aerobic performance.
How does endurance training delay OBLA and fatigue?
It increases capillarisation, improving oxygen and nutrient delivery and waste removal.
Under the all-or-none law, what must a nerve impulse do to activate a motor unit?
It must be sufficient to activate at least one motor unit.
Under the all-or-none law, how do muscle fibres in an activated motor unit respond?
All contract, or none do.
What is age-related muscle loss called, and around what age does it begin?
Sarcopenia; it begins around age 50.
How much muscle mass can physically inactive people lose per decade after age 30?
3% to 5%.
What is a cramp?
A sudden, involuntary muscle contraction that can be painful.
What does fitness training do to cardiac muscle?
It strengthens cardiac muscle.
How does a synergist assist the agonist?
It controls direction and makes movement more efficient.
What does a fixator stabilize to prevent unwanted movement?
A joint.
At which end of a muscle is the insertion tendon located?
At the moving end.
What influences muscle-fibre proportions and efficiency?
Proportions vary among individuals and muscle groups; the mix is largely inherited, while training can affect fibre efficiency.
What is the average human muscle-fibre mix given in the course?
60% fast-twitch and 40% slow-twitch fibres.
What do exercise-related breakdown reactions of carbohydrates and fats release?
Heat.
How is heat produced during exercise related to muscular work?
It is directly related to the amount of muscular work performed.
How does warming affect muscle flexibility and susceptibility to strains?
It makes muscles more pliable and flexible, helping them stretch further and reducing strain susceptibility.
What can accumulate during high-intensity anaerobic exercise and impair muscle contraction?
Lactate, which the course associates with burning and rapid fatigue.
When does DOMS occur, how long can it last, and with whom is it associated?
It occurs 24–48 hours after strenuous exercise, can last up to three days, and is especially associated with people inexperienced with the intensity.
How does regular exercise overload affect tendons?
It strengthens tendons.
What happens to joint cartilage with regular exercise?
It becomes thicker.
What does myoglobin do with oxygen in skeletal muscle?
It binds and stores oxygen, then transports it to mitochondria.
How does increased muscle glycogen storage benefit training?
It allows training at higher intensities for longer.
How can well-trained athletes produce energy when carbohydrate becomes scarce?
They use oxygen to produce energy from fatty acids.
Which muscles are the most common site of muscle cramps?
The leg muscles, particularly the calf.
What can help prevent muscle cramps during physical activity?
Drinking plenty of fluid and stretching.
Answer 24 questions on Muscular System in Sport.
1. Which classification correctly describes voluntary control of the three muscle types?
2. Which statement describes cardiac muscle in a healthy heart?
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