Week 3 Flashcards
Which of the following, in relation to dimensional theory, is not a factor that may contribute to a higher scaling of exponent of strength compared to height in children?
a) Recruitment of type I fibres
b) Central inhibition
c) Lower number of motor units
d) Transformation of type I to type II fibres
Lower number of motor units
When do testosterone levels accelerate in boys, increasing in muscle size and strength?
a) When they turn 8
b) Following puberty
c) Unpredictable and varies among children
d) Testosterone levels are constant throughout life
Following puberty
Which one of the following statements is false about muscle growth and strength in children?
a) Muscle strength increases as muscle mass increases
b) Girls and boys have similar muscle strength at the age of 16 years old
c) Girls and boys have similar muscle strength at the age of 8 years old
d) Muscle fibre number fixed soon after birth
Girls and boys have similar muscle strength at the age of 16 years old
According to dimensionality theory, area should relate to HEIGHT by the exponent:
a) 0.67
b) 1.0
c) 2.0
d) 1.5
2.0
When assessing the relationship between body mass and strength, Jaric et al. (2002) found the exponent for prepubescent athletes to be:
a) 0.67
b) 0.61
c) 0.63
d) 1.14
1.14
A motor unit is:
a single α-motor neuron and the muscle fibres it innervates
Nerve conduction velocity:
a) is inversely related to height
b) increases in adults as they age
c) is faster with distal segments than proximal
d) not influenced by axonal diameter
Is inversely related to height
In Dimensionality Theory, height is also used to predict an area or function of the body. In relation to the equation Y=aXb, (describing strength in relation to height) the little b = 2, therefore:
a) The line on the graph is linear and stays horizontal because the number is greater than 1
b) The slope decreases
c) The slope increases linearly
d) The slope gets steeper as height increases because ‘b’ is greater than 1
The slope gets steeper as height increases because ‘b’ is greater than 1
Does muscular strength decline and then plateau with age?
No, it plateaus and then declines
At what age does a rapid strength decline begin?
60s
a-motoneurons receive neural input from what three sources?
- efferent (descending) neuron from the brain
- afferent (sensory) neuron from the tissues
- Spinal neurons (including interneurons)
Premotor cortex function?
Coordinates sensory cues
Supplementary motor area function?
Programming the motor plan
Primary motor cortex function?
initiates and executes movement
In a study of adding and electrical pulse to a contracted muscle, what did they find?
Stimulation of motor nerves produced no additional torque in majority of elderly men and women (in smaller contractions, there was an electrical signal spike, however in maximal contractions there was no addition stimulation seen)
In the study adding electrical impulse to contracted muscles, the finding suggests that…?
Older populations remain able to utilise descending motor pathways for optimal muscle activation (descending control from the motor cortex is not the factor that reduces strength with age)
