Chapter 6 Flashcards
Define: muscular strength; how many reps should you do when training to improve your 1 rep max?
- greatest amount of force that a muscle or muscle group can produce a single maximal effort
- 1-6
Define: muscular endurance; how many reps should you do when training to improve your muscular endurance?
- ability of a muscle group to perform repeated contractions against a sub-maximal load for an extended period of time
- always greater than 10 reps
Define: muscular power
- ability to produce force quickly. Force x velocity (speed of contraction)
True or false: back squats are good for power (explain reasoning)
- false; you are decelerating for 1/3 of the movement
Explain the importance of your power to weight ratio; What is the magic power/weight ratio required to win the Tour de France?
- in sports sometimes relative power is more important than absolute (example: Tour de France! You need to generate a lot of power while also maintaining low body fat so you’re carrying less load)
- The 2012 winner for Tour De France gained 25s for a given power output on a 30 minute climb for every 1kg in weight he lost (just for reference I don’t think we need to memorize)
- 6.7 W/kg
Looking at table 6.1, can you understand the main characteristics of muscle fibre types?
- see google doc
Briefly differentiate between type 1, type 2a, and type 2X muscle fibres
- type 1: slow twitch fibres recruited in low intensity exercise
- type 2a: fast twitch oxidative fibres involved in moderate intensity exercise
- type 2b: fast twitch glycolytic fibres involved in high intensity but short exercises
explain the size principle
- states that as more force is needed, motor units are recruited in a precise order according to the magnitude of their force output, with small units being recruited first (type 1 then type 2; NOTE: type 1s don’t turn off during higher intensity exercise! they are still “on”)
What can be said about the strength of people and their motor units?
- people who are strong recruit more motor units
Look at table 6.2; Do you understand which muscle types are involved depending on the exercise?
- see google doc
Define: hypertrophy
- increase in cell size (commonly used word when referring to muscle fibres or fat cells)
Define: atrpohy
- decrease in cell size
Define: hyperplasia; when does this not occur in humans?
- increase in number of muscle fibres or fat cells (does not occur in adults!)
Define: isometric exercise; explain the disadvantages of isometric exercises (4)
- exercise where there is no change in the length of musculoteninous unit and the joint angle
DISADVANTAGES - strength is not increased THROUGHOUT the joint’s range of motion; only increased at the specific joint angle that training is performed
- isometric training does not optimally improve the ability to exert force fast (power)
- motivation is poor with isometric exercises in comparison to isotonic exercises
- this type of straining activity can greatly increase resistance to blood flow and increase arterial blood pressure; making the heart have to work very hard
Define: isotonic contraction
- type of muscular contraction where the tension/ force on the muscle is constant (moving a constant weight such as a barbell, dumbbell or body weight)
define: concentric exercises
- muscle contracts and shortens (bicep curl)
define: eccentric exercises
- muscle contracts and lengthens (lowering the arm with control after a bicep curl)
define: isokinetic
- muscle shortens/lengthens at a constant velocity
- done in a lab (hard to make velocity constant in a regular setting)
See figure 6.3; Do you understand the relationship?
- see google doc; there is a strong CORRELATION between muscle cross sectional area and strength
How important is muscle activation?
The recruitment, frequency, and synchronisation of active muscle fibres is important; some people are able to lift more because they’re simple able to recruit more existing fibre and fire them more frequently rather than actually increasing the size of their fibres.
What is the all or nothing law as it relates to motor units?
- it is not possible to fire all the fibres on a muscle by a small amount; either a muscle fibre (motor unit) is “on” and exerting maximal force, or it is “off”.
See figure 6.5; Do you understand it?
- see google doc; As the muscle is stretched to where the overlap of filaments in the sarcomere is compromised, the connective tissue and tendon will further resist stretching. Even if a sarcomere is stretched, there are protective forces that prevent the muscle from being torn apart and damaged
See figure 6.4; Do you understand it?
- see google doc; shows the force length curve for a muscle unit (aka sarcomere). The shaded area indicates the normal sarcomere length and the optimal length is the black circle.
Briefly describe the sliding filament theory. Where in figure 6.4 is there no overlap.
- The more the muscles (/filaments) overlap, the more force generated. When pulled apart, less overlap, less force generated.
- far right shows now overlap and therefore no force production
See figure 6.6; Do you understand it?
- see google doc; the faster a muscle shortens, the less force it is capable of generating
State the power equation; Where does optimal power occur? Where does maximum power occur?
- power = force x velocity
- optimal power occurs at medium forces and medium velocity
- maximum power is generated at ~1/3 the maximum force output and ~1/3 the maximal speed of shortening
See figure 6.7; Do you understand it?
- see google doc; muscle temperature is important. As deep muscle temperature increases (example: active warmup), so does the potential for a higher force output.
- saunas don’t count! best is to do an active warmup!
Give the equation for torque
- Torque = force x perpendicular distance (movement arm/ leverage)
See figure 6.9; Do you understand it?
- see google doc
Quiz yourself: If a subject can manage only 2 pushups before fatigue, this test is really a test of:
- muscular endurance
- muscular strength
- flexibility
- core stability
- none of the above
- muscular strength
Quiz yourself: Which of these is NOT a muscular contraction
- eccentric
- concentric
- isometric
- isotorque
- isokinetic
- isotorque
Quiz yourself: an eccentric contraction is where the muscle
- contracts and shortens
- contracts and stays the same length
- contracts and lengthens
- relaxes and shortens
- relaxes and lengthens
- contracts and lengthens
