Movement Science Unit 6 Flashcards
What is Muscle Tension?
The force produced when a contracting muscle acts on an object
- Internal force
What is Load?
The force exerted on the muscle by the object
- External force
(Maximum amount of weight that a person can possible lift for one rep)
(The max. amount of force that can be generated in one maximal contraction)
What is contraction?
The tension-producing process of the contractile elements within the muscle
- Isotonic, Isokinetic, and Isometric
What is Task Specific Muscle Strength?
The ability of a muscle or group of muscles to produce force enough to overcome or counteract on external resistance
How can muscle force be generated and measured?
Muscle force can be generated and measured only at certain perameters:
- Muscular force exerted to move a heavy object
- Force measured by a dynamometer
- Motor task, such as throwing, lifting, jumping
What is Maximal Strength?
The maximal amount of force a muscle or muscle group can generate in a specific movement pattern
- 1 Rep max (1RM) is the purest representation of maximum strength in context of specific task of movement pattern
What are some factors that affect Muscular Strength?
(3)
- Motor Performance Factors
- Biomechanical Factors
- Psychological Factors
What are mechanical factors/Relationships that influence muscle contraction? (4)
- Length-Tension-Angle Relationship
- Force-Velocity Relationship
- Elasticity-Force Relationship
- Physical attributes of the muscle
Describe the Force-Velocity Relationship.
During Negative Velocity (Eccentric) if there is a heavy load there will be more force and faster speed. If there is a lighter load, there will be less force and slower speed.
During Positive Velocity (Concentric) if there is a heavy load there will be more force and slower speed. If there is a lighter load, there will be less force and faster speed
What is Muscle Architecture?
When the organization of muscle shape affects force generation
- Force vector parallel with tendon
- Force vector of muscle fiber
- Angle of pennation
What is torque?
Force applied by the muscles through a moment arm of a given length, at a given angle to the joint.
- Attachment point of a tendon affects ability to generate torque
What is Moment Arm?
The perpendicular distance between the line of action of the muscle force and the joint center of rotation
What is the difference between Muscle size and Muscle Strength?
- Muscle size is an attribute
- Muscle size is a demonstration of performance
–Strength can be demonstrated without increase in size
–Gains in strength are disproportional to hypertrophy
–Effect of hypertrophy is greater when controlling for other factors
When activating muscle via the nervous system, what is the difference between Recruitment and Rate Coding?
Recruitment:
- The number of fiber involved in a muscle action
- Level of muscle force
- Rate of force development
Rate Coding:
- The frequency at which motor units are stimulated
- Increases with increasing muscular effort until a maximum rate is reached
What are factors of Movement Performance? (4)
- Technique: Movement strategy
- Motor Learning: Skill acquisition, and Practice
- Feedback: Coaching, and Cueing
- Experience: Environmental factors
What are some Physiological Factors that affect muscular strength and performance? (4)
- Arousal
- Motivation
- Pain avoidance apprehension
- Experience confidence
What are Primary Mechanism of Muscle Growth? (3)
- Mechanical Tension
- Metabolic Stress
- Muscle Damage
What is Mechanotransduction?
The process by which the body converts mechanical loading into cellular response, this promotes structural change.
What is Mechanical Tension?
The type of force that tries to stretch a material
- Mechanoreceptors are sensitive to both the magnitude and the duration of loading
- The primary driving force in the hypertrophic response to resistance training
What is Metabolic Stress? What does it promote?
Metabolic stress is associated with resistive training, promotes increase in muscle protein accretion.
- Maximized during exercise that relies heavily on anaerobic glycolysis for energy production
What is Muscle Damage/EIMD?
Which contraction promotes damage the most?
Exercise Induced Muscle Damage (EIMD) occurs with resistive exercise
- Mechanical damage to muscle proteins stimulates a repair response in the body.
- Excessive damage is clearly negative for muscle growth
- Eccentric muscle contractions thought to promote damage more than any other exercise
What are some examples of Mechanical Tension?
- Progressive overload
- Higher load
- Higher intensity
- Force-Velocity curve
What are some examples of Muscle Damage?
- Eccentrics
- Increased ROM
- Novel exercises or training routines
How long does muscle adaptation take?
- Neural adaptations from resistance exercise can happen after just one bout of Resistance Exercise
-Although changes in muscle cross-sectional area (CSA) has been reported as early as 3 weeks after resistance training, it is likely that these early changes largely affect muscle swelling due to muscle damage and inflammation. - More permanent changes in muscle CGA is observed >8 weeks of resistance training
What are some examples of Metabolic Stress? (4)
- Higher repetitions
- Shorter rest intervals
- Going to failure/fatigue
- BFR Training
How long does muscle detraining take?
(Short term, Long periods)
- Short term detraining (2 weeks) results in loss of Fast Twitch fibers first
- Longer periods of detraining (12 weeks) have been associated with a significant decrease in cross-sectional area of both fast twitch and slow twitch muscle fibers
Describe Type 1 Muscle Fiber?
(Metabolic name, Size of motor neuron, myoglobin content, glycogen stores, force production)
Metabolic name: Slow Oxidative
Size of Motor Neuron: Small
Myoglobin Content: Low
Glycogen Stores: Low
Force Production: Low
Describe Type 2A Muscle Fiber?
(Metabolic name, Size of motor neuron, myoglobin content, glycogen stores, force production)
Metabolic Name: Fast Oxidative/Glycolytic
Size of Motor Neuron: Medium
Myoglobin Content: High
Glycogen Stores: High
Force Production: Moderate
Describe Type 2X Muscle Fiber?
(Metabolic name, Size of motor neuron, myoglobin content, glycogen stores, force production)
Metabolic Name: Fast Glycolytic
Size of Motor Neuron: Large
Myoglobin Content: High
Glycogen Stores: High
Force Production: High
What is the equation of Force?
Force = Mass x Acceleration
What is the equation of Work?
Work = Force x Distance
What is the equation of Power?
Power = Work / Time
What is Isotonic muscle fiber/motor unit?
Constant force production: shortening, or lengthening
What is the intact muscles in humans in Isotonic muscle fiber/motor unit?
Dynamic Concentric: Muscle force varies as muscle shortens to accommodate change in muscle length and/or joint angles as limb moves through ROM while moving a constant external load.
OR
Dynamic Eccentric: Same as above except muscle lengthens
What is the external work in intact muscle in humans in Isotonic muscle fiber/motor unit?
Positive: External Load can be overcome
OR
Negative: External load assist lengthening