Chaper 7 Flashcards
What does stretching involve?
The Parallel Elastic Component (PEC)
The PEC derives from the muscle membranes and supplies resistance when the muscle is passively stretched.
What specific structures make up the Parallel Elastic Component (PEC)?
- Sarcolemma
- Epimysium
- Perimysium
- Endomysium
These structures are located in parallel with the contractile components.
What primarily contributes to the elasticity of skeletal muscle?
The Series Elastic Component (SEC)
The SEC stores energy when stretched and makes a major contribution to the elasticity of the human skeleton.
What are the major representatives of the Series Elastic Component (SEC)?
- Tendons
- Cross bridges between actin and myosin
Tendons are key in storing elastic energy.
What happens when a tensed muscle is stretched?
The SEC causes a ‘spring-like’ recoil effect
The stretch reflex initiates the development of tension.
What occurs to stored potential energy if the motion is paused?
The energy is dissipated in the form of heat
This results in a lower rebound height.
What are the characteristics of multi-articular muscles?
- Provide advantages
- Display inadequacies
They cannot shorten enough to move all of the joints simultaneously through their full ranges of motion.
Define active insufficiency.
Occurs when the muscle is already shortened by changing the joint angle
This reduces the ability to exert optimal force.
What sensation might one feel during active insufficiency?
A cramping sensation
This occurs because the muscle bunches up.
Define passive insufficiency.
Occurs when the muscle is already stretched and not able to stretch further
This is experienced during deep stretches, such as when reaching to touch toes.
What is the stretch-shortening cycle?
Muscles perform more work when they shorten immediately after being stretched than during isometric contraction
This is important in sports for maximizing performance.
What is the effect of prestretching in the stretch-shortening cycle?
It enhances muscle performance
The concentric phase must follow immediately after the countermovement, without pause.
What is reaction time?
Amount of time required for the motor cortex to address the specific alpha motor neurons
Example: In baseball, the time left for a batter to react is limited.
What is muscle architecture?
The arrangement of muscle fibers relative to the axis of force generation
This is vital in determining contractile properties.
How do sarcomeres arranged in series affect muscle velocity?
They increase the overall velocity of shortening
The velocities become additive.
What is the effect of sarcomeres arranged in parallel?
They increase the capacity for exerting force
More sarcomeres in parallel equate to greater force production.
Define specific force.
The force that can be sustained by the muscle fibers themselves
Specific force values range between 22 to 28 Newtons per sq.cm.
What is physiological cross-sectional area (PCSA)?
It is directly proportional to the maximum tetanic tension of the muscle
PCSA represents the sum of the cross-sectional areas of all muscle fibers within the muscle.
What factors affect the development of tension in muscles?
- Firing frequency
- Muscle fiber recruitment
- Synchronization of active fibers
- Relative size of the muscle
- Temperature of the muscle
- Degree of muscle fatigue
- Degree of pre-stretch
- Angle of muscle pull
Each factor can act independently or together.
What is temporal summation?
The time required for activation, contraction, and relaxation
The mechanical process of muscle contraction lags behind the process of activation.
What is the length-tension relationship?
An optimal length exists for force development, corresponding with maximum overlap of thick and thin filaments
Muscle force is greatest at approximately 120-130% of resting length.
What occurs during eccentric contractions?
The muscle is forced to lengthen due to an external load greater than it can generate
The muscle acts passively, assuming the role of resistance.
What is the force-velocity relationship?
The force generated by a muscle is a function of its velocity
Faster movements result in less ability to exert force.
What is muscle power?
The product of force and velocity
Maximal power output occurs at approximately 30% of maximal contraction force.
What does stretching involve regarding the Parallel Elastic Component (PEC)?
Stretching involves the Parallel Elastic Component (PEC) which derives from muscle membranes and supplies resistance when the muscle is passively stretched.
What specific structures make up the Parallel Elastic Component (PEC)?
The specific structures that make up the PEC include sarcolemma, epimysium, perimysium, endomysium, and sarcolemma.
What is the primary function of the Series Elastic Component (SEC)?
The primary function of the SEC is to store energy when stretched and contribute significantly to the elasticity of the human skeleton.
What are the major representatives of the Series Elastic Component (SEC)?
Tendons are the major representatives of the SEC, along with cross-bridges between actin and myosin.
What happens when a tensed muscle is stretched according to the SEC?
When a tensed muscle is stretched, the SEC causes a spring-like recoil effect and initiates the development of tension.
What energy is stored in the musculo-tendinous unit?
Potential energy is stored in the musculo-tendinous unit.
Why are tendons and ligaments considered viscoelastic structures?
Tendons and ligaments are considered viscoelastic structures because they do not behave elastically and dissipate energy as heat when motion is paused.
What occurs during active insufficiency?
Active insufficiency occurs when a muscle is already shortened by changing the joint angle, preventing it from shortening further and reducing the ability to exert optimal force.
What sensation might you feel during active insufficiency?
You may feel a cramping sensation because the muscle bunches up, representing the shortest possible length of a muscle.
What does passive insufficiency refer to?
Passive insufficiency occurs when the muscle is already stretched and cannot stretch further, often felt during deep stretches.
What is the effect of prestretching on muscle performance?
Muscles perform more work when they shorten immediately after being stretched than when in a state of isometric contraction.
What is critical for benefiting from the stretch-shortening cycle?
To benefit from the stretch-shortening cycle, the concentric phase of a movement must be performed immediately after the countermovement, with no pause.
What defines muscle architecture?
Muscle architecture is defined as the arrangement of muscle fibers relative to the axis of force generation.
How do sarcomeres arranged in series affect muscle velocity?
The number of sarcomeres arranged in series determines the velocity of shortening of the fiber; the velocities become additive and overall velocity increases.
What happens when sarcomeres are arranged in parallel?
Arranging sarcomeres in parallel increases the capacity for exerting force.
What does specific force refer to?
Specific force refers to the force that can be sustained by the muscle fibers themselves, an intrinsic property of muscle.
What is the physiological cross-sectional area (PCSA) important for?
PCSA measurements are important as they are directly proportional to the maximum tetanic tension of the muscle.
What factors affect the development of tension in muscles?
The development of tension in muscles is dependent on six factors, including firing frequency, muscle fiber recruitment, synchronization, muscle size, temperature, fatigue, pre-stretch, and the angle of muscle pull.
What is temporal summation in muscle mechanics?
Temporal summation refers to the time required for activation, contraction, and relaxation in muscles, where mechanical processes lag behind activation.
What is the relationship between length and tension in muscles?
For each muscle, there exists an optimal length for development that corresponds with the maximum overlap of thick and thin filaments.
What is the force-velocity relationship in muscle mechanics?
The force-velocity relationship indicates that the force generated by a muscle is a function of its velocity; faster movements result in less ability to exert force.
How does muscle power relate to force and velocity?
Muscle power is the product of force and velocity, with maximal power occurring at about 30% of maximal contraction force.
What does stretching involve in biomechanics?
Stretching involves the Parallel Elastic Component (PEC). The PEC derives from the muscle membranes and supplies resistance when the muscle is passively stretched.
What specific structures make up the Parallel Elastic Component (PEC)?
The specific structures that make up the PEC include sarcolemma, epimysium, perimysium, endomysium, and sarcolemma. All these structures are located in parallel with the contractile components.
What is the elasticity of skeletal muscle primarily due to?
The elasticity of skeletal muscle is primarily due to the Series Elastic Component (SEC).
What do tendons represent in the Series Elastic Component (SEC)?
Tendons are the major representatives of the series elastic component.
What happens when a tensed muscle is stretched?
When a tensed muscle is stretched, the SEC causes a ‘spring-like’ recoil effect, and the stretch reflex simultaneously initiates the development of tension.
What is stored in the musculo-tendinous unit during stretching?
Energy is stored in the form of potential energy.
What happens to the stored potential energy if the motion is paused?
If the motion is paused, the stored potential energy is dissipated in the form of heat.
What characterizes multi-articular muscles?
Multi-articular muscles provide some advantages but also display inadequacies, as they cannot shorten enough to move all of the joints simultaneously through their full ranges of motion.
What occurs during active insufficiency?
Active insufficiency occurs when the muscle is already shortened by changing the joint angle, preventing it from shortening further and reducing its ability to exert optimal force.
What is passive insufficiency?
Passive insufficiency occurs when the muscle is already stretched and is not able to stretch further, which is often felt as a deep stretch in the muscles.
What does the Stretch-Shortening Cycle involve?
The Stretch-Shortening Cycle involves numerous examples in sports and is characterized by enhanced performance when muscles shorten immediately after being stretched.
What is the relationship between the concentric phase of movement and the stretch-shortening cycle?
To benefit from the stretch-shortening cycle, the concentric phase of a movement must be performed immediately after the countermovement, with no pause.
What defines muscle architecture?
Muscle architecture refers to the arrangement of muscle fibers relative to the axis of force generation.
What happens to muscle velocity when sarcomeres are arranged in series?
The number of sarcomeres arranged in series determines the velocity of shortening of the fiber, and the velocities become additive, increasing overall velocity.
What is the importance of physiological cross-sectional area (PCSA) in muscle mechanics?
PCSA is important because it is directly proportional to the maximum tetanic tension of the muscle.
How does muscle temperature affect tension?
Greater tension is developed with increased muscle temperature.
What is the force-velocity relationship in muscle mechanics?
The force generated by a muscle is a function of its velocity, meaning that as the speed of movement increases, the ability to exert force decreases.
What is muscle power?
Muscle power is the product of force and velocity, and maximal power output occurs at approximately 30% of maximal contraction force.
What is the compromise for power in strength training?
For sports requiring high limb velocities, excessively slow, heavy repetitions are not recommended in weight training.
What is an important aspect of plyometric training?
In plyometric training, rebound must immediately follow landing.
How is muscle force increased in the short-term?
Muscle force can be increased by increasing the activation frequency of active motor units and by recruiting more motor units.
What factors affect the development of tension in muscles?
The development of tension in muscles is dependent on six factors including firing frequency, muscle fiber recruitment, synchronization of active fibers, relative muscle size, muscle temperature, and the degree of muscle fatigue.
What does stretching involve according to the lecture?
The Parallel Elastic Component (PEC), which derives from muscle membranes and supplies resistance when the muscle is passively stretched.
What specific structures make up the Parallel Elastic Component (PEC)?
Sarcolemma, epimysium, perimysium, endomysium, and sarcolemma, all located in parallel with the contractile components.
What does the elasticity of skeletal muscle primarily depend on?
The Series Elastic Component (SEC), which stores energy when stretched.
What are the major representatives of the Series Elastic Component (SEC)?
Tendons and cross bridges between actin and myosin.
What happens when a tensed muscle is stretched?
The SEC causes a spring-like recoil effect, while the stretch reflex initiates the development of tension.
What type of training is important regarding the viscoelastic structures of tendons and ligaments?
Plyometric training.
What occurs if there is a pause during a motion in relation to stored potential energy?
The stored potential energy is dissipated in the form of heat.
What is active insufficiency?
Active insufficiency occurs when the muscle is already shortened by changing the joint angle, preventing further shortening and reducing the ability to exert optimal force.
How do you experience active insufficiency?
You may feel cramping sensations because the muscle bunches up.
What is passive insufficiency?
Occurs when the muscle is already stretched and unable to stretch further.
In what situation might you feel passive insufficiency?
When reaching to touch your toes, you experience a deep stretch in the muscles.
What is the Stretch-Shortening Cycle?
It involves the benefits gained from prestretching, allowing muscles to perform more work when they shorten immediately after being stretched.
What factors influence reaction time?
The amount of time required for the motor cortex to address specific alpha motor neurons.
What was measured in the Ruler Drop Experiment related to reaction time?
The time left for the batter to activate arm and hand muscles.
What does muscle architecture determine?
It is vital in determining contractile properties.
How is muscle architecture defined?
The arrangement of muscle fibers relative to the axis of force generation.
How do sarcomeres affect muscle shortening velocity?
Sarcomeres arranged in series determine the velocity of shortening of the fiber.
How do sarcomeres arranged in parallel affect force exertion?
They increase the capacity for exerting force.
What is specific force?
The force that can be sustained by the muscle fibers themselves.
What is the current range for specific force values?
Between 22 to 28 Newtons per square centimeter.
What is the significance of Physiological Cross-Sectional Area (PCSA)?
PCSA measurements are important because they are directly proportional to the maximum tetanic tension of the muscle.
What do the factors influencing development of tension in muscles include?
Firing frequency, muscle fiber recruitment, synchronization of active fibers, muscle size, temperature, fatigue, pre-stretch, and angle of muscle pull.
What happens during temporal summation in muscle mechanics?
The time required for activation, contraction, and relaxation, resulting in higher force generation with shorter relaxation times.
What is the length-tension relationship?
For each muscle, an optimal length exists for development corresponding to maximum overlap of thick and thin filaments.
What occurs during concentric contractions?
Cross-bridge attachment increases as acto-myosin filaments connect when sliding towards the center.
How does the muscle behave during eccentric contractions?
It acts passively, assuming the role of resistance rather than the force generator.
What is the relationship between force and velocity in muscle mechanics?
The force generated by a muscle is a function of its velocity; faster movements result in less force exerted.
What does muscle power comprise?
The product of force and velocity.
At what point does maximal power output occur during muscle contraction?
At approximately 30% of maximal contraction force.
What type of training is not recommended for sports requiring high limb velocities?
Weight training with excessively slow, heavy repetitions.
What does stretching involve regarding the Parallel Elastic Component (PEC)?
Stretching involves the Parallel Elastic Component (PEC) which derives from muscle membranes and supplies resistance when the muscle is passively stretched.
What specific structures make up the Parallel Elastic Component (PEC)?
The specific structures that make up the PEC include sarcolemma, epimysium, perimysium, endomysium, and sarcolemma.
What is the primary function of the Series Elastic Component (SEC)?
The primary function of the SEC is to store energy when stretched and contribute significantly to the elasticity of the human skeleton.
What are the major representatives of the Series Elastic Component (SEC)?
Tendons are the major representatives of the SEC, along with cross-bridges between actin and myosin.
What happens when a tensed muscle is stretched according to the SEC?
When a tensed muscle is stretched, the SEC causes a spring-like recoil effect and initiates the development of tension.
What energy is stored in the musculo-tendinous unit?
Potential energy is stored in the musculo-tendinous unit.
Why are tendons and ligaments considered viscoelastic structures?
Tendons and ligaments are considered viscoelastic structures because they do not behave elastically and dissipate energy as heat when motion is paused.
What occurs during active insufficiency?
Active insufficiency occurs when a muscle is already shortened by changing the joint angle, preventing it from shortening further and reducing the ability to exert optimal force.
What sensation might you feel during active insufficiency?
You may feel a cramping sensation because the muscle bunches up, representing the shortest possible length of a muscle.
What does passive insufficiency refer to?
Passive insufficiency occurs when the muscle is already stretched and cannot stretch further, often felt during deep stretches.
What is the effect of prestretching on muscle performance?
Muscles perform more work when they shorten immediately after being stretched than when in a state of isometric contraction.
What is critical for benefiting from the stretch-shortening cycle?
To benefit from the stretch-shortening cycle, the concentric phase of a movement must be performed immediately after the countermovement, with no pause.
What defines muscle architecture?
Muscle architecture is defined as the arrangement of muscle fibers relative to the axis of force generation.
How do sarcomeres arranged in series affect muscle velocity?
The number of sarcomeres arranged in series determines the velocity of shortening of the fiber; the velocities become additive and overall velocity increases.
What happens when sarcomeres are arranged in parallel?
Arranging sarcomeres in parallel increases the capacity for exerting force.
What does specific force refer to?
Specific force refers to the force that can be sustained by the muscle fibers themselves, an intrinsic property of muscle.
What is the physiological cross-sectional area (PCSA) important for?
PCSA measurements are important as they are directly proportional to the maximum tetanic tension of the muscle.
What factors affect the development of tension in muscles?
The development of tension in muscles is dependent on six factors, including firing frequency, muscle fiber recruitment, synchronization, muscle size, temperature, fatigue, pre-stretch, and the angle of muscle pull.
What is temporal summation in muscle mechanics?
Temporal summation refers to the time required for activation, contraction, and relaxation in muscles, where mechanical processes lag behind activation.
What is the relationship between length and tension in muscles?
For each muscle, there exists an optimal length for development that corresponds with the maximum overlap of thick and thin filaments.
What is the force-velocity relationship in muscle mechanics?
The force-velocity relationship indicates that the force generated by a muscle is a function of its velocity; faster movements result in less ability to exert force.
How does muscle power relate to force and velocity?
Muscle power is the product of force and velocity, with maximal power occurring at about 30% of maximal contraction force.
What does stretching involve in biomechanics?
Stretching involves the Parallel Elastic Component (PEC). The PEC derives from the muscle membranes and supplies resistance when the muscle is passively stretched.
What specific structures make up the Parallel Elastic Component (PEC)?
The specific structures that make up the PEC include sarcolemma, epimysium, perimysium, endomysium, and sarcolemma. All these structures are located in parallel with the contractile components.
What does the elasticity of skeletal muscle primarily due to?
The elasticity of skeletal muscle is primarily due to the Series Elastic Component (SEC).
What do tendons represent in the Series Elastic Component (SEC)?
Tendons are the major representatives of the series elastic component.
What happens when a tensed muscle is stretched?
When a tensed muscle is stretched, the SEC causes a ‘spring-like’ recoil effect, and the stretch reflex simultaneously initiates the development of tension.
What is stored in the musculo-tendinous unit during stretching?
Energy is stored in the form of potential energy.
What happens to the stored potential energy if the motion is paused?
If the motion is paused, the stored potential energy is dissipated in the form of heat.
What characterizes multi-articular muscles?
Multi-articular muscles provide some advantages but also display inadequacies, as they cannot shorten enough to move all of the joints simultaneously through their full ranges of motion.
What occurs during active insufficiency?
Active insufficiency occurs when the muscle is already shortened by changing the joint angle, preventing it from shortening further and reducing its ability to exert optimal force.
What is passive insufficiency?
Passive insufficiency occurs when the muscle is already stretched and is not able to stretch further, which is often felt as a deep stretch in the muscles.
What does the Stretch-Shortening Cycle involve?
The Stretch-Shortening Cycle involves numerous examples in sports and is characterized by enhanced performance when muscles shorten immediately after being stretched.
What is the relationship between the concentric phase of movement and the stretch-shortening cycle?
To benefit from the stretch-shortening cycle, the concentric phase of a movement must be performed immediately after the countermovement, with no pause.
What defines muscle architecture?
Muscle architecture refers to the arrangement of muscle fibers relative to the axis of force generation.
What happens to muscle velocity when sarcomeres are arranged in series?
The number of sarcomeres arranged in series determines the velocity of shortening of the fiber, and the velocities become additive, increasing overall velocity.
What is the importance of physiological cross-sectional area (PCSA) in muscle mechanics?
PCSA is important because it is directly proportional to the maximum tetanic tension of the muscle.
How does muscle temperature affect tension?
Greater tension is developed with increased muscle temperature.
What is the force-velocity relationship in muscle mechanics?
The force generated by a muscle is a function of its velocity, meaning that as the speed of movement increases, the ability to exert force decreases.
What is muscle power?
Muscle power is the product of force and velocity, and maximal power output occurs at approximately 30% of maximal contraction force.
What is the compromise for power in strength training?
For sports requiring high limb velocities, excessively slow, heavy repetitions are not recommended in weight training.
What is an important aspect of plyometric training?
In plyometric training, rebound must immediately follow landing.
How is muscle force increased in the short-term?
Muscle force can be increased by increasing the activation frequency of active motor units and by recruiting more motor units.
What factors affect the development of tension in muscles?
The development of tension in muscles is dependent on six factors including firing frequency, muscle fiber recruitment, synchronization of active fibers, relative muscle size, muscle temperature, and the degree of muscle fatigue.
What does stretching involve according to the lecture?
The Parallel Elastic Component (PEC), which derives from muscle membranes and supplies resistance when the muscle is passively stretched.
What specific structures make up the Parallel Elastic Component (PEC)?
Sarcolemma, epimysium, perimysium, endomysium, and sarcolemma, all located in parallel with the contractile components.
What does the elasticity of skeletal muscle primarily depend on?
The Series Elastic Component (SEC), which stores energy when stretched.
What are the major representatives of the Series Elastic Component (SEC)?
Tendons and cross bridges between actin and myosin.
What happens when a tensed muscle is stretched?
The SEC causes a spring-like recoil effect, while the stretch reflex initiates the development of tension.
What type of training is important regarding the viscoelastic structures of tendons and ligaments?
Plyometric training.
What occurs if there is a pause during a motion in relation to stored potential energy?
The stored potential energy is dissipated in the form of heat.
What is active insufficiency?
Active insufficiency occurs when the muscle is already shortened by changing the joint angle, preventing further shortening and reducing the ability to exert optimal force.
How do you experience active insufficiency?
You may feel cramping sensations because the muscle bunches up.
What is passive insufficiency?
Occurs when the muscle is already stretched and unable to stretch further.
In what situation might you feel passive insufficiency?
When reaching to touch your toes, you experience a deep stretch in the muscles.
What is the Stretch-Shortening Cycle?
It involves the benefits gained from prestretching, allowing muscles to perform more work when they shorten immediately after being stretched.
What factors influence reaction time?
The amount of time required for the motor cortex to address specific alpha motor neurons.
What was measured in the Ruler Drop Experiment related to reaction time?
The time left for the batter to activate arm and hand muscles.
What does muscle architecture determine?
It is vital in determining contractile properties.
How is muscle architecture defined?
The arrangement of muscle fibers relative to the axis of force generation.
How do sarcomeres affect muscle shortening velocity?
Sarcomeres arranged in series determine the velocity of shortening of the fiber.
How do sarcomeres arranged in parallel affect force exertion?
They increase the capacity for exerting force.
What is specific force?
The force that can be sustained by the muscle fibers themselves.
What is the current range for specific force values?
Between 22 to 28 Newtons per square centimeter.
What is the significance of Physiological Cross-Sectional Area (PCSA)?
PCSA measurements are important because they are directly proportional to the maximum tetanic tension of the muscle.
What do the factors influencing development of tension in muscles include?
Firing frequency, muscle fiber recruitment, synchronization of active fibers, muscle size, temperature, fatigue, pre-stretch, and angle of muscle pull.
What happens during temporal summation in muscle mechanics?
The time required for activation, contraction, and relaxation, resulting in higher force generation with shorter relaxation times.
What is the length-tension relationship?
For each muscle, an optimal length exists for development corresponding to maximum overlap of thick and thin filaments.
What occurs during concentric contractions?
Cross-bridge attachment increases as acto-myosin filaments connect when sliding towards the center.
How does the muscle behave during eccentric contractions?
It acts passively, assuming the role of resistance rather than the force generator.
What is the relationship between force and velocity in muscle mechanics?
The force generated by a muscle is a function of its velocity; faster movements result in less force exerted.
What does muscle power comprise?
The product of force and velocity.
At what point does maximal power output occur during muscle contraction?
At approximately 30% of maximal contraction force.
What type of training is not recommended for sports requiring high limb velocities?
Weight training with excessively slow, heavy repetitions.
