Chapter 7 - Lesson 5 Flashcards
Force
An influence applied by one object to another, which results in an acceleration or deceleration of the second object.
Length-tension relationship
The resting length of a muscle and the tension the muscle can produce at this resting length.
Resting length
The length of a muscle when it is not actively contracting or being stretched.
Actin
The thin, stringlike, myofilament that acts along with myosin to produce muscular contraction.
Myosin
The thick myofilament that acts along with actin to produce muscular contraction.
Sarcomere
The structural unit of a myofibril composed of actin and myosin filaments between two Z-lines.
Muscle balanca
When all muscles surrounding a joint have optimal length-tension relationships, allowing the joint to rest in a neutral position.
Altered length-tension relationship
When a muscle’s resting length is too short or too long, reducing the amount of force it can produce.
(Muscle imbalance)
Reciprocal inhibition
When an agonist receives a signal to contract, its functional antagonist also receives an inhibitory signal allowing it to lengthen.
Altered reciprocal inhibition
Occurs when an overactive agonist muscle decreases the neural drive to its functional antagonist.
Muscle Imbalance
When muscles on each side of a joint have altered length-tension relationships.
Neutral Position
The optimal resting position of a joint that allows it to function efficiently through its entire normal range of motion.
Stretch-shortening cycle
Loading of a muscle eccentrically to prepare it for a rapid concentric contraction.
Series elastic component
Springlike non contractile component of muscle and tendon that stores elastic energy.
*Ex: getting into a squat position
Amortization phase
The transition from eccentric loading to concentric unloading during the stretch-shortening cycle.
Stretch reflex
Neurological signal from the muscle spindle that causes a muscle to contract to prevent excessive lengthening.
Integrated performance paradigm
To move with efficiency, forces must be dampened (eccentrically), stabilized (isometrically), and then accelerated (concentrically).
Tendons
A fibrous connective tissue that connects muscle to bone.
Force-couple relationship
The synergistic action of multiple muscles working together to produce movement around a joint.
Local muscular system
Local muscles generally attach on or near the vertebrae and serve the primary purpose of stabilizing the trunk of the body. The local muscular system is composed of the inner unit of the core and includes the rotatores, multifidus, transversus abdominis, diaphragm, pelvic floor, and quadratus lumborum.
Joint support systems
Muscular stabilization systems located in joints distal of the spine.
Global muscular system
The global muscular system is comprised of larger muscles that initiate movements and tend to function across one or more joints (Okubo et al., 2010). These muscles are generally larger and act as prime movers during many functional tasks, such as pushing, pulling, squatting, and walking. Because of this, the global muscular system is commonly referred to as the movement system. Examples of global muscles include the rectus abdominis, erector spinae, and latissimus dorsi.
Deep longitudinal subsystem (DLS)
Includes muscles of the lower leg, hamstrings, and lower back region
Posterior oblique subsystem (POS)
Includes latissimus dorsi, thoracolumbar fascia (connective tissue of the low-back), and contralateral gluteus maximus
Anterior oblique subsystem (AOS)
Includes obliques, the adductor (inner) thigh muscles, and the hip external rotators
Lateral subsystem (LS)
Include lateral hip (gluteus medius) and medial thigh muscles (adductors) and the contralateral quadratus lumborum, all of which provide movement in the frontal plane
First-class levers
First-class levers have the fulcrum in the middle, like a seesaw. Nodding the head is an example of a first-class lever, with the top of the spinal column as the fulcrum (Levangie et al., 2019).
Second-class levers
Second-class levers have a resistance in the middle with the fulcrum and effort on either side, similar to a load in a wheelbarrow where the axle and wheel are the fulcrum points.
Calf-raise
Second-class levers
Third-class levers have the effort placed between the resistance and the fulcrum
An example of a third-class lever is the human forearm; the fulcrum is the elbow, the effort is applied by the biceps brachii muscle, and the load is in the hand, such as a dumbbell when performing a biceps curl.
Rotary-motion
Movement of the bones around the joints.
*Example - A gymnast swinging on the rings
Torque
A force that produces rotation; common unit of measurement is the Newton meter (Nm).
An example of torque is using a wrench to loosen a bolt. The wrench serves as a lever, and torque would be a product of the force applied to the wrench and the length of the wrench’s handle.
