Chapter 7: Flexibility Training Concepts Flashcards
flexibility
the normal extensibility of all soft tissues that allows the full range of motion of a joint
extensibility
capability to be elongated or stretched
dynamic range of motion
- optimal control of movement throughout a joint’s entire range of motion
- the combination of flexibility and the nervous system’s ability to control this range of motion efficiently
neuromuscular efficiency
the ability of the nervous system to recruit the correct muscles (agonists, antagonists, synergists, and stabilizers) to produce force (concentrically), reduce force (eccentrically), and dynamically stabilize (isometrically) the body’s structure in all three planes of motion
postural distortion patterns
- predictable patterns of muscle imbalances
- patterns that develop if one or more segments of the HMS are misaligned and not functioning properly
relative flexibility
- the tendency of the body to seek the path of least resistance during functional movement patterns
- aka altered movement patterns
muscle imbalance
alteration of muscle length surrounding a joint
reciprocal inhibition
- the simultaneous contraction of one muscle and the relaxation of its antagonist to allow movement to take place
- a naturally occurring phenomenon that allows movement to take place
altered reciprocal inhibition
- the concept of muscle inhibition, caused by a tight agonist, which inhibits its functional antagonist
- caused by a tight agonist muscle decreasing the neural drive to its functional antagonist
synergistic dominance
the neuromuscular phenomenon that occurs when inappropriate muscles take over the function of a weak or inhibited prime mover
arthrokinematics
the motions of joints in the body
arthrokinetic dysfunction
- altered forces at the joint that result in abnormal muscular activity and impaired neuromuscular communication at the joint
- biomechanical and neuromuscular dysfunction leading to altered joint motion
autogenic inhibition
- the process by which neural impulses that sense tension are greater than the impulses that cause muscles to contract, providing an inhibitory effect to the muscle spindles
- “autogenic” because the contracting muscle is being inhibited by its own receptors
pattern overload
consistently repeating the same pattern of motion, which may place abnormal stresses on the body
Davis’s law
states that soft tissue models along the lines of stress
static stretching
the process of passively taking a muscle to the point of tension and holding the stretch for a minimum of 30 seconds
active-isolated stretch
the process of using agonists and synergists to dynamically move the joint into a range of motion
dynamic stretch
the active extension of a muscle, using force production and momentum, to move the joint through the full available range of motion
what is range of motion dictated by?
the normal extensibility of all soft tissues surrounding it
what is an important characteristic of soft tissue?
it will only achieve efficient extensibility if optimal control of movement is maintained throughout the entire ROM
factors that can influence flexibility
- genetics
- connective tissue elasticity
- composition of tendons or skin surrounding the joint
- joint structure
- strength of opposing muscle groups
- body composition
- sex
- age
- activity level
- previous injuries or existing medical issues
- repetitive movements (pattern overload)
what must individuals have to allow for optimal neuromuscular efficiency?
- proper flexibility in all three planes of motion
- this allows for the freedom of movement needed to perform everyday activities effectively
flexibility requires ___, which requires ___, which requires _____
flexibility requires extensibility, which requires dynamic range of motion, which requires neuromuscular efficiency
flexibility training must use a ____ approach, which integrates various flexibility techniques to achieve optimal soft tissue extensibility in all planes of motion
multifaceted
agonist in a cable pulldown exercise
latissimus dorsi
what does the agonist concentrically accelerate in a cable pulldown exercise?
shoulder extension, adduction, and internal rotation
synergists in a cable pulldown exercise
middle and lowerr trapezius and rhomboids
what do the synergists do in a cable pulldown exercise?
perform downward rotation of the scapulae
stabilizers in a cable pulldown exercise
rotator cuff musculature
what do the stabilizers do in a cable pulldown exercise?
dynamically stabilize the glenohumeral (shoulder) joint throughout the motion
human movement system (HMS)
- also known as the kinetic chain
- comprises the muscular, skeletal, and nervous systems
latissimus dorsi - sagittal movement
must have proper extensibility to allow for proper shoulder flexion
latissimus dorsi - frontal movement
must have proper extensibility to allow for proper shoulder abduction
latissimus dorsi - transverse movement
must have proper extensibility to allow for proper external humerus rotation
biceps femoris - sagittal movement
must have proper extensibility to allow for proper hip flexion, knee extension
biceps femoris - frontal movement
must have proper extensibility to allow for proper hip adduction
biceps femoris - transverse movement
must have proper extensibility to allow for proper hip and and knee internal rotation
gastrocnemius - sagittal movement
must have proper extensibility to allow for proper dorsiflexion of ankle
gastrocnemius - frontal movement
must have proper extensibiltiy to allow for proper inversion of calcaneus
gastrocnemius - transverse movement
must have proper extensibility to allow for proper internal rotation of femur
muscle imbalances lead to ___, which lead to ___, which lead to ___
muscle imbalances lead to poor posture, which lead to improper movement, which lead to injury
what are postural distortion patterns represented by?
a lack of structural integrity, resulting from decreased functioning of one (or more) components of the HMS
what can a lack of structural integrity result in?
- altered length-tension relationships (altered muscle lengths)
- altered force-couple relationships (altered muscle activation)
- altered arthrokinematics (altered joint motion)
maximal neuromuscular efficiency can only exist if what?
all components (muscular, skeletal, and neural) function optimally and interdependently
what is the ultimate goal of the HMS?
to maintain homeostasis (or dynamic postural equilibrium)
what can poor flexibility lead to?
the development of relative flexibility (or altered movement patterns)
relative flexibility example in the squat
- feet externally rotated
- because most people have tight calf muscles, they lack the proper amount of dorsiflexion at the ankle to perform a squat with proper mechanics
- by widening the stance and externally rotating the feet, it is possible to decrease the amount of dorsiflexion required at the ankle to perform a squat using good technique
relative flexibility example in the overhead shoulder press
- excessive lumbar extension (arched lower back)
- individuals who possess a tight latissimus dorsi will have decreased sagittal-plane shoulder flexion (inability to life arms directly overhead), and as a result, they compensate for this lack of range of motion at the shoulder in the lumbar spine to allow them to press the load completely above their head
overactive muscle imbalances
forcing compensation to occur
underactive muscle imbalances
allowing for the compensation to occur
mechanisms that may cause muscle imbalance
- postural stress
- emotional duress
- repetitive movement
- cumulative trauma
- poor training technique
- lack of core strength
- lack of neuromuscular efficiency
muscle imbalances may be caused by or result in the following:
- altered reciprocal inhibition
- synergistic dominance
- arthrokinetic dysfunction
- overall decreased neuromuscular control
example of reciprocal inhibition in the biceps curl
to perform elbow flexion during the biceps curl, the biceps brachii actively contracts while the triceps brachii (the antagonist muscle) relaxes to allow mvoement to occur
example of altered reciprocal inhibition in the hips
a tight psoas (hip flexor) would decrease neural drive of the gluteus maximus (hip extensor)
what does altered reciprocal inhibition alter?
force-couple relationships
what does altered reciprocal inhibition produce?
synergistic dominance
what does altered reciprocal inhibition lead to the development of?
- faulty movement patterns
- poor neuromuscular control
- arthrokinetic (joint) dysfunction
example of synergistic dominance in the hips
if the psoas is tight, it leads to altered reciprocal inhibition of the gluteus maximus, which in turn results in increased force output of the synergists for hip extension (hamstring complex, adductor magnus) to compensate for the weakened gluteus maximus
result of synergistic dominance
faulty movement patterns, leading to arthrokinetic dysfunction and eventual injury (such as hamstring strains)
what can altered joint motion be caused by?
altered length-tension relationships and force-couple relationships, which affect the joint and cause poor movement efficiency
performing a squat with excessively externally rotated feet (feet turned outward) forces what to happen?
- forces the tibia (shin bone) and femur (thigh bone) to also rotate externally
- this posture alters the length-tension relationships of the muscles at the knees and hips, putting the gluteus maximus in a shortened position and decreasing its ability to generate force
- the biceps femoris (hamstring muscle) and piriformis (outer hip muscle) becomes synergistically dominant, altering the force-couple relationships and ideal joint motion, increasing the stress on the knees and low back
with time, what can happen due to arthrokinetic dysfunction?
the stress associated with it can lead to pain, which can further alter muscle recruitment and joint mechanics
neuromuscular efficiency
the ability of the neuromuscular system to properly recruit muscles to produce force (concentrically), reduce force (eccentrically), and dynamically stabilize (isometrically) the entire kinetic chain in all
three planes of motion
what helps to determine muscle balance or imbalance?
mechanoreceptors (or sensory receptors)
what do mechanoreceptors include?
the muscle spindles and Golgi tendon organs
muscle spindles
the major sensory organ of the muscle
what are muscle spindles composed of?
microscopic fibers that lie parallel to the muscle fiber
what are muscle spindles sensitive to?
- change in muscle length
- rate of length change
what is the function of the muscle spindle?
to help prevent muscles from stretching too far or too fast
what happens when a muscle on one side of a joint is lengthened (because of a shortened muscle on the opposite side)?
- the spindles of the lengthened muscle are stretched
- this information is transmitting to the brain and spinal cord, exciting the muscle spindle and causing muscle fibers of the lengthened muscle to contract
- this often results in micro muscle spasms or a feeling of tightness
example - hamstring complex when the pelvis is rotated anteriorly
- the anterior superior iliac spines move downward and the ischium moves upward
- if the attachment of the hamstring complex is moved superiorly, it increases the distance between the two attachment sites and lengthens the hamstring complex
- in this case, the hamstring complex does not need to be statically stretched because it is already in a stretched position
- when a lengthened muscle is stretched, it increases the excitement of the muscle spindles and further creates a contraction (spasm) response
- with this scenario, the shortened hip flexors are helping to create the anterior pelvic rotation that is causing the lengthening of the hamstring complex
- instead, the hip flexors need to be stretched
example - knees adduct and internally rotate during a squat exercise
- the underactive muscle is the gluteus medius (hip abductor and external rotator), and the overactive muscles include the adductors (inner thighs) and tensor fascia latae (a hip flexor and hip internal rotator)
- thus, one would not need to stretch the gluteus medius, but instead stretch the adductor complex and tensor fascia latae, which in this case are overactive, pulling the femur into excessive adduction and internal rotation