What is a sarcomere?
The smallest functional unit of striated muscle, consisting of overlapping myofibrils (actin and myosin) that are arranged between Z lines
What is the sliding filament theory?
The theory that describes the cross-bridging activity that results in gross muscle function
The cross-bridging mechanism describes what?
The process by which myosin heads bind with and slide along actin filaments to produce gross muscle action
What is muscle resting length?
The length of a muscle when in a neutral or resting state: neither shortened nor lengthened. Often synonymous with optimal length and relates to a muscle’s ability to produce force
What is the muscle length-tension relationship?
An important factor related to force generation potential in skeletal muscle: tension produced by a muscle is affected by its length. Optimal active tension occurs at optimal length or resting length
What two receptors are involved in the muscle length-tension relationship?
The muscle spindle and Golgi Tendon Apparatus (GTO)
What is neural drive?
The rate and volume of nervous system commands sent out by the brain and spinal cord that is received by our muscles
What are the two primary mechanisms by which neural drive affects muscular tension, tone and force production?
Motor unit recruitment and rate coding
A state of elevated tone brought about by increased neural drive is a muscle that is?
Overactive/shortened/hypertonic/facilitated
A state of reduced tone brought about by decreased neural drive is a muscle that is?
Underactive/lengthened/hypotonic/inhibited
What is a muscle imbalance?
A state of altered muscular tone surrounding a joint, particularly in agonist-antagonist relationships. Contributes to postural distortion and is also related to force production imbalances
What is posture?
The position of the whole body and its parts, either when stationary (static) or when moving (transitional or dynamic). Related to alignment, which refers to relationships between anatomical parts or regions
A change in posture is related to what, and not what?
Tone, and not force production
What is a force-couple relationship?
The principle whereby two or more muscles, attached to different locations around a joint, synergistically contribute to the same joint action by creating forces in opposing directions to one another. Important to understand when investigating muscle tone and posture
What is the kinetic chain in relation to muscular force?
A functional anatomy concept stating that movement in one part of the body produces forces that are transmitted to adjacent parts. Thus, movement in one area has an effect on movement in another area of the body. Injury often results in kinetic chain dysfunction
Kinetic chain function can optimize?
Force production
What are the 3 parts of optimal neuromuscular efficiency?
- Optimal length-tension relationships (muscular system)
- Optimal force-couple relationships (nervous system)
- Optimal arthrokinematics (skeletal system)
Arthrokinematics = joint motion at the articular surfaces
What is local musculature, and what is its general role?
Typically deep muscles that cross a single joint (sometimes multiple joints in the case of spinal muscles). They perform an important role in joint stabilization
Local musculature is primarily composed of what type of muscle fibre?
Type I fibres
What is global musculature, and what is its general role?
Typically superficial muscles that cross a single joint (sometimes multiple joints in the case of long limb muscles). They perform an important role in force production and movement
Global musculature is primarily composed of more of what type of muscle fibre?
Type II fibres
What muscles are part of the deep longitudinal subsystem?
Peroneus Longus, Tibialis Anterior, Biceps Femoris, and the sacrotuberous ligament
What muscles are part of the posterior oblique subsystem?
Gluteus Maximus, Latissimus Dorsi, thoracolumbar fascia, and the sacroiliac joint
What muscles are part of the anterior oblique subsystem?
Adductors and the external obliques
