Chapter 7 - Human Movement Science

human movement system (HMS)

the collective components and structures that work together to move the body: muscular, skeletal, and nervous systems

kinetic chain

a concept that describes the human body as a chain of interdependent links that work together to perform movement

regional interdependence model

the concept describing the integrated functioning of multiple body systems or regions of the body

biomechanics

kinesiology

study of movement as it relates to anatomy and physiology

anatomic position

the position with the body erect, the arms at the sides, and the palms forward. It is the position of reference for anatomic nomenclature

medial

relatively closer to the midline of the body

lateral

relatively farther away from the midline or toward the outside of the body

contralateral

positioned on the opposite side of the body

ipsilateral

positioned on the same side of the body

anterior

positioned on or toward the front of the body

posterior

positioned on or toward the back of the body

proximal

positioned nearest to the center of the body or other identified reference point

distal

positioned farthest from the center of thebody or other identified reference point

inferior

positioned below an identified reference point

superior

positioned above an identified reference point

osteokinematics

movement of a limb that is visible

arthrokinematics

the description of joint surface movement; consists of three major types: roll, slide, and spin

sagittal plane

an imaginary bisector that divides the body into left and right halves

flexion

a bending movement in which the relative angle between two adjacent segments decreases

extension

a straightening movement in which the relative angle between two adjacent segments increase

hyperextension

extension of a joint beyond the normal limit or range of motion

dorsiflection

flexion occurring at the ankle

plantar flexion

extension occurring at the ankle

pointing the foot downwards

frontal plane

an imaginary bisector that divides the body into front and back halves

movement in the frontal plane includes abduction, adduction, and side-to-side motions

abduction

a movement in the frontal plane away from the midline of the body

adduction

movement in the frontal plane back toward the midline of the body

lateral flexion

bending of the spine from side to side

eversion

a movement in which the inferior calcaneus (heel bone) moves laterally

the bottom of foot faces outward

inversion

a movement in which the inferior calcaneus (heel bone) moves medially

bottom of foot faces inward

transverse plane

an imaginary bisector that divides the body into top and bottom halves

internal rotation

rotation of a body segment toward the middle of the body

external rotation

rotation of a body segment away from the middle of the body

horizontal abduction

movement of the arm or thigh in the transverse plane from an anterior position to a lateral position

horizontal adduction

movement of the arm or thigh in the transverse plane from a lateral position to an anterior position

radioulnar pronation

inward rotation of the forearm from a palm-up position to a palm-down position

radioulnar supination

Outward rotation of the forearm from a palm-down position to a palm-up position

pronation of the foot

multiplanar movement of the foot and ankle complex consisting of eversion, dorsiflexion, and ankle abduction; associated with force reduction

supination of the foot

multiplanar movement of the foot and ankle complex consisting of inversion, plantar flexion, and ankle adduction; associated with force production

gait

biomechanical motion of the lower extremities during walking, running, and sprinting

scapular retraction

adduction of scapulae; shoulder blades move toward the midline

scapular protraction

abduction of scapulae; shoulder blades move away from the midline

scapular depression

downward (inferior) motion of the scapulae

scapular elevation

upward (superior) motion of the scapulae

elasticity

the ability of soft tissues to return to resting length after being stretched

ligament

a fibrous connective tissue that connects bone to bone

flexibility

the normal extensibility of soft tissues that allows for full range of motion of a joint

hypermobility

a state where a lack of neuromuscular support leads to a joint having more range of motion than it should, greatly increasing the risk of injury at that joint

hypomobility

when range of motion at a joint is limited

eccentric muscle action

a muscle action that occurs when a muscle develops tension while lengthening

motor unit

a motor neuron and all of the muscle fibers that it innervates

concentric muscle action

a muscle action that occurs when a muscle is exerting force greater than the resistive force, resulting in a shortening of the muscle

isometric muscle action

when a muscle is exerting force equal to the force being placed on it leading to no visible change in the muscle length

core

the structures that make up the lumbo-pelvic-hip complex (LPHC), including the lumbar spine, pelvic girdle, abdomen, and hip joint

muscle action spectrum

the full range of eccentric, isometric, and concentric muscle contractions required to perform a movement

what are the three overarching types of muscle actions?

isotonic, isometric, and isokinetic

isotonic

force is produced as a muscle develops tension while visibly changing in length

eccentric or concentric

lowering and lifting phases

isokinetic

the muscle shortens at a constant speed over the full ROM

improve strength and endurance

agonists

the primary muscles providing force for a movement

synergists

muscles that assist agonists to produce a movement

stabilizers

muscles that contract isometrically to stabilize the trunk and joints as the body moves

feed-forward activation

when a muscle is automatically activated in anticipation of a movement

antagonists

muscles on the opposite side of a joint that are in direct opposition of agonist muscles

closed chain exercises

applying force into an immovable object, such as the floor, wall, or pull-up bar

ex: pull-up

open-chain exercises

ability to freely move the limbs, such as the hands and feet

ex: lat pulldown

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 balance

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

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 noncontractile component of muscle and tendon that stores elastic energy

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

joint support systems

muscular stabilization systems located in joints distal of the spine

local muscular system

generally attach on or near the vertebrae and serve the primary purpose of stabilizing the trunk of the body

composed of the *inner unit* of the core and includes the rotatores, multifidus, transversus abdominis, diaphragm, pelvic floor, and quadratus lumborum

global muscular system

comprised of larger muscles that initiate movements and tend to function across one or more joints

generally larger and act as prime movers during many functional tasks, such as pushing, pulling, squatting, and walking

deep longitudinal subsystem (DLS)

muscles of the lower leg, hamstrings, and lower back region

working together synergistically, these muscles create a contracting tension to absorb and control ground reaction forces during gait (walking, running)

posterior oblique subsystem (POS)

latissimus dorsi, thoracolumbar fascia (connective tissue of the low-back), and contralateral gluteus maximus

produce a pulling force across the thoracolumbar fascia and a stabilization force at the sacroiliac joint

anterior oblique subsystem (AOS)

muscles include the obliques, the adductor (inner) thigh muscles, and the hip external rotators

creates stability from the trunk, through the pelvis, and to the hips and contributes to rotational movement

lateral subsystem

made up of the lateral hip (gluteus medius) and medial thigh muscles (adductors) and the contralateral quadratus lumborum, all of which provide movement in the frontal plane

creating and maintaining frontal plane (side-to-side) stabilization of the LPHC during movement

rotary motion

movement of the bones around the joints

torque

a force that produces rotation; common unit of measurement is the Newton meter (Nm)

what does the term **force** refer to?

the ability of one entity to act on another entity, causing acceleration or deceleration

motor behavior

motor response to internal and external environmental stimuli

motor control

how the central nervous system integrates internal and external sensory information with previous experiences to produce a motor response

motor learning

integration of motor control processes through practice and experience, leading to a relatively permanent change in the capacity to produce skilled motor behavior

motor development

change in skilled motor behavior over time throughout the life span

muscle synergies

groups of muscles that are recruited simultaneously by the central nervous system to provide movement

mechanoreceptors

specialized structures that respond to mechanical forces (touch and pressure) within tissues and then transmit signals through sensory nerves