Newton’s 3 laws of motion
1) Law of inertia
2) Law of acceleration
3) Law of reaction
the study of the form, pattern, or sequence of movement without regard for the forces that may produce motion
kinematics
the branch of mechanics that describes the effects of forces on the body
kinetics
internal force is produced by…
e.g., the muscles
external force is produced by…
e.g., gravity’s pull on the barbell
the law that states that a body at rest will stay at rest and that a body in motion will stay in motion (with the same direction and velocity) unless acted upon by an external force
law of intertia
the law that states that the force acting on a body in a given direction is equal to the body’s mass multiplied by the body’s acceleration in that direction
law of acceleration
the law that states that every applied force is accompanied by and equal and opposite reaction force (for every action there is an equal and opposite reaction)
law of reaction
a change in an object’s position in relation to another object
motion
4 types of motion
1) rotary
2) translatory
3) curvilinear
4) general plane
motion around a joint (fixed axis point)
rotary
object in motion is not tied down and moves in a straight line
translatory
mixture of rotary and translatory motions
curvilinear
motions at various joints that are simultaneously linear and rotary
general plane
the fixed point of a lever
fulcrum
T/F: The center of a joint acts as a fulcrum for rotary motion of the body segments.
True
T/F: To lessen the resistance as fatigue occurs, move the weight closer to the working joint.
True
T/F: A longer lever arm (for motive force) and a shorter lever arm (for resistance) creates a situation where less muscular force is required to lift the same weight.
True
T/F: Longitudinal muscles allow for slow contractions but large force contractions.
False
Fast/speedy contractions but small force contractions
the 4 articulations (joints) of the shoulder joint complex
1) scapulothoracic (S/T) articulation
2) acromioclavicular (A/C) joint
3) glenohumeral (G/H) joint
4) sternoclavicular (S/C) joint
the junction of the sternum and the proximal clavicle
sternoclavicular (S/C) joint
the junction of the acromion process of the scapula with the distal clavicle
acromioclavicular (A/C) joint
the ball-and-socket joint composed of the glenoid fossa of the scapula and the humeral head
glenohumeral (G/H) joint
the muscles and fascia connecting the scapulae to the thorax
scapulothoracic (S/T) joint
the most mobile joint in the body
glenohumeral (G/H) joint
the relationship where the G/H and S/T joints work together to produce coordinated flexion and extension in the sagittal plane and abduction and adduction in the frontal plane
scapulohumeral rhythm
anterior shoulder girdle muscles
pectoralis minor and serratus anterior
The serratus anterior works as a synergist with what muscle to produce upward rotation of the scapula?
upper trapezius
posterior shoulder girdle muscles
trapezius, rhomboids, and levator scapulae
T/F: Both anterior and posterior shoulder girdle muscles have no attachment to the humerus, and their action does not directly result in glenohumeral motion.
True
the largest and most superficial of the posterior shoulder girdle muscles
trapezius
muscles (prime movers) that produce movement at the glenohumeral (G/H) joint
pectoralis major, deltoid, rotator cuff, latissimus dorsi, and teres major
the 3 sections/parts of the pectoralis major
1) clavicular
2) sternal
3) costal
the pectoralis major is a prime mover for which movements of the G/H joint
1) adduction
2) horizontal flexion
3) internal rotation
the muscle that acts as the primary abductor of the shoulder joint
deltoid
group of muscles that stabilize the G/H joint and humeral head
rotator cuff (supraspinatus, infraspinatus, teres minor, and subscapularis)
nickname for the teres major
little lat
latissimus dorsi and teres major produce these movements of the G/H joint
1) adduction
2) extension
3) internal rotation
2 obesity-related biomechanics that should be paid more attention
1) postural balance
2) walking gait
decreased muscle mass; often used to refer specifically to an age-related decline in muscle mass or lean-body tissue
sarcopenia
exercises for older individuals who may experience issues such as sarcopenia, osteoporosis, osteopenia, or have issues related to endurance, mobility, stability, and self-efficacy
1) chair-seated exercise
2) aquatic exercise
primary hip extensors (posterior hip muscles)
hamstrings (biceps femoris, semitendinosus, and semimembranosus) and the gluteus maximus
primary hip flexors (anterior hip muscles)
iliopsoas, rectus femoris, sartorius, and tensor fasciae latae
primary hip abductors
superior fibers of the gluteus maximus, gluteus medius, and gluteus minimus
primary hip external rotators (located deep to the gluteus maximus)
piriformis, superior gemellus, obturator internus, inferior gemellus, obturator externus, and quadratus femoris
primary hip adductors and internal rotators
adductor magnus, adductor longus, and adductor brevis
prime mover for knee extension when acting concentrically
rectus femoris
primary knee flexors
hamstrings (biceps femoris, semitendinosus, and semimembranosus)
primary internal rotators of the knee
semitendinosus and semimembranosus
primary external rotator of the knee
biceps femoris
responsible for initiating knee flexion and “unlocking” the knee from its extended position
popliteus
anterior leg muscles
dorsiflexors (anterior tibialis, extensor digitorum longus, extensor hallucis longus)
posterior leg muscles
plantarflexors (posterior tibialis, flexor digitorum longus, flexor hallucis longus, popliteus, soleus, gastrocnemius, and plantaris)
deep posterior compartment muscles
posterior tibialis, flexor digitorum longus, flexor hallucis longus, and popliteus
superficial posterior compartment muscles
soleus, gastrocnemius, and plantaris
lateral leg muscles (evertors)
peroneus longus and peroneus brevis
medial leg muscles (invertors)
anterior tibialis and posterior tibialis
the 2 muscles that are primarily responsible for concentric inversion (i.e., pulling the foot toward the midline in the frontal plane)
anterior tibialis and posterior tibialis
the biomechanical alignment of the individual body parts and the orientation of the body to the environment
posture
the ability to maintain the body’s position over its base of support within stability limits, both statically and dynamically
balance
abnormal posture condition which can result from psoas tightness (inflexibility) and passive hyperextension of the lumbar spine
lordosis
3 most common abnormal postures
lordosis, kyphosis, and scoliosis
excess anterior curvature of the spine that typically occurs at the low back; associated with anterior tilting of the pelvis
lordosis
excessive posterior curvature of the spine (typically seen in the thoracic region); gives the individual a “humpback” look with rounded shoulders, sunken chest, and head-forward posture with neck hyperextension
kyphosis
common abnormal posture among older adults with osteoporosis
kyphosis
decrease in the normal inward curve of the lower back with the pelvis in posterior tilt
flat-back
long outward curve of the thoracic spine with a decreased anterior lumbar curve and a backward shift of the upper trunk; accompanied by rounded shoulders, sunken chest, and forward-tilted head
sway-back
excessive lateral curvature of the spine, with the pelvis and shoulders being uneven and a posterior shifting of the rib cage on one side
scoliosis
T/F: Scoliosis is more common among men than women.
False
more common among women
