Study of human movement from biological and physical science perspectives
Application of mechanics to living organisms (mainly humans)
Study of form, pattern and sequence of movement without force
Branch of mechanics that describes the effects of forces on the body
Law of inertia
A body at rest will stay at rest; a body in motion will stay in motion unless acted on by an external force
Law of acceleration
Force on a body is equal to the body's mass times its acceleration
Law of reaction
For every action there is an equal and opposite reaction
What is the difference between motive and resistive forces?
A motive force causes and increase in speed or change in direction; a resistive force resists the motion of another external force; contracting muscle is motive force; gravity is resistive force
Difference between concentric and eccentric?
Concentric- muscle acts as a motive force and shortens; eccentric - muscle acts as a resistive force and lengthens as it creates tension.
Axis of rotation
Imaginary line or point about which a lever rotates
Axis of rotation for sagital plane?
Coronal or frontal plane
Axis of rotation for frontal plane?
Axis of rotation for movements in the transverse plane?
The longitudinal plane
When is a lever in balance = when does equilibrium occur?
If the force times the force arm equals the resistance times the resistance arm
Explain the third-class levers in the body
Force acts between the axis and resistance (see diagram 3-4 on page 110); this type of lever puts motive force muscles at a mechanical disadvantage, but is very conducive to force production when high velocities of motion are involved
Difference between penniform and longitudinal muscles?
Most muscles are penniform that produce higher force and have diagonal striations like a feather - quadriceps; longitudinal muscles have parallel fibers, they are long and thin; less force, but more speed of contraction; sartorial and rectus abdominus
What are co-contractors?
Agonist and antagonist muscles that contract together to provide stability, often called stabilizers
Define isometric, concentric and eccentric
Isometric - no visible movement occurs, resistance matches muscular tension; concentric - muscle shortens and overcomes resistive force; eccentric - the muscle is lengthening and producing force, or returning to its resting length
Closed-chain vs. open-chain exercise?
In closed-chain the end of the chain farthest from the body is stabilized, such as a squat; in open chain, the chain farthest is free, e.g., seated leg extension; CC exercises emphasize compression of joints to stabilize joints; OC tend to involve more shearing forces
Define the body's COG
The body's COG is the point where its mass is considered to concentrate and where it is balanced on either side of all planes; usually at the level of the second sacral vertebra
Four major hip flexors?
Iliopsoas, rectus femorus, sartorius and tensor fasciae latae.
Tightness in which muscle can result in hyperextension of the lumbar spine and lordosis?
What is the only four muscles of the quadriceps to cross the hip joint?
What are the primary hip extensors?
Hamstrings and gluteus maximus with the latter providing greatest power
What are the primary hip abductors?
Gluteus medius, minimus and maximus with assistance from the TFL (tensor fasciae latae)
What is a good stretch for hip external rotators?
Individual lies on back and pulls flexed knee and hip diagonally across the body
What two muscles serve as prime movers for inversion of the foot?
anterior and posterior tibialis
What are the primary plantar flexors?
Gastrocnemius and soleus
Difference between posture and balance?
Posture - biomechanics alignment of individual body parts and orientation of the body to the environment; balance - ability to maintain the body's position over its base of support within stability limits
What is neutral spine?
The balance of vertebrae in the three naturally occurring curves
What are the three deviations from neutral spine?
Kyphosis - excess posterior curvature of thoracic vertebrae; lordosis - excess anterior curvature of lumbar vertebrae; scoliosis - excessive lateral curvature
What exercises should be done to correct anterior pelvic tilt associated with lordosis?
Strengthen abdominal and hamstring muscles while stretching hip flexors and spine extensors
What is muscle balance?
The symmetry of the interconnected components of muscle and connective tissue
What are the three components of muscle balance?
Equal strength and flexibility on the right and left sides of the body; proportional strength ratios in opposing muscle groups; balance of flexibility
What are the three mechanisms that core muscles use to achieve trunk stability?
Intra-abdominal pressure, spinal compressive forces and hip and trunk muscle stiffness
What exercise activates the transverse abdominis?
Lying supine on floor and pulling navel toward spine
What is the formal name for the shoulder girdle?
What is scapulohumeral rhythm?
The glenohumeral joint and scapulothoracic articulation working together through sagittal plane and frontal plane
What is another name for adduction of the scapulae?
Which muscles attach the scapula to the front of the thorax?
The pectoralis minor and serratus anterior
What is one of the key functions of the serratus anterior?
To hold the medial border of the scapula against the rib cage to prevent "winging"
What are the posterior shoulder girdle muscles?
Trapezius, rhomboids and levator scapulae which attach the scapula to the posterior of the thorax
What muscles act concentrically during the push phase of the pushup?
Pectoralis major, serratus anterior and triceps brachii
What type of push-ups resulted in the highest degree of muscle activation?
Which muscles are called the "compressor" cuff because they stabilize the humeral head in the joint?
The rotator cuff
What is the main muscle action of the supraspinatus and infraspinatus?
Supraspinatus: Initiates abduction and prime mover through early abduction range of motion; Infraspinatus: synergist for external rotation of G/H joint
What is the main function of the subscapularis?
Internal rotator of the humerus
What is the main function of the latissmus dorsi?
Adduction, extension and internal rotation of the glenohumeral joint
What causes the "stooped" posture in older adults?
The vertical displacement of COG backward toward the heels
What accounts for stiffness as children grow into adolescents?
Bones growing faster than muscle; decreased flexibility in hamstrings caused by prolonged sitting in classrooms
What is the screw home mechanism?
It increases knee joint stability by locking the femur on the tibia when the knee is fully extended
What postural deviation is associated with weak abdominals and hip extensor muscles coupled with tight hip flexors and back extensors?
Which muscle groups of the core are activated to stabilize the core prior to any limb movements?
The multifidi and transverse abdominis