# Ace Essentials of Exercise Science - Chapter 3

## 53 terms

### Define kinesiology

Study of human movement from biological and physical science perspectives

### Define biomechanics

Application of mechanics to living organisms (mainly humans)

### Define kinematics

Study of form, pattern and sequence of movement without force

### Define kinetics

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

Sagital 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.

Psoas

Rectus femoris

### 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?

Scapulothoracic articulation

### What is scapulohumeral rhythm?

The glenohumeral joint and scapulothoracic articulation working together through sagittal plane and frontal plane

Retraction

### 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?

Plyometric pushups

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

Lordosis

### Which muscle groups of the core are activated to stabilize the core prior to any limb movements?

The multifidi and transverse abdominis