Fitness Theory Chap 4: Muscular System

Question 1

What are the four rotator cuff muscles (SITS)? What is their function?

Answer 1

1. supraspinatus
2. infraspinatus
3. teres minor
4. subscapularis

support the shoulder joint by holding the head of the humerus in the glenoid cavity of the scapula

Question 2

upper trapezius

Answer 2

extends the neck and elevates the scapula (e.g. a shoulder shrug)

Question 3

sternocleoidmastoid

Answer 3

flexion of the neck (when acting together)

rotation of the head (when one side contracting)

Question 4

middle trapezius

Answer 4

retraction, adduction, elevation and upward rotation of the scapula

Question 5

rhomboids

Answer 5

retraction, adduction and downward rotation of the scapula

Question 6

lower trapezius

Answer 6

depression of scapula

Question 7

levator scapula

Answer 7

elevates the scapulae and performs lateral flexion and rotation of the spine (cervical)

Question 8

latissimus dorsi

Answer 8

extension, adduction and medial rotation of the humerus (pulls arms down from the overhead position)

Question 9

erector spinae

Answer 9

extends the spine/back

Question 10

anterior deltoid

Answer 10

flexion and horizontal adduction of the humerus

Question 11

medial deltoid

Answer 11

abduction of the humerus

Question 12

posterior deltoid

Answer 12

extension and horizontal abduction of the humerus

Question 13

deltoids (all)

Answer 13

working all together perform abduction of the humerus

Question 14

pectoralis major

Answer 14

horizontal adduction (arms across the chest)

Question 15

Describe the action of the following abdominal muscles:

rectus abdominis
obliques
transverse abdominis

Answer 15

rectus abdominis: flexion of the spine
obliques: flexion and rotation of the spine
transverse abdominis: compresses the abdominal cavity (stabilizes the spine)

Question 16

Describe the action of the following elbow and forearm muscles:

triceps
biceps
brachialis
brachioradialis

Answer 16

triceps: elbow extension
biceps: elbow flexion
brachialis: elbow flexion
brachioradialis: assists in elbow flexion (strongest when the elbow is partially flexed and semi-pronated)

Question 17

Describe the action of the following hip/knee/ankle muscles:

gluteus maximus
gluteus medius
hamstrings
quadriceps
gastrocnemius (calves)
soleus
tibialis anterior
iliopsoas (hip flexors)

Answer 17

gluteus maximus: extends the hip (during forceful extension) and laterally rotates hip
gluteus medius: abduct the thigh, internal rotation, and laterally rotates the hip during abduction
hamstrings: knee flexion and hip extension
quadriceps: extension at the knee/hip flexion
gastrocnemius: plantarflexion of the ankle (assists in knee flexion)
soleus: plantarflexion of the ankle (when knee is flexed)
tibialis anterior: dorsiflexion of the ankle
iliopsoas: hip flexion

Question 18

List the muscles of respiration (chest and abdomen)

Answer 18

external intercostals: assists in raising the ribs during inhalation

internal intercostals: assists in depressing the ribs during exhalation to push air out of the lungs

diaphragm: contracts and flattens to increase the volume of the thoracic cavity during the respiration process

Question 19

List the muscles of the chest

Answer 19

pectoralis minor
serratus anterior
pectoralis major

Question 20

List the shoulder girdle and shoulder joint muscles

Answer 20

pectoralis major
deltoid
teres major
coracobrachialis

Question 21

List the adductor muscles (muscles that move the thigh at the hip)

Answer 21

adductor magnus
adductor longus
adductor brevis
gracilis

Question 22

List the opposing muscle group for the following:

biceps
chest
abdominals
quadriceps
calves

Answer 22

biceps: triceps
chest: back
abdominals: erector spinae
quadriceps: hamstrings
calves: anterior tibialis

Question 23

What are the three types of muscles and their location?

Answer 23

skeletal: primarily attached to bone
cardiac: heart
smooth: walls of hollow vessels and organs