BIOMECHANICS AND KINESIOLOGY II Flashcards
(1) Without the aid of reference, identify biomechanics
concepts without error. (0919-TRNG-2004ae)
a. Friction.
Friction is the force that results from the resistance of two objects moving against one another. Depending on the sport, we may desire increased or decreased friction. In running, we depend on the friction forces between our feet and the ground so we may exert force against the ground and propel forward. When friction is reduced, we are more likely to slip. To determine the amount of friction forces, we must consider both forces pressing against each other and coefficient of
friction (depends on hardness and surface texture).
b. Balance.
A body or object is said to be in equilibrium
when a) the sum of the forces acting on it is equal to zero and
also the sum of the torques acting on it is equal to zero. In
other words, there are no unbalancing forces or torques. On the
other hand, coaches and motor performance experts interpret
balance as a condition in which a body or object is not linearly
or angularly moving. It is stationary. In reference to the
human body, if it is not “falling over” it is said to be in
balance (e.g., a gymnast maintaining a handstand).
c. Stability.
Stability is a quality relating to the
degree to which a body resists being upset or moved. The major
factors that affect a person’s stability are: the area of the
base of support, the relation of the line of gravity to the edge
of the base, the height of the center of gravity, and the mass
of the person.
(2) Without the aid of reference, identify the
biomechanics of the foot and ankle without error. (0919-TRNG2004af)
a. Joints. There are many joints of the ankle and foot, we
will examine the most popular joints of the ankle.
(1) Talocrural (inferior tibia, fibula, and superior of talus).
(2) Subtalar joint (talocalcaneal joint).
b. Range of Motion. The ankle motion allows a person the
ability to run, jump, and cut on a variety of surfaces.
(1) Plantarflexion, dorsiflexion, inversion, eversion,
supination, pronation.
c. Muscles. While there are several muscles that control
the ankle, we will focus on three main muscles of the ankle.
(1) Gastrocnemius: The gastrocnemius muscle crosses the
knee joint slightly and assists with knee flexion. It’s main
action is plantarflexion of the foot.
(2) Soleus: The soleus muscle is deep to the
gastrocnemius and plantar flexes the foot.
(3) Peroneus group: Peroneal muscles originate at the
head of the fibula bone, attach to the lateral side of the foot
(base of 5th), and the primary function is eversion of the ankle.
d. Gait. Gait is the pattern in which someone is walking.
There are many biomechanical changes that can change strength,
performance, and efficiency.
(1) Phases of gait: Heel strike, mid-stance, push off,
and swing phase are the basic components. Normal gait starts
with a heel strike slightly on the lateral side of the heel.
Weight is then transferred to the arch during mid-stance and
then weight is transferred to the big toe during push off.
While the foot is in the air and not in contact with the ground,
this is the swing phase.
e. Applied Foot Mechanics. Many injuries can result from
poor foot and ankle mechanics. This may occur from a number of
variable such as injury or anatomical variance.
(1) Things to look for: While diagnosis is beyond the
scope of the FFI, it’s important to recognize unusual patterns
and refer them to the appropriate personnel. The FFI may notice
odd wear patterns on shoes/boots. There may be inefficient
movement about the ankle or hips. Finally, the side length or
uneven sound of foot strikes may be noticed.
(2) Heel lift: During the squat or lunge technique it
is important to have good flexibility in the ankle. Daily wear
of combat boots may predispose flexibility in the foot and
ankle.
(3) Pronated foot: During lifting techniques,
especially with heavy weight, there may be a tendency for the
foot to pronate. The Olympic weight lifting shoe provides a
solid counter platform. Running shoes are designed for cushion
and flexibility.
(3) Without the aid of reference, identify the phases of
gait without error. (0919-TRNG-2004ag)
d. Gait. Gait is the pattern in which someone is walking.
There are many biomechanical changes that can change strength,
performance, and efficiency.
(1) Phases of gait: Heel strike, mid-stance, push off,
and swing phase are the basic components. Normal gait starts
with a heel strike slightly on the lateral side of the heel.
Weight is then transferred to the arch during mid-stance and
then weight is transferred to the big toe during push off.
While the foot is in the air and not in contact with the ground,
this is the swing phase.
(4) Without the aid of reference, identify the
biomechanics of the knee without error. (0919-TRNG-2004ah)
a. Joints. There are three joints of the knee, we will
review the tibiofemoral joint.
(1) Tibiofemoral joint: The tibiofemoral joint holds
critical ligaments and cartilage of the knee.
b. Range of Motion. The main motions of the knee are
flexion and extension.
(1) Flexion and extension: The range of motion of the
knee is about 0 deg to 140 deg.
c. Muscles. There are several muscles that cross the knee
joint, we will focus on the main knee flexors and extensors.
(1) Quadriceps: The quadriceps muscle group encompasses
4 major muscles of the anterior thigh and its main function is
knee extension. Some of the muscle fibers cross the hip and can
assist in hip flexion.
(2) Hamstrings: The hamstring muscle group consists of
3 major muscle groups. The main function of the hamstrings are
knee flexion and hip extension.
5) Without the aid of reference, identify the
biomechanics of the hip without error. (0919-TRNG-2004ai)
BIOMECHANICS OF THE HIP.
a. Joints. The hip joint is one of the most stable and
protected joints in the human body.
(1) Acetabulum
b. Range of Motion. A large range of motion allows for
greater/stronger contraction for movement.
(1) Flexion, extension, abduction, adduction, internal
rotation, external rotation, and circumduction. The hip joint
has several motions; it has great range of motion and high
stability.
c. Muscles. Muscles of the hip serve mainly for
propulsion. Some of the strongest muscles of the body cross the
hip joint.
(1) Iliopsoas: The iliopsoas muscle group flexes the
hip
(2) Tensor Fascia Latae(TFL): The TFL is located on the
side of the hip and functions as a hip abductor. The TFL distal
tendon is commonly known as the iliotibial band.
(3) Gluteus maximus: The gluteus maximus is one of
three gluteus muscles. This is the strongest muscle of the body
and primarily serves as hip extension.
(6) Without the aid of reference, identify the
biomechanics of the lumbar spine without error. (0919-TRNG2004aj)
a. Joints.
There are 3 major regions of the vertebrae:
cervical, thoracic, and lumbar. The lumbar vertebrae are the
largest and thickest because they support the entire upper body
weight. The lumbar spine vertebrae are stacked upon each other
on cartilaginous discs.
(1) Levels: Lumbar joints are typically named by the 2
bones that are adjacent. For example: the first lumbar
vertebrae on top of the second lumbar vertebrae is called L1-L2.
b. Range of Motion. The range of motion of lumbar
vertebrae pivots on the intervertebral disc. The motion of each
vertebrae is typically not measured, it is typically graded in
total motion of that segment.
(1). The vertebrae individually have small motions,
however, as a group they are able to create large motion. The
motions are flexion, extension, side bending, and rotation
c. Muscles. There are a number of muscles that act on back
motion. The motion depends on if both muscle groups contract
together (flexion or extension) or if one side only contracts
(side bending).
(1) Back extensors: There are several groups of muscles
that run the length of the spine. In a combined contraction
they extend the spine and in a unilateral contraction rotation
will occur. Main muscles to identify are the latissimus dorsi,
trapezius, and erector spinae muscle group.
(2) Abdominals. The rectus abdominis is the most
recognized of the abdominal muscle group, commonly referred to
as the “6” or “8” pack. In a combined contraction, they flex
the spine, in a unilateral contraction rotation will occur. The
oblique muscle group’s primary function is rotation.
(7) Without the aid of reference, identify the
biomechanics of the elbow without error. (0919-TRNG-2004ak
a. Joints.
The elbow joint is a complex joint that
functions as a fulcrum for the forearm responsible for
positioning the hand in space.
(1) Humeroulnar. The humeroulnar joint is the classic
hinge joint of the elbow. It allows for flexion and extension
of the elbow.
(2) Radioulnar. The radioulnar joint allows for
pronation and supination of the hand and wrist.
b. Range of Motion.
(1) The range of motion for the elbow are: flexion,
extension, supination, and pronation. The elbow has a large
range of motion for flexion as in a bicep curl. The pronation
and supination allow for rotation, like turning a door handle.
c. Muscles.
(1) Biceps brachialis: The biceps muscle, which has two
heads, crosses the elbow joint and shoulder. The main function
is elbow flexion. The muscle can assist in shoulder flexion.
(2) Triceps: The triceps muscle, which has three heads,
crosses the posterior elbow joint. The main function is elbow
extension. The muscle can assist in shoulder extension.
(8) Without the aid of reference, identify the
biomechanics of the shoulder without error. (0919-TRNG-2004al)
a. Joints.
The shoulder links the upper extremity to the
trunk and acts in conjunction with the elbow to position the
hand in space for efficient motion.
(1) Glenohumeral: The main shoulder joint is the glen
humeral joint and is a classic ball and socket. The joint is
deepened by a cartilage ring on the glenoid.
b. Range of Motion. An absence of bony constraints allows
a wide range of motion at the expense of stability.
(1) The shoulder has a large amount of range of motion
but lacks stability. The motions for the shoulder are: flexion,
extension, rotation, abduction, adduction, and circumduction.
c. Muscles. Beyond ligaments, the muscle of the shoulder
serve as protection and increases stability. While there are
many muscles that control shoulder joint motion, we will review
the less known group, the rotator cuff.
(1) Rotator cuff: There are many muscles that control
the motions at the glen humeral joint. The rotator cuff is the
most important group for the overhead athlete. The group of
muscles are: Supraspinatus, Infraspinatus, Teres Minor,
Subscapularis (SITS).
