Quiz 1- Intro To Kinesiology

Joint movement in closed kinematic chains refers to the coordinated motion between adjacent joints. This type of movement is predictable and occurs in weight-bearing limbs of the human body. In closed kinematic chains, the motion of one joint affects the motion of the other joints in the chain. This is commonly observed in activities such as walking or squatting, where the joints of the lower extremities work together to provide stability and efficient movement. Therefore, the statement is true.

Too much pressure on soft tissues can indeed cause blisters, calluses, or skin breakdown. This is because excessive pressure can damage the skin and underlying tissues, leading to these conditions. To mitigate this, one can either increase the area of the body that is receiving the pressure, spreading it out over a larger surface area, or decrease the amount of time the area is under pressure. Therefore, the statement "Too much pressure on soft tissues can cause blisters, calluses, or skin breakdown" is true.

The action of balance of the head on the neck for head control is an example of a first class lever system. In a first class lever system, the fulcrum is located between the effort and the load. In this case, the fulcrum is the joint between the head and the neck, the effort is the contraction of muscles in the neck, and the load is the weight of the head. This lever system allows for precise control and movement of the head in various directions.

Isometric contraction occurs when there is no change in muscle length during the contraction. In this case, while holding a cup, the wrist flexors and extensors are contracting to maintain a stable position of the wrist at 0 degrees. There is no movement or change in muscle length happening during this contraction, hence it is classified as an isometric contraction.

A wide base of support provides more stability because it increases the area over which the weight of the body is distributed, making it less likely to tip over. A low center of gravity also enhances stability because it lowers the body's overall balance point, reducing the risk of toppling. Having the weight of the body within the base of support perimeter ensures that the body's weight is concentrated within the area of support, further enhancing stability.

During a push-up, the triceps muscle is responsible for extending the elbow joint and lowering the body towards the ground. This action requires the triceps to lengthen under tension, which is known as an eccentric contraction. Eccentric contractions occur when the muscle lengthens while still generating force, acting as a brake to control the movement and resist gravity. Therefore, the correct answer is eccentric.

During a chin-up, the biceps muscles in the arms contract to lift the body. This type of contraction, where the muscle shortens as it generates force, is known as a concentric contraction.

A third-class lever system is characterized by the effort force being applied between the fulcrum and the load. In the case of the deltoid muscle moving the humerus, the effort force is generated by the contraction of the deltoid muscle, the fulcrum is the shoulder joint, and the load is the weight of the arm. This arrangement allows for a greater range of motion and speed, but at the expense of force.

Flexion-extension refers to the movement that occurs in the sagittal plane. In this movement, the joint angle increases (extension) or decreases (flexion) along the anterior-posterior axis. The sagittal plane divides the body into left and right halves, and movements in this plane occur in a forward and backward direction. Therefore, flexion-extension is an example of a movement that occurs in the sagittal plane.

Pronation/Supination refers to the rotational movement of the forearm or foot. This movement occurs in the transverse plane, which is perpendicular to both the sagittal and frontal planes. In the transverse plane, the body is divided into upper and lower portions. Therefore, the correct answer is Transverse.

The given answer is correct because using your legs to squat down to the floor from a standing position is an example of movement in a closed kinematic chain, not an open kinematic chain. In a closed kinematic chain, the end segment is fixed or stabilized, such as when your feet are fixed on the ground while squatting. In an open kinematic chain, the end segment is free to move, such as when you use your arm to wave, reach, or your leg to kick a ball.

The center of gravity refers to the point in the body where mass is equally distributed. In anatomical position, this point is usually located at S-2. This means that if an object or person were to balance on a single point, that point would be at the center of gravity. It is important to understand the center of gravity for various activities such as maintaining balance, performing physical tasks, and understanding body mechanics.

A Second Class Lever is described as the mechanical advantage lever system; A-R-E. In a second class lever, the resistance is located between the effort and the fulcrum. This type of lever provides a mechanical advantage, meaning that a smaller effort can move a larger resistance. The mechanical advantage is achieved because the effort arm (distance between the effort and the fulcrum) is longer than the resistance arm (distance between the resistance and the fulcrum). This allows for easier lifting or moving of heavy objects.

Synovial joints are defined by several concepts, including their ability to move freely, their reinforcement and stabilization by ligaments, and the presence of a joint capsule made of connective tissue. However, synovial joints do have articular cartilage, which covers the ends of the bones and helps to reduce friction and absorb shock during movement.

A Third Class Lever is described as the wide arc of ROM system; A-E-R. This means that the lever has a wide range of motion, allowing for greater flexibility and movement. The effort arm is positioned between the fulcrum and the resistance, which means that a smaller effort force can move a larger resistance force. This type of lever is commonly found in human anatomy, such as when using the bicep to lift a weight.

A contraction involves muscles that move a joint, causing the joint to move. On the other hand, a contracture refers to the condition where a joint becomes immobile or stiff due to the shortening or tightening of muscles, tendons, or other tissues surrounding the joint. Therefore, the given statement is true as it accurately distinguishes between a contraction and a contracture based on their effects on joint mobility.

Newton's Law #2, also known as the Law of Acceleration, states that the force acting on an object is directly proportional to its mass and acceleration. In this case, the strength needed to lift a 10-pound bag of groceries is directly related to the mass (10 pounds) of the bag and the acceleration (upward motion) required to lift it. Therefore, it aligns with Newton's Law #2.

Concentric contraction refers to the shortening of the muscle while generating force. During a push-up, the triceps contract concentrically as they shorten and generate force to lift the body off the ground. This is the phase where the muscle is actively contracting and causing movement.

Plane joints and Ball & Socket joints are considered to be triaxial joints because they allow movement in three different axes or directions. Plane joints allow movement in two axes, such as the wrist joint, which allows flexion/extension and abduction/adduction. Ball & Socket joints, like the shoulder joint, allow movement in three axes, including flexion/extension, abduction/adduction, and rotation. Therefore, both types of joints are classified as triaxial joints.

Lateral trunk flexion refers to the movement of the trunk sideways, away from the midline of the body. This movement occurs in the frontal plane, which divides the body into front and back halves. The sagittal plane divides the body into left and right halves, while the transverse plane divides the body into upper and lower halves. Therefore, the correct answer is frontal.

The humero-radial joint of the elbow is an example of a uniaxial joint because it allows movement in only one plane, which is flexion and extension. This joint consists of the articulation between the humerus and the radius bone, with a single axis of rotation. The other options, such as the MCP joints in the hand, the glenohumeral joint of the shoulder, and the carpometacarpal joint of the thumb, are not uniaxial joints as they allow movement in multiple planes.

A second class lever system is characterized by the load being located between the fulcrum and the effort. In the case of standing on tip-toes, the gastrocnemius muscle acts as the effort, the fulcrum is located at the ankle joint, and the load is the body weight. When the gastrocnemius contracts, it applies force to the heel, causing the foot to pivot at the ankle joint and lift the body weight. This fulfills the criteria of a second class lever system, where the effort is further from the fulcrum than the load.

The metacarpal phalangeal joint is not an example of a synarthroses joint because it allows for movement. Synarthroses joints are immovable joints, such as the symphysis pubis, suture joints of the skull, and joints between the bodies of the vertebrae.

Its actually Maximal tension exists in the ligaments!

This answer is correct because a first-class lever is a type of lever where the fulcrum is located between the effort force and the resistance force. In this lever system, the effort arm (distance between the fulcrum and the effort force) is on one side of the fulcrum, while the resistance arm (distance between the fulcrum and the resistance force) is on the other side. This arrangement allows for balancing and equalizing the forces applied to the lever, hence creating a balance lever system.

When the hamstring muscles contract eccentrically, it means that they are lengthening while still generating force. In the given scenario, as the knee flexion decreases from 150 degrees to 0 degrees, the hamstring muscles are responsible for controlling the movement and slowing it down. This type of contraction is known as an eccentric contraction.

Neck whiplash that occurs when there is a sudden stop when driving is an example of Newton's Law #1, also known as the law of inertia. This law states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and in the same direction unless acted upon by an external force. In the case of a sudden stop, the body (including the neck) tends to continue moving forward due to its inertia, while the car comes to a stop. This causes the neck to snap backward, resulting in a whiplash injury.

The carpometacarpal joint of the thumb is an example of a biaxial joint. This joint allows for movement in two planes, allowing the thumb to move in a variety of directions. It is capable of flexion and extension, as well as abduction and adduction. This joint is important for the dexterity and fine motor movements of the hand, allowing for precise gripping and manipulation of objects.

Radial-ulnar deviation refers to the movement of the hand towards or away from the midline of the forearm. This movement occurs in the frontal plane, which divides the body into front and back halves. Therefore, radial-ulnar deviation is an example of a movement that occurs in the frontal plane.

False- The Effort arm is equal to or greater than the resistance arm

Tripping over a book on the floor and using your hands to catch your balance is an example of Newton's Law #3, also known as the law of action-reaction. According to this law, for every action, there is an equal and opposite reaction. In this scenario, the action is the force exerted on the book when tripped over, and the reaction is the force exerted by the hands to catch the balance and prevent falling.