Biomechanics

Question 1

Biomechanics concerns

Answer 1

Biomechanics concerns both the forces we exert on objects or the environment and the forces acting on us and other organisms. The focus is on the moments before, during or after movement.

Question 2

Internal forces

Answer 2

The muscles produce controlled movements by exerting force (pulling and pushing) on the limbs and joints. We call this force an internal force. It is a force that we can generate ourselves.

Question 3

External forces

Answer 3

contact forces and attractive forces. Both influence the surface we stand on.

Question 4

Static forces (external)

Answer 4

occur both at rest and during motion at a constant speed (no acceleration or deceleration), the opposing forces are equal and cancel each other out.

Question 5

Dynamic forces (external)

Answer 5

the forces do not cancel each other out, an imbalance of forces on the body, when someone accelerates or decelerates. To accelerate or decelerate, you must overcome or counteract an opposing force.

Question 6

types of human motion

Answer 6

Linear and Angular

Question 7

Linear motion

Answer 7

In a linear motion, some or all parts of a body move in the same direction. This can be a straight line or a slight curve.

Question 8

Angular motion

Answer 8

rotational (around an axis) or circular, some or all parts of a body rotate through the same angle around an axis of rotation. If the motion were completed fully, the body’s path would form a perfect circle.

Question 9

Center of gravity

Answer 9

The center of gravity is an imaginary point where all mass is concentrated. In the human body, the center of gravity is often near the navel, but this depends on the distribution of body weight and position.

Question 10

Moment/torque

Answer 10

Moment is a force that can initiate movement. If an object is fixed at one end (axis of rotation), it doesn’t move forward (linearly), but rotates around that point (angularly). The force (moment) that sets an object or body part in motion, resulting in rotation, is called torque.

Question 11

Moment arm rule

Answer 11

The greater the moment arm, the greater the impact of the moment. The smaller the moment arm, the smaller the impact of the moment

Question 12

First class lever

Answer 12

In a first-class lever, the fulcrum or pivot point is located between the effort and the resistance. (example - scale). A shorter moment arm requires greater force because the impact of the same force is smaller.

Question 13

Second-class lever

Answer 13

the load is situated between the fulcrum and the effort (ex wheelbarrow or door). In a second-class lever, the closer the load is to the fulcrum, the more weight can be lifted (moment arm of the load is smaller, reducing the impact of the weight)

Question 14

Third-class lever

Answer 14

the effort is positioned between the pivot point and the load.
most of the joints in our body function as third-class levers during the movements
as the moment arm of the load will always be greater than that of the effort
ex - biceps curl

Question 15

Biceps curl rules as a third class lever

Answer 15

The further the biceps insertion is from the elbow, the longer the effort moment arm is, and the less force needs to be applied with the same weight. This makes the lever more advantageous.

The longer the forearm, the longer the load moment arm is, and the more force needs to be applied with the same weight. This makes the lever less advantageous.

Question 16

Squat variations

Answer 16

a front squat - more knee/quads load (greater knee torque, longer knee MA)
high-bar back squat - more hip load
low-back squat - the biggest hip load, lower back load (longer hip MA)

Question 17

Hip hinge variations

Answer 17

Romanian deadlift and the good morning
Good morning - longer hip MA, more hip and lower back load, loads the entire posterior chain, with two large moment arms on the hip and spine.
Both have significant load on thoracic spine.
RDL allows to lift more weight