Exercise Science

Force

The mechanical interaction that goes on between two objects or bodies. It may involve contact (such as friction) or it may act at a distance (such as gravity). A force changes or tries to change the motion of the objects.

Mass

The amount of material in a body or object. It is usually measured in kilograms (kg). This is not the same as weight.

Weight

The effect of the force of gravity on mass.

1st Law of Inertia

An object will remain at rest or continue with constant velocity unless acted on by an unbalanced force.

2nd Law of Inertia

The amount of acceleration depends on the strength of the force applied to an object. Force is equal to mass multiplied by acceleration or F=ma

3rd Law of Inertia

For every action there is an equal and opposite reaction - when one body or object applies a force to another, the second body or object will apply a force equal in size but opposite in direction to the body or object.

Which is NOT true (facts about mass)

Muscles can be strengthened if they are not strong enough to decelerate the force of ballistic movements.

T/F: A narrow base of support and an elongated body position reduce stability.

True

Where do the axes pass through for the whole body?

The center of gravity

Which plane of movement does a cartwheel take place on?

Frontal Plane

What is the musculoskeletal system?

The arrangement of bones, joints, and muscles that permits movement of the human body in sports and exercise. The body segments are articulated by synovial joints. 

Flexion

Closing of the joint angle around the frontal axis at the joint

Example of elevation

Shrugging the shoulders at the acromioclavicular joint to elevate the scapula. 

Example of reposition

Returning the thumb to its anatomical position next to the index finger

Which one of Newton’s Laws applies to this situation, “A sprinter starts a race from the blocks. They must push backwards and downwards with large forces onto the blocks. The blocks will push back onto the sprinter with the same force, but in the opposite direction”

Newtons Third Law

Which one of Newton’s Laws applies to this situation, “A hockey puck will remain at rest on the ice or continue to move at a constant speed in a straight line unless acted upon by a force, such as a player’s stick hitting it.”

Newton’s 1st Law

What is torque?

If a force is applied to an object that is free to rotate around an axis, as long as the force is applied so that it does not act through the axis (centre of rotation), it will create a torque (sometimes called the moment of the force). The force that is applied is called an eccentric force. 

Plantarflexion

Extension of the ankle joint

What is Range of Motion

The magnitude of movement available at a joint or series of joints.

What is active ROM

The movement of a joint using only the muscles of that limb/area

Static Flexibility

The range of motion around a joint without consideration of the speed of movement (ex. holding a stretch).

Base of Support effect

A wider base of support in the direction of the force increases stability

Centre of Gravity effect

For maximum stability, the line of gravity must fall within the base of support

Dynamic Flexibility

The range of motion around a joint while in motion and using speed (ex. leg swing).

How does the COG shift during a high jump?

The athlete's COG is lowered during the run-up, then raised as they take off. Crucially, as the athlete arches over the bar, the COG may actually pass below the bar. 

What do ligaments do?

Ligaments (bone-to-bone) provide stability and prevent excessive or aberrant movement

Why do athletes often adopt a less stable, asymmetrical stance during the wind-up phase?

Athletes temporarily reduce stability to allow for greater range of motion (ROM), which in turn permits a greater application of force over a longer distance/time

What are tendons?

Tough, fibrous connective tissues that act as strong cords to connect muscles to bones, enabling movement by transferring muscle force to the skeleton

Identify the three axes that are simultaneously involved when performing the movement of circumduction at the shoulder joint.

It rotates around the Sagittal axis, the Frontal axis, and the Longitudinal axis.

Name the primary pair of movements occurring in the Sagittal plane

The primary movements are Flexion (decreasing the angle of a joint) and Extension (increasing the angle of a joint).