What Is A Force Vector

A Vector is a physics term used to depict a quantity with a magnitude (amount) and direction (angle of application). For case, forcefulness is a vector quantity. It has an amount (measured in force per unit area, tension, weight lifted, strain etc..) and a direction (which way the force is being practical).

Barbell Example

When someone is squatting, the barbell is applying a down strength on the torso (thanks to gravity). The magnitude is adamant by the load on the bar and the direction is determined by the placement of the bar.

The person belongings the bar is likewise applying a force. When not moving (in a static position), the force the person is applying upward is equal to that of the force the barbell is applying downward. Considering the forces are equal, no movement is occurring.

If the person begins to produce more force than the barbell, and so the bar will move upward. If the barbell produces more force than the person, then it volition move downward.

side note: The person is besides applying a strength into the ground (footing reaction force), which in turn propels the person upward and allows for a force to exist applied into the bar

Detailed video discussing free torso diagrams (extra material)

Body Positions and Vectors (how they influence muscles)

Barbell Bench Printing

The barbell demote press is done with the body laying in a supine position (on your back) with your upper half of the body parallel to the world's surface (on a flat bench). Because gravity works in straight line (pushing downwards), nosotros know that when we move the barbell we have to move information technology against gravity (upwards). Depending on how the body is positioned (parallel to the ground) nosotros can decide how the vectors volition more often than not influence the musculus producing the upward force (not talking most bracing muscles).

Generally speaking, this explains why the bench press emphasizes the chest more an incline press.

Vertical forces are produced by the horizontal adduction on the arms and extension of the triceps (overly simplified for the sake of the instance). Past keeping the elbows "tucked" to the torso, you lot eliminate some adduction of the arms, which is why narrow grip bench has a greater tricep emphasis.

See example picture beneath

My arms are essentially interim vector lines representing the force vectors of the movement

yellow line is external force of the barbell and dark-green line is the position of my trunk

Barbell Incline Press

The barbell incline press is done in the aforementioned vertical way (upward against gravity), just this fourth dimension we situate our body in a dissimilar position (on the incline bench). By changing our body position, we change how the same vertical force vectors of gravity are interim on our trunk.

Theoretically, if nosotros could manipulate gravity, nosotros could work against unlike forcefulness vectors in the same position. In essence, this is what machines exercise. This is why you can practise a car row in a position (standing with an erect posture) that you could never do a dumbbell row in. Instead with dumbbells, you have to motion your body to fit gravity'due south forcefulness vectors.

Generally speaking, by moving our body's position we are now putting greater emphasis on our shoulders and triceps and less on our chest. The vertical strength vectors of the person are predominantly being created by more vertical adduction of the shoulder and extension of the arm.

yellow line is external forcefulness of the barbell and green line is the position of my trunk

Application

Yes, this is an overly simplified case of how movements work, but it is a necessary pace to outset to understand what exactly influences our movements. Instead of thinking well-nigh exercises in forms of equipment, nosotros should expect at exercises in its well-nigh bones applicable forms (force vectors). Obviously there is much more than that goes in to movement than only force vectors and all of those other areas should exist explored, but it would exist erroneous to ignore the fundamental principles of physics.