Biomechanics of Resistance Exercise Key Terms Range of Motion Movement Planes Muscle Actions
Biomechanics of Resistance Exercise
Key Terms Range of Motion
Movement Planes
Muscle Actions
Anatomical LocationsKey Terms
• Midline: The invisible line that divides the body or a single body part in half down the center.
• Anterior: The surface of the body that would be considered the front.
o The pectorals are on the anterior aspect of the body
• Posterior: The surface of the body that would be considered the back.
o The rhomboids are on the posterior aspect of the body
• Superior: Toward the head or upper part of a structure:
o The humerus is superior to the radius
• Inferior: Toward the lower part of a structure
o The tibia is inferior to the femur
Anatomical LocationsKey Terms
• Medial: The surface that is closer to the midline of the body.
o The adductors are medial to the abductors
• Lateral: The surface that is further from the midline of the body.
o The abductors are on the lateral aspect of the leg
• Proximal: Closer to the origin of a point of reference
o The elbow is proximal to the wrist
• Distal: Further from the origin or point of reference
o The foot is distal to the knee
Muscle MovementsKey Terms
• Agonist- (prime mover) the muscle most directly involved in bringing about a movement
• Antagonist- the muscle that slows down or stops the movement. Opposes the agonist muscle
• Synergist- Assists indirectly in a movement
• Muscle origin (proximal attachment)- the point closest to the midline of the body where the
muscle attaches to the bone
• Muscle insertion (distal attachment)- the point farthest from the midline of the body where the muscle attaches to the bone
• Stabilizer muscles- muscles acting in a stabilizing role that aren’t directly involved in lifting a
weight, but instead keep certain parts of the body steady so that the primary working muscles
can do their job properly.
• Anatomical Position- The body is erect, the arms are down at the sides, and the palms face forward.
Examples of Agonist vs. Antagonist Muscles
Agonist (Prime Mover) Antagonist
Biceps Triceps
Deltoids Latissimus Dorsi
Pectoralis Major Trapezius/Rhomboids
Rectus Abdominis Erector Spinae
Quadriceps Hamstrings
Types of Muscular Contractions
• Concentric Muscle Action- A muscle action in which the muscle shortens because the contractile force is greater than
the resistive force.
• Eccentric Muscle Action- A muscle action in which the muscle lengthens because the contractile force is less than the resistive
force.
• Isometric Muscle Action-A muscle action in which the muscle length does not change because the contractile force is equal to
the resistive force.
The Three Movement Planes
• Sagittal Plane: Divides the body into right and left parts.
o Primary movements include Flexion and Extension
• Frontal Plane: Divides the body into anterior and posterior parts.
o Primary movements include Abduction, Adduction, and Lateral Flexion
• Transverse Plane: Divides the body into superior and inferior parts.
o Primary movements include Pronation, Supination, and any rotation about a vertical axis.
Movement Planes Anatomical Position
Anatomical Planes divide body or joint into 3 segments:
Sagittal
Frontal/Coronal
Transverse/Horizontal
Basic Description of Movement
• Flexion : Decreasing the angle of a given joint.
• Extension : Returning a joint from flexion.
• Abduction : Movement away from the midline in the frontal plane.
• Adduction : Movement toward the midline in the frontal plane.
• Rotation : Movement counterclockwise or clockwise about a vertical axis
• Pronation: Internal rotation resulting in appendage facing downward
• Supination: External rotation resulting in appendage facing upward
Examples of Planes and Motions
Plane Motion Example
Sagittal Flexion/Extension Walking, squatting, overhead press Frontal Abduction/adduction
Side Flexion
Star Jump
Lateral Arm Raise
Transverse
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