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Chapter 5 NASM study guide
Important definitions from chapter 5
- Biomechanics: The study of how internal and external forces affect a living body (especially for the skeletal system)
The terminology of location:
- Superior: A position above a point of reference.
- Inferior: A position below a point of reference.
- Proximal: A position near the center of your body or a point of reference. Your knee joint is more proximal to your hip joint then your ankle joint is.
- Distal: A position that is farther away from the center of your body or point of reference. Your ankle is more distal to your hips then your knees are.
- Anterior (Ventral): This refers to the front of your body facing forward. Your chest is anterior on your body.
- Posterior (Dorsal): This refers to the back of your body. Your back and your hamstrings are posterior.
- Medial: This refers to things close to the midline of the body. Your adductors are closer to the midline of your body compared to your abductors.
- Lateral: Positioned on the outside of the body. Your ears are on the lateral side of your head.
- Contralateral: These are things located on the opposite side of your body. Your left foot is contralateral to your right hand.
- Ipsilateral: These are things located on the same side of your body. You are left foot is ipsilateral to your left hand.
The planes of motion, joint motions, and axes
- Anatomic position: The anatomic position is important as a point of reference for anatomic nomenclature. The anatomic position is when the body is erect, the arms at your side and your palms facing forward. This way we can reference what is posterior, anterior, medial or lateral by referencing this default position.
- Sagittal plane: The sagittal plane splits the body into a right half and they left half. Extension and flexion are movements in this plane.
- Flexion: This is a bending movement where a relative angle between two adjacent sections decreases. It’s easier to imagine two separate reference points. A good example is of knee flexion. In this example, the two reference points are your calves and your hamstrings. As knee flexion occurs, the distance between your calves and hand strings decrease as they get closer to one another. As the knee goes into extension they move further away from each other, or the relative angle increases with the knee extension and decreases with knee flexion.
- Extension: This is the opposite of flexion. The relative angle between adjacent sections increases as with my knee extension example above.
- Hyperextension: This is the extension beyond the normal limits of the body.
- Frontal plane: This is a vertical plane that has right angles compared to the sagittal plane breaking up the body between frontal and posterior planes.
- Abduction: The act that typically moves a limb away from the midline of the body in the frontal plane.
- Adduction: The act that typically moves a limb towards the midline of the body in the frontal plane.
- Transverse plane: The plane that divides the body into a lower and upper section.
- Internal rotation When a limb rotates in the transverse plane going away from the midline of the body. If looked at from a bird’s eye view, a limb moving clockwise away from the midline of the body.
- External rotation: When a limb rotates in the transverse plane going towards the midline of the body. If looked from a bird’s eye view, a limb moving counterclockwise going towards the midline of the body.
- Horizontal adduction: Imagine the movement of a chest fly.
- Horizontal abduction: Imagine the movement of a rear deltoid fly.
- Scapular motion: The act of moving the shoulder blades away from the midline.
- Scapular retraction: The act of moving the shoulder blades in the direction of the midline.
- Scapular elevation: The act of elevating the shoulder blades towards the superior.
- Scapular depression: The active lowering the shoulder blades towards the inferior.
The muscle actions
- Concentric: A concentric muscle action: happens when the contraction is accompanied by the shortening of the muscle tissue.
- Eccentric: An eccentric muscle action: is accompanied by the lengthening of the muscle tissue.
- Isometric: In isometric muscle action is when no change in the length of the muscle happens.
- Isokinetic: in isokinetic muscle, action is when the contraction speed of a muscle is constant.
- Force: Any movement that results in the speeding up or slowing down of an object.
- Length-tension relationships: This is the perfect length of a muscle that will result in the most force produced. The ability of a muscle to produce force at its current range.
- Torque: Something that tends to produce rotation or torsion. The movement of a system or force that typically leads to a rotation.
- Rotary motion: This is rotational movements from the joints.
- Force couple: Groups of muscles that work with one another in order to produce a force on a joint.
The motor behaviors
- Sensorimotor integration: How the muscular and nervous system cooperates to gather and interpret information in order to execute the movement.
- Proprioception: This is the cumulative sensory input to the CNS (Central nervous system) from all of the various mechanoreceptors that can sense limb movement and body position. Proprioception training improves coordination, posture, and balance.
- Muscle synergies: Muscles that are controlled by the central nervous system in order to produce the same movements.
- Motor development: The maturation of muscle coordination.
- Motor learning: The process of improving one’s motor skills with practice. This results in lasting changes and one’s overall capability of responding.
- Motor control: The process where people use cognition in order to coordinate the muscles and limbs of the body.
- Motor behavior: Response to external and internal stimuli from the environment. The overall study of motor development, motor learning and motor control (a.k.a. movement).
- External feedback: This is information that one will get about their performance from external sources. Usually visual, verbal or written.
- Internal feedback: This is how you personally feel after you have practice or performed a certain skill.
- Feedback: This is a biological system where the response or the output affects the initial input. Your sensory system gathers input from your motor system in order to adapt and learn new motor skills.
The planes of motion again (important!)
- Splits the body into posterior and interior sections
- The axis of rotation: anterior and posterior
- Joint motion: abduction and adduction. Ankle inversion and eversion and lateral flexion.
- Exercise example: pull-ups, barbell shoulder press, Hip abduction and adduction with cable.
- Splits the body into upper and lower sections.
- The axis of rotation: longitudinal/vertical
- Joint motion: pronation, supination, internal rotation, external rotation, horizontal abduction/adduction.
- Exercise example: trunk rotation, internal rotation, wood chop, horizontal adduction, cable chest fly, horizontal abduction, rear delt fly (machine).
- Splits the body into right and left halves
- The axis of rotation: coronal (medial-lateral axis).
- Joint motion: Extension and flexion
- Exercise examples: Hamstring curls, bicep curls (barbell), Quadricep extension, skull crushers
Common force couples
Hips/Knee extension during walking, running, stair climbing = gluteus maximus, quadriceps, calf muscles.
Elbow flexion/bicep curls = shortening of the brachioradialis, brachialis and biceps brachii.
The three types of levers
The first type of lever is where the fulcrum sits directly between the energy moving the weight and the weight itself. Some good examples are scissors, seesaws, crowbars or a hammer extracting a nail.
The second type of lever is where the fulcrum is at one end, the weight is in the middle and the force is being applied on the other end. Some common levers that use this second type are wheelbarrows, can openers and staplers.
The third type of lever is where the fulcrum is on one end, the weight is on the other end and the forces being applied in the middle. With this type of lever, more force needs to be applied, but in return, the weight gets moved a much larger distance. Some good examples are a fishing rod, a broom or a baseball bat.