- Know definitions throughout the chapter in detail.
- Figure 5.3 Planes of Motion
- Table 5.1 Examples of Planes, Motions, and Axes
The planes of motion can be a bit tricky, so here is a little bit of clarification:
- NOT front to back movements
- Side to side movements
- Exercises involving abduction and/or adduction of the limbs
- Example: side lunge, lateral dumbbell raise, ice skater
Imagine a wall in front and in back of you. The ONLY movement this would allow is along that plane-sideways movements.
- Forward and backwards movements
- Movements involving pushing and/or pulling
- Movements involving flexion and/or extension at joints
- Example: bicep curl, front lunge, bench press, and rows
Imagine a wall on your right and left side. The ONLY movement this would allow is along that plane-or front and back movements.
- Rotational movements
- Diagonal movements
- Example: rotation, wood-chop throw, medicine ball rotation chest pass
- Figure 5.4 Joint Motions
- Figure 5.5 Joint Motions
- Figure 5.6 Joint Motions
- Figure 5.7 Joint Motions
- Table 5.2 Muscle Action Spectrum
- Table 5.3 Common force couples
- Figure 5.15 Levers
- Biomechanics – Science concerned with the internal and external forces acting on the human body and the effects produced by these forces.
- Superior – Positioned above a point of reference
- Inferior – Positioned below a point of reference
- Proximal – Positioned nearest the center of the body, or point of reference. – Knee more proximal to the hip th an ankle.
- Distal – Positioned farthest from the center of the body, or point of reference Ankle more distal to the hip than knee.
- Anterior (or Ventral) – On the front of the body On or forward, front of the body, quads are anterior on the thigh.
- Posterior (or Dorsal) – Ont he back of the body. Hamstring complex is posterior.
- Medial – Positioned near the middle of the body. Close to midline of the body. Adductors are medial side of thigh, side closest to midline of the body. Sternum more medial than shoulder.
- Lateral – Positioned on the outside of the body. Ears are on the lateral side of the head.
- Contralateral – Positioned on the opposite side of the body. Right foot is contralateral to the left hand.
- Ipsilateral – Positioned on the same side of the body. Right food is ipsilateral to right foot.
Planes of Motion, Axes, and Joint Motions
- Movement is said to occur more commonly on a specific plane if it is actually along the plane or parallel to it.
- Anatomic Position – Position with the body erect, arms at side, palms forward. Anatomic position is important in anatomy because it is the position reference for anatomic nomenclature. Anterior, posterior, medial, lateral apply to the body when it is in the anatomic position.
- Sagittal Plane – Bisects the body into left and right halves. Movements in sagittal plane include flexion and extension.
- Flexion – Bending movement in which the relative angle between two adjacent segments decreases.
- Extension – A straightening movement in which the relative angle between two adjacent segments increases.
- Hyperextension – Extension of joint beyond the normal limit or range of motion.
The Frontal Plane
- Frontal Plane – Bisects the body into front and back halves.
- Abduction – Movement in frontal plane away from the midline of the body. Similar to extension, increase in the angle between two adjoining segments in the frontal plane. Side lat raises.
- Adduction – Movement in frontal plane back toward midline of the body.
- Transverse Plane – Imaginary bisetor divides body into top and bottom halves. Upper and lower halve.
- Internal Rotation – Rotation of a joint toward the middle of the body.
- External rotation – Rotation of a joint away from the midline of the body.
- Horizontal Abduction – Movement of the arm or thigh in the transverse plane from an anterior position to a lateral position. Movement from a front position to aside position.
- Horizontal Adduction – Movement of the arm or thigh in the transverse plane from a lateral position to an anterior position. Side to front.
- Scapular Retraction – Adduction of scapula; shoulder blades move toward midline
- Scapular Protraction – Abduction of scapula; shoulder blades move away from midline.
- Scapular Depression – Downward(inferior) motion of the scapula.
- Scapular Elevation – Upward(superior) motion of the scapula.
- Three primary types of muscle actions: isotonic(eccentric and concentric), isometric, and isokinetic. Iso means same or equal. Tonic means tension. Metric means length. Kinetic means motion.
- Isotonic – constant muscle tension. Isometric – constant muscle length. Isokinetic – constant velocity of motion.
- Force is produced, muscle tension developed, movement occurs. Two components – eccentric and concentric phase.
- Eccentric – Muscle develops tension while lengthening. Synonymous with deceleration. Observed in many movements such as landing from a jump. Lowering the weight during resistance exercise. “negatives”.
- Concentric – Muscle is exerting force greater than resistive force, resulting in shortening of the muscle. Contractile force is greater than resistive force, shortening of muscle. The lifting portion of exercise.
- Isometric – Muscle is exerting force equal to force being placed on it leading to no visible change in muscle length. Pause during resistance training. In sports, used to dynamically stabilize the body.
- Isokinetic – Muscle shortens at a constant speed over the full range of motion. Harder individual pushes or pulls, more resistance they feel, requires expensive machinery. Usually only seen in rehab clinics.
- Force – Influence applied by one object to another, which results in acceleration or deceleration of the second object. Characterized by magnitude(how much) and direction(which way).
- Length-Tension Relationship – Resting length of a muscle and the tension the muscle can produce at this resting length. Optimal muscle length is where acting and myosin filaments in the sarcomere have the greatest degree of overlap, this results in ability of myosin to make maximal amount of connections with actin and thus results in potential for maximal force production of tha tmuscle. Lengthening a muscle beyond this optimal length and then stimulating it reduces the amount of actin and myosin overlap, reducing force production. Shortening muscle too much places actin and myosin in state of maximal overlap and allows fo rno further movement.
- If muscle lengths are altered, ex misaligned joints, then they will not generate the needed force to allow for efficient movement.
- Force velocity curve – relationship of muscle’s ability to produce tension at differing shortening velocities. As velocity of concentric muscle action increases, its ability to produce force decreases.
- Force couple – Muscle groups moving together to produce movement around a joint. Muscles in force couple provide divergent pulls on bone or bones they connect to, this is a result from the fact that each muscle has different attachment sites, pull at a different angle, and creates a different force on that joint.
Muscular Leverage and Arthrokinematics
- Levers are classified by first, second, and third class.
- First class levers have fulcrum in the middle, like a seesaw. Nodding hte head is first class lever.
- Second-class levers have resistance in the middle(with fulcrum and effort on either side. Like a load in a wheelbarrow. Body acts as second class lever when engaged in pushup or calf raise. Calf raise ball of foot is fulcrum, bodyweight is resistance, effort is applied by calf musculature.
- Third-class levers have effort placed between resistance and fulcrum. Most limbs are operated as third class levers. Ex. forearm, fulcrum is elbow, effort applied by biceps muscle, and load is in the hand.
- Rotary Motion – Movement of bones around the joints.
- Torque – Force that produces rotation. Common unit of torque is newton-meter of Nm.
- Motor Behavior – Motor response to internal and external environmental stimuli. Manner in which nervous, skeletal, and muscular systems interact to produce skilled movement using sensory information from internal and external environments.
- Motor control – How the CNS integrates internal and external sensory information with previous experiences to produce a motor response. Learning from previous experiences.
- Motor learning – Integration of motor control processes through practice and experience, leading to relatively permanent change in capacity to produce skilled movements.
- Motor development – Change in motor skill behavior over time throughout the lifespan.
- Process of controling neural, skeletal, and muscular components to produce movement is known as motor control. Focuses on the involved structures and mechanisms used by the CNS to integrate internal and external sensory information with previous experiences to produce skilled motor response.
- Muscle Synergies – Groups of muscles that are recruited by the central nervous system to provide movement.
- Proprioception – Cumulative sensory input to the CNS from all mechanoreceptors that sense body position and limb movement. Mechanoreceptors are the muscle spindle, Golgi tendon organ, and joint receptors.
- Sensorimotor Integration – Cooperation of the nervous and muscular system in gathering and interpreting information and executing movement. Nervous system ultimately dictates movement. Individuals training with improper form will develop improper sensory information, leading to movement compensations and potential injury.
- Integration of motor control processes, with practice and experience, leading to a relatively permanent change in capacity to produce skilled movements.
- Feedback – Use of sensory information and sensorimotor integration to help the human movement system in motor learning.
- Internal feedback – process where sensory information is used by the body to reactively monitor movement and the environment. Length-tension relationships, force couple relations, and arthrokinematics. Internal feedback acts as a guide, steering HMS to proper force, speed, and amplitude of movement patterns.
- External Feedback – Info provided by external source, such as health and fitness professional, tape, mirror, HR monitor. Knowledge of results – feedback used after completion of movement to help inform client about outcome of his performance. “your squats were good” Knowledge of performance – feedback that provides information about quality of movement during exercise. Ex – Noticing feet externally rotated during squats, asking if client felt or saw anything different about those reps.