Planes of Motion, Muscle Actions, Functional Anatomy of Muscles

Any time the body is in motion, numerous muscles take turns creating isometric actions to dynamically stabilize the peripheral joints and spine. For example during squat movements, ......

abductor and adductor muscles of the hip contract isometrically to prevent unnecessary movement (instability) in the frontal and transverse planes, while the gluteals, quadriceps, and hamstrings work concentrically and eccentrically in the sagittal plane

Isokinetic

The speed of movement is fixed, and resistance varies with the force exerted. It requires sophisticated training equipment often seen in rehabilitation or exercise physiology laboratories.

Core

The structures that make up the lumbo-pelvic-hip complex (LPHC), including the lumbar spine, pelvic girdle, abdomen, and hip joint.

While not required, a majority of closed-chain activities are ----

Weight bearing; . Examples of closed-chain exercises include push-ups, squats, pull-ups, or lunges.

Feed-forward activitation

When a muscle is automatically activated in anticipation of a movement.

Isometric Muscle Action

When a muscle is exerting force equal to the force being placed on it leading to no visible change in the muscle length.

A concentric muscle action is synonymous with

acceleration and can be observed in many movements, such as jumping upward and the "lifting" phase during a resistance training exercise.

Hypomobility

When range of motion at a joint is limited.

During isokinetic muscle actions,

he muscle shortens at a constant speed over the full ROM. An isokinetic muscle action requires the use of expensive and sophisticated equipment that measures the amount of force generated by the muscles and adjusts the resistance (load) so that no matter how much muscular tension is produced, movement speed remains constant. In other words, the harder an individual pushes or pulls, the more resistance they feel. During a full isokinetic contraction, the tension in the muscle is at its maximum throughout the whole ROM, which is believed to improve strength and endurance. However, the types of movements that are able to be performed on isokinetic machines are rather limited, and these machines often are only seen in rehabilitation clinics or exercise physiology laboratories.

Concentric muscle actions expend the ---- amount of energy when compared to isometric and eccentric muscle actions

highest

eccentric motion moves --------- direction as the resistance is moving, known as direction of resistance

in the same direction

Fronal Plane Exercises

jumping jacks, side lunges, lateral shoulder raises, and side shuffling.

the weight of either the body or an external load must be decelerated before it can be stabilized isometrically and subsequently accelerated concentrically.

just wanted to remember this one

Transverse Plane exercises

performing a cable trunk rotation, a dumbbell chest fly, and swinging a bat or golf club.

Isolated scapular movements—

termed translations, because they do not rotate around a fixed axis—are primarily retraction, protraction, elevation, and depression

Flexion

A bending movement in which the relative angle between two adjacent segments decreases.

Frontal Plane

An imaginary bisector that divides the body into front and back halves. Movement in the frontal plane includes abduction, adduction, and side-to-side motions.

Sagittal Plane

An imaginary bisector that divides the body into left and right halves.

Transverse Plane

An imaginary bisector that divides the body into top and bottom halves.

External Rotation

Rotation of a body segment away from the middle of the body.

Internal Rotation

Rotation of a body segment toward the middle of the body.

During a concentric muscle contraction....

"positive work" is being done by the muscle as the joint moves through a ROM to move a load against the pull of gravity

Fitness professionals should not neglect the eccentric portion of a resistance training exercise because

A body of evidence has shown that exercises comprised of only eccentric muscle actions will, when appropriately loaded, stimulate anabolic hormones to a greater degree than exercises comprised of only concentric muscle actions.

Ligament

A fibrous connective tissue that connects bone to bone.

Motor unit

A motor neuron and all of the muscle fibers that it innervates.

Abduction

A movement in the frontal plane away from the midline of the body. (push)

Eversion

A movement in which the inferior calcaneus (heel bone) moves laterally. The bottom of foot faces outward. (crossover lunge foot)

Inversion

A movement in which the inferior calcaneus (heel bone) moves medially. Bottom of foot faces inward.

Eccentric muscle action

A muscle action that occurs when a muscle develops tension while lengthening.

Concentric muscle action

A muscle action that occurs when a muscle is exerting force greater than the resistive force, resulting in a shortening of the muscle.

Hypermobility

A state where a lack of neuromuscular support leads to a joint having more range of motion than it should, greatly increasing the risk of injury at that joint.

Extension

A straightening movement in which the relative angle between two adjacent segments increases.

rotating the foot outward at the ankle (transervse plane)

Abduction

Scapular Protraction

Abduction of scapulae; shoulder blades move away from the midline.

Scapular Retraction

Adduction of scapulae; shoulder blades move toward the midline.

Lateral flexion

Bending of the spine from side to side.

Gait

Biomechanical motion of the lower extremities during walking, running, and sprinting.

Scapular Depression

Downward (inferior) motion of the scapulae.

plantar flexion

Extension occurring at the ankle. Pointing the foot downwards; ankle> toe down; To remember plantar flexion, think about planting a garden in the ground. In this context, plantar represents the bottom side of the foot and the direction it moves when the ankle extends.

Hyperextension

Extension of a joint beyond the normal limit or range of motion.

dorsiflexion

Flexion occurring at the ankle / ankle> toe up; To best remember dorsiflexion, think about the dorsal fin of a dolphin on the top side of its body. In this context, dorsal represents the top side of the foot and the direction it moves when the ankle flexes.

Antagonist Examples

For example, the biceps brachii (an elbow flexor) is an antagonist to the triceps brachii during elbow extension. Conversely, during elbow flexion, the triceps become the antagonist to the biceps. Another example includes how the hip flexor complex is antagonistic to the gluteus maximus during hip extension, whereas the gluteus maximus is antagonistic to the hip flexor complex during hip flexion.

Agonists Examples

For example, the gluteus maximus is the agonist for hip extension, the quadriceps are the agonists for knee extension, the anterior deltoid is the agonist for shoulder flexion, the biceps brachii is the agonist for elbow flexion, and the triceps brachii is the agonist for elbow extension

Synergist examples

For example, the hamstring complex and the erector spinae (muscles of the back) are synergistic with the gluteus maximus during hip extension (Kendall et al., 2005), whereas the brachioradialis and brachialis (forearm muscles) assist the biceps brachii during a biceps curl. Additional examples include the triceps brachii assisting the pectoral muscles during a chest press and the biceps brachii assisting the latissimus dorsi during a pull-up.

Stabilizer muscle examples

For example, the transversus abdominis (a deep abdominal muscle), internal obliques, and multifidus (deep muscles of the spine) stabilize the LPHC during hip extension. Another example is the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis), which stabilize the shoulder during upper extremity movements

Isotonic

Force is produced, muscle tension is developed, and movement occurs through a given range of motion. Isotonic muscle actions are subdivided into concentric and eccentric muscle actions.

Hip Flexion in the Sagittal Plane

Hip flexion occurs when an individual decreases the angle between the femur (thigh bone) and the pelvis or lumbar spine. This can occur when an individual elevates the knee toward the abdomen (femoral-on-pelvic hip flexion). During this motion, the pelvis and spine are fixed while the femur rotates. Another version of hip flexion can occur when an individual bends forward from the trunk (as if touching their toes). In this instance, the pelvis and lumbar spine rotate together over a fixed femur (pelvic-on-femoral rotation).

To better understand the sagittal plane, imagine being stuck in a very narrow hallway with no room to move to the left or right or to rotate in any fashion...

In addition, the walls are made completely of glass, which you don't want to break. Based on this analogy, the only available movements in our narrow sagittal plane hallway are front-to-back and up-and-down movements.

Radioulnar pronation

Inward rotation of the forearm from a palm-up position to a palm-down position.

What are the three overarching types of muscle actions?

Isotonic, isometric, and isokinetic

As the muscle lengthens because the external force acting on the muscle (i.e., the source of resistance) is greater than the internal muscle force. As the muscle lengthens, the actin and myosin cross-bridges are pulled apart and reattach, allowing the muscle to functionally lengthen

Just saying

As the muscle shortens, the actin and myosin cross-bridges move together (i.e., sliding-filament theory), allowing the muscle to shorten

Just saying

To better understand the frontal plane, imagine walls in front of and behind you, with no room to move forward or backward or to rotate...

Like last time, the walls are made completely of glass, which you do not want to break. As a result, movements in the frontal plane are primarily side-to-side motions.

Joint Motion

Movement in each plane occurs on an axis running perpendicular to that plane, much like the axle that a car wheel revolves around.

Adduction

Movement in the frontal plane back toward the midline of the body. (pull)

Osteokinematics

Movement of a limb that is visible.

Horizontal Adduction

Movement of the arm or thigh in the transverse plane from a lateral position to an anterior position.

Horizontal Abduction

Movement of the arm or thigh in the transverse plane from an anterior position to a lateral position.

Pronation of foot

Multiplanar movement of the foot and ankle complex consisting of eversion, dorsiflexion, and ankle abduction; associated with force reduction.

Supination of Foot

Multiplanar movement of the foot and ankle complex consisting of inversion, plantar flexion, and ankle adduction; associated with force production.

Isometric

Muscle tension is created without a change in muscle length and no visible movement of the joint.

Antagonists

Muscles on the opposite side of a joint that are in direct opposition of agonist muscles.

Synergists

Muscles that assist agonists to produce a movement.

Stabilizers

Muscles that contract isometrically to stabilize the trunk and joints as the body moves.

closed-chain movements

Occur when the distal segment (like hands and feet) of the joint is fixed in space. E.g., for knee joint is standing barbell squats; Additionally, closed-chain exercises often require the movement of multiple joints in a predictable manner with the contraction of multiple muscle groups

Radioulnar supination

Outward rotation of the forearm from a palm-down position to a palm-up position.

Elasticity

The ability of soft tissues to return to resting length after being stretched.

Arthrokinematics

The description of joint surface movement; consists of three major types: roll, slide, and spin.

Muscle action spectrum

The full range of eccentric, isometric, and concentric muscle contractions required to perform a movement.

Flexibility

The normal extensibility of soft tissues that allows for full range of motion of a joint.

Agonists

The primary muscles providing force for a movement; in other words, they are the muscles most responsible for generating the primary forces for a particular movement.

What is the imaginary line that bisects the body into right and left sides?

The sagittal plane

Scapular Elevation

Upward (superior) motion of the scapulae.

Transverse Plane exercises continued

The transverse plane involves rotational movement of the head, torso, arms, and legs. In addition, movement in the transverse plane involves horizontal abduction and adduction, which can occur at either the shoulders or hips. For example, a machine chest fly exercise involves horizontal abduction and adduction at the shoulder, whereas a hip abductor machine involves horizontal abduction and adduction at the hips.

Unlike closed-chain exercises, which ----, open-chain exercises tend to focus on ----

activate multiple muscles; isolating the prime mover muscles

inward rotation of the foot at the ankle (transverse plane)

adduction

Closed-chain exercises involve applying force into .....

an immovable object, such as the floor, wall, or pull-up bar. In other words, the hands or feet are typically fixed and do not move. (pull up closed chain for back musculature)

When performing a biceps curl exercise with the palm facing up, the ---- is the primary muscle targeted

biceps brachii

Examples of predominantly sagittal plane exercises include ...

biceps curls, triceps pushdowns, squats, front lunges, calf raises, walking, running, vertical jump, climbing stairs, and shooting a basketball.

Changing the hand position to palm down targets the ---- to a greater degree

brachialis

Whereas performing the exercise with the thumb up (hammer curls) targets the ---- muscle to a greater extent

brachioradialis

Eccentric motion is synomymous with

deceleration and can be observed in many movements, such as landing from a jump or lowering weights during a resistance exercise

Eccentric muscle actions are more...

efficient than concentric contractions and require less energy to complete a task

lifting a heavy weight likely requires a ---- tempo than lowering that same weight.

faster; Eccentric muscle actions are able to resist more weight than concentric actions. Therefore, to optimally load muscles during the eccentric phase, resistance implements (dumbbells, barbells, and so on) can be lowered more slowly than they are lifted to increase the time under tension for better strength improvements

Open-chain exercises involve the ability to...

freely move the limbs, such as the hands and feet. (lat pulldown is open chain for same muscle group - back musculature)

Movement patterns that take the body through motions in more than one plane

multiplanar.

Eccentric motion is referred to as

negative work. The term negative was derived from the fact that in eccentric movement, work is actually being done on the muscle, such as slowing a load being pulled toward the earth by gravity, rather than the muscle doing the work, such as internal muscular forces generated to move a load against gravity

While not required, a majority of open-chain activities are -----

nonweight-bearing; Examples of open-chain exercises include lat pulldown, biceps curl, bench press, leg curl, and leg extension exercises;

The integrated function of the HMS can be recognized during a squat. Clients with limited dorsiflexion of the ankle will be limited in the depth of their squat during the eccentric phase. A quick method for these individuals to gain a deeper squat ROM is to...

place a small board (or weight plates) under their heels. A longer-term solution would be to address the stiffness of the ankle joints by performing routine stretching (Macrum et al., 2012).

During gait (walking and running), the foot and ankle complex moves between ...

pronation during force reduction (when the foot lands) and supination during force production (when the foot pushes off the ground) with every step.

three imaginary planes

sagittal, frontal, and transverse

Scapular protraction primarily requires

serratus anterior muscle, with some assistance from the pectoral muscles.

Open chain movement

the distal segments (hands and feet) are not fixed, and they are free to move in space. Additionally, open-chain exercises have independent joint movement of only the segments distal to the moving joint itself

Isotonic muscle actions represent

the lowering and lifting phases of resistance training exercises, respectively. For example, during a biceps curl, the biceps brachii muscle contracts concentrically and shortens to flex the elbow and curl the dumbbell up to the shoulder and contracts eccentrically while the elbow extends and lowers the dumbbell back down.

Scapular retraction requires several muscles including

the middle trapezius and rhomboid

turning toward left hand is

trunk left rotation

turning toward right hand is

trunk right rotation