Comprehensive Kinesiology Review: Fundamentals, Biomechanics, and Human Movement
Fundamental Concepts and Clinical Utility of Kinesiology
Kinesiology is defined as the study of movement through the multifaceted application of anatomy, physiology, physics, and motor learning.
While the human body contains over muscles, the primary focus of this discipline is to achieve an adequate knowledge of major muscle groups and body parts. This includes understanding why and how specific exercises are performed in relation to building strength in those groups.
Clinical applications for professionals such as physical therapists, occupational therapists, and personal trainers require understanding the "why" behind every movement.
Example: Performing a lateral lift exercise focuses on the deltoid. Specifically, it targets all three heads: the anterior, middle, and posterior deltoids. If an athlete presents with deltoid weakness, lateral exercises can target all three portions effectively if they can be performed without pain.
The broader goal of kinesiology is to improve and maintain the human body, enhancing daily life and movement for patients in various care settings.
Biomechanics and Mechanical Analysis of Human Motion
Biomechanics focuses on the mechanical analysis and physics involved in movement, specifically looking at forces, velocity, and angles of motion to improve efficiency.
While both kinesiology and biomechanics study movement, biomechanics is the science of improving efficiency through physics, whereas the kinesiology discussed here focuses on identifying which specific muscles are involved in a given movement.
Kinematics involves the study of forces that are applied to the body.
Arthrokinematic and Osteokinematic Mechanisms
Arthrokinematics refers to the movements that occur at the joint surfaces between bones. These are essentially internal motions necessary for larger visible movements.
For a joint to function, bones must perform specific motions upon each other: spinning, rolling, or gliding. Without these arthrokinematic motions, bones may collide or the joint may become stuck.
Example: During knee extension, the femur articulates on top of the tibia. Specifically, the femur rolls and glides on the tibia to allow the full extension of the knee.
Osteokinematics refers to the movements of bones through space about a joint. These are the observable motions commonly recognized in anatomy and exercise science.
These include standard movements such as flexion, extension, and abduction.
A full comprehension of these motions for the major joints is required by the end of the study period.
Anatomical Position and Standardized Descriptive Terminology
The anatomical position serves as a universal reference point to ensure consistency in medical notes and injury assessments. It is defined as a position where the body is:
Erect.
Face forward.
Eyes forward.
Feet forward.
Palms forward.
Importance of Reference: Without a standardized position, descriptions like "anterior" or "lateral" would be subjective based on how a person is standing.
Case Study: A football player with a potential fracture located at the distal anterior side of the radius. Because of the anatomical position, medical professionals know the radius is on the thumb side and "anterior" refers to the side associated with the palms, regardless of the patient's current posture.
Descriptive and Directional Terms:
Superior: Above another structure.
Inferior: Below another structure.
Cranial: Towards the head.
Caudal: Towards the tail (commonly used in veterinary medicine or human embryology).
Anterior / Ventral: Towards the front or the belly.
Posterior / Dorsal: Towards the back (similar to the dorsal fin of a dolphin).
Medial: Closer toward the midline of the body.
Lateral: Farthest away from the midline.
Example: In the anatomical position, the pinky finger is medial, while the thumb is lateral. On the foot, the big toe is medial, and the baby toe is lateral.
Ligament applications: The Medial Collateral Ligament (MCL) is on the inside of the knee; the Lateral Collateral Ligament (LCL) is on the outside. Both the knee and elbow have medial and lateral collateral ligaments.
Proximal: Closer to the trunk or origin point.
Distal: Farthest away from the trunk or origin point (think of "distance").
Example: The shoulder is proximal to the elbow; the elbow is distal to the shoulder. The wrist is proximal to the fingers; the fingers are distal to the wrist.
Superficial: Closest to the surface skin layers.
Deep: Farther down into the internal structures.
Prone: Lying face down on the stomach.
Supine: Lying face up on the back.
Dexter: Refers to the right side of the body.
Sinister: Refers to the left side of the body.
Contralateral: The opposite side of the body (e.g., comparing an injured wrist to the contralateral wrist for a bilateral comparison of swelling).
Ipsilateral: The same side of the body.
Kinetic Chain Dynamics: Open and Closed Systems
The body is viewed as a kinetic chain, which is a series of connected limbs and segments that influence movement types.
Chain Integration: An injury in one segment, such as a chronic ankle injury, affects the entire chain. A limp in the ankle puts stress on the contralateral support leg and causes muscle weakness and improper extension in the ipsilateral knee, hip, and lower back. These compensations may cause long-term pain as a patient reaches ages or .
Closed Kinetic Chain:
The distal segment (e.g., feet or hands) is fixed and does not move.
The proximal segment is free to move.
These are usually multi-joint, compound exercises involving several muscles.
Examples: Push-ups (hands and feet fixed), Lunges (foot planted), Squats, Deadlifts.
Open Kinetic Chain:
The distal segment is free to move, while the proximal segment is seated or fixed.
These are often single-joint, isolated exercises.
Examples: Bicep curls, Bench press (arms move), Leg extensions.
Spatial Dynamics: Planes of Motion and Axes of Rotation
Sagittal Plane:
Divides the body into left and right halves.
Movements occur forward and backward (e.g., kicking a ball, flexion, extension, bicep curls).
Rotation occurs around a Frontal Axis (a horizontal pin through the center).
Frontal Plane:
Divides the body into front and back halves.
Movements occur side-to-side (e.g., jumping jacks, abduction, adduction).
Rotation occurs around a Sagittal Axis.
Transverse Plane:
Divides the body into upper and lower halves.
Movements are rotational (e.g., trunk twists).
Rotation occurs around a Vertical Axis (like opening vertical blinds).
Exercise Classifications:
Squat: Frontal plane, sagittal axis.
Incline Shoulder Press: Frontal plane, sagittal axis.
Seated Row: Sagittal plane, frontal axis.
Hamstring Curls: Sagittal plane, frontal axis.
Bicep Curls: Sagittal plane, frontal axis.
Tricep Extension: Sagittal plane, frontal axis.
Sit-ups: Sagittal plane, frontal axis.
Trunk Twists: Transverse plane, vertical axis.
Systematic Review of Osteokinematic Joint Movements
Neck and Trunk:
Flexion (downward).
Extension (upward/straight).
Lateral Flexion (side-to-side).
Rotation (left/right).
Shoulder Girdle (Scapula):
Elevation (shrugging up).
Depression (moving down).
Protraction (moving forward).
Retraction (moving backward).
Upward/Downward Rotation (occurring when arms move above degrees).
Shoulder and Hip (Ball and Socket):
Flexion and Extension.
Abduction (away from body) and Adduction (added to body).
Internal/Medial Rotation and External/Lateral Rotation.
Horizontal Adduction and Horizontal Abduction (specific to the shoulder).
Circumduction (a combination of flexion, extension, abduction, and adduction).
Elbow and Knee:
Flexion.
Extension.
Radioulnar Joint:
Supination (carrying a bowl of soup; palms up).
Pronation (palms down).
Wrist:
Flexion and Extension.
Ulnar Deviation (Adduction).
Radial Deviation (Abduction).
Fingers and Toes:
Flexion (curling).
Extension (straightening).
Abduction and Adduction.
Thumb:
Opposition.
Reposition.
Ankle:
Plantar Flexion (pointing toes down).
Dorsiflexion (pulling toes toward the shin).
Inversion (turning foot inward).
Eversion (turning foot outward).
Degrees of Freedom, Range of Motion, and Clinical Assessment
Degrees of Freedom: Refers to the number of planes in which a joint can move.
Uniaxial: Movement in plane around axis ( degree of freedom). Example: The elbow joint (flexion/extension only).
Biaxial: Movement in planes around axes ( degrees of freedom). Examples: The wrist and the thumb (flexion/extension and deviation/circumduction).
Triaxial: Movement in planes with degrees of freedom. Examples: The shoulder and hip joints.
Range of Motion (ROM): The total amount of motion available at a joint.
Every joint has a general standard for healthy ROM (e.g., degrees for certain milestones).
Clinical Assessment: ROM is measured using a tool called a goniometer.
Rehabilitation Goal: In cases of injury (e.g., a major elbow dislocation splinted for months), the goal of rehab is to use the goniometer to track progress from limited movement back toward standardized degrees or toward the ROM of the patient's "good" (uninjured) arm.
Anatomical Zero: The starting point in the anatomical position before movement occurs; the baseline for measuring degrees of motion.
Questions & Discussion
Question: When discussing the deltoid, which head are we focusing on in a lateral exercise?
Answer: It targets all three: the anterior, middle, and posterior heads.
Question: Why is it important to know internal/external versus medial/lateral rotation?
Answer: References vary by clinic and head therapist. Being professional requires knowing both sets of interchangeable terms to avoid confusion in a clinical setting.
Question: Can shorthand like "traps," "bis," and "tris" be used on exams?
Answer: No. Professional kinesiology requires full anatomical names (e.g., trapezius, biceps brachii, triceps brachii, pectoralis major). Shorthand is for gym settings; formal terminology is for clinical professionals.
Observation: The concept of planes and axes is found in every kinesiology textbook, yet is rarely discussed by name in the real world of therapist-to-patient interaction. Regardless, it remains a core part of the academic curriculum.