21 topics
Kinesiology help, from joint action to energy system
The first hard skill in kinesiology is movement analysis, and it fails at a predictable place: naming a muscle as the agonist when it is actually working eccentrically to control the movement gravity is already causing. Lowering a dumbbell slowly is not triceps work. It is the biceps lengthening under tension. Get that distinction right and the rest of the analysis, from plane and axis through to lever class, follows in order.
Where students get stuck
Concentric or eccentric — I guess, and half the time I am wrong
Do not ask which way the limb moved. Ask which muscle is under tension, then ask whether that muscle is getting shorter or longer. Concentric means the muscle shortens while producing force and the joint angle closes in its direction. Eccentric means the muscle produces force while being lengthened, acting as a brake. That is why a slow curl down is eccentric biceps work, not triceps work: gravity supplies the movement, and the biceps only resists it. Eccentric contractions produce more force than concentric ones because of the passive elastic contribution and slower cross-bridge detachment, which is also why they cause most of the delayed onset muscle soreness a day or two later. The general rule for exams: if the movement is going with gravity and is controlled, it is eccentric work by the muscle that would otherwise cause the opposite movement.
Agonist, antagonist, synergist and stabiliser feel arbitrary
They are roles, not muscle identities, and the same muscle changes role between movements. The agonist is whichever muscle is the prime mover for the specific action being described. The antagonist is the one on the opposite side that must relax and lengthen for it to happen. So the biceps is the agonist in elbow flexion and the antagonist in elbow extension, and there is no contradiction. A synergist assists the movement or cancels an unwanted secondary action, which is what the brachialis does in a curl. A stabiliser holds a segment still so the prime mover has something to pull against, which is what the rotator cuff does at the shoulder during almost any arm movement. Always name the movement first, then assign the roles, and never assign a role to a muscle in the abstract.
Planes and axes swap in my head on every test
The trick is that movement happens in a plane and rotates about the axis perpendicular to it, so the two names never match. Sagittal plane movement, meaning flexion and extension, occurs about a frontal axis running side to side, which is what a biceps curl and a walking stride are. Frontal plane movement, meaning abduction and adduction, occurs about a sagittal axis running front to back, which is a jumping jack or a lateral raise. Transverse plane movement, meaning rotation, occurs about a longitudinal axis running head to toe, which is a golf swing or a torso twist. Learn the pairings as the three opposites rather than as six separate facts, and check yourself by pointing a finger along the axis you think the segment spins around.
Almost every muscle is a third class lever and I do not see why that helps
In a third class lever the effort sits between the fulcrum and the load, which in the body means the muscle inserts close to the joint while the weight is out at the end of a long limb. That arrangement is at a mechanical disadvantage: the muscle must generate far more force than the load weighs, because its moment arm is tiny compared with the load's moment arm. What you get in exchange is speed and range, since a small, fast muscle shortening swings the far end of the limb a long way very quickly, which is what throwing and kicking require. That trade-off is the answer to most lever questions. It also explains why holding a weight with a straight arm is so much harder than holding it tucked in: you have lengthened the load's moment arm without changing the muscle's.
The three energy systems blur, and I still think lactic acid causes soreness
Separate them by how fast they supply ATP and how long they last, since that is what every question is really testing. The ATP-PC system is immediate and unlimited in power but lasts roughly ten seconds, which covers a shot put or a short sprint. Anaerobic glycolysis takes over for high intensity work up to about two minutes and produces ATP quickly without oxygen. The aerobic system is slow to ramp but effectively unlimited in duration, and it is the only one that fully oxidises fuel. They are never used one at a time; they overlap, and the question is which one dominates. On the soreness point, lactate is a fuel that gets shuttled to the heart and liver and is cleared within about an hour. Soreness that arrives a day later is mechanical damage from eccentric loading, not acid left over from training.
What's covered
Kinesiology topics you can work through with a tutor, generate practice on, or turn into flashcards and a study plan.
Anatomical foundations
- Anatomical position and directional terminology
- Planes of motion and their corresponding axes
- Joint classification and degrees of freedom
- Named joint actions at each major joint
Muscles and movement analysis
- Origin, insertion and line of pull
- Agonist, antagonist, synergist and stabiliser roles
- Concentric, eccentric and isometric contractions
- Muscle fibre types and recruitment order
- Sliding filament theory and the motor unit
Biomechanics
- Lever classes and mechanical advantage
- Torque, moment arms and centre of gravity
- Newton's laws applied to human movement
- Ground reaction force and impulse
- Gait cycle and running mechanics
Exercise physiology
- ATP-PC, glycolytic and oxidative energy systems
- Cardiovascular and respiratory responses to exercise
- VO2 max, lactate threshold and testing protocols
- Training principles, overload and adaptation
Motor control and skill
- Stages of motor learning and feedback types
- Proprioception and the stretch reflex
- Practice design and skill transfer
Kinesiology questions
Can it walk through a movement analysis assignment with me?
Yes, and that is one of the better uses of the voice session. Describe the movement or share a video frame on screen, and it will take you through it phase by phase, since most marks are lost by analysing a whole action as one block instead of splitting it into preparation, execution and follow-through. It will make you name the joint action before naming any muscle, which is the order markers expect.
How do I memorise origins and insertions without hating my life?
Stop memorising them as text and derive the action instead. If you know roughly where a muscle starts and ends, its action is whatever shortening the line between those points would do to the joint in between. Build flashcards that ask for the action given the attachments rather than the reverse, since that is the direction exams test, and you will find the attachments stick as a by-product.
Can it give me a training programme or tell me if my squat form is safe?
No. It is a tutor for your coursework, not a coach or a clinician, and it will not prescribe training or assess whether a movement is safe for your body. It can explain what the textbook says about knee joint torque during a squat and why depth changes the moment arm. Anything about your own body, an injury or a training plan belongs with a qualified professional who can see you in person.
My programme calls this biomechanics or human movement science. Same thing?
The overlap is large and the material here covers it. Departments split the name differently, with biomechanics leaning towards forces, torques and instrumentation, and kinesiology courses spending more time on qualitative movement analysis and physiology. If your course is the physics-heavy version, expect more free body diagrams and vector work, and it is worth doing the mechanics alongside the anatomy rather than after it.
Stuck on kinesiology right now?
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