K-band – A region within the sarcomere seen under a microscope, part of the microscopic muscle structure.

K+ channel – A protein channel in cell membranes that allows potassium ions (K⁺) to move, affecting nerve and muscle excitability.

Kainate – A neurotransmitter receptor type in the central nervous system activated by kainic acid.

Kal – Pertains to potassium, as in “hypokalaemia” meaning low potassium levels.

Kcal (kilocalorie) – A unit of energy used to measure the amount of energy in food and energy expenditure during exercise.

Kegel exercises – Movements designed to strengthen the pelvic floor muscles, important for core stability and intra-abdominal pressure.

Kemp’s test – A diagnostic test used in sports medicine to detect lumbar spine dysfunction or pain.

Kent’s training zones – A model dividing training intensities into zones based on heart rate and fitness goals.

Keratolysis – A skin condition common among athletes, causing breakdown of skin protein from repetitive moisture.

Keratohyalin – A protein found in skin that contributes to its barrier function.

Kettlebell – A round weight with a handle used in functional strength and conditioning exercises.

Kettlebell swing – A ballistic strength movement that trains the posterior chain and cardiovascular endurance.

Kettlebell snatch – A dynamic overhead lift involving power, control, and coordination.

Kettlebell clean – A strength exercise that brings the kettlebell to the shoulder in one fluid motion.

Key performance indicator (KPI) – A measurable value that reflects performance success in an athlete or team.

Kick – A biomechanical action using the lower limb to strike an object, commonly seen in football or martial arts.

Kick serve – A topspin tennis serve that bounces high and is difficult to return.

Kick-off – The method of restarting play in football, rugby, and similar team sports.

Kickback exercise – A resistance exercise commonly targeting the triceps or hip extensors.

Kicking board – A tool used in swimming to isolate leg movement during training.

Kicking efficiency – A measure of force and technique applied during a kicking action.

Kicking leg – The dominant leg used to strike or kick in sports.

Kicking technique – The biomechanical execution of a controlled and purposeful leg movement to strike.

Kinematic chain – A sequence of joints and muscles acting together to produce coordinated movement.

Kinematic feedback – Visual or technical information about movement mechanics used to improve performance.

Kinematic variables – Measurable motion-related factors such as velocity, displacement, and acceleration.

Kinematics – The study of motion in terms of speed, displacement, and angles, without considering force.

Kinanthropometry – The scientific study of human body size, composition, and proportion related to movement.

Kinase – An enzyme that transfers phosphate groups and plays roles in muscle signalling and adaptation.

Kinesiophobia – The fear of movement, often seen in injured athletes returning to sport.

Kinesiologist – A professional who analyses human movement to improve performance or assist rehabilitation.

Kinesiology – The study of human movement, integrating anatomy, biomechanics, and physiology.

Kinesiology tape (K-tape) – An elastic tape applied to muscles or joints to support and enhance proprioception.

Kinesiotaping – A therapeutic taping method used to support movement without restricting range.

Kinetics – The study of forces that cause or result from motion.

Kinetic chain – A model describing how body segments and joints work together in complex movement.

Kinetic energy – The energy a body possesses due to its motion.

Knee – A hinge joint connecting the femur, tibia, and patella, crucial for locomotion.

Knee alignment – The relative positioning of the femur, patella, and tibia during standing or movement.

Knee brace – A support device used to stabilise and protect the knee joint during activity or recovery.

Knee capsule – The fibrous structure that surrounds the knee joint, providing protection and lubrication.

Knee extension – Straightening the leg at the knee, increasing the joint angle.

Knee flexion – Bending the leg at the knee, decreasing the joint angle.

Knee joint proprioception – The sense of joint position and movement at the knee, crucial for stability.

Knee joint reaction force – The force exchanged between joint surfaces during movement.

Knee ligaments – The ACL, PCL, MCL, and LCL are key stabilisers of the knee joint.

Knee loading – The mechanical stress placed on the knee during weight-bearing or explosive activity.

Knee sleeve – A compression garment used to support the knee during physical activity.

Knee taping – A supportive technique using athletic tape to stabilise the knee.

Knee valgus – A movement fault where the knees collapse inward during movement, increasing injury risk.

Knee varus – A condition where the knees bow outward, placing stress on lateral knee structures.

Knee trauma – Acute or chronic injury to structures of the knee, such as ligaments or cartilage.

Kneeling posture – A body position used in certain assessments and exercises to stabilise the lower body.

Knock-on effect – An indirect consequence or chain reaction resulting from a change in training or strategy.

Knowledge of performance (KP) – Feedback relating to the quality or form of the movement performed.

Knowledge of results (KR) – Feedback related to the outcome or success of a movement or skill.

Known-groups method – A validation technique where measures are tested across groups with known differences.

Krebs cycle (Citric Acid Cycle) – A key part of aerobic metabolism that produces ATP in the mitochondria.

Kyphosis – An excessive outward curve of the thoracic spine, affecting posture and performance.

THE SIMPLY SPORT SCIENCE A-Z