Fartlek training – A training method blending continuous and interval running with varied intensity.

Fast-twitch fibres – Muscle fibres that contract quickly and generate high force for short durations.

Fat oxidation – The process of breaking down fat to produce energy during aerobic activity.

Fat-soluble vitamins – Vitamins (A, D, E, K) stored in body fat and used in small amounts.

Fatigue index – A measure of how quickly power output declines during repeated efforts.

Feedback loop – A system of continuous performance monitoring and adjustment using feedback.

Feldenkrais method – A movement approach focused on body awareness and efficient motion.

Female athlete triad – A syndrome involving energy deficiency, menstrual dysfunction, and low bone density.

Fibre recruitment – The activation of motor units to produce muscular force.

Field-based testing – Fitness or performance assessments conducted outside the lab in real-world settings.

Fine motor skill – A skill involving small muscle groups and precision, like writing or shooting.

First-class lever – A lever with the fulcrum between the effort and the load, like a seesaw.

FITT principle – A training principle: Frequency, Intensity, Time, and Type of activity.

Fixator muscle – A muscle that stabilises a body part while another moves.

Fixed practice – Repeating the same skill in a stable, unchanging environment.

Flexibility training – Exercises aimed at improving the range of motion at joints.

Flexion – A movement that decreases the angle between two bones at a joint.

Flight phase – The airborne part of a movement when both feet are off the ground.

Fluid intelligence – The ability to solve new problems using logic and reasoning.

Fluid mechanics – The study of how liquids and gases affect movement.

Force couple – Two equal and opposite forces causing rotational movement.

Force plate – A device that measures ground reaction force in activities like jumping or landing.

Force summation – The coordination of multiple body parts to generate maximum force.

Force-time curve – A graph showing how force is produced over time.

Foreperiod – The time between a warning signal and the presentation of a stimulus.

Formative assessment – Ongoing feedback during learning to guide improvement.

Fossa – A shallow depression in a bone, often where muscles or tendons attach.

Fracture – A break or crack in a bone caused by impact or stress.

Framing effect – The way information is presented influences how it is understood or acted on.

Framing of practice – How a coach introduces and structures training to maximise learning.

Frontal lobe – The part of the brain involved in planning, problem-solving, and voluntary movement.

Frontal plane – A vertical plane dividing the body into front and back halves.

Fuel utilisation – The body’s selection of fats, carbohydrates, or proteins for energy.

Functional fitness – Training that improves everyday movement ability and muscle coordination.

Functional movement – Natural or purposeful movement patterns used in sport and daily life.

Functional overreaching – A short-term increase in training load to boost performance after recovery.

Functional residual capacity – The volume of air remaining in the lungs after normal exhalation.

Functional strength – Strength that enhances performance in sport-specific or everyday movements.

Fundamental movement skills – Basic motor patterns like running, jumping, and throwing are developed in childhood.

Fusiform muscle – A spindle-shaped muscle with fibres that run parallel to the length.

Feedback inhibition – A process where output of a system slows or stops the process itself.

Fat-free mass – The total body mass minus fat, including bone, muscle, and water.

Friction – The resistance that occurs when one surface moves over another.

Free weights – Unrestricted weight training equipment like dumbbells and barbells.

Functional magnetic resonance imaging (fMRI) – A brain scan showing activity during cognitive or motor tasks.

Force velocity curve – A graph showing how force output varies with speed of contraction.

Fitness component – A category of physical ability such as strength, endurance, or agility.

Fitness testing battery – A group of standardised tests used to assess different aspects of fitness.

Flexion-relaxation phenomenon – A reduction in muscle activity in the spine when bending forward passively.

Flight time – The duration spent in the air during a jump or movement phase.

Foot strike pattern – The part of the foot that first contacts the ground during running.