Glossary

When discussing technical or physiological concepts in this book, I’ve used the simplest language possible to ensure clarity and readability. In some cases, I haven’t always included definitions or explanations in the text, trusting that many readers will already have a basic understanding of the context. This brief glossary provides additional information about key concepts, ideas, and topics addressed in the book for those who might need or want them.

80/20 principle
A training philosophy where 80% of workouts are done at low intensity and 20% at high intensity.

Achilles
A tendon connecting the calf muscles to the heel bone, commonly stressed in running.

Active recovery
Low-intensity exercise performed after intense activity to promote recovery.

Adaptations
Physiological changes in the body in response to consistent training, such as improved endurance and muscle strength.

Aerobic base
The foundation of cardiovascular fitness, built through low-intensity endurance training.

Aerobic reset
A period of exclusive low-intensity aerobic training to rebuild the aerobic system and correct imbalances.

Aerobic system
The energy system that uses oxygen to convert fat and carbohydrates into energy during sustained efforts.

Anaerobic metabolism
The energy system that generates power without oxygen, used during short, intense efforts.

Anorexia
An eating disorder characterized by self-imposed starvation and excessive weight loss, detrimental to performance and health.

Anterior chain
The group of muscles on the front of the body, including the hip flexors and quadriceps, important for running posture.

Biomechanics
The study of movement mechanics, important for efficient and injury-free running.

Bulimia
An eating disorder involving binge eating followed by purging, harmful to both health and athletic performance.

Cadence
The number of steps a runner takes per minute, often linked to running efficiency and injury prevention.

Calorie
Unit of energy provided by food, essential for fueling training and recovery.

Capillaries
Tiny blood vessels that deliver oxygen and nutrients to muscles and remove waste products.

Carbohydrate
A macronutrient and primary energy source for runners, stored in muscles and liver as glycogen.

Cardiovascular system
The heart and blood vessels that transport oxygen and nutrients throughout the body.

CO₂ tolerance
The body’s ability to tolerate higher levels of carbon dioxide, often improved through breath training.

Cognitive Behavioral Therapy for Insomnia (CBTI)
A structured, evidence-based treatment for sleep issues, beneficial for recovery.

Continuous glucose monitoring
A method to track blood sugar levels in real time, useful for nutrition and energy management.

Electrolyte
Minerals like sodium and potassium essential for hydration and muscle function during endurance activities.

Epsom salts
Magnesium sulfate used in baths to help relax muscles and reduce soreness.

Fartlek
A form of unstructured interval training combining periods of fast running with slower recovery jogs.

Fat oxidation
The process by which the body uses fat as fuel, particularly during lower-intensity exercise.

Flexion
A bending movement that decreases the angle between two body parts, important in running mechanics.

Flow state
A mental state of deep focus and immersion, often experienced during optimal running performance.

Fructose
A simple sugar found in fruit; used in some sports nutrition for quick energy.

Glucose
A simple sugar that is a key energy source for muscles during running.

Glycogen
The stored form of glucose in muscles and liver, used as fuel during prolonged exercise.

Habit stacking
A behavior strategy that builds new habits by attaching them to existing routines.

Hip flexors
Muscles that lift the thigh toward the torso, critical for running stride and posture.

Hyponatremia
A dangerous drop in blood sodium levels, often caused by excessive fluid intake during endurance events.

Insulin sensitivity
How responsive cells are to insulin; improved with regular aerobic exercise and beneficial for energy use.

Intensity discipline
The practice of staying within prescribed effort zones to maximize training benefits and avoid burnout.

Intercostal muscles
Muscles between the ribs that support breathing, particularly important during high-intensity running.

Intermittent fasting
An eating pattern that alternates periods of eating with fasting, sometimes used for metabolic benefits.

Intervals
Training sessions with repeated bouts of high-intensity running followed by recovery periods.

IT bands
Iliotibial bands; connective tissues running along the outer thigh, often implicated in running injuries.

Karvonen Formula
A method to calculate target heart rate using resting and maximum heart rate for individualized training.

Lactate threshold
The intensity of exercise at which lactate starts to accumulate in the blood, key for endurance performance.

Lactic acid
A byproduct of anaerobic metabolism that contributes to muscle fatigue during intense exercise.

MAF Method
Maximum Aerobic Function Method; a heart-rate-based approach to improve aerobic efficiency and fat burning.

Meditation
A mental practice that enhances focus, reduces stress, and can support recovery and performance.

Metabolic pathways
Biochemical routes the body uses to convert food into energy, including aerobic and anaerobic systems.

Mitochondria
Cellular structures that generate energy from oxygen and nutrients, crucial for endurance.

Naked carbs
Carbohydrates eaten without protein, fat, or fiber, which can lead to blood sugar spikes.

PB
Personal Best; the fastest time an individual has achieved for a specific running distance.

pelvic floor
Muscles at the base of the pelvis that support posture and stability during running.

polarized training
A method where most training is done at low intensity with some very high-intensity sessions.

PR
Personal Record; synonymous with Personal Best, used to track progress in race times.

progression runs
Runs that gradually increase in pace, used to simulate race conditions and improve stamina.

reactive hypoglycemia
A drop in blood sugar after eating, potentially affecting energy levels during running.

stride
The length and rhythm of a runner’s step, influencing efficiency and speed.

Super Shoes
High-tech running shoes with carbon plates and foam designed to improve performance.

sympathetic nervous system
The part of the nervous system responsible for the fight-or-flight response, activated during intense exercise.

tempo runs
Steady runs at a “comfortably hard” pace to improve lactate threshold and endurance.

training intensity
The level of effort or exertion in a workout, typically measured by heart rate or perceived effort.

training volume
The total amount of running over a period, usually measured in miles or hours per week.

two-minute rule
A strategy to overcome procrastination by committing to just two minutes of activity to build momentum.

vagus nerve
A nerve involved in parasympathetic control of the heart and digestion, associated with recovery and stress regulation.

vision board
A visual tool displaying goals and aspirations to motivate and focus training efforts.

vitamin D deficiency
A lack of vitamin D, which can affect bone health and energy levels, particularly in endurance athletes.

VO2 max
The maximum amount of oxygen the body can use during intense exercise; a key indicator of aerobic fitness.