Sports & Fitness Glossary

Active recovery is very low-intensity exercise performed to promote blood flow and recovery between hard training sessions. It's typically done at 50-60% of maximum heart rate and helps clear metabolic waste while maintaining movement patterns.

Base phase is the foundational training period focused on building aerobic capacity through high-volume, low-intensity work. It typically lasts 8-16 weeks and emphasizes Zone 2 training to develop the aerobic engine that powers all harder efforts.

Bonking (hitting the wall) is the sudden onset of fatigue and weakness that occurs when glycogen stores are depleted during prolonged exercise. It typically happens 90-120 minutes into intense exercise when the body can no longer maintain blood glucose levels for muscle and brain function.

A brick workout is a training session that combines two disciplines back-to-back, most commonly cycling immediately followed by running. The name comes from how your legs feel "like bricks" when you start running after cycling.

Build phase is the training period that follows base phase, where intensity increases and race-specific workouts are introduced. Volume remains high while threshold, tempo, and interval training become the focus for 6-10 weeks before peak and taper phases.

A calorie (technically kilocalorie or kcal) is a unit of energy. In exercise, calories measure how much energy your body burns during physical activity. The number of calories burned depends on activity type, intensity, duration, and body weight.

Carb loading is the practice of consuming extra carbohydrates before endurance events to maximize glycogen storage in muscles and liver. Done correctly, it can increase glycogen stores by 25-100% and delay fatigue during races lasting 90+ minutes.

CdA (Coefficient of Drag times frontal Area) is the primary measure of aerodynamic efficiency in cycling. A lower CdA means less air resistance, allowing faster speeds at the same power output. Typical values range from 0.20 m² (TT position) to 0.40 m² (upright position).

Critical Speed (CS) is the highest running velocity that can be maintained in a "metabolic steady state"—where oxygen supply meets demand and lactate doesn't continuously rise. It's similar to lactate threshold pace but derived differently, using time trials rather than blood tests.

CSS (Critical Swim Speed) is the swimming equivalent of lactate threshold—the fastest pace you can maintain aerobically without accumulating fatigue. It's calculated from time trials and used to prescribe swimming training zones.

Cycling cadence is the number of complete pedal revolutions per minute (RPM). Most cyclists pedal between 80-100 RPM, though optimal cadence varies based on terrain, intensity, and individual physiology. Higher cadence reduces muscle fatigue; lower cadence produces more torque.

Easy pace is a comfortable, conversational running intensity typically 60-90 seconds per mile slower than your 5K race pace. It's the foundation of distance running training, building aerobic fitness while allowing recovery between hard workouts.

Electrolytes are minerals that carry electrical charges in the body, essential for muscle contraction, nerve function, and fluid balance. The key electrolytes for athletes are sodium, potassium, magnesium, and calcium, with sodium being most important during exercise.

FTP (Functional Threshold Power) is the highest average power output, measured in watts, that a cyclist can sustain for approximately one hour. It represents the boundary between sustainable and unsustainable exercise intensity.

Gear ratio is the relationship between the number of teeth on your chainring (front) and cassette cog (rear). A 50/25 combination gives a 2:1 ratio, meaning the rear wheel rotates twice for every pedal revolution. Higher ratios are harder to pedal but faster; lower ratios are easier for climbing.

Glycogen is the storage form of glucose in muscles and liver, serving as the body's primary fuel for exercise. The body can store approximately 400-600 grams of glycogen, providing enough energy for 90-120 minutes of moderate to high-intensity exercise.

A Half Ironman (officially Ironman 70.3) is a middle-distance triathlon consisting of a 1.9km swim, 90km bike, and 21.1km run (half marathon). The "70.3" refers to the total distance in miles. Finish times typically range from 4:30 to 8:00+ hours.

Heart rate zones are intensity categories based on percentage of your maximum heart rate (or heart rate reserve). They range from Zone 1 (very easy) to Zone 5 (maximum effort) and help guide training intensity for different fitness adaptations.

Hydration is the process of maintaining adequate fluid levels in the body during exercise. Proper hydration supports performance, temperature regulation, and overall health. Athletes should aim to replace 80-100% of sweat losses, typically 400-800ml per hour depending on conditions.

Intensity Factor (IF) is the ratio of your Normalized Power to your FTP, expressed as a decimal. An IF of 1.0 means you rode at your threshold; IF of 0.75 means 75% of threshold. IF is essential for calculating TSS and assessing ride difficulty.

An Ironman is a full-distance triathlon consisting of a 3.8km (2.4mi) swim, 180km (112mi) bike, and a full 42.2km (26.2mi) marathon run. It's widely considered one of the most challenging single-day endurance events in the world, with finish times typically ranging from 8-17 hours.

Lactate threshold is the exercise intensity at which lactate production exceeds the body's ability to clear it, causing rapid fatigue. There are two thresholds: LT1 (aerobic threshold) and LT2 (anaerobic threshold), with LT2 closely corresponding to FTP.

MET (Metabolic Equivalent of Task) is a measure of exercise intensity expressed as a ratio to resting metabolic rate. One MET equals your energy expenditure at rest (~3.5 mL oxygen/kg/min). Walking is about 3 METs; running is 8-12+ METs.

A negative split means running the second half of a race faster than the first half. For example, running the first 13.1 miles of a marathon in 1:50:00 and the second half in 1:45:00. This strategy conserves energy early for a stronger finish.

Normalized Power (NP) is a weighted average power that accounts for the greater physiological cost of variable-intensity riding. Unlike average power, NP reflects how hard a ride actually felt by giving more weight to harder efforts.

An Olympic triathlon (also called Standard Distance or International Distance) consists of a 1.5km swim, 40km bike, and 10km run. It's the distance used in the Olympic Games and typically takes 2-3 hours to complete.

Open water swimming (OWS) is swimming in natural bodies of water—lakes, rivers, and oceans—rather than pools. It requires additional skills like sighting, navigation, and handling varied conditions. In triathlon, the swim leg is almost always in open water.

Overtraining syndrome occurs when training stress consistently exceeds recovery capacity, leading to persistent fatigue, declining performance, and various physical and psychological symptoms. It can take weeks to months to recover from true overtraining.

Running pace is the time it takes to run a specific distance, typically expressed as minutes per mile (min/mi) or minutes per kilometer (min/km). For example, an 8:00 min/mi pace means you complete each mile in 8 minutes.

Periodization is the strategic division of training into specific phases (periods), each with distinct goals and training emphases. It prevents overtraining, maximizes adaptation, and peaks performance for key events.

A power meter is a device that measures how much power (in watts) you produce while cycling. It uses strain gauges to measure force and combines it with angular velocity to calculate power. Power meters enable precise training, pacing, and performance tracking.

Rolling resistance (Crr) is the energy lost as a tire deforms when rolling on a surface. It's measured as a coefficient typically ranging from 0.002-0.010 for cycling. Lower rolling resistance means more of your power goes to moving forward instead of being lost in the tire.

Running cadence is the number of steps (footstrikes) you take per minute, typically measured as SPM (steps per minute). Most recreational runners have a cadence of 150-170 SPM, while elite runners often maintain 180+ SPM.

Running economy is the oxygen cost of running at a submaximal pace. Better running economy means using less oxygen (and energy) to run the same speed, allowing you to run faster or longer with the same effort.

A sprint triathlon is the shortest standard triathlon distance: 750m swim, 20km (12.4mi) bike, and 5km (3.1mi) run. It's ideal for beginners and takes most athletes 1-2 hours to complete.

Sweet spot is a training intensity between 88-94% of FTP that provides most of threshold training's benefits with significantly less fatigue and faster recovery. It's considered the most time-efficient zone for building cycling fitness.

Swim pace is the time it takes to swim a specific distance, typically expressed as minutes and seconds per 100 meters (min:sec/100m). For example, a 2:00/100m pace means swimming 100 meters in 2 minutes.

SWOLF (Swim + Golf) is a swimming efficiency score calculated by adding your time in seconds to your stroke count for a length. Lower SWOLF scores indicate more efficient swimming. Like golf, a lower score is better.

Taper is the strategic reduction in training volume before a key race while maintaining some intensity. A proper taper reduces fatigue without significantly decreasing fitness, allowing peak performance on race day.

Tempo pace is a "comfortably hard" running intensity at approximately 85-90% of maximum heart rate or your lactate threshold pace. It's sustainable for 20-40 minutes and trains your body to clear lactate more efficiently.

Threshold pace is the fastest running speed you can sustain for approximately one hour—the point where lactate production equals clearance. It's typically 10K to 15K race pace and forms the foundation for structured running training.

Training zones are intensity categories based on power output or heart rate, typically numbered 1-7 (or 1-5). Each zone targets different physiological adaptations, from recovery (Zone 1) to maximum sprinting (Zone 7).

Transitions in triathlon are the changeovers between disciplines: T1 (swim-to-bike) and T2 (bike-to-run). Often called the "fourth discipline," transitions can make or break a race and require practice to execute efficiently.

TSS (Training Stress Score) is a metric that quantifies the training load of a workout by combining duration and intensity relative to your FTP. A TSS of 100 equals one hour at your threshold power (FTP).

VDOT is a running fitness score developed by Dr. Jack Daniels that represents your current running ability. It's used to predict race times across distances and calculate optimal training paces for easy runs, tempo runs, intervals, and repetitions.

VO2 Max (maximal oxygen uptake) is the maximum amount of oxygen your body can consume and use during intense exercise, measured in milliliters per kilogram of body weight per minute (mL/kg/min). It represents the ceiling of your aerobic capacity.

Watts per kilogram (W/kg) is your power-to-weight ratio—your cycling power output divided by your body weight. It's the key metric for climbing and overall cycling performance, making it easier to compare cyclists of different sizes.

Watts (W) measure power output in cycling—the rate at which work is done. One watt equals one joule of energy per second. Power meters measure watts directly, providing objective, instant feedback on how hard you're riding.

Zone 2 training is low-intensity aerobic exercise performed at 60-70% of maximum heart rate. It builds your aerobic base, improves fat oxidation, and should comprise approximately 80% of your training volume for optimal endurance development.