A
The strong tendon connecting your calf muscles to your heel bone. This is one of the most commonly injured areas in running, especially when increasing mileage too quickly or running on hard surfaces without proper warm-up.
Example: If you feel pain or tightness in the back of your ankle, especially in the morning, you may have Achilles tendinitis.
Running at a comfortable pace where your body uses oxygen to convert fuel into energy efficiently. This is the foundation of endurance training and should make up 70-80% of your weekly mileage. At this pace, you should be able to hold a conversation.
Example: Your easy morning jog at a comfortable pace is aerobic running - it builds endurance without excessive fatigue.
Training at high elevation (typically above 2,400 meters or 8,000 feet) where there is less oxygen in the air. This forces your body to produce more red blood cells, improving oxygen delivery when you return to lower altitude.
Example: Many elite runners train in Boulder, Colorado or Flagstaff, Arizona to benefit from altitude training.
High-intensity running where your body cannot supply enough oxygen, forcing it to break down glucose without oxygen. This produces lactic acid, causing that burning sensation in your muscles. These efforts can only be sustained briefly.
Example: Sprinting all-out for 400 meters is anaerobic - you will feel your muscles burn and need recovery.
A low-impact exercise where you simulate running movements while suspended in deep water with a flotation belt. Excellent for maintaining fitness while injured, as it provides cardiovascular training without impact stress.
Example: If you have a stress fracture, aqua jogging lets you maintain fitness without weight-bearing impact.
The average time it takes to complete one kilometer or mile over your entire run, calculated by dividing total time by distance. This is the most common metric runners use to measure performance.
Example: Running 5 kilometers in 25 minutes gives you an average pace of 5:00 per kilometer.
B
Running without shoes, typically for very short distances on soft surfaces. While it can help you become aware of your natural foot strike, it is not recommended as a primary training method due to injury risk.
Example: Some runners do 50-100 meters of barefoot running on grass after runs to work on form.
The average weekly distance you run when not training for a race. This is your fitness foundation and determines what training plans you can safely follow. Building base takes months of consistent running.
Example: If you consistently run 50 kilometers per week, that is your base mileage.
A short to moderate-length run at an easy, comfortable pace. These runs build aerobic capacity without excessive fatigue and should feel relaxed, leaving you energized.
Example: A typical base run is 30-60 minutes at a pace where you can chat comfortably.
The initial phase of training focused on building aerobic fitness and gradually increasing mileage. Typically 4-8 weeks of mainly easy runs, preparing your body for more intense work later.
Example: Spend 6-8 weeks doing base training before starting intense marathon preparation.
C
The number of steps you take per minute while running. Optimal cadence is around 170-180 for most runners. Higher cadence often means better efficiency and lower injury risk. Count steps for 30 seconds and multiply by 2.
Example: Taking 85 steps in 30 seconds means your cadence is 170 steps per minute.
Skin irritation from repeated friction between skin and clothing, or skin-on-skin contact, worsened by sweat. Technical running fabrics and anti-chafe products like Body Glide help prevent this uncomfortable problem.
Example: Cotton shirts can cause nipple chafing on long runs - technical fabrics reduce this risk.
Easy running or walking (5-15 minutes) after your main workout to gradually lower heart rate, promote recovery blood flow, and reduce muscle soreness. Never stop abruptly after hard efforts.
Example: After finishing your tempo run, jog easily for 10 minutes to cool down properly.
Running on natural terrain like grass, dirt, mud, and hills rather than paved roads. Requires different skills and equipment than road running, strengthens stabilizing muscles, and is popular in schools.
Example: A cross-country race might wind through parks with grass, mud, and hills requiring trail shoes.
Non-running exercises that build fitness while giving running muscles a break. Common activities: cycling, swimming, yoga, strength training. Prevents overuse injuries and improves overall fitness.
Example: Cycling an hour on your rest day is cross-training that maintains fitness without running impact.
D
Active movements taking joints and muscles through full range of motion to prepare for running. Unlike static stretching, these use controlled motion and are best before runs. Examples: leg swings, high knees.
Example: Do leg swings, high knees, and butt kicks as dynamic stretches before your run.
E
Total uphill climbing in a run or race, measured in feet or meters. Critical for understanding difficulty - same distance with double elevation is significantly harder.
Example: A 10K with 500m elevation gain is much harder than a flat 10K.
Maintaining consistent pace throughout a run or race, running each mile or kilometer at nearly the same speed. Common pacing strategy for steady performances.
Example: Running every mile of a 10K at exactly 7:00 demonstrates perfect even splits.
F
Swedish for "speed play" - unstructured interval training alternating fast and slow based on feel rather than specific times. Fun way to improve speed and endurance without rigid structure.
Example: Sprint to a mailbox, jog to recover, run hard uphill - all based on feel during your run.
Your body's ability to maintain performance as you tire during long runs or races. Improves with endurance training and is crucial for marathon success. Mental toughness plays a big role.
Example: Long runs improve fatigue resistance so you maintain pace in final marathon miles.
The part of your foot contacting ground first: heel strike, midfoot strike, or forefoot strike. No universally "best" pattern, but changing too quickly risks injury.
Example: Many elite distance runners use midfoot strike, landing on the middle of the foot.
Your overall running posture and technique including foot strike, cadence, arm swing, and body position. Good form: upright, relaxed, efficient. Poor form leads to injuries and wasted energy.
Example: Good form includes relaxed shoulders, engaged core, and quiet foot landings.
G
Gluteal muscles (maximus, medius, minimus) in your buttocks. Critical for powerful running, especially uphill. Weak glutes cause common injuries like IT band syndrome. Strength training is essential.
Example: Squats and lunges strengthen glutes for more powerful, injury-free running.
Practicing consuming fuel (gels, chews, drinks) during training to teach your digestive system to process food while running. Crucial for marathon/ultra success - race-day fueling without practice causes stomach issues.
Example: Practice taking energy gels on long runs to prepare your gut for marathon fueling.
H
Three muscles along the back of your thigh from hip to knee. Heavily used in running, especially during push-off and at faster speeds. Tight or weak hamstrings increase injury risk.
Example: Hamstring pulls are common in sprinting - proper warm-up and strength prevent them.
Number of heartbeats per minute, measuring exercise intensity. Lower resting heart rate indicates better fitness. Many runners train based on heart rate zones rather than pace.
Example: A well-trained runner might have a resting heart rate of 45-50 beats per minute.
Variation in time between heartbeats. Higher HRV generally indicates better recovery and readiness to train. Low HRV may signal fatigue or overtraining. Many runners track HRV to optimize training.
Example: Unusually low morning HRV might signal you need an easy day or rest.
Deliberately training in hot conditions or using heat exposure (sauna, hot bath) to adapt your body for better heat performance. Improves cooling ability and can enhance performance even in moderate temps.
Example: Taking hot baths after runs for 2 weeks before a summer marathon is heat training.
Short bursts (15-30 seconds) of fast uphill running with good form emphasis. Build power and strength without flat sprinting impact, making them excellent for injury prevention.
Example: After your easy run, do 6-8 hill strides up a moderate incline, driving your knees.
I
Immersing in very cold water (10-15°C) after hard training to theoretically reduce inflammation. Scientific evidence is mixed - some research suggests it may blunt training adaptations.
Example: Some runners take 10-minute ice baths after long runs, though cold showers work similarly.
Structured workouts alternating high-intensity efforts with recovery periods. Improves speed, VO2 max, and running economy. Common formats: track repeats (400m, 800m) with timed rest.
Example: Classic interval: 8 x 400m at 5K pace with 90 seconds jogging recovery.
J
Miles run at ineffective pace - too fast to build aerobic base but too slow for training stimulus. Accumulate from not running easy enough on easy days or hard enough on hard days.
Example: Running easy days at medium effort because you feel good creates junk miles - stay disciplined.
L
Byproduct of anaerobic energy production building up during intense exercise, causing muscle burning. Training improves your ability to clear lactate and tolerate higher levels.
Example: The burning in your legs during a 5K final sprint is from lactic acid buildup.
M
The specific pace you can sustain for full marathon distance. Determined through training and race experience, typically 30-90 seconds per mile slower than half marathon pace. Proper pacing is crucial.
Example: With a 1:30 half marathon, your marathon pace might be 7:15/mile for a 3:10 finish.
Ability to move joints through full range of motion with control. Different from flexibility - mobility includes strength through the movement. Reduces injury risk, improves efficiency.
Example: Hip mobility exercises like leg swings maintain proper form and prevent injuries.
Running in mountainous terrain with steep climbs, high altitudes, scrambling, and technical descents. More challenging than regular trail running, requires specialized equipment and skills.
Example: Mountain running a 14er in Colorado means predawn starts and weather preparedness.
N
A pacing strategy where you run the second half faster than the first half. Widely considered optimal as it prevents starting too fast and often leads to better results and stronger finishes.
Example: Running marathon first half in 1:35 and second in 1:32 is excellent negative splitting.
O
When your foot rolls excessively inward during your stride, which can cause pain and injuries. Stability or motion-control shoes help correct this. However, some pronation is normal and necessary.
Example: If inside of shoes wears much faster than outside, you might overpronate - try stability shoes.
P
Your personal best time for a specific distance or course. Getting a PR is a major goal for most runners and indicates improved fitness. Can be set in races or training runs.
Example: Breaking 20 minutes in a 5K for the first time is a significant PR for many runners.
Natural inward roll of your foot as it lands and pushes off. Normal pronation helps absorb impact and distribute forces. Only excessive pronation (overpronation) or underpron ation (supination) need correction.
Example: Your foot naturally pronates slightly each step - this is normal, healthy biomechanics.
R
Very easy, short run (20-45 minutes) done day after hard workout or race. Promotes active recovery - blood flow aids healing while avoiding training stress. Should feel extremely comfortable.
Example: Day after your 20-mile long run, do 30-minute recovery run at very easy pace.
Short, intense running segments repeated multiple times with recovery between. Similar to intervals but often emphasizes specific distances (400m repeats) or durations (2-minute hill repeats).
Example: Track workout: 10 x 200-meter repeats at mile pace with 200m jog recovery.
Complete day off from running to allow body recovery and adaptation. Rest days are when you actually get stronger - just as important as training. Some do light cross-training instead.
Example: Taking 1-2 complete rest days per week prevents overtraining and reduces injuries.
Interval approach alternating running and walking, used by beginners building endurance or experienced runners in ultra-marathons. Jeff Galloway popularized this for marathon training.
Example: Beginner: 1 minute running, 1 minute walking for 20 minutes, gradually increasing run time.
Running at least one mile every single day for extended period. Some maintain streaks for years or decades. While showing dedication, requires careful management to avoid overuse injuries.
Example: Some runners maintain 10+ year streaks by running just one easy mile on rest days.
Euphoric feeling and reduced anxiety during or after running. Once thought from endorphins, research shows it's primarily endocannabinoids - natural chemicals similar to cannabis creating well-being.
Example: Many runners experience runner's high around 45-60 minutes in, feeling energized and happy.
Common overuse injury causing pain around or behind kneecap, often from weak hip/glute muslces or overtraining. Worsens running downhill or descending stairs. Strengthening and proper progression prevent it.
Example: Front knee pain worsening with hills might be runner's knee - reduce mileage and strengthen glutes.
How efficiently your body uses oxygen at a given pace - your "miles per gallon." Better economy means less energy for same pace. Improves with consistent training and good form.
Example: Two runners at same pace with different heart rates - lower heart rate has better economy.
S
Any training focused on running faster than normal pace. Includes intervals, tempo runs, fartleks, hill repeats. Improves VO2 max, lactate threshold, and race performance.
Example: Tuesday track sessions with clubs often focus on speedwork like 400m or 800m repeats.
Pace or time for individual segments of your run, typically per mile or kilometer. Analyzing splits shows pacing strategy and whether you started too fast, slowed down, or stayed consistent.
Example: Looking at mile splits after a 10K shows if you paced evenly or faded.
Short accelerations (80-100m or 20-30 seconds) gradually building to 85-90% max speed, then slowing. Improve form, turnover, and neuromuscular coordination with minimal fatigue.
Example: After easy run, do 4-6 strides on flat stretch, focusing on smooth acceleration and form.
When foot doesn't roll inward enough during stride, causing excessive stress on outside of foot and ankle. Runners with high arches often supinate and need neutral or cushioned shoes. Less common than overpronation.
Example: Shoes wearing primarily on outside edge means you likely supinate - choose cushioned neutral shoes.
T
Period of reduced training volume before goal race, typically 1-3 weeks depending on distance. Allows full recovery and training absorption while maintaining fitness. Proper taper can improve performance 2-3%.
Example: For marathon, run last long run 3 weeks before, then gradually reduce weekly mileage.
Sustained effort at "comfortably hard" pace, typically 15-40 minutes at or just below lactate threshold. Improves ability to clear lactate and sustain faster paces. Often described as one-hour race pace.
Example: Typical tempo: warm up 10 min, run 20 min at tempo pace, cool down 10 min.
Similar to tempo - running at lactate threshold pace to improve body's ability to buffer and clear lactate. Fastest pace you can sustain aerobically before significant lactate accumulation.
Example: Threshold pace is typically 25-30 seconds per mile slower than current 5K race pace.
Specific pace where body transitions from primarily aerobic to increasingly anaerobic energy. Training at this improves running faster before lactate accumulation. Roughly one-hour race pace.
Example: With 45-minute 10K, threshold pace is approximately 7:15 per mile.
Running on unpaved surfaces like dirt paths, forest trails, or mountains rather than roads. Provides softer surfaces, beautiful scenery, varied terrain challenging muscles differently. Requires appropriate shoes, often slower paces.
Example: Trail running in local preserves offers peaceful alternative to pounding pavement.
V
Maximum volume of oxygen your body can use during intense exercise, measured in ml/kg/min. Considered best indicator of aerobic fitness. Elite male marathoners typically have 70-75+ ml/kg/min.
Example: VO2 max lab test involves running on treadmill with mask measuring oxygen to exhaustion.
Very intense intervals (3-5 minutes) at pace maximizing oxygen consumption. Among hardest workouts runners do, significantly improving aerobic capacity. Recovery between repeats is important.
Example: Run 5 x 1000m at current 5K race pace with 2-3 minutes recovery jogs.
W
Easy running or exercise starting workout to gradually increase heart rate, warm muscles, prepare body for harder effort. Reduces injury risk, improves performance. Typically 10-20 minutes easy jogging plus dynamic stretches.
Example: Before track workout, jog 10 min easy, do dynamic stretches, then 4-6 strides to complete warm-up.
Total distance run in one week, measuring training volume. Gradually increasing builds fitness, but more than 10% per week raises injury risk.
Example: At 30 km per week, increase to no more than 33 km next week to avoid overtraining.
Y
Popular workout by Bart Yasso: run 10 x 800m with equal recovery. Theory: average 800m time in min/sec predicts marathon time in hrs/min (3:30 800s = 3:30 marathon). While not scientifically proven, it's a great workout.
Example: Averaging 3 minutes for 10 x 800m repeats suggests readiness for sub-3-hour marathon.