Running Jargon Buster

A comfortable, conversational-pace run where you could hold a full conversation. Should make up the majority of your weekly mileage — typically 60–80% of all your running. Often underestimated but crucial for building aerobic fitness.

Your longest run of the week, typically done at an easy pace. Builds endurance, teaches your body to burn fat as fuel, and prepares you mentally for race day. For marathon runners, long runs can reach 20+ miles during peak training.

A sustained, "comfortably hard" effort — usually 20–40 minutes at your lactate threshold pace. Sometimes called a threshold run. You can speak in short sentences but couldn't hold a conversation. One of the most effective sessions for improving race performance.

Repeated hard efforts separated by recovery periods. For example: 6 × 1km at 5K pace with 90 seconds rest between each. Intervals train your body to run faster by pushing into uncomfortable effort zones in short, manageable bursts.

Swedish for "speed play." Unstructured intervals where you vary your pace naturally — sprint to the next lamppost, jog to the corner, pick it up again. Great for building speed without the rigidity of a track session. Popular with beginners and experienced runners alike.

Short, controlled accelerations of around 20–30 seconds, usually tacked onto the end of an easy run. Not a full sprint — more like 85–90% effort. Strides improve your running form and neuromuscular efficiency without adding meaningful fatigue.

Repeated hard efforts running uphill, jogging back down to recover. One of the best sessions for building leg strength, power and running economy. Often called "speed work in disguise" because the hill naturally limits your pace and reduces injury risk.

A run that starts easy and gradually gets faster. Teaches your body to run hard on tired legs — great race-day preparation. A common format: first third easy, middle third steady, final third at marathon pace or faster.

A very short, very easy run the day after a hard session. Keeps blood flowing to tired muscles to speed recovery without adding stress. If it feels too hard, it's not a recovery run — slow down.

A period of consistent, mostly easy-paced running to build your aerobic foundation before introducing harder sessions. Think of it as laying the groundwork — without a solid base, speed work and race-specific training won't be as effective.

The planned reduction in training volume in the final 2–3 weeks before a race. Your mileage drops but intensity stays similar, allowing your body to recover and arrive at the start line fresh. Many runners find tapering mentally challenging — the urge to keep training is real.

Structuring your training into distinct phases over weeks or months — typically base, build, peak and taper. Each phase has a specific purpose. Rather than training the same way all year, periodisation ensures you peak at the right time for your goal race.

Personal Best (UK) or Personal Record (US) — your fastest ever time at a given distance. Chasing a PB is the most common goal in recreational running. Every runner has one, whether it's a 5K in 40 minutes or a marathon in 2:58.

Running the second half of a race faster than the first. Widely regarded as the ideal race strategy — starting conservatively and finishing strong. Most PBs are run on negative or even splits. Going out too fast is the most common race-day mistake.

Running the first half of a race faster than the second — usually a sign you went out too hard. Common in marathons, especially for less experienced runners. Often leads to the dreaded "wall" in the later miles.

Gun time is measured from when the race starts (the gun fires). Chip time is measured from when you personally cross the start line — tracked by a timing chip on your bib or shoe. In large races, chip time is your "real" time. PBs are usually measured by chip time.

Good For Age — a guaranteed entry to certain races (notably London Marathon) if you run under a time standard for your age group. For example, men aged 40–44 need sub-3:05 to earn a GFA place at London. A popular goal for club runners.

Boston Qualifier — running fast enough to qualify for the Boston Marathon, one of the world's most prestigious road races. Standards vary by age and gender; for men aged 40–44, the qualifying time is sub-3:10. One of the most coveted goals in amateur marathon running.

DNF = Did Not Finish; DNS = Did Not Start. Both appear in race results. DNF usually means a runner withdrew mid-race due to injury or illness. DNS means they entered but didn't make the start line. Neither is shameful — knowing when to stop is part of smart racing.

Also called "bonking" — the sudden, severe fatigue that hits when your body runs out of glycogen (stored carbohydrate). Most common around miles 18–22 in a marathon. Proper pacing, fuelling and training significantly reduce the risk. Proper fuelling during the race is essential to avoid it.

A free, weekly timed 5K run held at hundreds of locations across the UK (and worldwide) every Saturday at 9am. Not a race — a timed event open to all ages and abilities. Brilliant for beginners, great for speedwork for experienced runners, and a fantastic community.

The maximum rate at which your body can consume oxygen during exercise. Often described as the gold standard measure of aerobic fitness. Higher VO2 max = greater potential. It's partly genetic but significantly trainable — especially through interval training and consistent long runs.

A running fitness score developed by Dr Jack Daniels based on your race performances. Rather than testing your actual VO2 max in a lab, VDOT estimates it from race times and is used to set training paces. A VDOT of 50 is solid club runner level; 60+ is elite amateur territory. Use the calculator to find yours.

The effort level at which lactic acid accumulates in your blood faster than your body can clear it. Running above this threshold is unsustainable for long. Training at or near threshold pace (tempo runs) raises this ceiling — allowing you to run faster before fatigue sets in. A key marker for race performance.

Aerobic means "with oxygen" — easy to moderate efforts your body can sustain for long periods. Anaerobic means "without oxygen" — very hard efforts that can only be maintained for short bursts. Most running is aerobic; sprints and very hard intervals are anaerobic. Training both systems makes you a more complete runner.

Training intensity bands based on your maximum heart rate (MHR). Zone 1–2 is easy/aerobic; Zone 3 is steady; Zone 4 is threshold; Zone 5 is max effort. Training in the correct zones for each session is key — many runners run their easy days too hard and their hard days not hard enough.

The number of steps you take per minute. Often cited ideal is around 170–180 steps per minute, though this varies by runner. Increasing cadence slightly can reduce overstriding, lower impact forces and improve efficiency. Most GPS watches now measure cadence automatically.

How efficiently you use oxygen at a given pace — essentially your miles per gallon. Two runners with the same VO2 max can have very different performances if one has better running economy. Improved by strength training, good form, strides and consistent mileage over time.

A video assessment of how you run — looking at foot strike, hip alignment, arm swing, cadence and posture. Used to identify inefficiencies or injury risks. Can be done on a treadmill at a specialist running shop (often free) or by a running coach.

The natural inward roll of your foot as it strikes the ground. Overpronation (rolling too far inward) and supination (rolling outward) can lead to injury if not addressed through appropriate footwear or strength work. Most runners are neutral or mild overpronators.

Increasing carbohydrate intake in the 2–3 days before a long race to maximise glycogen stores. Most beneficial for efforts lasting 90 minutes or more. Doesn't mean eating huge amounts — more about shifting the balance of your diet toward carbs rather than fat and protein.

Small sachets of concentrated carbohydrate used for fuelling during long runs and races. Typically taken every 30–45 minutes from around 45–60 minutes into a run. Practice using them in training — never try a new gel on race day. Stomach issues from gels are common if you haven't trained with them.

Minerals — mainly sodium, potassium and magnesium — lost in sweat. Replenishing electrolytes during long runs (via sports drinks, tablets or salty foods) helps prevent cramping, maintains fluid balance and keeps performance levels up. More important in heat or for heavy sweaters.

Taking in carbohydrate during a run to maintain energy levels. Generally needed for runs longer than 60–75 minutes. Good fuelling can be the difference between a strong finish and hitting the wall. Many recreational runners underfuel — practising your race-day nutrition strategy in training is essential.

Racing shoes with a stiff carbon fibre plate embedded in a thick foam midsole. The plate acts like a spring, improving running economy by up to 4%. Examples: Nike Vaporfly, Adidas Adizero Adios Pro. Beneficial at race pace but not recommended for everyday training — save them for races and key sessions.

The thickness of the foam between your foot and the ground. Higher stack = more cushioning. Modern marathon shoes often have 35–40mm stacks. More cushioning isn't always better for everyone — it can affect ground feel and stability, particularly for shorter distances.

The height difference between the heel and forefoot of a shoe, measured in millimetres. A 10mm drop is fairly standard; zero-drop shoes sit flat like bare feet. Lower drop encourages a more midfoot or forefoot strike but requires a careful transition to avoid injury to the Achilles and calves.

A running watch that uses GPS to track pace, distance, route and often heart rate. Popular brands include Garmin, Polar, COROS and Suunto. An invaluable training tool — though be cautious of becoming too reliant on pace data and ignoring how you actually feel.

A social fitness app where runners (and cyclists) log and share their activities. Widely used by the running community for tracking training, joining challenges and following other athletes. Segments allow you to compare your times on specific routes. A great motivational tool — and occasionally a source of unnecessary competitiveness.