10-K pace, when used in a workout to describe how fast to run, is simply the pace of a runner's last 10-K race."10-K pace" is therefore different for every runner; for a 62-minute 10-K runner, "10-K pace" is 10 minutes per mile; for 31:00, it's 5 minutes per mile; for Paul Tergat, it's4:16 per mile.

5-K/8-K/10-K

K is for kilometers, 1,000 meters. A 5-K is equal to 3.1 miles; 8-K is 4.96 miles; 10-K is equal to 6.2 miles.

400 meters equivalent to a quarter mile; 1 lap around a standard track

800 meters equivalent to a half-mile, 2 laps around a standard track

Anaerobic threshold (AT) the level of activity at which the aerobic energy system can no longer supply most of the demands of the body or the exercise intensity above which blood lactate concentration increases fairly dramatically. Good training will increase AT by teaching the muscles to use oxygen at higher rates, so that less lactate is produced. Also known as "lactate threshold"

"World best" A recorded best time for an event in which formal world records are not kept. For instance, the fastest time at 150m, a non-standard distance, is a "world best" rather than a "world record." Similar distinctions are made for road races which do not meet certain standards, such as races with excessive amounts of downhill.

Cool-down slow running or jogging done after a workout or competition to loosen muscles and rid the body of lactic acid

CR Course Record

Cushioning (or shock absorption) the ability of a shoe to absorb the impact of footstrike

DOMS delayed onset muscle soreness. This type of muscle soreness normally peaks about 48 hours after a particularly intense or long run.

Fartlek Swedish for "speed play;" variable pace running; a mixture of slow running, running at a moderate pace and short, fast bursts. Fartlek training is a "creative way" to increase speed and endurance.

Intervals training in which short, fast "repeats" or "repetitions" often 200 to 800 meters, are alternated with show "intervals" of jogging for recovery; usually based on a rigid format such as "six times 400 meters fast [these are the repeats] with 400-meter recovery jogs [the intervals]," interval training builds speed and endurance

Junior According to the IAAF, a junior is any athlete who is under 20 on December 31 of that year. For example, an athlete whose birthday is November 12, 1979 will be a junior in 1998 but not in 1999.

Lactic acid a substance which forms in the muscles as a result of the incomplete breakdown of glucose. Lactic acid is associated with muscles fatigue and sore muscles.  lactate threshold see "anaerobic threshold"

Last A last is a shaped piece of wood or metal on which the shoe is built. The shape of the last determines the shape of the shoe. Shoes are made in three basic shapes: straight, curved and semi-curved but all three shapes vary from company to company as each company has its own lasts.

Lateral referring to the outer edge of a shoe

Master An athlete 40 years of age or older is designated a "master" in the U.S. Many other countries use the term "veteran."

Maximum heart rate the highest heart-rate reached during a specified period of time

Medial referring to the inner side (or arch side) of a shoe

"Metric mile" 1500m, the international racing distance closest to the imperial mile.

Midsole the area of the shoe between the upper and outsole that's primarily responsible for the shoe's cushioning. Most midsoles are made of foams: either EVA (ethylene vinyl acetate) or polyurethane. EVA is lighter and more flexible than polyurethane, but it also breaks down more quickly. Many midsoles also have additional cushioning elements such as air, gel and various embedded plastic units.

Mile 1609 meters, 5280 feet, or 1760 yards. Note: 1600m is not a mile.

Motion control the ability of a shoe to limit overpronation

Negative splits running the second half of a race faster than the first half

NR National Record

Outsole the material, usually made of hard carbon rubber, on the bottom of most running shoes; the layer of the shoe that contacts the ground

Over-pronation the excessive inward roll of the foot before toe-off. Overpronation is believed to be the cause of many running injuries.

Pick-ups accelerations done during a run, normally done in shorter durations that fartleks. Pick-ups are simply another way to spice up what would otherwise be an easy-run day.

Post (or medial post) firmer density of midsole material added to the inner side of the shoe. A post is designed to reduce overpronation.

Prep In the U.S., a high school athlete. From the term "preparatory school," a school for preparing for college. Slightly different from the IAAF definition of "Junior."

Pronation Pronation begins immediately after the heel contacts the ground. It is a normal and necessary motion for walking or running. Pronation is the distinctive, inward roll of the foot as the arch collapses.

PR/PB personal record, personal best

Repeats see "intervals"

Ride the ability of a shoe to provide a smooth transfer of a runner's weight from heel-strike to toe-off. Ride is a largely subjective quality, but shoe wearers know it when a shoe has or lacks a good ride.

Runner's high a feeling, usually unexpected, of exhilaration and well-being directly associated with vigorous running; apparently related to the secretion of endorphins

Running economy refers to how much oxygen you use when you run; When you improve your economy, you are able to run at a smaller percentage of max VO2 (your maximum rate of oxygen utilization).

Stability the ability of a shoe to resist excessive foot motion

Strides short, fast but controlled runs of 50 to 150 meters; Strides, which are used both in training and to warm up before a race, build speed and efficiency.

Supination The opposite of pronation. It's an outward rolling of the forefoot that naturally occurs during the stride cycle at toe-off. Oversupination occurs when the foot remains on its outside edge after heel strike instead of pronating. A true oversupinating foot underpronates or does not pronate at all so it doesn't absorb shock well. It is a rare condition occurring in less than 1 percent of the running population.

Taper Runners usually cut back mileage (or taper) one day to three weeks (depending on race distance) before a big race. Tapering helps muscles rest so that they are ready for peak performance on race day. For more on tapering, see Owen Anderson's "Taper Talk."

Target heart rate a range of heart rate reached during aerobic training which enables an athlete to gain maximum benefit

Tempo runs sustained effort training runs, usually 20 to 30 minutes in length, at 10 to 15 seconds per mile slower than 10-K race pace. Another way to gauge the pace of tempo runs-- a pace about midway between short-interval training speed and your easy running pace.

Threshold runs runs of 5 to 20 minutes at a pace just a little slower than your 10-K racing pace; Threshold pace is roughly equivalent to what exercise physiologists call "lactate threshold," or the point at which your muscles start fatiguing at a rapid rate. Running at or near lactate threshold is believed to raise your lactate threshold , which should allow you to run faster in the future.

Toebox the front portion of a shoe's upper. A wide toebox allows plenty of room for the toes to spread upper the leather or mesh material that encloses the foot

Veteran International term similar to "master" in the U.S. According to the IAAF, men become "veterans" on their 40th birthday; women, on their 35th birthday.

VO2Max (maximal oxygen consumption) the maximal amount of oxygen that a person can extract from the atmosphere and then transport and use in the body's tissues

Warm-up five to twenty minutes of easy jogging/walking before a race or a workout. The point of a warm-up is to raise one's heart rate so the body (and its muscles) are looser before a tough workout begins.

WR world record