AG: is Age Group.
AR: is American Record
AT: is Achilles Tendon.
BQ: is to Boston Qualify as in to meet the standards to qualify to run in the Boston Marathon.
C25K: is Couch to 5K, a common beginner's running program.
CR: is course record
DFL: is Dead &$%&* Last
DLF: is Dead Last Finish
DNF: is Did Not Finish
DNS: is Did Not Start
DOMS: is delayed onset muscle soreness
ED: usually is used to refer to an eating disorder.
EIA: is exercise induced asthma
EPO: is short for the natural occurring hormone called erythropoietin. EPO can be used to enhance performance illegally and is associated with the dangerous process known as "blood doping."
FF: is a fast finish
Full: Refers to a "full marathon," i.e. running 26.2 miles.
FIRST: Furman Institute of Running and Scientific Training
GA: is general aerobic
GPS: is global positioning system
HM: is half marathon (13.1 miles). Can also be referred to as "the half" or as a pikermi.
HR: is heart rate
HRmax, MHR or HRM: means the maximum heart rate that one can reach while running. Training intensities are often determined by percent of HRmax.
HRR (HRres): means Heart Rate Reserve, which is the difference between HRmax and RHR (HRmax - RHR = HRR). Some runners base training on percent of HRR instead of HRmax.
IOC: is International Olympic Committee
ITBS: refers to the illotibial band syndrome, a common overuse running knee injury.
KM: is a kilometer, also may be abbreviated simply as K.
LRS: is local running store.
LSD: is long slow (or steady) distance.
LVD: is long varied distance.
MP: is marathon pace.
MPM: is usually minutes per mile
MPW: Miles per week.
MHR: is maximum heart rate
MTSS: is Medial Tibial Stress Syndrome; another name for the infamous "shin splints."
NB: is New Balance, a shoe company.
NSAID: is a non-steroidal anti-inflammatory drug; ie Advil, Aleve, Motrin, etc.
PDR: is Philadelphia Distance Run
PF: is plantar fascitis
Pfitz: refers to runner/coach Pete Pfitzinger or his popular marathon plans. For example "Pfitz 70" would refer to a Pfitz marathon plan that peaks at 70 miles per week.
PR and PB: is personal record or personal best. PB may also stand for peanut butter. :)
PT: is physical therapy.
PW: is personal worst.
Quads: the quadriceps muscles in the front of the thigh
RD: is Race Director
RHR: is resting heart rate
RICE: rest, ice, compression, elevation
ROM: is range of motion
RT: Running Times.
RW: Runner's World.
ST: Sportstracks, a popular form of logging software.
SFX: is stress fracture
TM: is treadmill
USATF: is USA Track and Field
WR: is world record
XC: is Cross Country
XT: is Cross training