Recovery Runs – See “Cool-down” 

Repeats -- another term for "Intervals"

Resting Heart Rate – the speed at which a person’s heart beats when he or she is inactive, best to measure before getting up in the morning

Rest , Ice, Compression, and Elevation (RICE) – the treatment process for an athletic injury, such as a sprain

Ride – the feel of movement in a running shoe, especially in relation to the transition between the impact of the “Heel Strike” and the following “Toe Off”

Road Races – a run across a human-improved pathway, such as a street or running path, open to everyone

Road Runners Clubs of America (RRCA) – a nationwide association of running clubs with more than 700,000 members in the U.S.

Runner's High –a euphoric state that sometimes comes after an intense workout; the scientific cause is debated, “Endorphins” are generally credited, but recent research indicates the state may be brought on by anandamide, a cannabinoid neurotransmitter similar in makeup to THC in marijuana

Runner's Knee – a dull, throbbing pain in or around the knee cap when knees are bent, often caused by the knee cap’s improper movement during running, resulting from a weak inner thigh muscle

Running Economy –a measurement of the amount of oxygen a runner requires to produce the energy needed to run a specific distance