Half Marathon:
This is a foot race of 13.1 miles, half the distance of a marathon.

Hamstring Muscles:
The large muscles at the back of the thigh that primarily flex the knee.

Hip Flexors:
The large muscles that are powerful flexors of the hip joint.

Hypertrophy:
The increase in size or mass of a cell, tissue, or organ, such as the increase in muscle fiber size resulting from strength training.

Hard Set Perform a prescribed number of repetitions of an exercise using maximum effort.

High Density Lipoprotein (HDL) A blood substance that picks up cholesterol and helps remove it from the body; often called "GOOD CHOLESTEROL."

Hormones Regulators of various biological processes through their ability to control the action of enzymes. Made from proteins, such as insulin for blood sugar control, or cholesterol for testosterone control.

Hyper kinetic Condition A disease/illness or health condition caused or contributed by excessive exercise.

Hypertension High blood pressure.

Hypertrophy Increase in size of muscle fibre.

Hypoglycemia A common occurrence in diabetics, this is low blood sugar levels, resulting in anxiety and fatigue.In severe untreated cases it can lead to coma and even death.