It grows up to 12 feet tall in USDA zones 5 through 9. Another shrub, called the wayfaringtree viburnum (Viburnum lantana Mohican), grows 7 or 8 feet tall, blooms for three weeks in May and produces orange-red berries in July that ripen to black near summer's end. It grows in USDA zones 4 through 8.
fast-twitch (FT) fiber. a muscle fiber that can develop high tension rapidly. It is usually innervated by a single alpha neuron and has low fatigue resistance, low capillary density, low levels of aerobic enzymes, and low oxygen availability. FT fibers are used in such activities as sprinting, jumping, and weight-lifting.
Two criteria to consider when classifying the types of muscle fibers are how fast some fibers contract relative to others, and how fibers produce ATP. Using these criteria, there are three main types of skeletal muscle fibers. Slow oxidative (SO) fibers contract relatively slowly and use aerobic respiration (oxygen and glucose) to produce ATP. Fast oxidative (FO) fibers have fast contractions and primarily use aerobic respiration, but because they may switch to anaerobic respiration (glycolysis), can fatigue more quickly than SO fibers.