Breeds & Muscle Types

ST= slow twitch, FTH= Fast twitch, high oxidative, and FT=fast twitch.

Type or breed of horse: Percent of muscle type:
Top endurance horses: 40% ST, 55% FTH, and 5% FT
Top sprint horses: 6% ST, 54% FTH, and 40% FT
Heavy hunters: 30% ST, 35% FTH, and 35% FT
Ponies: 20% ST, 40% FTH, and 40% FT
Standardbreds: 20% ST, 50% FTH, and 30% FT
Arabians: 20% ST, 50% FTH, and 30% FT
Thoroughbreds: 12% ST, 53% FTH, and 35% FT
Quarter Horses: 8 % ST, 50% FTH, and 42% FT
Man (mid-distance runners) 60% ST, 35% FTH, and 5 % FT

Biopsies were taken in the middle gluteal muscle about 9 inches below the tuber coxae at a depth of 3 inches. Information compiled by Lewis.