Editing American Quarter Horse (section)

===Halter type===
Horses shown in-hand in [[halter (horse show)|Halter]] competition are larger yet, with a very heavily muscled appearance, while retaining small heads with wide jowls and refined muzzles.  There is controversy amongst owners, breeder and veterinarians regarding the health effects of the extreme muscle mass that is currently fashionable in the specialized halter horse, which typically is {{hands|15.2|to|16}} and weighs in at over {{convert|1200|lb}} when fitted for halter competition. Not only are there concerns about the weight to frame ratio on the horse's [[Horse anatomy|skeletal system]], but the massive build is also linked to [[hyperkalemic periodic paralysis (equine)|hyperkalemic periodic paralysis]] (HYPP) in descendants of the stallion [[Impressive (horse)|Impressive]] (see [[#Genetic diseases|Genetic diseases]] below).