I’m not a doctor, while I do have a bit of knowledge regarding kinesiology attained through swing research and a lifetime of athletic pursuits, but this article really set my Spider Senses tingling when I read about Jordan Spieth’s wayward ECU tendon.
Basically, the sheath that holds his left ECU tendon in place is torn and it pops out from time to time, leading to his having to WD from events or miss them altogether when this occurs.
WAX Golf 