Jack is always saying that equipment is responsible for all the distance increase. It seems to me that the constant would be swing speed. Did they measure it back then ? And if so, how does Jack's compare to modern players.
Was speaking with Simon Owen on the range (runner up to Jack in The Open) yesterday and he hits it further now then he ever did - his swing speed is relatively the same...he can really nail his drives.
If Jack hit it big compared to the Guys in his day his swing speed was as fast as any of the pros today.
