I tend to agree with Slowman on this one. The guys pushing the limits in the early to mid 80's just did it cause it was there. They beat down the trail on which today's Ironman athletes followed. Everything from your Friday 4000 m swim, Sat 120 mile ride followed by 30 min transition run and Sunday 2.5 hour run, was invented by trial and error by the big 4, Pigg, Souza and others from that era.
Often, these guys would train like pro cyclists, run like Olympic marathoners and swim 40,000m all in the same way. That's not to say that this is the way to go, but it was by pushing their personal limits and one another that they found out what worked and what did not. Ironman times quickly dropped from 10 to 9 to 8:30 to sub 8:10....and these guys were banging out these times on equipment that your local 14.5 hour Ironman age grouper is using today (and usually old HED CX or Zipp 440's are not good enough for the same 14.5 hour crowd...).
Lots of the guys I see today are scared to do volume and/or intensity. You just need to do it at the right time at the right intensity in the right quanitities that your body has adapted to. Like Tim DeBoom says, it takes many years of training to train for an Ironman. Piling on mega bike or mega run weeks every so often is one of the ingredients that gets you there.
Often, these guys would train like pro cyclists, run like Olympic marathoners and swim 40,000m all in the same way. That's not to say that this is the way to go, but it was by pushing their personal limits and one another that they found out what worked and what did not. Ironman times quickly dropped from 10 to 9 to 8:30 to sub 8:10....and these guys were banging out these times on equipment that your local 14.5 hour Ironman age grouper is using today (and usually old HED CX or Zipp 440's are not good enough for the same 14.5 hour crowd...).
Lots of the guys I see today are scared to do volume and/or intensity. You just need to do it at the right time at the right intensity in the right quanitities that your body has adapted to. Like Tim DeBoom says, it takes many years of training to train for an Ironman. Piling on mega bike or mega run weeks every so often is one of the ingredients that gets you there.