Distance vs Time

I'm having more luck with time based work outs than I ever had with distance based ones.

 This year and next year I'm going to do time based stuff.  I might worry about changing things after I get a couple HIMs under my belt but not before.

I train by time for the bike and run, and the swim is distance.

However, after a while, I found they are pretty related, so it makes little difference (ONLY if you are disciplined enough to not cheat yourself).

For example, if I have a 60 minute Z2 run, I know that I will be getting 6 miles in (including a slow WU and CD).  I'm easily within 5% of that as long as I'm working as hard as I'm supposed to.

I know that my swim times are 2:00/100 or less (including rest breaks and WU/CD)  So if the plan calls for 3000 yards - I plan on an hour.  I'm almost always 1 or 2 minutes away from that.

So either method is fine as lone as you don't cheat yourself by slacking...

Your body knows time; it does not know distance. Aside from the swim, most training is done by time.

You should not be going easy or hard based on wanting to get the workout done quickly or wanting to fill the time, there should be specific goals for each session. Those goals will indicate the intensity.

x2

My coach has me doing distance. Harder to measure rate vs effort when your going by time, unless you do gps. That's not to say anything inherently wrong with time based training. Just a different philosophy. It certainly makes scheduling easier.

I always have targetted distance during swim workouts because it is so much easier to count the distance than having to keep looking at the real clock (unfortunately, i wear glasses and goggles are not making it easier to see clearly).

 During run workouts, it definitely helps to put a number on the distance, since I can count it around the track, and keep track my avg mpm pace time. However, if for some reason, there's an indefinite paths and trails around that you run once in a while (which I do at my campus), I just put a minimum time to run (say 2 hrs min). Same applies for my bike sessions since I don't have any gadgets that can count distance for me.

It definitely depends on what comes easier and/or convenient to you, either counting a definite distance or definite time. On the plus side, I know that office workers near Embarcadero in san francisco usually run along the bay during lunch breaks and they have limited time. However, they do keep the pace and same intensity as they would if they were doing distanced.

Train by time.  Your body only knows time; i.e. how long it has been working at a specific intensity.  Your body doesn't know or care how far you've run or biked or swam.  Training by time also compensates for differing environmental conditions.  For example, if you ride 20 miles in windless conditions it might take you 1 hour.  Whereas, riding 20 miles in 25 mph headwind might take you 1.5 hours.  In the later case you spent more time working harder.  This might not fit into your training plan. 

Another reason to trian by time is that time is easier to schedule into your daily, weekly, monthly routine than distance.

TJ 

As someone said, as time goes by, I learned how much distance I would do in X amount of time give or take. (this was helpful when I was away last week and had no idea how far I ran).

However, when first starting out or when I moved from a sprint to an oly, distance was important because I wanted to make sure I could cover the distance of a race. I'm not fast so my time is considerably longer for distances that some can complete in much faster times. So I needed to make sure my body could handle that time needed to complete the distance.