We tend to go into every workout with a goal. I want to hit 4 minutes on the 1K repeats or I want to run my goal 10 mile pace on these tempo intervals; however, the reality of things is we often show up to workouts just not feeling good. Why does it happen? Any number of reasons including (but not limited to):
Poor quality sleep
Bad meal in the day
Exhausting day at work
Lack of recovery from prior workout
Wind is really high
Heat index is high
The key here is to know when you make the adjustment to your expectations on a compromised workout. The schedule and targets aren't written in stone, they need to have a level of flexibility for the 'off' days. If you show up, force a workout, and leave with the mindset that you "failed" it creates a negative feedback loop, I want you to have the ability to redefine your expectations and turn the workout into a positive experience.
There are three approaches to adjusting your run:
Slow the goal time for the intervals
Adjust the number of repeats
Increase the recovery time between the repeats
Your workout has two components, intensity and duration. The first two options are tweaking these variables. Let's say your workout is 6 x 1K Repeats with 3 minute recovery and you have a goal pace of 4:55/km. For approach #1, go into the workout with the goal of running a 5:05/km pace instead. Get yourself settled in and complete the workout. Pushing on a day where you just don't have it will only encourage overtraining. Focus on the prescribed effort (ie. med-hard), knowing you did it and your body will still see positive adaptations. This is the preferred approach for longer distances from 10K to Marathon.
Under option #2, which is preferred for those practicing for shorter races - 5K and less - you may reduce the number of repeats to 3 or 4. Goal is to still get in some practice at race pace while reducing the overall duration.
Option #3 can be used along with the other 2 choices, to help improve the workout experience. Increase the 3 minute recovery to 4 or 5 minutes, whatever you need.
Key is to be comfortable/accepting of these changes and learning to make them on the fly. You want to set yourself up for success as much as possible.
Another possibility on workout day is that you are sick or your body feels weakened. Just don't have the energy to run hard or the wind is making it impossible. What adjustment should you make? In these cases, just scrap the planned workout. Take a rest day or cross train, maybe do a nice easy/recovery run if it's a viable option, but if nothing positive can be salvaged from the day, you do not do it.
If you have any questions reach out to me through Final Surge, e-mail: markdidham@gmail.com; or Facebook PM.