Missing workouts can be frustrating especially if you are someone who likes to check off all of your boxes every week. Missing a workout can make it feel like you have not done a complete job with your training and often we focus more on the single workout we missed than on the ten we completed.
So, what should you do if you miss a workout? First, you need to establish why you missed it and second you need to ask yourself whether it was important to enough to schedule in at a later date.
If you were sick, run down, incredibly fatigued or injured then the answer is simple and so is the solution. If your body was in a place that it could not do the workout because of one of these things then you should skip it and move on because your body clearly needs the rest more than it needs the workout. Your body is good at telling you what it needs but often we are poor listeners. You will not lose fitness if you miss one workout and if it helps you recover enough to get back on a consistent track you will be better for it in the long run.
If you missed a workout because of unexpected time constraints (work, family etc) you need to take a step back and evaluate how important that workout was before deciding whether you need to reschedule it. If the workout did not involve a critical training stress load like race pace work or long endurance work or whatever your coach considers a key training stress load then you should probably move on and not look back. If however the workout did involve a crucial training load then you might want to consider rescheduling it. To be clear, this is not simply a matter of adding the workout to another day or adding it to the next day. You need to make sure it fits in appropriately at a different time.
If you missed a workout because you are lazy or unmotivated then you might want to ask yourself why you are feeling this way. Sometimes lack of motivation can be linked to a general state of fatigue. Our ability to be mentally tough and motivated has a close link to how fatigued we are feeling. If lazy and unmotivated are regular states for you then you might want to consider the path you are on and whether you actually want to be on it. These are bigger picture issues that require deeper thought and longer term solutions like doing something different.
The biggest mistake athletes make when they miss a workout is to simply add it to another day without giving any thought to the bigger picture. On rare occasions athletes will make the most egregious error of lumping several missed workouts onto the same day along with whatever was planned for that day and turn it into an epic training day. This strategy is absolutely ludicrous and results primarily from a deeper insecurity about needing perfection for results. When athletes do this they do a disservice to one of the most fundamental training principles- applying appropriate training loads and then recovering. When a huge amount of training stress is lumped into a smaller time frame the risk for sickness, injury and crappy workouts goes up significantly. For the sake of checking all of the workout boxes you might end up doing longer term damage. The other issue with playing catch up is that the workouts often lack the quality they need to actually create a training stress response. Put quite simply, if you are someone who lumps all of your missed workouts into one massive training day please just stop doing this!
If you miss a workout as yourself why and then ask yourself if you need to make it up or just move on. For the most part you can just move- often this requires more mental toughness and confidence than trying to cram it in somewhere else.