To understand why at a certain point in training a deload can make sense, let's take a look at the very basic principle of training, the supercompensation principle. The principle tells us, that we need to train to get on a higher fitness level. Nothing new so far. But this process is divided into different phases. We start at our base level of fitness. We start training and accumulate fatigue in that training, we are getting tired and exhausted which causes our fitness level to decline. After training, we are entering the recovery phase and the supercomensation phase. So after we are fully recovered there is a time frame where our body adapted to the training and prepares itself for more. If you don't hit your next workout in that timeframe, your fitness level goes back to the baseline. If you work out, you can improve your fitness even more.
WHY AND WHEN YOU SHOULD DELOAD
During your training mesocycle, you will accumulate fatigue. The longer and the harder you train the more fatigue will be accumulated. More fatigue consequences in longer recovery periods to achieve supercomensation. This means, that at a certain point in your mesocycle it can happen, that you collected so much fatigue, that your normal recovery time is not enough anymore to achieve supercompensation. At this point in your training, you will most likely experience a drop in performance, perhaps an increase in joint/tendon pain and a decline in training motivation. Once this happens, it is time for a deload. A deload is a training period of active recovery to get your body back to the base level you achieved.
THEORY VS PRACTICE
In theory that sounds very easy. It also is. But there are some things that you will need to do/be capable of, to use deloads wisely.
1. Track your training parameters
Only if you track your training you can see a drop in performance. Only if you can compare different but similar microcycles to another you can see if your performance dropped. Numbers don't lie.
2. Optimize your recovery
Maybe you don't need a deload, just more average sleep? Or better nutrition? Or less stress in your work-life? Optimize what you can to improve your normal recovery. This can lengthen the duration of your mesocycles for weeks. Which means valuable weeks of more gains without needing a deload.
3. Fatigue management
Are you training to failure every time? Do you max out often? If so, you should definitely start to think about a better program. Maxing out and training to failure is just not necessary in every session. You can achieve better and more healthy gains by managing your fatigue better with a smart program that allows you to work out on a high power level for long time period.
HOW TO DELOAD
A deload can be structured in many different ways. They all have in common, that you cut your workload during that week massively in comparison to your regular training. That means you can cut the intensity, which means you work with lower weights than usually. You can cut reps or sets. So just do fewer reps or set in training. Cut your total workout days. Instead of 5 sessions a week, do only 2-3 this week. Or combine all. In the end, you must design your deload light enough to recover, but also specific enough to not lose strength gains. For most people, 1 deload week is enough. Depending on your fatigue and training, it can be programmed also longer or shorter. This is individual for every athlete. If you never accumulate enough fatigue to reach the point described higher in this article, you may never need a deload, or 2-3 days off training will do the job as good as a deload. Just listen to your body and your tracked numbers.