The body needs a break and rest from our routines. When we change the routines, we are allowing our bodies to rest and recover properly. For example, a runner might need to rest from an injury. The water can be a great source of active recovery for people who exercise and athletes. Using a pool to do a light workout can be one way to change our routines. The key is allowing the muscles to recover by doing something completely different and less intense for our bodies. Stretching and using a foam roller are commonly used for active recovery techniques since it may help prevent injury. Stretching is often overlooked but is a great idea for active recovery since everyone needs flexibility.
Active recovery is not to be confused with cross-training. Both are different but the main difference is the activities for cross-training might still be intense. The activities for active recovery would most likely be less intense. This is only because the muscles need rest and recovery. Someone doing cross-training might run and swim with the same intensity on different days. A person should try to do less on off days and remember they are recovering from the main activity they are focusing on. This is why I strongly feel the exercise should be lighter and not as challenging.