Imagery is a mental skill with which many of us are familiar. If done correctly, and adapted for the needs of the athlete, imagery can be an effective mental skill that can improve performance. Imagery can allow the mind to practice being in a be in a high-pressure situation before the big event.
Use all the senses. Imagery is not the same as visualisation. In its best form, imagery uses all the senses. It should not only include seeing the anticipated performance, but also the smells, noises, and most importantly the emotions that accompany sport performance. When an athlete is able to extend imagery past just using visualisation and get the relevant emotions involved, it can allow that athlete to practice responding to the nerves and ahead of time, which will help that athlete to react to those emotions with control on the big day.
The good, the bad, and the ugly. Imagery does not mean only imaging the positive outcomes. In fact, having the athlete imagine scenarios that are less than ideal and respond ahead of time to difficult situations can help the athlete feel more in control and thus lower performance anxiety. For example, what does happen if a swimmer rips her suit? Or a runner gets his least favourite lane assignment? What if the other team is awarded a penalty kick? As these examples suggest, the imagery can extend beyond just the moment of pivotal performance. Imagining these scenarios days or even weeks before a high-pressure event can allow an athlete to make the necessary preparations both physical and mental.
Teaching and Practicing Imagery. As with so many things in sport, imagery takes practice. When teaching imagery, it is best to start with an “easy” scenario. For instance, have the athlete(s) imagine what it is like to walk into their home after training and wander into the kitchen (something all athletes do day in and day out!). Then ask athlete(s) what the weather was like in their imagined scenario? What was being cooked in the kitchen? Was anyone else home? Draw their attention to the other senses involved in imagery. Once comfortable with the imagery of arriving home after training, have the athlete(s) choose a sport performance scenario to practice with next. Again, ask the same questions regarding the other senses, and have the athlete re-imagine the performance scenario adding in a another sense each time. The goal is to eventually include emotional elements when using imagery such that the imagery is most helpful for high-performance situations.
It is important to note that imagery does not have to be done in a dark room, lying down with eyes closed. It certainly can be, but it can also be done pitch or pool side. In fact, if done in the sport environment the athlete does not have to imagine the smell of the chlorine, or sound of the whistle, it will already be in place. If natural, the athlete can also stand and act out the movements that will be required. A great example can be found here: https://www.nytimes.com/2014/02/23/sports/olympics/olympians-use-imagery-as-mental-training.html
As always, teaching imagery is about getting the athlete familiar and comfortable with the mental skill such that it can adapted it to fit his/her needs and overall pre-performance routine.