# Motor Imagery and Sport Performance: A Systematic Review on the PETTLEP Model
## 3 Results
### Methodological Quality
#### 4.1.7 P--Perspective Component  
Perspective refers to the way imagery is viewed. Kinesthetic imagery is characterized by an internal and first-person view of the performer. Visual imagery can be internal (first person) or external (third person), depending on if the athlete is imagining himself performing the task from his eye perspective or as from a distance [53]. Different studies support the view that it may be beneficial for athletes to combine alternative perspectives together instead of using preferentially only one [21; 81]. Visual and kinesthetic imagery share common neural areas; for this reason, it seems that using the two perspectives independently from each other may require the brain of the athlete to perform an extra effort because it would be necessary to inhibit regions of the same network shared by the two modalities [82]. However, the two perspectives have been suggested to be differently useful and to rely on the level of experience, therefore of expertise, in order to boost the potentiality of imagery-based interventions. Indeed, it is suggested to be easier to use internal imagery when one's ability in a task is high [81; 83]. During motor skill learning, instead, athletes are more likely to use external imagery [21; 81]. Furthermore, while some authors provided evidence for a higher efficacy of visual MI whilst learning form-based skills such as gymnastic moves [31; 81], others found instead kinesthetic imagery to be more effective for this kind of learning [53]. Moreover, it was assumed that the most experienced performers are able to switch between different perspectives to benefit equally from both and ultimately optimize the imagery experience [53]. Recently, scholars have shown that first-person kinesthetic internal perspective can be used to develop and improve performance of an already internalized movement [30]. On the other hand, an external perspective has proved to be useful in learning, and subsequently improving, a movement sequence of recent acquisition [84]. Such data provide novel and valuable insights into the use of motor imagery techniques, particularly in the field of sport performance.  
There is growing evidence suggesting the combination of MI and action observation (AO) could be the optimal practice, especially when there is no possibility to engage in physical training. Research on mirror neurons [85], as well as the study of [PERSON] et al. [86], found a tight temporal coupling between an observed action and its mental representation. However, temporal coupling between AO and MI still requires further investigation. The first studies assessing the validity of applying MI+AO in sport found such a combination to be effective in increasing performance on a golf putting task [87] and biceps strength [54].  
Moreover, [PERSON] et al. [88] found that when imitating hand movements, subjects performing MI+AO or paying close attention to the observed kinematics were significantly better in imitating the movements. Two studies support the hypothesis of a greater corticospinal excitability [89] and larger BOLD activity [90] in the left hemisphere when performing MI. Since MI ability declines with age [91], implementing AO to MI training could also be useful to support the degraded imagery abilities of elderly or neurological patients [92]. In conclusion, it seems preferable to implement AO in MI training in order to decrease the mental load of the MI task. Having a visual support to the imagery could help subjects focus on the imagery task and obtain better results. This could help athletes who are still learning how to perform some movements, as well as both the elderly and children, which are characterized by limited imagery abilities in terms of reproducing real performances [91].