The present research was designed with the purpose of studying the effect of one period of the selected Pilates exercise program on the functional balance and falling risk among patients with Parkinson. Considering the results obtained in the present research, it was observed that taking the selected Pilates exercises for 8 weeks is accompanied by the significant improvement of functional balance in patients (P = 0.001) while the difference observed in the functional balance of control group who walked in a similar duration was not significant (P = 0.364). In addition, the difference evaluated between the score results of functional balance scale in the posttest was significant between two Pilates exercise and control groups (P = 0.001). The postural instability was one of the most debilitating aspects of Parkinson disease and could lead to the increase of falling and reduction of mobility and functional capacity of patients. Patients with Parkinson suffer less stability range and more postural sways compared to their peers and the impaired postural control is significantly related to the increased falling risk in these people [
3]. Many studies claim that taking regular exercises affects the improvement of motor and non-motor symptoms in these people. Indices of body posture control are important aspects affecting the independence maintenance and life quality among these patients who significantly look for improvable exercise interventions [
5,
28,
29]. Different exercise interventions including aerobic exercises, hydrotherapy, balance exercises and walking could have significant treatment advantages with the increase of functional capacity among patients with Parkinson [
7,
30]. There are different theories about the effect of exercise program on the improvement of balance [
31]. Considering results of researches conducted, it was determined that exercises accompanied by resistance and balance exercises affected the improvement of balance disorders, especially in patients with mild and moderate levels of Parkinson more than other exercises [
8]. Since Pilates exercises are a kind of resistance exercise in which the body weight is imposed and the principle of overload is in the form of replications increase and based on physiological principles, skeletal muscles can be severely influenced by these exercise [
32]. The balance improvement resulted from the effect of Pilates exercises can be studied based on the theory of systems. According to the theory of systems, the ability of body control is the result of simultaneous and complex interaction between nervous, muscular and skeletal systems (postural control system). In order to control posture for maintaining balance and consequently motion through the above systems, the combination of sensory data (for determining the body condition in space) and the ability of musculoskeletal system for imposing proper force are necessary. In this model, the central nervous system is studied using the information of visual, vestibular and proprioceptive system (including joint position sense and environmental sense), the center of gravity’s situation against the gravity and supporting surface conditions, and a proper motor response is provided in the form of pre-planned motor patterns. Therefore, referring to the theory of systems and the effect of physical activity on the improvement of each of these systems, Pilates exercises can be accompanied by the improvement of balance in patients with Parkinson who suffer balance disorders resulted from functional decline in the central nervous system [
33,
34]. Furthermore, the improvement of balance as the result of Pilates exercises is due to the improvement of muscular power and mental factors (stress and anxiety) in participants because the reduction of lower limb muscle strength puts the center of gravity in front of the ankle joint leading to a disturbance in balance and falling. On the other hand, improvement of muscular power can lead to the dislocation of center of gravity to the ankle and improve the balance. Therefore, it seems that Pilates exercise method affects the modification of impaired balance by focusing on the improvement of core muscular performance and body axial stability through muscular nervous compatibilities [
12,
16,
32,
35]. In this regard, according to Kibar et al. (2015), the effect of 8 weeks of Pilates exercises is accompanied by useful effects on the static and dynamic balance and body central endurance among elderly people while no significant relationship was found between the body central endurance and balance [
36]. It was concluded by Kloubec (2010) that Pilates exercises were accompanied by a significant improvement in the body core muscular power in elderly people while they did not have any significant effect on the balance and body condition [
37]. In the comparison of the effects of Pilate’s exercises and balance exercises on the unstable level and balance abilities of elderly women, Hyun showed that both exercise methods significantly affected the improvement of static and dynamic balance among elderly women and were accompanied by the increase of balance abilities in these people. Nevertheless, considering the security of most Pilates exercises, it seems that they are a more reliable method for improving the balance capacity of elderly people [
38]. Given a significant difference in the functional balance of people who participated in Pilates exercise program compared to the control group, it can be concluded that the selected Pilates exercise program used in this research has an optimal effectiveness in order to improve impaired balance among patients with Parkinson and results of the present research are consistent with results of Bird et al. (2013), Campos de Oliviera et al. (2015), Mesquita et al. (2015) and Jonson et al. (2013) [
16,
18,
20,
33,
39].
In addition, results of the present research showed that taking the selected Pilates exercises for 8 weeks was accompanied by a significant improvement in the reduction of danger among patients with Parkinson (P = 0.001) while no significant difference was observed in terms of falling risk in the control group (P = 0.816) and the difference in results relating to the anticipation of falling risk in the posttest was significant between two groups (P = 0.001). Generally, patients with Parkinson are at risk two times more than other peers. In these patients, compensatory steps for keeping balance during falling were 1.5 times shorter than the normal state and they need an effort to achieve objects safely by keeping balance [
40]. Many researches show that physical exercises lead to the improvement of control of situation and reduction of falling in patients with Parkinson [
8,
31]. Research findings indicate positive effects of exercise interventions on the improvement of parameters relating to balance and walking as well as the reduction of falling among these patients. Results of studies conducted in this area show the early effectiveness of exercise on the improvement of balance components while there is no study on the early effectiveness of exercises on the reduction of falling in these people [
11,
28]. In a research by Sparrow et al. (2016), the effect of progressive balance exercises and in a research by Allen et al. (2015), the effect of combined walking, balance and strength exercises on the reduction of falling, improvement of balance and reduction of fear to fall were significantly positive [
12,
15]. In this regard, in a research with the purpose of determining the possible effect of exercise program on the improvement of falling factors among patients with Parkinson, a significant improvement in factors such as dynamic balance, muscular power and walking quality among these people as the result of participating at strength and balance exercise programs was reported by Canning et al. (2009) [
6]. Muscular weakness, reduction of ankle irritability and loss of muscle synergy mechanisms all have a role in the falling. Therefore, implementation of the physical readiness program is a proper strategy to avoid falling because it leads to the increase of muscular power, flexibility and motion control. By providing exercise opportunities and challenges for balance mechanisms, the physical activity improves them. In the meantime, Pilates is an exercise program which encourages the use of thinking for controlling muscles. It emphasizes the ability of muscles condition for balancing the body and supporting the improvement of vertebral column situation [
29,
41]. Considering the significant difference in the reduction of falling risk in Pilates group compared to the control one, it can be concluded that one period of exercise program based on Pilates principles is accompanied by the reduction of falling risk among patients with Parkinson and the results obtained from this research are consistent with the results of studies conducted by Irez et al. (2011), Josephs et al. (2016) [
17,
42-
44]. The effect of Pilates exercises on the reduction of falling risk through physical readiness factors including balance, muscular power and flexibility among elderly population was evaluated as a significant positive effect by Barker et al. (2016) and Bird et al. [
22,
45]. Pilates exercise can lead to the improvement of balance and risk of factors affecting the falling of elderly people. On the other hand, some of the characteristics of a proper exercise program in reducing the falling risk among elderly people include strength during progressive exercises, specialty, proper intensity, implementation at home or in group and involvement of parameters affecting the body condition control, including Pilates exercise method.