Parkinson’s disease (PD) is a neurodegenerative disorder characterized by rigi- dity, tremor, bradykinesia and postural instability. Adapted physical activity (APA) is useful to reduce the physical inefficiency caused by Parkinson’s disease    . The maintenance of a muscle-joint structure functional level seems to be the only way to preserve the residual motor abilities and to slow disability progression process, that relentless influences quality of life. Body response to physical activity in Parkinson’s Disease is slow, because of biological aging  , so an appropriate training program should be continued for at least six-month  . It was demonstrated that Nordic walking is well tolerated by subjects with PD, improving body balance, gait cycle and lower limbs strength  . Resistance strength training  has positive effects in maintaining body posture  . Multi-joint isometric exercises are able to improve lower limbs functionality  . Several studies have demonstrated that aerobic endurance workout on treadmill positively influences lower limb motor tasks  , increases oxygen consumption and improves movement economy  . In addition, walking with an additional overweight enhance body balance  . Furthermore Yang et al.  investigated as downhill walking training (slope between 3% and 8%) is useful to improve posture trunk and create a positive effect on knee extensor muscle strength.
Finally, one of the recurrent disorders of PD is the freezing of gait  . Emphasis on this deficit is caused by a reduction of the hamstring muscle-tendon flexibility combined with lower limbs strength and coordination decrease  . So, basing on what literature said, the aim of this study was to investigate whe- ther a protocol of overweight exercises (applied on wrist and ankle) compared with exercises performed thought elastic bands might cause changes in physical efficiency in subjects with PD.
2. Materials and Methods
Twenty-one PD subjects volunteers, able to walk unassisted with a disability score using the Hoehn & Yahr scale  of 2 ± 0.5 were recruited for this study. Subjects were randomly assigned to Micro-loads Group (11 subjects, age 69 ± 10 years; weight 72 ± 12 kg, height 171 ± 7 cm) or to Elastic band Group (9 subjects, age 70 ± 11 years; weight 69 ± 15 kg and high 169 ± 9 cm). As shown in Figure 1, two sessions of physical activity per week were performed. Both group executed the same exercises schedule but the first group completed it using micro-loads applied on wrists and ankles, while the second one exercises themselves with elastic bands. Before starting our 5 month training program, all people were informed about the purpose of the study and signed an informed consent.
Both groups were measured three times during training period:
- After the first training month (T0). In this period subjects learned exercises technique, their basal physical condition was identified and exercises intensity was set basing on the results of this evaluation.
- After two months from T0, to verify the effects caused by the first two train-
ing months (T1).
Figure 1. Sit and reach.
- After 2 months from T1, to verify the effects caused by the first four training months (T2).
The parameters investigated were: 1) posture and flexibility of spine and hamstring muscle; 2) the body balance in upright position, and 3) the strength of the lower limbs.
3. Devices and Test Protocol
3.1. Sit and Reach Test
This test, consisting in a forward torso flexion from sitted position with extended legs. It was performed on a new sit and reach box, in which a digital distance meter (±1 mm) was installed (Bosch, Germany). (Figure 1). This device provides more accurate measures respect a traditional sit and reach box. For this reason, it was chosen for this study.
3.2. Stabilometric Test
Static posturography (Figure 2) is used to asses balance capacity in patients with nervous system disease  . This test was performed with stabilometric platform (Prokin, Tecnoboby Bergamo, Italy). Centre of Pressure (CoP) positions were computed to calculate the following variables:
Length [mm]: length of CoP trajectory computed as sum of CoP displacement on the platform surface;
Area [mm2]: elliptical area computed as CoP trajectory
Sway AP and ML [mm]: standard deviation of CoP along anterior-posterior (Sway AP) and medio-lateral (Sway ML) axes;
Velocity AP and ML [mm/s]: velocity of oscillations along anterior-posterior (Vel AP) and medio-lateral (Vel ML) axes.
Participants will perform the following stabilometric test with 1 minute of rest between the two test:
1) A bipodalic test with eyes open (OA) lasting 30 seconds;
2) A bipodalic test with eyes closed (OC) lasting 30 seconds.
3.3. Morphological Evaluation of Vertebral Column
The vertebral column morphology evaluation is obtained using the Spinal Mouse® (Idiag, Voletswil, Switzerland) on sagittal planes  . The Spinal Mouse® (Figure 3) measures the length (mm) and the angle (degrees) of the column.
The Spinal Mouse® allows to measure thoracic segment (ThSp), between the first (ThSp1) and the last thoracic vertebra (ThSp12), lumbar segment (LSp) between ThSp12 to first sacral vertebra S1, the inclination (Incl) as the slope of connection line between S1 and ThSp1. In the sagittal plane the vertebral column is evaluated in three positions:
1) Standing upright (in relaxed position, focusing on a marker at eye level, feet aligned with shoulders, knees straight, arms along the trunk).
Figure 2. Stabilometric platform.
Figure 3. Spinal Mouse®.
2) Maximal flexion (legs extended, trunk bent forward in an attempt to reach the floor).
3) Maximal extension (legs extended, arms crossed over the chest, chin against the sternum, trunk extended backwards).
3.4. Sit to Stand Test
The test consists in measuring the maximum number of times that the subject sits down and stands up in 30 seconds (Figure 4)  . An Optojump® (Microgate, Italy) was used to identified the number of movements that subjects done.
3.5. Exercises Protocol
Both MG and EG trained on the same muscles and for the same amount of time but with different fitness tools. MG used overweight applied on wrists and ankles while EG stimulated muscles using elastic bands. Exercises targets were: 1) to stimulate muscle-joint structure multilateralism; 2) to exercise monotony; 3) to keep the sample groups interested into activity program. Both MG (Table 1) and EG (Table 2), started stimulating resistance training (20 repetitions) and continuing progressively towards the stimulation of muscular strength (10 and 15 repetitions). Both groups performed 2 set within 2 minutes rest between sets.
Figure 4. Sit To Stand Test: 1) Starting position; 2) Final position.
Table 1. Training program MG.
Table 2. Training program EG.
Figure 5. Sit to stand EG.
3.6. Statistical Analysis
The following statistical tests were used: Friedman ANOVA; Dunn post-hoc. Percentages differences were calculated with the following formula: ((Fv-Iv)/Iv) × 100; Fv is final value and Iv is initial value. The significance was fixed at P = 0.05. Each analysis was carried out using the GraphPad software (GraphPad Software, Inc., USA).
All participants completed the exercise program without any negative effects and were able to manage the progressive exercise difficulty increment during the entire period of the study. As shown in Figure 5, there was a significant increase in sit to stand test (STS) in elastic group (T0 vs T2; Friedman ANOVA, p < 0.001, post hoc, p < 0.01, +19%). No significant change was observed in the MG.
This study has shown that a 4-months elastic bands exercise program is useful to PD patients. Data analysis highlight a statistically significant positive improvement in EG on the Sit to Stand test. This result underlines that a progressive workout with elastic bands increase lower limbs muscle strength outcomes. Furthermore, this findings suggest that these kind of exercises with elastic band might improve the subject functionality in daily activities. No statistically significant variation of the parameters investigated was found on MG.
Both micro-loads and elastic band exercises were well tolerated by patients with PD and nobody denounced problem insurgence during activity. The study highlights the positive effect of a longitudinal muscle strength training program in the lower limbs strength.