Abstract
Introduction
Treadmill training (TT) provides a promising investigational therapeutic approach in the rehabilitation program in patients with Parkinson’s disease (PD) (Borrione et al., 2014). Most research on the efficacy of TT in PD focused on single training programs where TT is the only activity performed(Bello & Fernandez-Del-Olmo, 2012), while few and recent investigations have tried to compare the effects of TT against other rehabilitation training programs (Shulman et al., 2013; Bello et al., 2013). Thus, studies are needed to identify the potential benefits of TT on PD patients when combined with other exercise training modalities. In this regard, the combination of water and land exercise programs is a promising new rehabilitation approach in PD, although further research is needed in order to confirm its beneficial effects in this population (Ayán et al.,2013).
This pilot study aims at identifying and comparing the effects of a multicomponent rehabilitationprogram based on the performance of TT plus water and land-based exercise sessions on the illness impact, quality of life (QoL) and fitness level in patients with mild to moderate PD.
Methods
Participants
Patients with PD were recruited through personal letters from the Bueu Parkinson Association, using the following inclusion criteria: 1. Stages 1 through 3 on the Hoehn and Yahr Staging Scale, 2. Stable reaction to anti-parkinsonian medication. Persons with PD unable to walk independently or with comorbidities other than PD or any acute illness that would make training inappropriate were excluded. The study was approved by the Local Ethics Committee, and all participants gave written consent.
Measurements
The Spanish validated version of the Unified Parkinson’s Disease Rating Scale (UPDRS) (Martínez-Martín et al., 1994) and the 39-item Parkinson’s disease Questionnaire (PDQ-39) (Martínez & Frades, 1998) were used to evaluate the effects of the intervention on the patients’ illness impact and QoL respectively. The Senior Fitness Test (SFT) (Rikli & Jones, 1999), was used to assess the sample’s fitness level. The medical staff of the association performed all measurements one week before and one week after the intervention period. All participants were tested on their “on” phase (1 to 1.5 hours after taking their PD medications). All pharmacological treatments were maintained at a stable dosage throughout the study.
Intervention
According to their time availability and exercise preferences the participants were assigned to two exercise groups: water and land-based exercise (WL) or WL plus treadmill training (TWL). The WL Group carried out one water-based exercise and one land-based exercise session of 50 minutes of duration each per week for 15 weeks, performed in separate days. The water and land-based sessions were aimed at improving aerobic capacity, muscular resistance, balance and flexibility (Ayán et al., 2013). Participants in the TWL added two sessions of 15 minutes of TT to this schedule performed in the days where no land or water-based exercise was carried out. Subjects started the TT at their comfortable walking speed, with training parameters being progressively adjusted according to their ability to tolerate the exercise. Heart rate, blood pressure and perceived effort (modified Borg scale) were recorded before and after each session in order to confirm exercise tolerance (Fig. 1). All sessions were supervised by a physiotherapist and a specialist in physical exercise with previous experience in PD.
Statistical analysis
The variables were compared at baseline using Student’s t-test for independent measures. The Kolgomorov– Smirnov’s test with Lilliefors correction examined the normality of the data. Student’s t-test for paired samples was used to analyze the effects of the programs (WL, TWL). An analysis of variance was applied for each variable and outcomes were interpreted based on main effects and interactions. The within-subject factor was moment; the between-subject factor was the program (WL, TWL). A statistically significant outcome of the interaction moment x program would prove that TWL and WL protocols had different effects. Statistical analysis was performed using the Statistical Package for the Social Sciences (SPSS for Windows, version 19.0; SPSS Inc., Chicago, IL, USA). The significance level was set at 5%.
Results
A total of 23 subjects participated initially in the study. There were 3 dropouts (1 in TWL group; 2 in WL group) due to causes not related to the exercise program. The adherence to the program was over 80% in both groups. The participants’ characteristics that finished the program are shown in Table 1. At baseline, there were no significant differences between both groups in any variable of interest.
The combination of water and land-based exercise (WL Group) showed significant benefits in the disease impact (UPDRS t = 3.083; p = 0.029) and QoL (PDQ-39 t = 2.942; p = 0.036). The addition of TT did not have any significant effect on these variables. Both programs were equally effective on the fitness level as judged by the significant increase in shoulder range of motion and aerobic endurance (Table 2).
Discussion
This pilot study indicates that TT does not improve QoL nor has any disease impact in PD patients. These results are somewhat unexpected and counterintuitive (Borrione et al., 2014). A plausible explanation may be the duration of the program since the positive effects have been reported in TT programs with less than two months’ duration (Herman, Giladi, &Hausdorff, 2009). Regarding longer interventions, significant improvements in QoL have been reported after TT programs of 24-weeks’ duration but only on the patients who exercised on a tilted treadmill (Nadeau, Pourcher, & Corbeil, 2013). Similarly, another 3-month long TT program significantly improved subjects’ total UPDRS scores and included the performance of exercise on a tilted treadmill (Skidmore et al., 2008). Therefore, besides the duration of the program the type of exercise protocol (including tilted treadmill) may be a factor to consider. However, Shulman et al. (2013) compared the effects of exercising on a tilted treadmill versus exercising on a treadmill with 0% slope for three months in a sample of PD patients and they did not observe benefits nor differences in disease impact or QoL. The authors attributed this to a hypothetical marginal improvement (ceiling effect) of patients with these variables.
This reasoning should not apply in the present study since the participants in the WL group experimented significant improvement in these variables and both groups were homogeneous and thuscomparable. In addition the positive effects of combining both water and land-based training was expected (Ayan & Cancela, 2013), but disappeared after adding TT, while both programs showed similar improvement in fitness level.
Having mentioned the above, patients in the TWL group exercised four times per week and for over 3 months, making it a high intensity exercise program type (Shu et al., 2014), and this indicated by theelevated effort load reported by the participants. This excessive total exercise load may have limited the potential positive effects on QoL and disease impact. To our knowledge, in the only study performed in which PD patients exercised on treadmill 4 times per week and for over 3 months there were no significant benefits on these variables although, and in line with our findings, some fitness components improved significantly (Schenkman et al., 2012).
We acknowledge limitations in this study and basically related with its design. Worthy of mention are the small sample size, its non-random distribution and the different training-load proposed for both groups. These considerations make it difficult to make definite conclusions after comparing both programs.
Conclusion
Our results suggest that the addition of TT to a combination of water and land-based exercise programs may have limited effects on QoL and the impact on the disease. In order to bypass this potential negative influence we suggest using a tilted treadmill and adjust the weekly training load to a moderate intensity level.
Conflict of interest
The authors report no declarations of interest.