Introduction
Falls among adults aged 65 years and older often result in moderate to severe injuries and can increase the risk of death. The economic burden caused by fall-related injuries is substantial for developed countries. Approximately 30% of falls result in an injury requiring medical attention (6 16
Postural stability, gait, and balance decrease with age (2,12 falls , gait, and balance deficits have been identified as some of the most important intrinsic fall risk factors in community-dwelling populations (3,36 falls and fear of falling and improvement in quality of life (21 24,27
Proprioception was defined as “the perception of joint and body movement as well as position of the body, or body segments, in space” (35 19 falls (20 15 proprioceptive training.
A training that involves strength, balance, and improved transfer must form part of an optimum intervention strategy to prevent falls (41 34 physical activity may improve motor responses and postural control in the elderly (7,11,34 physical activity on proprioception preservation during aging . Petrella et al. (30
Many studies include unstable surface in proprioception training. This type of training stimulates proprioceptive system producing motor responses and stabilizing the joints from the 3 levels of neural protection (22 proprioceptive program with both tools provides great differences in core stability and body mass index (BMI) decrease (38
It seems to be consensual and well established that proprioception diminishes with aging , and regular physical activity seems to have a basic role in the preservation of proprioceptive function. Therefore, it might be important to develop and implement strategies to attenuate the age-related decline in proprioception and its consequences. Since there is no conclusive evidence that any type of gait and balance training program is better than another and the studies focused on proprioceptive training with Swiss ball and BOSU are scarce, the purpose of this study was to compare the effects of traditional and proprioceptive training programs on postural stability, gait and balance, and fall prevention in adults aged 65 years and older. We hypothesized that significant improvements in static posturography (primary outcome) and in functional balance tests (secondary outcome) could be achieved through a 12-week proprioceptive training program with Swiss ball and BOSU in adults older than 65 years.
Methods
Experimental Approach to the Problem
A controlled trial with allocation of participants into the experimental (n = 20) or control (n = 24) groups was carried out from March 2010 to June 2011. For practical and ethical reasons, it was not possible to randomize the patients. We had an ethical obligation with the Andalusian Federation of older people's organizations (Spain) to provide treatment to all older adults willing to participate in the study, but because of limitation of resources, we created a waiting list. The older adults who were in the waiting list agreed to be part of the usual care group (control group) and were offered the intervention program at the end of the follow-up period. Data collected only during the control period were included in the current analysis.
Subjects
We contacted a total of 208 older adults from the Andalusian Federation of older people's organizations (Spain), and 76 potentially eligible older adults responded. The inclusion criteria included subjects who were 65 years of age or older and able to follow simple directions, for example, left, right, up, or down. The exclusion criteria included people with functional blindness (acuity level worse than 20/200) and those with major chronic medical or physical conditions, including rheumatoid arthritis or osteoarthritis; severe low-back pain; severe lower limb deformities, as diagnosed by a physician, that resulted in the inability to ambulate independently or with the use of an assistive device.
A total of 12 patients were not included in the study (8 had physical activity contraindications, 2 had locomotion problems, and 2 reported schedule problems). After the first day of the baseline measurements, 2 patients refused to participate. Therefore, a final sample of 54 older adults started the study, and 44 subjects concluded it (control group, n = 24 and experimental group, n = 20). Participants were not engaged in regular physical activity >20 minutes on >3 days/week. The investigation was approved by the Ethics Committee of the University of Jaén and written informed consent was obtained from each subject before participation according to the standards of the Declaration of Helsinki ( revised2008).
Procedures
Baseline characteristics of the participants (Table 1 ) were initially collected on the day of consultation by means of self-administered questionnaires in the presence of well-trained interviewers. A 100–130 kg precision digital weight scale (Tefal) and a t201-t4 Asimed adult height scale were used to obtain weight and height, respectively. The question: “have you experienced a fall to the ground in the last twelve months?” was used for collecting their history of falls in the previous year.
Table 1: Baseline characteristics of the participants, differentiated by groups.
Proprioception Intervention
The subjects included in the experimental group participated in a 12-week proprioception training program, performed 2 days per week (Monday and Wednesday), with a total of 24 sessions. Participants of the control group were asked not to change their activity levels and medication during the 12-week intervention period. They met weekly for an hour with the researchers to discuss topics of interest to older people. The exercise sessions were carefully supervised by a fitness specialist and by a physical therapist, who worked with groups of 10–12 older people. This program took place in the exercise room of the self-care residential facilities. The participants were asked to maintain their usual food intake (lunch time from 13:30 to 14:30), 2 L of daily water intake and 8 hours of sleep. The daily training was performed in the morning.
The type and intensity (mild to moderate) of the exercises of the present study were specially chosen so that the participants could perform them. A list of weekly attendance controlled the absences of each patient. Tests were conducted among the participants before and after the 12-week intervention.
Each exercise session included 50 minutes (10-minutes warm-up period with slow walk, mobility and stretching exercises, followed by 30 minutes of proprioceptive exercises program, and finishing with a 10-minute cool down period of stretching and relaxation exercises). A total of 6 Swiss balls (75 cm diameter) and 6 BOSU (BOSU Balance Trainer) were used for the proprioceptive training program (Figure 1 ). This program training consisted of 6 specific proprioceptive exercises, which were conducted in static and dynamic positions for a period of 30 minutes. Training was progressively structured in 2 or 3 phases, according to the exercise: Initial phase: weeks 1–5; intermediate phase: weeks 5–8; and advanced phase: weeks 8–12. The exercise program was exercises No. 1–No. 5 consisted of 2 sets of 10–15 repetitions with 1 minute of rest between sets. Two sets of 15 seconds and 1 minute rest between sets were performed in exercise No. 6. Training intensity was controlled by the rate of perceived exertion (RPE) based on Borg's conventional (6–20 point) scale. The medium values of RPE were 12 ± 2 on Monday and 13 ± 3 on Wednesday. These RPE values correspond to a subjective perceived exertion of “fairly light exertion and somewhat hard exertion,” that is, low to moderate intensity. Tests were conducted among the participants before and after the 12-week intervention. Proprioceptive exercises were adapted to the study population according the method suggested by Franco et al. (13
Figure 1: Exercises and protocols. Each session lasted 50 minutes (10 minutes of warm-up period, 30 minutes of proprioceptive exercises program, and 10 minutes of cool down), and 6 exercises were included. Exercises No 1–No 5 consisted of 2 sets of 10–15 repetitions with 1 minute of rest between sets. Two sets of 15 seconds and 1-minute rest between sets were performed in exercise No 6. No warming up exercises were performed. Initial phase: weeks 1–5, intermediate phase: week 5–8, and advanced phase: week 8–12.
Outcome Measures
Pre- and postintervention assessments were carried out on 2 separate days with at least 48 hours between each session, to prevent fatigue and enhance muscle recovery after exercise. The assessment of the tender-points static posturography: stability test with eyes open and closed and Tinetti and Berg tests were carried out on the first and second days, respectively. Both the intervention and usual care groups were assessed the week immediately before the intervention started and the week after the intervention was finished. All measurements were performed in the same order by the same trained physiotherapist.
Static Posturography (Primary Outcome)
EPS/C (Electronic Pressure System/Capacitive) force platform and EPS-System-Footchecker software were used to measure stabilometric parameters. The platform dimensions are 680 × 520 mm, with an active surface of 480 × 480 mm, 5-mm thick, and 2.304 sensors. Reliability of this test has been shown in earlier studies (4,13 X ) and anterior-posterior plane (Y ). It also measures the surface covered by the center of pressure (S), the speed of the center of pressure movement (Sp), the distance covered by the center of pressure (D), and the Romberg quotient (eyes closed/eyes open) about surface (RombergS), about speed (RombergSp), and about distance (RombergD). The static posturography tests performed at the beginning of the study demonstrated a good test-retest reliability. Intraclass correlation coefficients showed 0.624–0.924%, 0.571–0.912%, 0.737–0.939%, and 0.666–0.916 95% confidence intervals for XEO, XEC, YEO, and YEC, respectively.
Functional Balance (Secondary Outcome)
The Berg balance scale was used to assess the balance ability of the subjects. It is a performance-based measure of balance consisting of 14 observable tasks common to daily life activities used to evaluate functional balance (5,25 25 42 1
We also assessed participants' gait and balance abilities using the Tinetti scale (41 falls , and the risk of falling is high with a score <19. The validity of this test for screening old adults at risk for falling is well established (32
Statistical Analyses
Student's t test and Chi-square test were used to compare anthropometric (age, weight, height, and BMI) and demographic variables (marital, occupational, and educational status and income), respectively, between both experimental and control groups. Repeated measures ANCOVA (2 group × 2 time) with age as covariate was used to assess the effects of 12 weeks training on stabilometric variables (X, Y, and Romberg quotient), Tinetti and Berg tests values, and Bonferroni's post hoc adjustment was used. The nonparametric Kruskal-Wallis test for independent samples and Wilcoxon test for dependent samples were used for the data that did not show homoscedasticity (Levene's test) and normality (Kolmogorov-Smirnov test). Pearson's correlation was performed to determine correlations between the scores of Tinetti and Berg tests. The assessment of the CoP displacement, and not the sense of this displacement [right and forward (+), left and backwards (−)], is the main goal of this study, and to erase the influence of the positive and negative signs in the significant differences analysis, the analysis of variance of the CoP was performed after multiplying X and Y negative values by −1. A p value <0.05 was used to identify statistical significance. Intraclass correlation analysis was used to assess the reliability of the stabilometry tests at the beginning of the study. All analyses were performed separately. Percentage of change after training (postmeasurement − premeasurement)/premeasurement × 100) was calculated. Analyses were performed using the Statistical Package for Social Sciences (SPSS, v. 19.0 for Windows; SPSS, Chicago, IL, USA).
Results
X and Y Stabilometric Variables
Figure 2 shows the results of the mean center of pressure position in the medial-lateral plane with eyes open (XEO) and eyes closed (XEC) and in the anterior-posterior plane with eyes open (YEO) and eyes closed (YEC). After 12 weeks, medial-lateral displacements with eyes open (XEO) (Figure 2A ) described group main effect F [1,41] = 5.27, η2 = 1.114, p = 0.027. More precisely, the experimental group shows a smaller oscillation displacement in the x- axis compared with the control group (M = 0.74 ±1.44 and M = −1.74 ± 1.28 mm, respectively, p = 0.012). Intrasubject effect was not significant (p = 0.085 for the largest). The XEC analysis did not reveal any significant inter- or intrasubject effect (p = 0.102 for the largest, Figure 2B ). On the other hand, anterior-posterior displacements significantly improved (decrease of the mean CoP position) in both tests: YEO F [1,41] = 5.04, η2 = 1.109, p = 0.030 (Figure 2C ) and YEC F [1,40] = 4.12, η2 = 0.93, p = 0.049 (Figure 2D ). Post hoc analysis revealed that the improvement of the experimental group in comparison with the control group control was 78% in eyes open test (M = 0.46 ± 4.43 vs. M = 2.11 ± 1.24 mm, respectively, p = 0.010) and 139% in eyes closed test (M = 0.82 ± 1.07 mm vs. M = 2.05 ± 0.97 mm, respectively, p = 0.008). No significant inter or intrasubject effects were observed in YEO and YEC analysis (p = 0.096 and p = 0.390, respectively, for the largest).
Figure 2: Pre and postresults of the intervention in the experimental (n = 20) and control (n = 24) groups. (A) XEO = mean position center of pressure in the medial-lateral plane with eyes open; (B) XEC = mean position center of pressure in the medial-lateral plane with eyes closed; (C) YEO = mean position center of pressure in the anterior-posterior plane with eyes open; (D) YEC = mean position center of pressure in the anterior-posterior plane with eyes closed. *p < 0.05; **p < 0.01 indicates postmeasurement differences between experimental and control groups. Note: Graphic values are real. In the analysis of variance of the CoP, X and Y negative values were multiplied by −1 to avoid the influence of the positive and negative signs in the analysis of significant differences. There were no presignificant-postsignificant differences in experimental or control groups (p > 0.05).
Romberg Quotient
Romberg quotient is the ratio of the variable values obtained in the condition “eyes closed” and “eyes open.” We have calculated the Romberg quotient for the average surface (Figure 3A ), speed (Figure 3B ), and distance (Figure 3C ). The analysis of the Romberg quotient about the surface (Kruskal-Wallis test) revealed significant differences between the experimental (85.37 ± 25.62) and the control (207.17 ± 44.97) groups in the postintervention measurements (p = 0.039). No more inter- or intrasubject differences were identified (p > 0.05). The results of the Romberg quotient about speed revealed a group main effect (F [1,41] = 7.32, η2 = 0.152, p = 0.010) and a group × time interaction (F [1,41] = 5.25, η2 = 0.114, p = 0.027). In the post hoc analysis, significant differences were observed between the experimental and the control groups (46.16 ± 27.25 vs. 108.66 ± 43.11, respectively, p < 0.001). After 12 weeks of proprioceptive training, significant improvement was observed in the experimental group (p < 0.001) but not in the control group (p = 0.090). No time effect or group × time interaction were observed (p = 0.057 for the largest). No intra- or intersubjects effects were observed in Romberg quotient about distance (p = 0.061 for the largest).
Figure 3: Romberg quotient about surface (A), speed (B), and distance (C). Pre- and postresults of the intervention in the experimental (n = 20) and control (n = 24) groups. Dist = distance; Sp = speed; Surf = surface; EO = eyes open test; EC = eyes closed test. *p < 0.05 and **p < 0.01 indicate differences between the experimental and control groups. †††p < 0.001 indicates differences about the same group.
Balance and Gait Tests
The results of Tinetti and Berg balance scales are represented in Figure 4 . After 12 weeks of proprioceptive treatment, we could observe a group main effect F [1,41] = 10.74, η2 = 0.208, p = 0.002 and F [1,41] = 11.69, η2 = 0.222, p = 0.001, respectively, in both tests. Post hoc analysis revealed that the experimental group obtained a significantly higher score (p s < 0.001) compared with the control group in Tinetti scale (26.2 vs. 22.9 points, respectively) and Berg balance scale (47.2 vs. 42.3 points, respectively). A group × time interaction was also observed for both Tinetti (F [1,41] = 58.19, η2 = 0.59, p < 0.001) and Berg (F [1,41] = 74.42, η2 = 0.65, p < 0.001) tests. After 12 weeks of proprioceptive training, the experimental group obtained significantly higher scores in Tinetti and Berg balance scales (p s < 0.001). There were no pre-post differences in the control group (p > 0.05). The results of the balance and gait tests after the study period were very similar in both tests, with a very high correlation coefficient (r = 0.833 [p < 0.001] and r = 0.869 [p < 0.001], in pre- and postmeasurements, respectively).
Figure 4: Average scores of gait (Tinetti test) and balance (Berg balance scale). Pre- and postresults of the intervention in the experimental (n = 20) and control (n = 24) groups. ***p < 0.001 indicates postmeasurement differences between the experimental and control groups. †††p < 0.001 indicates differences about the same group.
Discussion
This study was designed to evaluate the effects of 12-weeks proprioception training program in postural stability, gait, and balance in older adults (aged 65–90 years). Although our training protocol differs from those used in previous studies, our findings are consistent with these works, and our protocol seems to be effective in static and dynamic stability, leading to an improvement in gait and postural balance (8,11,25
Falls , as mentioned above, are considered as one of the most important geriatric problems, with a high incidence, morbidity, and mortality. Several studies have described that the risk of falling can decrease with proprioceptive exercises in older adults, improving balance and preventing falls (17,26
Balance control depends on a coordinated effort of the sensory systems (visual, vestibular, and proprioceptive systems) and many works have shown that older individuals have reduced balance control compared with young individuals (23 falls in ≥65-year-old adults (24
Based on our results, we can state that the experimental group improves in the medial-lateral displacements of the center of pressure with eyes open, supporting evidences from Brouwer et al. (7 physical activity program in older people. In eyes closed test, no significant improvements were observed in the experimental group, similar to other authors' observations, who didn't report any progression in both eyes open and closed tests, whereas we could observe this improvement in eyes open test (11
In our analysis of anterior-posterior displacements of the center of pressure, the experimental group significantly improved in eyes open test, corroborating the results of Brouwer et al. (7 11
In older adult population, the ankle, hip, or mixed strategies are used to maintain upright stance (10 37
According to our findings, the effect of proprioceptive training was also shown in Romberg quotients about surface and speed, with improvements of 58.6% and 60.3%, respectively. These results agree with some studies, which described that the improvement was produced by the increase of the speed of the motor responses (39 14
Pérennou et al. (29 28
Consistent with Iwamoto et al. (18 8 proprioceptive training increases Tinetti and Berg scores (14.66% and 11.47%, p s < 0.001, respectively), and it leads to improved balance. On the other hand, Berg balance test score was the most significant result obtained by Badke et al. (1 31
The scores obtained with the Berg balance scale seem to be appropriate, as a score of <45 was shown to be predictive of multiple falls in older adults (4 40 proprioceptive training, placing the score higher than the cutoff score described in the studies mentioned above. Similar studies with exercise interventions in older people had shown improvement in balance, reaction time, strength, and flexibility (20
Various studies have indicated that performance on combined agility/dynamic balance tasks is a predictor of recurrent falling (41 33
In conclusion, the results of this study suggest that a proprioceptive training program is associated with significant improvements in static posturography and functional balance, and it can reduce the risk of falling in people aged 65 years and older. A 12-week proprioceptive training program, with 30-minute sessions (2 days per week) leads to positive effects on lateral and anterior-posterior stability in older adults. There were also significant improvements in the surface and speed of the center of pressure (Romberg test) but not in the distance. The use of Swiss ball and BOSU as proprioceptive training tools showed highly significant improvements (p < 0.001) in both standing balance and fall prevention in adults older than 65 years.
Practical Applications
This study shows that, compared with a traditional training program, a 12-week proprioceptive training with Swiss ball and BOSU has positive effects on postural stability, gait, and balance in older people. This study also indicates that this proprioceptive training may be important in preventing falls and subsequent injuries in adults older than 65 years. It is recommended that this population should engage in long-term regular proprioception exercise to help them gain more health benefits in gait and balance capacity. Assessing balance may have important implications for improving the quality of rehabilitation services for older people with postural balance problems not only in home-dwelling population but also in older adults who are living in other settings. Standardized functional measures should be used to assess balance in the screening for potential fallers among older people.
Acknowledgments
The authors would like to thank the direction and stuff members of “Sebastián Estepa Llaurens” retirement home and “Sebastián Estepa Llaurens” center for their collaboration in this study.
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