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Entrenamiento del Tren Inferior para el Equilibrio en Mujeres Mayores Sanas con el T-Bow®

A Lower-Limb Training Program to Improve Balance in Healthy Elderly Women Using the T-Bow® Device

In Chulvi-Medrano; Juan C. Colado, PhD; Carlos Pablos, PhD; Femando Naclerio, PhD; Xavier García-Massó


Abstract: Ageing impairs balance, which increases the risk of falls. Fall-related injuries are a serious health problem associated with dependency and disability in the elderly and results in high costs to public health systems. This study aims to determine the effects of a training programto develop balanceusing a new device called the T-Bow®. A total of28 women > 65 years were randomly assigned to an experimental group (EG) (n = 18; 69.50 [0.99] years), or a control group (CG) (n = 10; 70.70 [2.18) years). A program for lower limbs was appliedfor 8 weeks using 5 exercises on the T-Bow®: squat, lateral and frontal swings, lunges, and plantarflexions. The intensity of the exercises was controlled by time of exposure, supportbase, and ratings of perceived exertion. Clinical tests were used to evaluate variables of balance. Staticbalance was measuredby a 1-leg balance test (unipedal stancetest), dynamic balancewas measured by the 8-foot-up-and-go test, and overall balance was measured using theTinetti test. Results for the EG showed an increase of 35.2% in static balance (P < 0.005), 12.7% in dynamic balance (P < 0.005), and 5.9% in overallbalance (P > O.OS). Results for the CG showed a decline of 5.79% in static balance (P > O.OS) but no change in the other balance variables. Thus the data suggest that implementing a training program using the T-Bow® could improve balance in healthy older women.

Keywords: falls; geriatrics; physicalexercise; swinging; instability; T-Bow®

lván Chulvi-Medrano1 Juan C. Colado, PhD1 Carlos Pablos, PhD1 Fernando Naclerlo, PhD' Xavier Garcfa-Massó1

1Department of Physical Education and Sports, University of Valencia, Spaln; 'Department of theFundaments of Motricity and Training, European University of Madrid, Madrid, Spain


Ageing is associated with the deterioration of many biological systems and functional capabilities. 1-3 This impairment significantly reduces mobility and functional fitness,and increases dependency in the elderly. Balancecan be seen as a skill that will gradually deteriorate with age,4.S causing a greater risk of falls and fall-related injuries, which in turn affects healthylife expectancy.6 Falls are the result of any event that suddenly and unintentionally precipitates a person to the ground.7 Researchers have estimated that one-third of those 65 years will suffer a falls-12 Thisrisk increases by 8 timesin those 80 years.13 Within this risk group, one-half may suffer anotherfall,8-9 which could result in weakness and dependence.'4

Balance is the ability to maintain the body's position over its base of support involving static and dynamic components. 15 It requires postural stability, which isthe ability to maintain the body in spatial equilibrium under both static and dynamic conditions. 16 Reactive balance is conceived as postural con­ trol that involves effective responses to situations of disturbed or changed stability.17 In general, these abilities can facilitate the process by which the center of body mass is controlled, using the support base, in a static or dynamic way during voluntary stances or movements and as a response to externa! shocks.18 Toe deterioriation of theseabilities has been identified as one of the most common risk factors for falling among the elderly.15·'9 About 10% to 25% of falls are associated with poor balance and gait abnormalities.16 Because the ability to maintain balanceis influenced by such a variety of factors, the mechanisms that explain the age-related deterioration of balance are difficult to identify. Nevertheless, intrinsic factors are significant.For example, Choy et al 21 showed that changes in sensation and vision in women 40 years could be the principal reasons for deterioration in balance.

Physical activity programs have been successfully used to strengthen the physical parameters associated with fall risk, including improving balance. Both specific programs(balance activities) and comprehensive programs (to integrate the strengthening of lower limbs, specific balance, overall strengthening, flexibility,and agility)have been shown to have a positiveinfluence on a subject's balancing ability, thus reducing the risk of falls.22-26 Success in such programs has led to the development or design of specific devices to help improve balance. One device recently developed by T-Bow® Switzerland (Sandra Bonacina and Viktor Denoth, Zurich University) (Figure 1) consists of a multifunctional arch that allows for a wide range of exercises to strengthen lower limbs, enhance specific balance, and improve general strength, flexibility, and agility. We speculate that this device could increasegeneral physical fitness and all the specific abilities related to balance. Scientific knowledge about the benefitsof improving balance in older people using physical conditioning exercises and specific balance exercises performed with a T-Bow® is sparse. This study aims to quantify the effects of a trainingprogram using the T-Bow®, on the ability to maintain balance in a group of healthy elderly women.

Materials and Methods

Study Design

A randomized controlled trial was used to assess the effects on balance of different exercises using the T-Bow® for a period of 8 weeks. Subjects were randomly assigned to an experimental group (EG) or a control group (CG). Toe EG performed a program based on resistance trainingusing the T-Bow®_Toe CG continued normally, without performing other kinds of exercise. Pretest and post-test measures were recorded for both groups.


An advertisement was placed in a geriatric center. The study's principal researcher used a questionnaire and a complementary interview to assess the physical and sporting activities of a total of 55 elderly women. The inclusion criteria for the exercisegroups were: a) age 65 years; b) predominantly healthy and withno history of significant cardiovascular, pulmonary, metabolic, musculoskeletal, or neurological disease; e) no prior history of falls; d) no use of specific medication known to impair balanceor strength; and e) living independently in the community with a normally active lifestyle. Eleven subjects <lid not meet the inclusion criteria and 16 refusedto participate. Eventually, 28 women were randomly divided into the EG or the CG (Figure 1).

Based on the results providedin previous research,27 a power analysis for a comparison within the EG estimated that a sample of lS subjectswas needed to detecta size effect of O.79, with a power of 0.80 anda 2-tailed alpha of <O.OS. Power analyses were performed with the software GPower (GPower, v.3.0.10, Universitat Kiel, Alemania) using the outcome variable 10-minutewalking test similarto 8-foot-up-and-go test. We decided to employ a no equilibrated design because only 28 women met the inclusion criteria. To achieve sufficient statistical power to enable detection of significant differences within an experimental group,at least 15 subjects were needed. Inview of the possibility of drop-out, we decided to expand the sample size of theexercise group by 20%. Thus, the EG and CG were formed with 18 and 10 subjects, respectively. Table 1 shows descriptive data on the characteristics of participants in each group. All subjects were informed of the training and testing involved by means of a consent form. Toe women were told not to modify their behaviorand were strictlyforbidden to perform any other type of physical exercise. The study was approved by a research commission from the Department of Physical Education and Sports of the University of Valencia, Spain. Procedures Several balance measures were used to assess whethersubjects in the EG improved their balance. A Tinetti test, 1-leg stance test, and 8-foot-up-and-go test were appliedin both pretest and posttest. Participants performed each test twice, separated by 3 minutes betweenattempts. The best result of each participant was stored for further statistical analysis. Tinetti Test This test is usually applied to evaluate the risk of falls among the elderly229 and is a good too! to assessprogress in overall balancing skills after performing a physical training pro­ gram.30Thus, it is a useful, effective, and reliable clinical assessment too!, which applies a questionnaire that includes items addressing transition skills such assitting to standing or standing to sitting, as well as gait variables. Toe value of the sum of the scores of all items can vary from O to 28; values < 26 are related to an impairedcondition of balanceand values < 19 may involve a high risk of falls.30 One-leg Stance Test Static balance was assessed using the 1-leg stance test,31 which is a reliable marker of frailty during the aging.31,32 The test can be applied to elderly patients with impaired balance orto healthy elderly patietns.30 In this test, theparticipant stands on the preferredfoot, while restingthe hands at waist level, then raises the other foot approximately 10 cm off the floor. Balance is scored by the number of seconds for which the foot is kept raised or until balance is lost. Timing is terminated when the subject touches the free foot to the floor, removes the hands from the waist, or moves the supporting foot from the original starting position.The maximum stance is 30 sec, because after this time those tested demonstrate a high level of balancing skills.14•32 This test has been used on subjectswith motor impairment to assess balancedisorders in otherwise healthy people,33 and applied in a wide variety of ages.4J1.J2

Eight-foot-up-and-go Test

Dynamic balance was assessed using the 8-foot-up-and-go test, which is included in the Senior Fitness Test, a series of functional assessments aimed at the elderly, conducted by Rikli and Jones.34.35 The intra-class correlation coefficient inferior. Taking advantage of the convexshape of the T-Bow, subjects performed ankle flexo-extensions.

The intensity of these exercises was controlled by exposure time, by modifying the supportbase, and accordingto the obtained for this test has revealed good test-retest reliability (r = 0.95).34 The test has also been found to be significantly correlated to the Berg Balance Scale (r = -0.81), to gait speed (r = 0.61), and to the Barthel Activitiesof Daily Lives Index (r= 0.78). The test procedures were taken from Rikli and Jones.34 The purpose of the 8-foot-up-and-go test is to assess physical mobility in terms of speed, agility, and dynamic balance. The score is based on the number of seconds required to get up from a seated position (!mee flexion around 90°), walk 8 feet (2.44 m), turn around, and return to a seated position as fast as possible without running. Enhancing the skillsneeded to reduce the time to complete the distance in an easy and secure manner is important becausethese same skillsare needed in the activities of daily life.35

Training Program

The T-Bow® can be positioned on the floor concave or convex side down depending on the type of exercise required. The dimensions of the T-Bow®-were 700 mm (length) X 500 mm (width) X 170 mm (depth), and the weight was 3.2 kg. The T-Bow® will be unstable if the convex side is facing downward, and the instability may be lateral or anteroposterior depending on how the subject's weight is distributed. The training program consisted of 5 exercises using the T-Bow®-.

1) Squat. Figure 2 shows the start position. A flexo-extension movement of the hips and knees was performeduntil the thighs were positioned in a parallel position to the floor.

2-3) Side andfrontal swinging. With the convex side of the T-Bow® on the floor, the subjects performed swinging movements with the flexo-extension of each leg alternately. They performed lateral swinging fast and then frontal swinging.

4) Frontal lunges. With the concave side of the T-Bowe in contact with the floor, the subjects placed 1 leg above the T-Bow. They performed classical frontal lunges until the frontal thigh was parallelwith the floor (Figure 3).

5) Plantar flexo-extensions. With the concave side of the T-Bowe in contact with the floor, the subjects placed 1 leg on each side of the T-Bow®,firmly in the Adult OMNI Perceived Exertion Scale for Resistance Exercise (OMNI-Res).

Balance exercise intensity was implemented by the time of the stance while balancing. The maximum length of stay was 30 sec. If subjects could maintain their position correctly for 30 sec the base of support was increased to allow a higher leve! of swing in the next set. Subjects were asked to maintain a rating of perceived exertionof between 4 and 5 on the OMNI-Res.36 The intensity of strengthening exercises and balance training was monitored according to the OMNI-Res.36 The exercise had to be moderate or somewhat easy (scored by 4or 5), with the researcher asking to be shown thescore of each set (12 repetitions ofl-3 sets). For squats and frontal and lateral swinging the intensity was changed, widening the gap betweenthe support of the feet, while for the lunges and plantar flexo-extensions a slight elastic band was employed to adjust the number of repetitions at the target level of effort. The effectiveness of this monitoring has been reported in previous research24 and allowed for sustained moderate effort throughout the intervention program.

Two weekly 30-minute sessions were held over a period of8 weeks.We chose this duration because it has been shown tobe effective in improving the balance of elderly,37 especially when applying specific exercises to improve balance.38 Training sessions for the entire group were always led by someone with a professional degree in physical activity and sport. At least1 trained monitor was always present tocorroborate the correct application of the methodology, ensuring a closely supervised training study.

Statistical Analyses

The data were processed using SPSS 15.0. The Kolmogorov­ Smirnov test (K-S test) for normality and Levene's test for homoscedasticity were used to verify all variables before analysis. Standard statistical methods were used to obtain the descriptive statistics. The data are expressed as mean (standard error of mean). A mixed-model analysis of variance (ANOVA) 2 (tests of the program) X 2 (group) was applied to determinethe effects of the trainingprogram on balance. Multivariate analysis was used to avoid increasing family-wise error (ie, increase the possibilities of one type I error) because 3 dependent variables were included in the analysis. Pair-wise comparisons were requested when theANOVA showed a sig­ nificant effect. The level of significance was set at 5%.


The program had a significant main effect on the outcome variables (F[3,24) = 8.36; P = 0.001). Pair-wise comparisons showed that the time on 1-leg stance test was greater and the time to performthe 8-foot-up-and-go testwas less (P < 0.005). Nonetheless, the group had no significant main effect on the outcome variables (F[3,24) = 1.73; P = 0.187).

There was also a significant interaction effect between the training program and the subjects (F[3,24) = 7.96; P= 0.001). 1his result indicates that changes in test performance between pretest and post-test were different in the EG and CG. Post-hoc analysis revealed that the EGspent less time performing the 8-foot-up-and-go test, and the group's 1-leg stance time was greater in the post-test comparedwith pretest (P < 0.001).

The CG showed no significant differences between pretestand post-test. No significant difference between the groups in the pretest was found. However, the EG showed a higher Tinetti test score that the CG in the post-test (P = 0.003).


The results of ourstudy show a discreteincrease inthe values of static and dynamic balance after a period of 8 weeks of comprehensive training using the T-Bow® by healthy and active elderly women. The results demonstrate a slight effectiveness ofthe training program that we implemented with the T-Bow®. However,we found no differences between thegroupsinthe1-legstancetestorinthe8-foot-up-and-go test in the post-test, possibly because the sample size was large enoughtofindintragroupdifferences,butnottoestablish

any intergroup differences, or because the intervention was not sufficiently intense for women who were healthy and active. To our knowledge, Hugener and Reidt39 are the only authors to have previously conducted a study on the imple­ menting the T-Bow as a device for training. Toe design of this comprehensive study was very similar to ours (45-rninute sessions, 2 days per week for 8 weeks). Although Hugener and Reidt did not use the same exercises or assessment tools, their results were similar to those obtained in our study. Their research led to greater improvements in balance and strength than those obtained in our study, perhaps because our study used active participants, whereas theirs used women with a sedentary lifestyle. Our study of physically active participants showed that a resistance training program using the T-Bow could be a more effective way to improve balance than other types of exercise, because participants were able to improve their balance. To confirm our findings, detailed comparisons between training programs using the T-Bow® and other train­ ings programs, such as traditional resistance training or tai chi, are needed. Furthermore, the balance tests used in our study were more functional tests than the tests employed by Hugener and Reidt.39 A tendency to increase balance capacity in the short term is not a surprising discovery because early improvement of balance performance is known to follow physical exercise.37 Improvement in balance is more significant after specific exercises _J.BPor instance, it is possible to measure improvements in balance after 4 weeks ofspecific exercise training.40 Other studies have employed more balance-specific training pro­ grams using tai chi,41-43 unstable surfaces,44.45 specific exer­ cises and changes in the support base,25 and multimoda] exercises.46-47 These programs are effective because they target specific physiological systems involved in balance control (visual, vestibular, somatosensory, and musculoskeletal systems), and appear to improve balance in older adults. However, the difference between these proposals and our research usingthe T-Bow®- must be stressed. T-Bow®- exercises can be understood as balancing exercises that work by counteracting body weight resistance whereas other forrns of exercise such as tai chi involve changes in the distribu­ tion ofbody weightand unipedal stances. Furthermore, our study introduces the possibility of applying sorne resistance exercises for the lower extremities using the same device. Although this variable is not directlymeasured it is possible that the increase in strength could provoke additional posi­ tive effects on balance.26

We found that both static and dynamic balance irnproved after the intervention proposed, as previously shown in other 10-week trialsapplying specific balancingexercise.25-48 Our data showed that the greatest increase was recorded in the length of unipedal stance (35.20%), while dynamicbalance improved by 12.7%; finally, the Tinetti test showed a ten­ dency toward improvernent, although not to a statistically significant degree (P > O.OS). We can reasonablyconclude that the exercises we used showed greater effectiveness in the development of static balance because they did not involve displacements. Otherexercise programs based on exercises such as ballates', step aerobics, and walking-which ali include dynamic maneuvers-have been shownto produce a very significant increase in the capacity of dynamic balance in women aged 50 to 75 years.49

Rogers and Mille50 explain another possiblecontributing factor to an improvement in balancing skills.These authors cite the importance of lateral postural controlon the risk of falls in older people. Deterioration in the ability to respond effectively to loss of lateral stability increases the risk of side falls.51 Other research has demonstrated that medial-lateral balance in the elderly is superior to that of falls in young and elderly patients, but worse when compared with young patients who do not fall.52-54In this situation, these authors recommended activities in which lateral and medial lower­ limb muscle groups are activated, using the subject's own bodyweight. Toe peculiarand specific shape of the T-Bowenabled our program to include lateral balancing/swinging exercises, as outlinedby Rogers and Mille,50 which can be a major factor in justifying improved balance performance.

A final factor that rnay improve balance is the instabil­ ity ofthe T-Bow• for lower-limb strengthening exercises.55 In our study, 3 calisthenics exercises aimed at strengthen­ ing lower lirnbs were performed on labile surfaces, which offer a degree of instability due to rolling, thus leading to improved balance. Por healthy older women at low risk for falls, engaging in a broad range of specific balancing physical activity with the T-Bowis likely to be sufficient to substantially reduce the risk of falling as a result of an improvement in balancing skills. The sample size in our study was limited. Perhaps a larger sample may reveal intergroup differences in the post­ test. The lack of comparison between this intervention and other kinds of programs could be an additional limitation. Future research is required to obtain a quantitative assessment of balance level after T-Bowtraining in older women. Finally,we suggest further studies to verify the effects that we foundin our study in other groups,and more comparative research on various specificbalance training exercises, and other populations groups. The T-Bow® can be an effective device to improve performance balance in a short time in elderly subjects. Because ageing leads to a deterioration of many capacities such as balance,extensive studies have established training programs to avoid this deterioration. The present study has important clinical implications. It showed a significant clíni­ cal improvement of the balance function in elderly people who completed a training program using the T-Bow®-. Thus, this type of intervention is effective to prevent and treat impaired balance as a result of ageing. Safety issues need to be considered when subjects use the T-Bow•, however, and some modifications of the device may be needed for balance-impaired individuals. In conclusion, the main clinical highlight of this study is our demonstration that theT-Bow® could be an effective tool to gain moderate improvement of balance in healthy older women. Thus, it could be applied in conjunction with other traditional devices. Conflict of lnterest Statement Iván Chulvi-Medrano, Juan C. Colado, PhD, Carlos Pablos, PhD, Fernando Naclerio, PhD, and Xavier García-Massó have no conflicts of interest to disclose.

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