Design Development and Testing of Chair Accessory for Lower Limb Exercising for the Elderly.
In Thailand, the elderly population is growing every year. The office of the National Economic and Social Development anticipated that in 2021, Thailand would become a completely aged society, which has populations with age at least 60 years for 20% and in 2036, Thailand will be the super aged society, which has populations with age at least 60 years for 30% (4,9). The percentage of elderly adults tends to rise continuously while populations at working age in Thailand is likely to decrease significantly and finally become aged (3,4). From above problem, the proportion of populations will be equal and the average of retirement of working populations is higher when they enter the aged society that they will have more physical injuries leading to chronic issues. Apart from higher medical budget for the elderly people, having good health of the elderly is another factor to render the aged adults to live their routine life normally. Also, another benefit is that the budget for caregiving and healthcare from chronic disease can be reduced. Therefore, emphasis should be placed on promoting good health and illness prevention among the elderly.
According to Naanat et al. (8), people in the age range of 50 to 60 years, 15% of muscles strength is lost per decade. Elderly people need to exercise to prevent a significant decrease in their knee extensor muscles strength. Otherwise, performing daily activities such as getting up from a chair becomes essentially impossible without help. Also, since elderly adults rely on their lower limbs to move about, a decrease in muscle strength is a major problem. Hence, it is necessary to move to prevent health-related issues, and exercising is essential for the elderly's health to delay degeneration and to strengthen body organs. Additionally, regular exercise improves mental health. Those who do not exercise will experience physical and organ degeneration along with a less effective nervous system, bodily movements, and a decrease in muscular strength and bone density. Therefore, it is imperative that elderly people engage in regular exercise (8).
The problem is that the majority of the elderly people are not active. They barely do any physical activities, especially in the COVID-19 situation because they cannot go outside for outdoor activities or participate in group exercise as they may have before. Additionally, researchers (10,13) have concluded that if the elderly do not move, do not engage in routine activities, or the patients in a wheelchair are physically inactive, then they become a bed-ridden elderly.
To help the elderly people exercise their joints and muscles regularly, a leg-press exercise accessory was designed and developed to be easily installed with a chair for lower limb exercising. The equipment is light weight, cheap, and safe to help promote regular exercise among the elderly.
Design and Development of Chair Accessory for Lower Limb Exercising for the Elderly.
This study designed and developed an accessory with a chair for lower limb exercising for the elderly. This equipment is structured, conveniently moved, and used with any type of chairs including wheelchairs. Furthermore, resistance and leg degree can be adjusted while leg-press exercising to be suitable for each elderly as illustrated in Figure 1 (a), (b), and (c) which shows the design of chair accessory for lower limb exercising for the elderly. The accessory was designed to be used by the elderly, but it can also be used with stroke patients and other adults with Parkinson or muscular dystrophy.
The purpose of the accessory for exercising is to strengthen the muscles of the lower limbs, given that the equipment will be like a leg press exercise as shown in Figure 2 (a) and (b). The legs will stretch out with a focus on the quadriceps, the hamstrings, the gluteus maximus, and the gastrocnemius muscles.
The chair accessory for the lower limb exercises both the left and the right sides weigh 3 kg (1.5 kg per each side), as shown in Figure 3 (a) and (b). It has a component of an additional chair and wheelchair for exercising the elderly people as demonstrated in Figure 4, which indicates the components of the chair accessory for the lower limb exercise that includes: (1) the pedal; (2) the helical spring; (3) the resistance-adjustment button; and (4) the knee-degree adjustment button while exercising. In the case of the wheelchair, the old wheelchairs' pedals were cut out and then the equipment was attached. When the wheelchair is normally used, the installed equipment and mechanism will be locked and deactivated, and it will be just a pedal. The total cost of the equipment is around $160 (USA currency).
As to resistance, the accessory is design to allow for adjustments by rolling the resistance button at the stick end of the equipment. Note in Figure 4 (i.e., #3), the resistance-adjustment button. This button is a puller to stretch the spring so that it will become rigid. The more rigid the spring becomes the more resistance, and it is directly variable with the spring's rigidity.
When the resistance is adjusted by rolling this button to the right at the stick of the equipment, the level of resistance is indicated for the user. The adjusted is reliable, and the equipment's resistance can be adjusted for 3 levels, from 2 kg, 4 kg, and 6 kg levels (19.61, 39.23, and 58.84 newton).
Inside the equipment, the mechanism provides resistance when stretching the legs out, of which is due to the spring. The spring specification has 2 mm of wire diameter, 10 mm of outer diameter, 150 mm of length inside hooks, and 115.5 mm of spring length, with the extension rate (k) of 4.5 N/mm, as shown in Figure 5 (a) and (b).
The design and development of chair accessory for lower limb exercising for the elderly can be adjusted for angle for exercising from 90[degrees] to 180[degrees], as indicated in Figure 6 (a) and (b) that shows degrees of equipment adjustment. Also, Figure 6 (c) shows the knee degree-adjustment button. The resistance and leg degree can be adjusted while exercising to best suit each user.
Testing of Chair Accessory for Lower Limb Exercising for the Elderly
The Factor of Safety (FOS) of Chair Accessory.
The design of the chair accessory for lower limb exercising by the elderly passed the test with SolidWorks 2018 Program. The researchers simulated its functioning to examine the "factor of safety". The chair's accessory strength was determined to be at 2.8 FOS (Figure 7). According to the engineering principle, this value is adequate for the equipment's functioning with repetitive use without damage arising from usage as long as the equipment is used in a right way. It is important to note that the equipment is strong enough to support the maximum user weight of no more than 150 kg.
When the accessory equipment is not in use, the initial length is 25 cm. When necessary, it can be extended to 35 cm with extension distance 10 cm as shown in Figure 8 (a) shows the length of the chair accessory while being active, and (b) shows the length of the chair accessory while being inactive, and (c) shows the length of the chair accessory while being inactive (left side) and active (right side).
The Adjustable Angle of Chair Accessory.
The researchers measured the adjustable knee angle (90 [degrees] to 180[degrees] movement) for both the left and the right sides of the chair accessory for lower limb exercise by Kinovea program and Goniometer as shown in Figure 9, which shows the adjustable knee angle measured by Kinovea Program. This would be useful for the users in case of some elderly people having movement limitations. This equipment can be adjusted to an angle of use that would be suitable for the elderly people so that they could exercise safely.
The Resistance Validity of the Chair Accessory
For validity testing of resistance of the chair accessory (Figure 10). The data collection for equipment validation started from installing the equipment with a chair tightly, putting the pedal down, attaching a weight scale, letting the pedal stretch for the spring to shrink with its power before collecting the data from the weight scale, and recording the results for 30 times/resistance level (The sample size calculated by G*power program; the effect size d = 0.952 (6), significance set at an alpha level of P<0.05, power (1- [beta]) = 0.95). The obtained data were validity analyzed in each level compared with the standard level using One Sample test (set at an alpha level of P<0.05).
According to Table 1: Measurement of resistance and average resistance at each level for 30 times for both the left and the right sides. The spring resistance data is slightly swing, however, the average resistance of 30 times testing in each level is equal to the stand level. The data are normally distributed. The average resistance and the standard deviation at level 1 is 2.00 [+ or -] 2.020 kg for the left side and 2.00 [+ or -] 2.018 kg for the right side. The average resistance and the standard deviation at level 2 is 4.00 [+ or -] 0.010 kg for the left side and 4.00 [+ or -] 0.012 kg for the right side, and the average resistance and the standard deviation at level 3 is 6.00 [+ or -] 0.008 kg for the left side and 6.00 [+ or -] 0.008 kg for the right side, respectively.
According to Table 2: The analysis of validity relation between standard resistance and resistance actually measured (30 times) of the equipment is found that this equipment is valid in aspect of resistance with no significant difference compared with standard resistance at 2 kg (left side; P = 0.869, and right side; P = 0.738), at 4 kg (left side; P = 0.856, and right side; P = 0.763), at 6 kg (left side; P = 0.059, and right side; P = 0.059). The findings indicate that the chair accessory for lower limb exercising for the elderly had resistance validity, and that the users can use it safely.
Results of the spring resistance testing for the chair accessory for lower limb exercising for the elderly reveal that the spring resistance is slightly swing, however, it is valid. The results show that it is not significantly different from the standard level. This chair's accessory relies on the principle of resistance spring. There are research studies that mentioned the use of the resistance spring or band for exercising. Overall, exercising with the resistance was more effective than a general workout (9), and exercising with the resistance spring or band helped to develop the bone and muscular systems, and it helped to increase muscular strength that improved living capability of the elderly people (7,12). Additionally, exercising with the resistance helped in developing lower limb muscle strength, physical stability while being still and yet moving. As a result, the elderly people could expect an improvement in their physical performance that would allow them the freedom to do activities themselves (1,2).
The goals of Chair Accessory for Lower Limb Exercising for the Elderly are to enable the elderly in Thailand to access an inexpensive exercise and rehabilitation machine that can help them: (a) to improve strength of the musculoskeletal system and joints; and (b) to reduce the burden of healthcare. In the future, the researchers also plan to have it used with elderly subjects to ensure that the Chair Accessory for Lower Limb Exercise for the Elderly will be practical.
This study helps to demonstrate the importance of the design and development that went into an accessory to be installed with a chair for lower limb exercising for the elderly. It is designed to be used with any type of chairs including wheelchairs. Resistance and leg degree can be adjusted while exercising to best suit each user. The researchers tested its function by studying the chair accessory's strength, the stretch distance of the chair accessory, and the chair accessory's adjustable angle and validity of the resistance. The findings indicate that the design of chair accessory for lower limb exercising for the elderly has a factor of safety that is 2.8, which is adequate with repetitive usage with no damage to the user. It can stretch a distance from 0 to 10 cm, and it can adjust to the degree of movement from 90[degrees] to 180[degrees] that would be useful for the elderly people who have movement limitations. It could be used to adjust resistance level from 2, 4, and 6 kg. Exercising for the elderly is extremely necessary, especially since it enables them to have better health and quality of life. It is safe, valid, and convenient, easy to use, and the overall cost is low.
We would like to extend our thanks to Thammasat University Research Unit in Health, Physical Performance, Movement and Quality of Life for Longevity Society for the funding and offering us the resources.
Address for correspondence: Sairag Saadprai, PhD, Thammasat University, Research Unit in Health, Physical Performance, Movement and Quality of Life for Longevity Society, Department of Sports Science and Sports Development, Faculty of Allied Health Sciences, Thammasat University, 25230 Thailand. Email: firstname.lastname@example.org
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Sairag Saadprai (1), Sudarat Apibantaveesakul (1), Plaiwan Suttanon (2), Bunyong Rungroungdouyboon (3)
(1)Thammasat University Research Unit in Health, Physical Performance, Movement and Quality of Life for Longevity Society, Department of Sports Science and Sports Development, Faculty of Allied Health Sciences, Thammasat University, 12120 Thailand, (2)Thammasat University Research Unit in Health, Physical Performance, Movement and Quality of Life for Longevity Society, Department of Physical Therapy, Faculty of Allied Health Sciences, Thammasat University, 12120 Thailand, (3)Department of Mechanical Engineering, Faculty of Engineering, Thammasat University, 12120 Thailand
The opinions expressed in JEPonline are those of the authors and are not attributable to JEPonline, the editorial staff or the ASEP organization.
Table 1. Measurement of Resistance, Average Resistance and Standard Deviation at Each Level for 30 times both Left and Right Sides. Testing Level 1 (2 kg) Level 2 (4 kg) No. Left Right Left 1 2.00 2.00 4.00 2 2.00 2.01 4.01 3 1.99 1.98 4.00 4 2.00 2.00 4.01 5 2.00 1.99 4.00 6 2.00 2.00 4.01 7 2.00 2.00 4.00 8 1.98 2.00 4.01 9 1.99 2.00 4.00 10 2.00 2.00 4.01 11 2.00 2.00 3.99 12 2.00 1.99 4.00 13 2.00 2.00 4.01 14 1.98 2.00 4.00 15 2.00 2.00 4.00 16 1.99 2.00 4.01 17 1.99 2.01 4.00 18 2.00 2.00 4.01 19 2.00 1.98 3.98 20 2.00 2.01 3.99 21 1.99 2.00 4.00 22 1.98 2.02 4.00 23 2.00 2.02 3.98 24 2.00 1.99 3.99 25 2.00 2.02 4.00 26 1.99 2.00 4.02 27 1.99 2.02 3.99 28 1.99 2.00 3.99 29 2.00 2.00 4.00 30 2.00 1.98 3.98 X [+ or -] SD 2.00 [+ or -] 2.020 2.00 + 2.018 4.00 + 0.010 08 Testing Level 2 (4 kg) Level 3 (6 kg) No. Right Left Right 1 4.01 6.00 6.00 2 4.00 6.00 6.00 3 4.00 6.00 5.99 4 4.00 6.00 6.02 5 4.01 6.01 6.00 6 4.01 5.99 6.00 7 4.00 5.99 6.01 8 3.99 6.00 6.00 9 4.00 6.01 6.00 10 3.99 6.00 6.01 11 3.99 6.00 6.02 12 4.01 6.01 6.00 13 4.01 6.01 6.00 14 4.00 5.99 6.02 15 4.00 6.00 6.01 16 4.00 6.00 6.00 17 4.01 5.99 6.00 18 3.98 6.02 6.00 19 3.98 6.00 6.00 20 4.02 6.00 6.00 21 4.02 6.01 6.01 22 4.00 6.00 5.99 23 4.02 6.00 5.99 24 4.00 6.01 6.00 25 4.00 6.02 6.01 26 4.02 6.00 6.00 27 3.98 6.00 6.00 28 3.98 6.02 6.01 29 4.00 6.01 6.01 30 3.99 6.00 5.99 X [+ or -] SD 4.00 + 0.012 6.00 + 0.008 6.00 + 0.008
Table 2. Show the Analysis of Validity Relation between Standard Resistance and the Resistance Actually Measured. Level of Resistance/Standard Level P-value Level 1 (2.00 kg) Left 0.869 Level 1 (2.00 kg) Right 0.738 Level 2 (4.00 kg) Left 0.856 Level 2 (4.00 kg) Right 0.763 Level 3 (6.00 kg) Left 0.059 Level 3 (6.00 kg) Right 0.059 (*) Significance at the P<0.05 level
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|Author:||Saadprai, Sairag; Apibantaveesakul, Sudarat; Suttanon, Plaiwan; Rungroungdouyboon, Bunyong|
|Publication:||Journal of Exercise Physiology Online|
|Date:||Aug 1, 2021|
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