Effectiveness of progressive resistance exercise on functional fitness among community-residing elderly

Autor: Ling-Zhen Jiang, 江怜臻
Rok vydání: 2018
Druh dokumentu: 學位論文 ; thesis
Popis: 106
Background: Starting in 1993, Taiwan began to become an aging society and the elderly population now account for about 14% of the total population. As a result of this, the challenges associated with chronic diseases and various disabilities have increased. To address these issues, a strong emphasis has been placed in Taiwan on maintaining a healthy and active lifestyle. Aim: To explore the effect of resistance exercise on the percentage of skeletal muscle, the percentage of body fat and upper/lower body extremity muscle strength among elderly individuals who reside in the community. Method: A total of 71 elderly who live in the community were identified in the Beitou District of Taipei, Taiwan; these were assigned into two groups (n=36) and the experimental group then took part in a 12 weeks resistance exercise program developed by exercise coaches. The program undertaken by the experimental group was considered to be safe, progressive and to adhere to the overload principle. It consisted of stages one to three of different intensities aimed at eight different muscle groups (the pectoral muscles, the deltoid muscles, the latissimus, the leg muscle group, the abdominal muscle group, the lower back muscle group, the triceps, and the biceps). The frequency of this program was three times/week with each session lasting 60 minutes (10 minutes of warm-up exercise, 40 minutes of main exercise, and 10 minutes of cool down). There was a gradually increase in the intensity with one stage lasting four weeks; there were ten items that had ten repetitions. In addition to a coach being present, there was also two trained coaching assistants present who had the task of adjusting the intensity of training of each individual elderly person according to their capabilities. Thus, specifically, the status of each elderly person was taken into account continuously. The control group did not undergo any intervention over the same period of 12 weeks. However, the control group did each receive the same resistance exercise teaching manual that was given to the experimental group after the experiment had finished. The testing of elderly subject's physical fitness was carried out before and after the intervention period. Body fat and skeletal muscle were measured using a Precision Body Composition Analysis Inbody 720. The functional fitness of the upper body was measured using a hand-grip detector that is able to assess upper muscle strength. Lower muscle strength was measured via the 30 second sit to stand test. The data-set was analyzed using SPSS for Windows 24. Descriptive statistics were used to present the participants' baseline characteristics. Independent t-tests and Chi-squared tests were performed to determine the baseline homogeneity of the functional fitness measures between the two groups. A generalized estimating equations (GEE) analysis was performed to assess the effect of the 12 weeks of resistance exercise on the percentage of skeletal muscle, the percentage of body fat, the muscle strength of the upper extremities and the muscle strength of the lower extremities after adjusting covariance to control for age and gender. Results: A total of 71 individuals completed the study. The experimental group consisted of 36 people, namely 6 males (16.67%) and 30 females. The control group consisted of 35 people, namely 3 males (8.57%) and 32 females. In order to use the chi-square test, an independent t-test was used to compare homogeneity across gender, age, the percentage of skeletal muscle, the percentage of body fat, the muscle strength of the upper extremities and the muscle strength of the lower extremities. These indicators showed there were no significant differences (P> 0.05). After receiving 12 weeks of resistance exercise, the percentage of skeletal muscle in the experimental group was found to have increased from 21.03±3.03% before the intervention to 21.60±2.72% after the intervention; this is an absolute increase and a percentage improvement of 2.71%. The same values for the control group pre-test was 20.79±3.48%, and this only change marginal post-test to 20.76±3.24%, which is a decrease of 0.03%. The percentage improvement between the two groups was 0.14% and after GEE analysis the interaction was significant (β= 0.35, P< 0.001). The percentage of body fat in the experimental group was 33.67±5.35% before the intervention, and this was found post-test to have reduced to 32.03±5.46%, a decrease of 1.64%. This is a percentage improvement of 4.87%. The same values for the control group pre-test was 34.09±5.75%, and post-test was 33.95±5.85%; which is a decrease of 0.07%. The percentage improvement between the two groups was 0.41% and after GEE analysis the interaction was significant (β= -0.39, P< 0.001). The upper extremity muscle strength of the experimental group's right hand was 22.28±7.21kg before the intervention, and this had increased post-test to 23.58±6.21kg, which is an increase of 1.3kg and the percentage improvement was 5.83%. The same measurements for the left hand were 21.82±5.96kg before the intervention and 22.47±5.94 kg post-test, which is an increase of 0.65kg and a percentage improvement of 2.98%. The same results for the control group for the right hand were 21.89±7.33 kg pre-test and 20.79±6.87kg post-test, which is a decrease of 1.1kg. The percentage improvement between the two groups was 5.03%. Similarly, for left hand, the values were 21.89±7.33 kg pre-test and 20.38±6.21kg post-test, which is a decrease of 1kg. The percentage improvement between the groups was 4.68% and after GEE analysis the interactions with respect to upper extremity muscle strength were both significant (right hand: β= 0.39, P< 0.001) (left hand: β= 0.31, P= 0.006). The lower extremity muscle strength in the experimental group was 20.06±5.80 times sit to stands before the intervention, and 22.69±3.89 times sit-stands after the intervention, which is an increase of 2.63 sit-stands. The percentage improvement between the groups is 13.11%. For the control group, the pre-test value was 19.86±5.31 times sit-stands, and the post-test value was 18.20±5.12 times sit-stands, which is a decrease of 1.66 sit-stands. The percentage improvement between the groups was 8.36% and after GEE analysis the interaction was significant (β= 4.94, P< 0.001). Conclusion and Suggestions: This study found that there were significantly improvements in all of the indicators among the intervention group and the results are better than those founds in various previous in the literature. This difference may be attributed to the following: (1) the use of a high-dose over a short period. Many studies have used interventions at less than three times per week and the elderly study subjects may often have personal reasons for absenteeism, which can significantly affect the program. To avoid this problem, in our study the highest dose possible was administered to the participants. (2) Coaching assistance allowed the training intensity of the program to be adjusted according to Borg's Rating of Perceived Exertion of the elderly. (3) There was sufficient training intensity to have an effect and the training intensity was adjusted by increasing it over time. (4) The strength of the core muscles was investigated using the 30-second chair stand test. This test not only relies on the lower limb muscles, but also the abdominal muscles. In addition to training the lower limb muscles, the intervention was also aimed at an enhanced training of the abdomen via the use of sit-ups. (5) The teaching was contextualized, with the training actions being packaged into a situational teaching model, with music of different melodies being played during the warm-up, the main exercises, and the cool down. This increased interaction between the participants. (6) Posture correction was carried out before each training session, with the body line of the participants being adjusted to one that is correct for either standing or sitting; these adjustments included the body line of the spine, the knees and the shoulders. However, this study does have some limitation. For example, it did not take into account a number of aspects that might have an effect on the study participants performance, such as nutrient intake and protein intake, both of which might affect muscle mass. In future studies it would be better to match the diets of the elderly participants as much as possible. Currently, resistance training is a collective training; nevertheless, it has been proposed that, in the future, such training might be conducted at home after primary caregivers having undertaken training. This is a good suggestion as sitting in a chair for a long time can result in lower limb weakness and increased bodily feebleness. Such a home based approach would be suitable for individuals who cannot leave the home or elderly persons who have problems keeping appointments.
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