Background and aim: With the advancing of age knee osteoarthritis has become the common musculoskeletal condition among males and females, various treatment strategies have been applied to improve the patient symptoms therefore the aim of this study is to compare the effectiveness of low resistance versus high resistance exercises along with stretching exercises on pain, physical function, & walking time in knee osteoarthritis.
Methodology: Considering the pre-assessment inclusion criteria, a total no of 170 participants were enrolled in the study and divided into 5 groups by random apportion. Group A received a high resistance exercise, group B received low resistance exercises, group C high resistance exercises and stretching exercises, group D low resistance exercises and stretching exercises and group E received only stretching exercises for 3 weeks. After that pain, function, and walking time were reassessed.
Study design: Experimental study, randomized control trial.
Results: The intergroup results were significant with a p-value of <0.001. We assumed that all 5 groups’ interventions in the current study show a clinically meaningful reduction in pain and enhanced the level of functional activities. Effects of various exercise training are the same in all groups. Therefore, no significant difference has been noted.
Conclusion: All 5 groups’ high resistance exercise along with stretching, low resistance exercise along with stretching, high resistance exercise, low resistance exercise, and stretching exercise reduced pain and improved functional activity in patients with knee osteoarthritis.
Keywords: Gait, quads drill, biomechanics, isometric exercise, cryotherapy, rheumatic disorder.
The knee joint is the complex and biggest weight-bearing joint in the human body; it’s a synovial joint of a hinge variety, which allows two movements that are flexion and extension with the help of a supportive group of muscles known as hamstring and quadriceps. The joint is formed by the femur and tibia. Anteriorly a patella is present which glides over the patellar surface of femur and forms a gliding joint. The stability of the joint depends upon ligament attachment. The menisci (fibrocartilage structures) present around the knee joint act as shock absorbers, whereas the presence of fluid-filled sacs called bursa helps in movement 1.
With advancing age, the knee joint undergoes irreversible degenerative changes. The most common musculoskeletal condition affecting the knee joint is osteoarthritis (OA), in which many of the structures are involved but hyaline cartilage gets affected the most2. The weakness of the Quadriceps femoris muscle considers the consequence of knee pain and functional disability3.
Globally, osteoarthritis is declared as the 4th leading cause of mobility impairment and non-fatal burden of disease of Year lives with disability (YLDs). The data estimated the prevalence of the KOA (knee osteoarthritis) 1,770 in males and 2,693 in females. It summarized that OA affects females more as compared to males4.
Worldwide the prevalence of KOA found in the USA is 42.1% in women and 31.2% in men, 28% in Pakistani urban areas and 25% in rural areas, 5.8% in rural regions of India and approximately 28% in urban regions, while 7.5% Bangladeshi rural areas, 9.2% in urban slum and 10.6% in urban affluent communities respectively. Whereas it was found that KOA is 7.5% prevalent in Chinese people, 7% in the Australian population and 41.9% prevalent in the Iranian population4.
The classification of KOA is either primary (idiopathic) or secondary but diagnosed mainly based on symptoms. It includes joint pain, limitation of movement, difficulty in initiating movement, crepitus, joint effusion pain and mobility disability 5. These are the most common perturbing factors. However, other risk factors include older age, female gender, obesity, vitamin D deficiency or calcium insufficiency, osteoporosis, profession-related problems, sporting activities, earlier trauma, less muscular strength or dysfunction, proprioceptive insufficiency, smoking, enzymes level and hereditary factors 6.
The management approach of OA is either conservative or surgical. The non-invasive management includes NSAIDs or pain killers whereas the rehabilitative management includes panoptic innovation which consists of conventional therapy, dry needling, intraarticular injections, and exercises 7. Evidence of the different research shown that knee OA gains beneficial effects from rehabilitation exercises than non-exercises 8. The frequently prescribed rehabilitative strategy for weak muscles across the world for lower limb osteoarthritis (OA) is strengthening exercises, which improve the muscles activities by reducing pain and disability9-10. But the recommendation of exercises is still a great concern as there is limited data on strengthening exercises, thus selection of specific exercises needs more valid data and research with the evidence-based practice and by the expertise opinions.
Therefore, this study has been conducted to find out the effectiveness of high resistance (HR) versus low resistance (LR) exercises along with stretching exercises in KOA among Pakistani KOA patients, to find out the effectiveness of the various exercises’ regimens.
This study has been conducted from Aug 2018- Aug 2021; a sample size of 170 was calculated by using Open EPI calculator version 3.0. All the participants enrolled in the study were explained about KOA, weight reduction strategies, behavioral adaptation to gain better functional outcomes and taught about discomfort and pain management. Confidential and informed consent has been taken; by simple randomized sampling technique participants were allocated into 5 groups, each group includes 34 participants. An orthopedic surgeon made the diagnosis of KOA based on clinical and radiological classification (ACR) criteria. Both male and female gender, who were aged between 45-60 years old presented with mild to moderate KOA (according to Kellgren and Lawrence classification), knee pain (according to American College of Rheumatology criteria) and had quadriceps & hamstring muscles strength of grade 3 or more (according to manual muscle testing -MMT) were enrolled in the study. Participants who were osteoporotic or had a history of recent lower limb fractures, surgery, involve in any kind of knee rehabilitation program from the past 3 months and on any pain killers/ steroids/ NSAIDs were excluded from this study.
To obtain the difference between HRX and LRX along with stretching exercises the Group A would be treated with HRX along with stretching exercises. Group B was treated with LRX along with stretching exercises. Group C treated only with HRX. Group D was treated with LRX. Group E was treated only with stretching exercises. To observe accurate effects on participants, we asked them to quit any other workouts, exercise, or therapies.
Pre and post assessment were made on a self-designed questionnaire which consists of 2 parts, part A includes demographics measurement of height and weight, whereas part B composed of assessment of walk time (to find out the problem during walking on different surfaces (I. Level ground, ii. Stairs, iii, Figure eight patterns, IV. Spongy surface) and The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) to assess pain and physical function sub score.
In the initial 3 days range of motion exercises, knee strengthening exercises, cryotherapy or TENS was applied according to the patient’s condition. After that treatment protocol was applied which includes flexion, extension, static Quads, leg press, Quads drill, static stretching exercises of hams, quads and calf muscles and theraband exercises according to patients group respectively. The high and low resistances were given according to the muscular strength and severity of pain. The resistance was set as 90 kg and 50 kg 1RM for HRX and LRX respectively3. For RX resistance was provided by different colors therabands.
All participants received 30 mints treatment session which comprises 10 minutes warm-up on a stationary bike (Enraf-Nonius), 3 sets of therapeutic exercises and cryotherapy for 10 minutes at the knee. Each set comprised 10 repetitions with a 10 second hold, after the completion of 1 set pt. rested for 1 min and between right and left leg 5 minutes rest interval was set. After 3 weeks of reassessment, the results were observed and concluded.
Data were analyzed by using a parametric test, paired t-test, Chi-square, and ANOVA on SPSS version 23.0.
There was a significant difference among the demographics variables of all 5 groups.
The frequencies of females were 104 and males were 66 out of 170 participants. The mean percentage of female participants is highest i: e (61.2%), whereas the overall mean age of participants is 52 ± 5.7, the mean height is 65 ± 4.07, mean weight is 66.3 ± 11.3 and mean onset of KOA duration is 6.55 ± 4.6. On X-Ray, the highest frequency of grade I KOA is found which is about 44.5%, whereas grade II is about 41.8%, and grade III is 14.1%.
In comparison between variables of age, height, weight and KOA onset duration with exercise groups of HRX with stretching, LRX with stretching, HRX, LRX and stretching. The mean age is highest in HRX with stretching which is 53.8 ± 5.64, p-value 0.149, whereas the highest mean height among participants in different groups is more in a stretching group which is 66.5 ± 11.96, p-value 0.081, the highest mean weight 70.3 ± 11.12, p-value 0.021 and the highest mean of onset of KOA duration is 7.29 ± 5.07, p-value 0.591 is again highest in the stretching group.
In the comparison of knee involvement, according to chi-square test, involvement of right (Rt) knee is more than left (Lt) and both knees, which is N=18(52.9%) in HRX along with stretching exercise, N=16(47.1%) in LRX along with stretching exercise, N=19(55.9%) in HRX, N=20(58.8%) in LRX, N=20(58.8%) in stretching exercise. So, the Rt knee N=93(54.7%) involves which is highest than left N=49(28.8%) and both 28(16.5%) therefore p-value 0.460.
In the comparison of X-Ray grades, grade I N=75(44.1%) is more than other grades, grade II has N=71(41.8%), grade III has N=24(14.1%). In HRX along with stretching the percentage and frequency of grade II is more N=16(47.1%) than grade I N=11(32.4%) and grade III N=7(20.6%), whereas, in LRX along.
With stretching, grade II is more, which is N=15(44.1%) than I N=14(41.2%) and grade III N=5(14.7%). In the HRX group grade ll is again more N=16(47.1%) than l N=12(35.3%) and grade lll N=6(17.6%). But in the LRX group grade l is more N=19(55.9%) than grade ll N=12(35.3%) and grade lll N=3(8.8%) and in a stretching group the percentage of grade l is high N=19(55.9%) than grade ll N=12(35.3%) and grade lll N=3(8.8%), hence p-value 0.462.
The comparison of pre- and post-assessment WOMAC subscale score and walking time in different groups is presented below in the tabular form.
Evident literature is present on the effectiveness of exercises on KOA5. Therapeutic exercises have greater benefits in KOA but regimen and the selection of specific exercise matters 11.
NejatiParisa. et al worked on the different non-pharmacological modalities, self-management techniques, strengthening & water-based exercises, and their effects. His observations concluded that strengthening exercise reduces the risk of rising KOA12. Another research data revealed that the effects of exercise therapy on KOA, in the study showed that regular KOA exercises provide a significant effect in relieving pain and advance knee functions 13.
The mean age of the study participant was 52 (St. 5.7) & the p-value=0.149 which was not significant because all participants had a different age between 45-60 years old. On the other hand, a p-value of gender is 0.766 which is also insignificant. The study reveals that the male population is less affected by KOA than females. Iqbal, N.M conducted an observational study to find out the frequency and associated factors of KOA in tertiary care hospital, the average age of affected participants were ≥55 years old, more overly females were also affected the most in their study 6. Therefore, this can be concluded that the mean age of occurrence KOA ≥45 years old and the disease is more common in the female population.
KOA can limit the range of motion by causing severe pain, a researcher applied resisted exercises on KOA and remarked that RX not only plays a vital role in pain despite that it also gives psychological support to the patient14.
Results of research, clinical effects of HRX and LRX training for patients with KOA had shown a great impact on the patient with the age of more than 50 yrs. Participants were allocated into 3 groups, on which group 1 performed LRX, group 2 performed HRX with max reps and group 3 was a control group. The intensity of pain, functional activities and walking time were observed. The observer noticed decreases in the intensity of pain more in group 1 but no significant difference was observed in overall condition3.
Therefore, in this study, significant results were found in group C and group D but no comparison could be made due insufficiency of literature.
Another systematic review was done by Lange AK. et al to explore the efficacy of strength training for the treatment of KOA. Results demonstrated that RX not only improves muscular strength and the level of physical activities but also reduces the pain15. Whereas Afonso, J et.al obscure that in order to get the optimal increase in ROM stretching and strengthening exercises some mechanical loading exercises also be prescribed to the patient16.
The research done by Latham N et.al concluded even in old age-progressive RX have tremendous, it improves pain intensity and performance ADLS as compared to elderly aged KOA pts, accounting that Garishma et. Al mentioned in knee OA pts,low RX are more effective than the high RX 17-18.
Furthermore, in another study acute RX was performed in KOA pts. Results revealed that irrespective of age there is decreased in pain but not in the level of tolerance19.
However, progressive eccentric or concentric RX training for KOA concludes that level of ADLS and strength of the lower limb can enhance by eccentric and concentric modes of RX20.
Progressive RX with eccentric loading for the management of KOA summarized that the patient shows development in muscle power, enhancement in ADLS level and decrease in pain after 12 weeks of eccentric strengthening exercise training21.
Similarly, in our research when comparison has been made between the treatments of the participants who performed HRX or LRX substantial results were observed.
Clark DI et. al establishes a result that proprioceptive muscle stretching and strengthening traits of exercise is the efficacious schema for KOA, which permit patients to release from physiotherapy 22. Likewise, in our study participants who only performed stretching exercises for the treatment of KOA also mentioned the effectiveness of treatment.
Walking is an essential functional activity of daily life. A RX was given to participants and walking time was noted before and after treatment. It was observed that walking time is improved in all groups3. Similarly, when in our study after training walking time was observed on different terrains p-value found to be significant, therefore it concludes that training sessions not only improves pain but also improve neuromuscular control of lower extremity.
After nine months ‘Follow up a study showed the beneficial effects of exercise debilitated over a period and finally vanish 23,24.
Consequently, in this research effectiveness of all groups treatments was significant but inter groups comparison doesn’t reveal any marked improvement and efficacy of treatment. Perhaps results couldn’t be summarized as the treatment was only given for 3 weeks and no follow-ups were taken after that.
Therefore, it is important to focus on the targeted muscles, type of exercises and the choice of exercise in the pain management and increase of KOA 25.
All 5 groups’ HRX along with stretching, LRX along with stretching, HRX, LRX and stretching exercises WOMAC scores were improved and no significant difference detected among the treatment of various groups. Might be better results could be observed if the treatment protocol followed longer for a month or 2.
Ethical approval was obtained by the Institutional Review Board of Isra institute of rehabilitation sciences, Isra University, Karachi campus.
Assuring confidentiality and informed consent has been taken for publishing the data regarding their cases
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The Ziauddin University is on the list of I4OA (https://i4oa.org/) & I4OC (https://i4oc.org/).
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0). https://creativecommons.org/licenses/by/4.0/
Conflict of Interest: The author (s) have no conflict.
[i] Assistant Professor Physiotherapy JSMU
ORCID ID: 0000-0002-5399-6548
[ii] Lecturer Baqai institute of physical therapy rehabilitation medicine Baqai medical university
ORCID ID: 0000-0001-9297-423X
[iii] Lecturer Department of physiology Sindh medical college Jinnah Sindh medical university
ORCID ID: 0000-0003-1619-3575
[iv] Vice principal & assistant professor Isra university of rehabilitation sciences Isra university
ORCID ID: 0000-0001-8448-5997