To evaluate the impact of a 2-year home-based strength-training program on physical function in patients with early rheumatoid arthritis (RA) after a subsequent 3-year followup.
To evaluate the impact of a 2-year home-based strength-training program on physical function in patients with early rheumatoid arthritis (RA) after a subsequent 3-year followup.
Seventy patients with early RA were randomized to perform either strength training (experimental group [EG]) or range-of-motion exercises (control group [CG]). Maximal strength values were recorded by dynamometers. The Modified Disease Activity Score (DAS28), pain, Health Assessment Questionnaire (HAQ), walking speed, and stair-climbing speed were also measured.
The maximum strength of assessed muscle groups increased by 19–59% in the EG during the training period and remained at the reached level throughout the subsequent 3 years. Muscle strength improved in the CG by 1–31%, but less compared with the EG. During the 2-year training period, DAS28 decreased by 50% and 45% and pain by 67% and 39% in the EG and CG, respectively. The differences in muscle strength, DAS28, and HAQ were significantly in favor of the EG both at the 2-year and 5-year followup assessments.
The improvements achieved during the 2-year strength-training period were sustained for 3 years in patients with early RA.
Despite important developments in medical treatment of rheumatoid arthritis (RA), the performance of activities of daily living and participation in society are seriously hampered in people with RA. Especially during the exacerbation of disease, joint swelling, pain, and systemic symptoms lead to a decrease in physical activity (1). Thus, reduced muscle strength, muscle atrophy, and a decline in functional capacity are often observed early in the course of RA, forcing patients to perform daily activities and paid work at a higher percentage of their maximum physiologic reserve (2, 3). Maintaining or restoring functional capacity in RA patients is an important public health issue (4). Several studies have evaluated the effects of physical activity on outcome measures in RA (5–7). The most consistent and important finding in these rather short-term trials is that regular exercise does not exacerbate pain or disease activity. However, up until now, there are few studies concerning the long-term effects of physical exercise on muscle strength and disease activity in patients with RA (8).
The complex interplay of biopsychosocial factors determines a person's function and behavior. Thus, the management of RA should be multifaceted and targeted to alleviate symptoms and prevent disability. The physician's key functions are to diagnose the disease early and to master drug therapy. Disease-modifying antirheumatic drugs (DMARDs) reduce inflammation, reduce symptoms, delay or prevent structural damage (e.g., joint erosions), and improve functional performance of the patients (9). Other health professionals (such as physical and occupational therapists, nurses, dietitians, psychologists, and social workers) support and motivate the patients by teaching self-management techniques that help the patients to cope with the disease in a positive way. One important self-management strategy is to perform physical exercises on a regular basis to prevent functional disability, which contributes to the development of handicaps.
The purpose of the present study was to evaluate the long-term effects of a 2-year, minimally supervised home-based strength training program on muscle strength and physical function in patients with early RA. The association of training compliance with changes in physical function was also studied.
Seventy patients with early RA according to the 1987 American College of Rheumatology (formerly American Rheumatism Association) criteria (10) were randomly assigned either to the strength training group (EG) or to the control group (CG) (Table 1). During the 2-year training period, 2 patients from the EG and 3 from the CG were lost (2 discontinued the exercises, 1 fell ill with cancer, 1 drowned, and 1 was involved in an accident and had neurologic symptoms) and 3 cases were excluded due to changed diagnoses. Three years later, 59 patients of the 62 who completed the training period were reexamined. Two patients had moved from the county and 1 was not interested in participating.
|Variable||EG n = 31||CG n = 31|
|Age, years, mean (SD)||49 (10)||49 (11)|
|Body weight, kg, mean (SD)||74 (14)||72 (11)|
|Body height, cm, mean (SD)||169 (8)||167 (9)|
|Duration of symptoms, months, mean (SD)||10 (10)||8 (12)|
|Rheumatoid factor positive, no.||19||19|
|Active smokers, no.||8||2|
The patients in the strength-training group were personally instructed to perform a home-based strength training for 24 months (8). The training program included exercises for all muscle groups of the arms, legs, and trunk using rubber bands and dumbbells as resistance. Subjects were instructed to exercise twice a week with moderate loads (50–70% of the repetition maximum), 2 sets per exercise, and 8–12 repetitions per set. The average stay in the rheumatology unit was 5 days and thus the patients performed the training program 3 times under the individual supervision of an experienced physiotherapist to learn the program properly. In addition, the whole staff of the unit supported the patients to improve their adherence and motivation for exercise. The intensity and technique of exercises were checked at 6-, 12-, 18-, and 24-month followup visits. The patients in the CG were instructed to perform range-of-motion and stretching exercises twice a week. In addition, all patients were encouraged to perform recreational physical activities 2–3 times per week.
After the 2-year measurements, the control subjects were instructed to carry out a strength training program. However, the instructions for the CG patients were given only once without any check-up visits.
The maximum unilateral concentric strength of the knee extensors was measured using the David 200 dynamometer (Outokumpu, Finland) (11), and maximal isometric trunk flexion and extension forces were measured by an isometric strain-gauge dynamometer (12). Isometric grip strength was measured by a dynamometer (Newtest Oy, Oulu, Finland) (13). Detailed descriptions of the measurements were published earlier (8). In the analysis, the best absolute result of each strength measurement (knee extension, trunk extension and flexion, and grip strength) was combined into a muscle strength index.
The Finnish version of the Health Assessment Questionnaire (HAQ), with scoring from 0 to 3, was applied to measure functional capacity (14, 15). The maximal walking speed over a distance of 30 meters (meters/second) and the time to climb up and down 10 steps were measured.
The Modified Disease Activity Score (DAS28), including tender and swollen joints, patient's self report of general health (on a 0–100-mm visual analog scale), and erythrocyte sedimentation rate, were used to evaluate clinical disease activity (16). Pain, as assessed on visual analog scale (17), and morning stiffness (minutes) were also evaluated.
All subjects completed training diaries and mailed them to investigators every second month during the 2-year study period. In addition, the type, frequency, and duration of leisure-time physical activities during the last 12 months were assessed by a questionnaire at the 5-year followup visit.
Descriptive statistics were used. The results are expressed as means with standard deviations and percentages. The most important descriptive values are expressed with 95% confidence intervals. Statistical comparison of changes in outcome measurements was performed using analysis of covariance. Correlations were estimated with Pearson's correlation coefficient method.
After initial assessments, therapy with DMARDs (sulfasalazine as the first drug with a few exceptions) was instituted in all patients. However, 24% and 50% of the patients were taking methotrexate (MTX) or a combination of DMARDs including MTX at 6-month and 2-year visits, respectively; a majority of the patients (70%) were taking these drugs at the 5-year visit (Figure 1). Three patients in both groups used no DMARDs at the 5-year visit due to remission. Ten patients in the EG and 20 in the CG were treated with low-dose prednisolone (2.5–7.5 mg/day) for an average of 8.0 (SD 7.5) months in the EG and 32.9 (SD 23.1) months in the CG during the 5 years.
During the 2-year training period, strength training compliance averaged 1.4–1.5 times a week in the EG. The mean (SD) time spent in various types of physical exercises (including strength training in the EG) during the first 2 years was 245 (115) minutes per week for the EG and 195 (104) minutes for the CG. During the fifth year, the corresponding times were 237 (147) and 223 (131) minutes. Twenty patients from the EG and 12 from the CG reported at least occasional intensive exercise (leading to sweating and getting out of breath). Ten EG patients and no CG patients exercised in the gym during the fifth followup year.
The maximal muscle strength values did not differ statistically significantly between the groups at baseline (Figure 2). During the 24-month strength-training period, the knee extension strength values increased by 59% (P < 0.001) and 31% (P < 0.001) in the EG and CG, respectively. At the 5-year followup, the respective values were 49% (P < 0.001) and 29% (P = 0.111) higher than baseline values. The corresponding increases in grip strength were 50% (P < 0.001) and 24% (P < 0.001) during the 2 years of training and 50% (P < 0.001) and 34% (P < 0.001) at the 5-year assessment. Trunk extension and flexion strength improvements during the training period were 19% (P < 0.001) and 24% (P < 0.001) in the EG and 1% (P = 0.465) and 20% (P = 0.007) in the CG. At the 5-year followup visit, the respective improvements compared with the baseline values were 16% (P < 0.001) and 25% (P < 0.001) in the EG versus 0% (P = 0.632) and 18% (P = 0.014) in the CG. In summary, at the 5-year followup visit, strength of all assessed muscle groups were in favor of the EG (Figure 2), and the between-group differences in knee extension (P = 0.02) and trunk extension (P = 0.04) strengths reached statistical significance. The mean (SD) strength indices were comparable between the groups at the baseline: 221 (84) kg in the EG and 194 (69) kg in the CG. However, both at the 2-year assessment (287  kg in the EG versus 230  kg in the CG; P = 0.025) and at the 5-year assessment (275  kg versus 225  kg; P = 0.029)], the indices proved to be in favor of the EG patients.
At baseline, HAQ indices, walking speeds, and stair-climbing times were comparable between the groups (Table 2). The HAQ index improved statistically significantly in both groups during the 2-year training period and remained relatively constant throughout the followup. During the 2-year training period, the mean walking speed increased by 21% (P < 0.001) and 9% (P = 0.025) in the EG and CG, respectively. The corresponding improvements in stair-climbing times were 15% (P = 0.026) and 9% (P = 0.155). The changes both in walking speed and stair-climbing times were minor subsequently and the values did not differ statistically significantly at the 5-year followup.
|Experimental group||Control group||Difference between groups (95% CI)|
|HAQ index, scale 0–3|
|Baseline||0.60 (0.53)||0.77 (0.55)||−0.17 (−0.4, 0.1)|
|2 years||0.13 (0.21)||0.35 (0.45)||−0.22 (−0.4, −0.004)|
|5 years||0.30 (0.42)||0.40 (0.51)||−0.10 (−0.3, 0.1)|
|Walking speed, meters/second|
|Baseline||1.9 (0.5)||1.9 (0.4)||0.0 (−0.2, 0.3)|
|2 years||2.4 (0.5)||2.1 (0.6)||0.3 (−0.1, 0.5)|
|5 years||2.1 (0.5)||2.0 (0.5)||0.1 (−0.1, 0.4)|
|Stair climbing time, seconds|
|Baseline||9.3 (2.0)||10.1 (2.3)||−0.8 (−1.8, 0.3)|
|2 years||8.4 (1.5)||9.2 (2.5)||−0.8 (−1.8, 0.3)|
|5 years||8.6 (1.5)||9.5 (2.7)||−0.9 (−2.0, 0.3)|
Clinical disease activity of the patients was moderate at baseline, before the initiation of drug management (Table 3). During the 2-year training period, the parameters mirroring disease activity decreased statistically significantly in both groups. Pain (P = 0.033) and morning stiffness (P = 0.019) were in favor of the EG after the 2-year training period, but at the 5-year followup, the significance in the between-group difference had disappeared. DAS28 improved by 50% (P < 0.001) in the EG and by 45% (P < 0.001) in the CG during the training period. Although the changes of DAS28 were minor during the following 3 years, there was a significant between-group difference (P = 0.012) in favor of the EG at the 5-year visit.
|Parameter||Experimental group||Control group||Difference between groups (95% CI)|
|Baseline||24.4 (17.8)||24.8 (15.7)||−0.4 (−8.8, 8.2)|
|2 years||10.9 (9.8)||15.4 (11.5)||−4.5 (−10.0, 0.9)|
|5 years||9.9 (12.1)||13.8 (12.1)||−3.9 (−10.2, 2.4)|
|Pain, 0–100 mm|
|Baseline||41.7 (19.5)||41.3 (27.1)||0.4 (−11.6, 12.4)|
|2 years||13.7 (16.2)||24.9 (22.8)||−11.2 (−21.4, −0.96)|
|5 years||22.0 (19.9)||25.9 (24.2)||−3.9 (−15.5, 2.2)|
|Morning stiffness, minutes|
|Baseline||72.4 (54.5)||81.5 (90.4)||−9.0 (46.9, 28.9)|
|2 years||16.3 (21.3)||37.7 (43.8)||−21.4 (−39.2, −3.5)|
|5 years||32.7 (55.2)||34.9 (49.9)||−2.2 (−30.3, 25.9)|
|DAS28 index, 0–10|
|Baseline||4.4 (1.1)||9 (1.1)||−0.5 (−1.1, 0.03)|
|2 years||2.2 (1.2)||2.7 (1.2)||−0.5 (−1.2, 0.04)|
|5 years||2.3 (1.0)||3.0 (1.2)||−0.6 (−1.3, −0.2)|
At the 5-year followup visit, the intensity of training was associated with the strength index (r = 0.34, P = 0.010) but not with time used for physical exercises. The strength index correlated with HAQ (r = –0.45, P < 0.001), walking speed (r = 0.61, P < 0.001), and stair climbing (r = 0.39, P = 0.005).
The main target of physical exercise is the maintenance or improvement of one's physiologic reserve to ensure functional independence and higher quality of life. In the present study, the strength training for 2 years had positive effects on physical functional capacity in patients with early RA. Moreover, the improvements were sustained for 3 years after discontinuation of the 2-year, minimally supervised home-based exercise program. Furthermore, the strength level obtained was associated with the measures mirroring physical function, emphasizing the importance of training for these patients.
As reported earlier (8), the maximal strength of the measured muscle groups increased by 19–59% in the EG during the 24-month training period. More importantly, it was interesting to find out that the strength levels remained 16–50% above the baseline level throughout the 5-year followup period. The increases in the CG were 1–31% and 0–29% at the respective checkup assessments. In the present study, the remarkable increase of 49% in knee extension strength was maintained by the EG patients up to 5 years. In the earlier studies with RA patients, in which the special isokinetic devices were applied for the strength training with the intensity of 50–80% of maximal voluntary contraction, the increases in knee extension strength varied from 14% to 37% (18–20). However, in these studies the length of the training period usually remained rather short, 3–12 weeks, and the use of the isokinetic devices usually needs supervision and guidance. In the long-term trials, where the patients were instructed to perform the exercises at home for 6–24 months, the corresponding strength increases were 45–49% (5, 21). However, the specificity of training seems to be important; in the studies where aerobic exercises were used solely (water exercises, bicycle ergometer, aerobic dance), the increases in knee extension strength varied from 0% to 17% (22–25).
From an important practical standpoint, the present study indicates that the frequency of strength training in previously untrained RA patients can be as low as 1.4 times per week during the first 2 years (and even less later), provided the loading and duration of training remain sufficient. In addition to strength training in the EG, both groups were encouraged to perform aerobic exercises and thus the CG patients were also able to improve their muscle strength to some extent. Regardless of the initial group assignment, the time the patients used for physical activities continued to be 4–5 hours per week throughout the followup period. After the 2-year intervention, 10 patients in the EG continued strength training with the elastic band and dumbbells at home or went to exercise at a gym as a part of their physical exercise. However, because these patients already had some strength training background, their strength levels did not differ from those of other EG patients at the 5-year followup visit. Aerobic exercises were performed by 20 EG and 12 CG patients at least with moderate intensity (sweating and getting out of breath while exercising). Thus, both the type and the intensity of training in the EG patients may explain a substantial part of the difference in observed muscle strength in favor of the EG.
The short-term effects of strength training are well described in several studies carried out with RA patients (5, 18, 26, 27). However, the positive results achieved disappear soon, if there was a total or partial cessation of training (28–30). On the other hand, maintaining the individuals' motivation to exercise is not easy. Consequently, the dropout rates for most organized exercise programs are about 50% within 3–6 months (31–33). In the present study, only 6% of the patients in the EG dropped out during the first 2-year training period and 80% of them continued to exercise individually up to 5 years. The patients were encouraged and motivated to the minimally supervised strength training during their stay in the rheumatology department and at the scheduled followup visits. After the 2-year visit, they exercised on their own volition. In addition to personal, detailed instructions to carry out the individualized strength-training program, the staff of the unit, including physicians, nurses, physiotherapists, and occupational therapists, increased the positive attitude towards the patients' self-care responsibilities and the physical exercises as an integral part of the patient management. The patient's role as an active partner and a central figure in the team of health care providers was emphasized. The same physiotherapist, rheumatologist, and nurse who met the patient in the rheumatology unit took care of the patient during the followup visits at the outpatient clinic. The patients were also encouraged to contact the staff of the hospital by phone whenever needed. We assume that the social support from the staff plays an important role in increasing the adherence to therapy (32, 34).
A patient education program is integral to the success of getting patients with chronic conditions to follow exercise instructions given by health care providers (35). The goals and versatile benefits of exercise should be thoroughly discussed with the patients. The patients should also be familiarized with the specifics of exercise, e.g., sufficient intensity, duration, and frequency as well as the precautions necessary in performing exercises (36). The patients should understand that physical performance and disease activity may fluctuate even on a daily basis and most of the signs during or after exercise are not harmful (e.g., joint pain during or 1–2 hours after the exercise, delayed muscle soreness). Long-term compliance also improves if the patients are aware of their bodies' response to different exercises and if they learn to modify various training programs according to fitness and changes in disease activity. Because the exercises in the present study were carried out at home, diaries were used as a feedback of the regularity of training.
Several factors determine a person's functional capacity, muscle strength being only one, and the complex interaction of the factors cannot be measured directly. In the present study, a self-report questionnaire rating the individuals' functional capacity was applied together with direct observation of the patients' performance. The results showed that muscle strength index was associated both with the HAQ index and with objectively measured walking and stair-climbing times. It has been shown that increases in the strength of leg muscles improve postural and gait stability, chair rise, and stair climbing, and thus reduce the risk of falling (37–39).
Patients in this study were actively treated with DMARDs during the entire followup period, and the efficacy and safety were confirmed with regular clinical assessments and laboratory tests by the rheumatologist. The prompt initiation of effective drug treatment certainly contributed to the improved outcome of all patients. Only 2 EG and 4 CG patients experienced disability (HAQ > 1) at the 5-year checkup visit. Pain and morning stiffness at the 2-year and DAS28 at the 5-year assessments confirmed the safety of active training within the premises applied.
In conclusion, this is the first study to show the long-term (5 years) benefits of physical training in patients with early RA. Individually tailored and regularly conducted physical exercises in the beginning of the disease lead to long-term increases in the physiologic reserve and consequently the functional capacity of RA patients, provided that the duration and intensity of muscle exercises are sufficient. In-depth information and motivation of the patients are other prerequisites for success.