In 2022, the ACR recommended hand exercises to improve mobility and strength, with low certainty evidence suggesting that mind-body exercise can improve physical function. As far as we know, this is the first randomized controlled trial aimed at examining how Yijinjing affects hand function in patients with rheumatoid arthritis (RA). First of all, in RA patients with low disease activity who underwent 12 weeks of Yijinjing exercise, the hand function score dramatically improved. Second, there was a notable improvement in handgrip strength and active range of motion, showing no progression in inflammation under ultrasound. Third, not the disease activity of YJJG did worsen, but the quality of life, anxiety and depression also gradually ameliorated.
Yijinjing can improve hand function scores in RA patients. Due to successive progressive joint erosion, RA often leads to functional disability, typically resulting in hand dysfunction. The Michigan Hand Outcomes Questionnaire (MHQ) is widely used to evaluate hand function in clinical chronic hand diseases[37]. Dilek Durmu’s study[38] showed that MHQ scores moderately correlate with disease activity, in which higher DAS28 scores tended to correlate with lower MHQ scores, indicating worse hand function. Our study revealed that the YJJG and CG had relatively low MHQ scores of approximately 50 points at baseline, especially for overall function, work, aesthetics, and hand satisfaction, which revealed that most patients with low disease activity or remission were not satisfied with their hand function even without moderate or severe joint pain. The MHQ total and each subscale score in YJJG improved more significantly than CG compared with baseline, indicating that Yijinjing rehabilitation exercise for 12 weeks could effectively ameliorate the satisfaction of RA patients with their hand function. This finding was consistent with previous studies[39] showing that strengthening and stretching for rheumatoid arthritis of the hand (SARAH) for 12 weeks can improve the MHQ in RA patients. The Yijinjing exercise is highly similar to the SARAH program. For example, the first posture Wei tuo xian chu requires putting your hands together before your chest and maintaining as far as possible 90° wrist extension to exercise the wrist fully. Our study preliminarily showed that Yijinjing exercise can effectively improve MHQ hand function in RA patients. In the future, further multi-center RCTs should be carried out, and a positive control, such as SARAH, could be set up to obtain more evidence.
Yijinjing can enhance handgrip strength and flexibility in RA patients. According to previous studies, handgrip strength is critical for assessing hand function and can predict disability and joint impairment in RA[40–41]. The active range of motion (ROM) reflects hand flexibility quantitatively[42]. High disease activity, more pain, severe dysfunction, hand disability, and bone erosion in RA patients have been associated with low grip strength[43] and worse ROM[44]. For healthy people, the grip strength in a neutral position in the dominant hand was 29.1 kg, with a wrist flexion of 79.7°, a wrist extension of 74.4°, a pronation position ulnar deviation of 32.8° and a radial deviation of 21.1° in Stacy Fan’s study[45]. However, for RAs with high disease activity, the grip strength was 11.4 kg[46], with wrist flexion of 38.7°, wrist extension of 35.2°, ulnar deviation of 29.7° and radial deviation of 13.1°[47]. In terms of our study, we included 95% RA with low disease activity. The grip strength at baseline was less than 20 kg, which was weaker than healthy individuals but better than RA with high disease activity, showing a similar trend in ROM, which may be related to less pain. Our study revealed that handgrip strength and ROM were significantly greater in the YJJG than CG at 12 weeks (p < 0.05), indicating that Yijinjing exercise could effectively improve hand muscle strength and ameliorate hand flexibility. This finding was consistent with Mark A Williams[48], but due to the use of different grip devices, we did not measure the pinch grip force, which was one of the limitations of our study. The lack of a healthy ROM can be explained as follows. First, this study was carried out in RA patients with constant hand dysfunction. Second, even though the RA is relatively stable, still exists subclinical synovitis, referred to as synovitis under ultrasound or MRI, still exists with no signs of joint swelling. In addition, this may be related to the insufficient length of the intervention. However, there is no standard method for measuring RA joint mobility. Naoto Ienaga[49] developed a smartphone-based system to assess the ROM of the wrist joint, whose accuracy was within a clinically usable error range. The Yijinjing exercise contains multiple hand or wrist movements. As a result, Yijinjing can effectively promote muscular strength and dexterity in the hand.
Yijinjing did not increase inflammation in RA patients. As recommended by the EULAR[50], the semi-quantitative grading of musculoskeletal ultrasound is more sensitive for diagnosing subclinical synovitis in the wrist and hand[51]. This study revealed that subclinical synovitis and tenosynovitis were present in both groups at baseline. There was a slight decrease in YJJG compared with baseline, while mild aggravation in CG after 12 weeks of intervention. Although no significant difference was found between the two groups, a gradual improvement was noted in YJJG, indicating that Yijinjing does not exacerbate synovitis and is safe for treating RA. A prospective intervention study made clear that strengthening exercise is beneficial for enhancing the cross-sectional area of the rectus femoris via ultrasonography[52]. In addition, training did not increase blood flow on ultrasound Doppler induced by inflammation, indicating that it had no adverse effect on RA[53]. Therefore, it is necessary to introduce ultrasound as an evaluation to monitor the safety of exercise in RA. If the ultrasound score significantly increases, it hints at reducing intensity or stopping temporarily.
The morning stiffness duration, patient global assessment of disease activity, TJC, SJC, RF, CRP, and ESR are associated with RA disease activity. DAS28-ESR < 2.6, as a remission criterion, may be appropriate for most patients in the clinic[54]. At 12 weeks, the above outcomes of YJJG were almost improved compared with CG, indicating that Yijinjing could further reduce the activity of stable RA, gradually run up to remission, and did not aggravate joint inflammation. The effect of aerobic exercise on the prevention and treatment of RA dysfunction and disease activity has been gradually recognized. A study affirmed that aerobic and resistance exercise improved physical fitness in terms of aerobic capacity, endurance, and strength in older adults with RA[55]. Tai Chi is safe for RA patients, but more evidence is needed to improve physical function and pain with active RA[56]. Future researchers could attach importance to exercise in ameliorating function with moderate/severe disease activity RA. Exercise can not only improve function but also control inflammation, and the best duration and intensity of exercise should be explored in the future.
Yijinjing is beneficial for mind-body function in RA patients. RA with dysfunction often affects quality of life, and RA with lower disease activity have lower HAQ scores and better mobility[57]. Depression and anxiety are common comorbidities of RA, with the prevalence of depression varying from 14–48%[58], and the prevalence of anxiety was 62.1%, which is even greater than depression[59]. Therefore, we should not only control the disease activity of RA but also pay attention to improving quality of life and mental health. It showed that the daily activities of RA in the YJJG were basically not difficult, and anxiety and depression scores were obviously reduced in our study. During the follow-up, most patients said that they expected to be able to exercise, but they were afraid that the strenuous exercise would aggravate joint disorders, and they were irritable or depressed in the long term, which not only affected mental health but also further influenced body function. Yijinjing exercise made the patient sweat slightly, relaxed their mind and body, and they were willing to maintain the exercise. This study provided a rehabilitation treatment plan for RA patients with psychosomatic benefits.
This study had several limitations. First, our study focused on RA patients with a DAS28 < 3.2 and showed that Yijinjing is safe and effective in treating RA with low disease activity. Subsequent research can further expand the DAS28 to clarify its impact on RA with medium and high disease activity. In addition, some outcomes did not show significant differences, so exercise could be prolonged to 24 weeks to observe long-term efficacy. In addition, our sample size was not large enough; we included only one center participant and did not have a positive control. Further multi-center clinical studies could be conducted to add positive controls to obtain higher-level evidence.
In conclusion, Yijinjing exercise can improve hand function and enhance handgrip strength and flexibility in RA patients with low disease activity while ameliorating quality of life and alleviating anxiety and depression while safe and not aggravating joint inflammation.