Department of Physical Medicine and Rehabilitation, Dongguk University College of Medicine, Goyang, Korea.
Corresponding author: Ho Jun Lee. Department of Physical Medicine and Rehabilitation, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, 27 Dongguk-ro, Ilsandong-gu, Goyang 410-773, Korea. Tel: +82-31-961-7487, Fax: +82-31-961-7488, hjrhee1@dumc.or.kr
• Received: December 26, 2012 • Accepted: June 10, 2013
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
To investigate the effect on pain reduction and strengthening of the whole body vibration (WBV) in chronic knee osteoarthritis (OA).
Methods
Patients were randomly divided into two groups: the study group (WBV with home based exercise) and control group (home based exercise only). They performed exercise and training for 8 weeks. Eleven patients in each group completed the study. Pain intensity was measured with the Numeric Rating Scale (NRS), functional scales were measured with Korean Western Ontario McMaster score (KWOMAC) and Lysholm Scoring Scale (LSS), quadriceps strength was measured with isokinetic torque and isometric torque and dynamic balance was measured with the Biodex Stability System. These measurements were performed before training, at 1 month after training and at 2 months after training.
Results
NRS was significantly decreased in each group, and change of pain intensity was significantly larger in the study group than in the control group after treatment. Functional improvements in KWOMAC and LSS were found in both groups, but no significant differences between the groups after treatment. Dynamic balance, isokinetic strength of right quadriceps and isometric strengths of both quadriceps muscles improved in both groups, but no significant differences between the groups after treatment. Isokinetic strength of left quadriceps did not improve in both groups after treatment.
Conclusion
In chronic knee OA patients, WBV reduced pain intensity and increased strength of the right quadriceps and dynamic balance performance. In comparison with the home based exercise program, WBV was superior only in pain reduction and similarly effective in strengthening of the quadriceps muscle and balance improvement.
Knee osteoarthritis (OA) is the most common type of OA, with an estimated 12.1% of adults in the United States suffering from pain and functional limitations [1]. Knee OA is commonly defined as a degenerative, noninfectious disease of the knee joint. The main symptoms of OA are stiffness, loss of mobility, swelling, and pain.
No curative agent has been known in treatment of OA. The primary goals for OA therapy are pain relief, maintenance of joint integrity, improvement in functional status, as well as lessening deformity and instability [2]. The American College of Rheumatology (ACR) guidelines recommend a combination of non-pharmacological and pharmacologic treatments for symptomatic knee OA and conservative management plans must be individualized and adjusted according to the responses of patients [3]. Non-pharmacological treatments, such as active modalities and physical agents effectiveness in reducing pain and disability, as well as improving quality of life without side effects in chronic knee OA patients [3,4]. In addition, physical agents, such as short-wave diathermy, transcutaneous electrical nerve stimulation (TENS), ultrasound, and hot packs are passive; non-invasive and safe modalities commonly used to control both acute and chronic pain [7].
The muscles around the knee, especially quadriceps and hamstring, are known to act as dynamic stabilizer and also as stabilization of the posture and even distribution of shock and the stress during the physical motion [5]. Quadriceps muscle weakness is a common clinical sign associated with tibiofemoral OA [6], and is considered to be a critical determinant of disability [7]. Loss of hyaline articular cartilage and impairment of bony remodeling can even result in capsular damage and muscle weakness [8], and impairment of knee proprioception has consistently been related to individuals with knee OA [9]. ACR guideline recommends strengthening exercise of the quadriceps [3]. Weakness of knee flexor and extensor muscles could lead to a decreased joint stability and be combined with the associated decreased biomechanical efficiency. Thus, we need an effective modality for pain relief and also muscle strengthening.
The whole body vibration (WBV) machinery and tools has recently been paid attention to because it seems to be easy and safe to perform. Ultrasound makes the platform to vibrate precisely vertically, which induces involuntary muscle contractions of the whole body. Various studies regarding application of WBV reported improvement of muscle strength, power, joint proprioception, balance, and flexibility [10-13]. Some studies reported its effects of especially quadriceps strengthening [10-13]. Improvements are thought to be due to reflex activation of the a-motor neuron, via muscle spindle activation [14]. The WBV exercise is a time-saving and safe method for rehabilitation of women with knee OA [15]. WBV could be thought as a useful modality in the patients who are unable to participate in active modalities because of severe disability according to advancing age and progression of knee OA.
This study was conducted to investigate the therapeutic effects, such as pain reduction and strengthening, and safety of WBV in chronic knee OA.
MATERIALS AND METHODS
Subjects and study design
Forty-four female ambulatory community-based patients were recruited with a diagnosis of chronic knee OA. Inclusion criteria of subjects were age at least or above 50 years, diagnosed as symptomatic knee OA for at least 6 months according to the clinical criteria of the ACR [3], and radiographic findings compatible with knee OA and Kellgren-Lawrence grades II and III in simple X-ray [16]. Further, patients had no previous history of serious knee trauma, surgery and arthroplasty, or intra-articular injection of hyaluronic acid or steroid in the last 6 months. Exclusion criteria were acute symptomatic OA, comorbidities such as any peripheral or central neurologic disorders, and previous surgery of knee during the last 6 months, and radiologic findings of Kellgren-Lawrence grade IV. Informed consents were obtained from all patients. Forty-four patients were randomized into two groups using the blocked randomization method. Eight patients (study group, 5; control group, 3) were excluded at screening due to severe OA on radiologic findings. Patients in the study group (n=17; mean age, 60.0±5.7 years) received WBV (20 minutes, 3 times every week) with home based exercise (HBE) and those in the control group (n=19; mean age, 62.5±6.2 years) performed only HBE after education for 8 weeks. During the training period, fourteen patients dropped out (study group, 8; control group, 6) because of personal business and tiresomeness, herpes zoster, low back pain, and knee pain aggravation. Finally, eleven patients finished training for 2 months in each group.
Out of 22 patients of the control group, only one patient was on aspirin (Astrix 100 mg/day) due to underlying heart disease. Other patients were not on analgesic drugs, such as non-steroidal anti-inflammatory drugs, and during the study, such medication was not given. Also, during the study period, no other treatments, such as physical modalities (e.g., short-wave diathermy, TENS, ultrasound, and hot packs, etc.) nor injection technique was done to the patients, except for the HBE and WBV. Various measurements were performed before training, at 1 month after training, and at 2 months after training. Pain intensity was measured with the Numeric Rating Scale (NRS), functional scores of pain with Korean Western Ontario McMaster score (KWOMAC) and Lysholm Scoring Scale (LSS). The strength of the quadriceps muscle was measured with isokinetic peak torque (at 60°/sec), isometric torque and dynamic balance were measured. Information of clinical characteristics, such as age, height, body weight, Kellgren-Lawrence system, and body mass index were collected.
All study designs were approved by the Institutional Review Board of our institution.
Intervention
Whole body vibration training
WBV training was performed with TurboSonic (TS Korea Co., Ltd, Seoul, Korea). The patients were asked to stand barefoot on the platform with a slight knee flexion during training. To prevent the feeling of uncomfort and anxiety, the patient can hold a handle during training. The training of WBV was performed for 20 minutes and over three times a week for 8 weeks. During training of one set, patients were instructed to perform 2 training cycles of 10 minutes, and rest of 5 minutes between cycles. Vibration was delivered at a low frequency (12-14 Hz) with a vertical displacement of 2.5-5 mm (Fig. 1).
Home based exercise
HBE consists of five exercise programs. The exercise protocol consisted of active range-of-motion exercises, muscle strengthening, and muscle stretching. The protocol was based on increasing muscle strength, and facilitation techniques are used for improving the proprioceptive, flexibility, and range of motion. The first session included a lecture that provided information about knee OA, its risk factors and information on the importance of regular exercise. The protocol for exercises was presented to patients for practice [17]. Most of the exercises prescribed can be incorporated into daily life; for example, while sitting on a chair, patients were instructed to slowly straighten their leg out in front of them for each leg. The patients were asked to perform each exercise up to 10 times each. Each patient received a detailed handout containing instructions and photographs of the exercises. Patients will attend HBE sessions over 3 times a week for eight weeks. Patients were instructed that pain should be avoided in all exercises.
Outcome measurements
Pain intensity
Pain intensity was measured with NRS.
Functional status
Functional status of patients with knee OA evaluated using KWOMAC and LSS. KWOMAC is a modified Korean version of WOMAC [18]. KWOMAC is a set of standardized questionnaires used by health professionals to evaluate the condition of patients with OA of the knee and hip. KWOMAC consists of 24 questionnaires, which compose 3 sub-concepts, such as pain, joint stiffness, and functional status. KWOMAC scores range from 0 to 96, with higher scores indicating severe OA.
LSS consists of 8 questionnaires with contents of pain, clinical symptom and functional status. LSS scores range from 0 to 100, with lower scores indicating severe OA.
Muscle strength
Maximal isokinetic torque: The maximal voluntary knee extensor strength was measured as isokinetic peak torque with an isokinetic dynamometer (model 900-240; Biodex Medical Systems, Shirley, NY, USA). The patient was tested in a seated position with the hip at 90° of flexion, and strapping was placed across the waist and chest to stabilize the torso. The axis of rotation of the dynamometer lever arm was aligned to the femoral lateral condyle, and the lever arm was secured to the tibia just proximal to the medial malleolus via an ankle cuff.
Following a warm-up comprising 1 submaximal and 1 maximal contraction, all of the patients performed 2 maximal trials for 5 seconds with a 1-minute rest interval. Patients were instructed to extend their knee as fast and forcefully as possible for at least 2 to 3 seconds. In each trial, the peak torque normalized to the patient's body mass was recorded, and the higher measurement of 2 valid trials was analyzed.
Maximal isometric torque
Following one submaximal trial contraction, two maximal isometric knee-extensions were performed at knee angles of 60°. Maximal contractions were interspersed by 90-second rest intervals. The highest isometric extension torque of the manually smoothed curves at each knee angle was selected as the maximal isometric torque.
Dynamic balance
Standing balance control scores were acquired from Biodex Stability System (Biodex Medical Systems). The platform is connected to computer software (ver. 3.1, Biodex Medical Systems) that enables the device to measure the balance objectively. Patients were instructed to stand barefoot on the platform with a slight knee flexion and attached to the feet on the platform. Before the start of the stability trials, the subjects were asked to maintain a quiet stance on the platform for seconds for initialization. During that time, center of pressure were assessed. Immediately after the quiet stance, 6 stability trials (3 trials per each state) were performed 30 seconds during opening of the eyes. The device measured and analyzed the medial-lateral (ML) index and anterior-posterior (AP) index as the mean±standard deviation. ML index represents the stability of the coronal plane and AP index represents the stability of the sagittal plane.
Data analysis and statistics
To investigate and compare the changes of each outcome at each period (baseline, 1 month after treatment, and 2 months after treatment) in each group, and to compare the changes between the study group and control group, analysis with repeated measures analysis of variance (RMANOVA) was performed. To test significant differences from the baseline at each time (1 month and 2 months) and to test the significance of the time effect for each group, linear contrasts were performed. The statistical significance level was determined as p-value <0.05. All outputs were produced using a statistical software package SAS ver. 9.3 (SAS Institute Inc., Cary, NC, USA).
RESULTS
The clinical characteristics of patients, such as age, height, body weight, Kellgren-Lawrence grade and body mass index are described and there were no statistical differences between the study group and control group at baseline (Table 1).
Many parameters were measured and analyzed to investigate the change during training in each group and to compare the difference of change during training between the study group and control group.
Pain intensity (NRS) of knee pain significantly decreased after training in each group and the decrease of pain intensity was significantly more in the study group than the control group at 2 months after training (Table 2).
RMANOVA analysis revealed that the overall change of pain related physical functions, such as KWOMAC, and LSS after training were not significantly different between the study and control groups (Table 3). An analysis using linear contrast revealed that KWOMAC was significantly improved in both groups at 2 months in comparison with the baseline (p=0.035, from analysis using contrast for test between 2 months and the baseline), but there was no significant difference between the study group and control group during the training period. Further, LSS improved significantly from the baseline to 2 months (p=0.038, from analysis using contrast for test between 2 months and the baseline) and there was no statistical difference between the study group and control group (Fig. 2).
RMANOVA revealed that the overall change of isokinetic torque and isometric torque were not significantly different between WBV and HBE during 2 months (Table 4). The strengthening effect of WBV might be similar to HBE. An analysis using linear contrast revealed that isokinetic torque at 60°/sec of right knee extensor significantly improved in both groups during the training period (p=0.0175, from analysis using contrast for test between 1 month and the baseline; p<0.0001, from analysis using contrast for test between 2 months and the baseline), but there was no significant difference between the study group and control group. Isokinetic torque of left knee extensor improved, but not significant between each time and baseline in both groups. Isokinetic torque improved only in right knee extensor in both groups (Fig. 3A). Isometric torque of both knee extensors significantly increased at 1 month (p=0.0146 for right knee extensor and p=0.0039 for left knee extensor, from analysis using contrast for test between 1 month and the baseline) and at 2 months (p=0.0013 for right knee extensor and p=0.0001 for left knee extensor, from analysis using contrast for test between 2 months and the baseline), but there was no significant difference between the study group and control group (Fig. 3B).
The effects on dynamic balance were not significantly different between the study group and control group (Table 5). AP index and ML index significantly improved at 1 month (p=0.0222 in AP index and p=0.0255 in ML index, from analysis using contrast for test between 1 month and the baseline) and at 2 months (p=0.0081 in AP index and p=0.0022 in ML index, from analysis using contrast for test between 2 months and the baseline) from the baseline in both groups, but there were no significant difference between 1 and 2 months in each group and no difference between the groups at each time. Dynamic balance after WBV significantly improved, but not significantly different with that after HBE (Fig. 4).
DISCUSSION
WBV has been reported that low-amplitude, low frequency mechanical vibration is a safe and effective method to improve muscle strength [19-21]. Vibration exercise imposes hyper-gravity activity due to the high accelerations. While mechanical vibration applied to the muscle, fast and short changes occurred in the length of the muscle-tendon complex in skeletal muscles [22]. Vibrations elicit a response called "tonic vibration reflex". It was produced by mechanical activation of muscle spindles, mediation of the neural signals by Ia afferents, and activation of muscle fibers via large α-motor neurons [23]. Tonic vibration reflex is increased in recruitment of the motor units through activation of the muscle spindles and polysynaptic pathways [24]. WBV induced a more efficient use of the positive proprioceptive feedback loop [19-21,24]. This mechanism showed that the principle of the WBV-exercise regime increased muscle strength and proprioception.
Many studies were reported that WBV training improved neuromuscular performance in healthy people and along with other diseases [10-15]. Trans et al. [15] recently reported the effect of WBV exercise on muscle strength and proprioception in females with knee OA. This study compared WBV exercise with the control group who did not participate in any training. It showed that the WBV-exercise regime increased muscle strength and proprioception.
TurboSonic WBV used in this study produces vibration from an ultrasound, which can deliver an extremely low frequency vibration to the whole body. This advantage means that vibration is effectively propagated to the knee joint in standing position. In addition, the intensity of vibration can be adjusted to each individual patient to minimize discomforts and hazards. The target of the device could be the improvements proprioception of the knee joints and strengthening of knee extensor, as well as optimization of neuronal reactivation of the muscles and thereby, improved joint stability. We supposed that the TurboSonic WBV can be a safe and effective treatment intervention for strengthening of knee extensor and improvement of dynamic balance in patients with knee OA.
This study investigated the effects of WBV training on pain, dynamic balance, muscle strength and functional capacity for 2 months in mild to moderate knee OA patients. The analyses showed that the effects of WBV on pain reduction and improvement of pain related functions and also on strengthening of knee extensor and improvement of dynamic balance control as expected. However statistical analysis revealed these effects of WBV was not superior to those of the HBE except pain reduction.
The results of this study show that therapeutic effect of WBV was similar to the HBE except pain reduction, which was only superior in the WBV group. Pain reduction is essential to the functional disability in knee OA. However, the mechanism of pain reduction is not clear. We supposed that the WBV could influence slowly adapting receptors (Meissner corpuscles) [25,26]. The reductions of pain may result from a desensitization of Meissner corpuscles and Merkel cell that occurs after low frequency vibration [27]. Locally applied skin vibration can result in a reversible decrement in vibro-tactile afferent sensitivity, and it is thought that the threshold sensitivity of these afferents increases with frequency and amplitude [28,29]. Further, we suggested that repeated WBV stimulation increasing influence of the afferent threshold sensitivity. To our knowledge this is the first study to investigate the impact of WBV on decreased pain in females with knee OA.
The change of KWOMAC and LSS representing physical disability was not significantly different between WBV and HBEs. KWOMAC showed no significant change over 1 month in both groups, and after 2 months KWOMAC was similarly significantly improved in both groups. We did not analyze the difference in the items, such as pain, stiffness, and physical function. The change of LSS seemed to be different to KWOMAC. Though there were no statistical difference between WBV and HBE, the mean values of LSS in the WBV group improved consistently from the baseline to 2 months and those in the control group improved only over first 1 month. LSS is composed of 8 different entries and sub-concepts of pain, clinical symptoms, and functional status. Whereas KWOMAC is composed of 24 entries without clinical symptom sub-concept, but has joint stiffness entry in which LSS does not have.
Dynamic balance significantly improved only over the first 1 month in both groups and no statistical difference between the WBV and HBE. Isometric torque of knee extensor and knee flexor improved more than isokinetic torque in each group; therefore, both WBV and HBE might be helpful to improve isometric torque of quadriceps and hamstring, and also improved dynamic balance. If we analyzed the correlation between isometric torque and dynamic balance, we could suggest a more detailed association of these outcomes. Strengthening of quadriceps is important and we could find the strengthening effect of WBV and HBE. The quadriceps muscle acts as a dynamic stabilizer of the knee joint and might have some association with balance. We suggest the possibility that WBV could be helpful to dynamic balance through improvement of isometric torque of the quadriceps muscle.
In this study, both the study group and control group showed improvements of isometric torque of both knee extensors. However, as for the isokinetic torque of knee extensors, both groups showed improvements only in the right side. This result could be due to many different factors. Because most of strengthening exercise of HBE is composed of isometric exercise, the components of HBE could be the cause of significant improvement of isometric torque compared to isokinetic torque. In addition, because of joint stiffness and pain of chronic knee OA patients, the measurement may have not been precise.
The limb dominance may be the cause of improvement of isokinetic torque only in the right side. Limb dominance has been defined as one limb demonstrating increased dynamic control as a result of an imbalance in muscular strength and recruitment patterns [30-32]. In this study, except for 1 patient in the study group, all the other patients were right limb dominance and this could have affected the isokinetic strengthening. However, no study was done about the relationship between the limb dominance and strengthening effect, and further researches are needed.
We set the therapeutic intervention of HBE in the control group. Because of ethical problems, we thought this was the least intervention to patients with knee OA. This was the difference from another study [15], which designed the control group with no therapeutic intervention. If we set the control group with no intervention like the other study, results of this study might have changed to be advantageous over the control group with various measurements.
HBE composed of light strengthening exercise has been known as a good intervention for patients with knee OA. It was reported to be superior to no exercise group over the two years [33], and as effective as the standard physical therapy [34] and hyaluronate injection [35]. Recent ACR guideline strongly recommends that all patients with symptomatic knee have been enrolled in an exercise program commensurate with their ability to perform these activities [3]. Therefore, we suggest that WBV might be valuable therapeutic intervention in knee OA because therapeutic effect of WBV seems to be as effective as HBE, which is proved as effective.
This study has several limitations to the generalization of the results. The sample size was small. The small sample sizes used probably decreased statistical power. The other limitation is long-term measurement of efficacy, and the lack of the control group did not participate in any training and only the WBV treatment group. Lastly, both the study group and control group showed improvements of isokinetic torque of knee extensors only in the right side. To support these results, many probable causes are explained above, but the evidence is yet scarce. Therefore, this point should further be evaluated.
Many studies reported that long-term occupational exposure to intense WBV seems to be associated with an increased risk of low back pain [36-38]. Because the long-term exposure to WBV can lead to muscle fatigue and pathological change of musculoskeletal system [36]. However, short term exposure to WBV has been reported to increase muscle power by improved muscle activation [39]. In our study, adverse events, such as low back pain and aggravation of knee pain, occurred only in one patient in the study group, which is smaller than in the control group. Therefore, we can suggest TurboSonic which seems to be a safe WBV exercise device. However, vesicles on the buttock in one patient, which was diagnosed as herpes zoster, might be not be related to the whole body vibrator due to no reports of herpes zoster after WBV.
In chronic knee OA patients, WBV reduced pain intensity and increased strength of the right quadriceps and performance of dynamic balance. In comparison with HBE program, WBV was superior only in pain reduction and similarly effective in strengthening of the quadriceps muscle and improvement of dynamic balance.
ACKNOWLEDGMENTS
ACKNOWLEDGMENTS
This study was supported by a grant of the Korea Healthcare technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (A090084).
Special thanks to biostatistician (Chi-Yeon Lim, PhD) of the Department of Data Management and Statistics Institute, Dongguk University.
CONFLICTS OF INTEREST
No potential conflict of interest relevant to this article was reported.
REFERENCES
1. Dillon CF, Rasch EK, Gu Q, Hirsch R. Prevalence of knee osteoarthritis in the United States: arthritis data from the Third National Health and Nutrition Examination Survey 1991-94. J Rheumatol 2006;33:2271-2279.
2. Hochberg MC, Altman RD, April KT, Benkhalti M, Guyatt G, McGowan J, et al. American College of Rheumatology 2012 recommendations for the use of nonpharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip, and knee. Arthritis Care Res (Hoboken) 2012;64:465-474.
3. Iwamoto J, Takeda T, Sato Y. Effect of muscle strengthening exercises on the muscle strength in patients with osteoarthritis of the knee. Knee 2007;14:224-230.
4. Devos-Comby L, Cronan T, Roesch SC. Do exercise and self-management interventions benefit patients with osteoarthritis of the knee? A metaanalytic review. J Rheumatol 2006;33:744-756.
5. Tan J, Balci N, Sepici V, Gener FA. Isokinetic and isometric strength in osteoarthrosis of the knee: a comparative study with healthy women. Am J Phys Med Rehabil 1995;74:364-369.
6. Hootman JM, FitzGerald SJ, Macera CA, Blair SN. Lower extremity muscle strength and risk of self-reported hip or knee osteoarthritis. J Phys Act Health 2004;1:321-330.
8. Kirkley A, Webster-Bogaert S, Litchfield R, Amendola A, MacDonald S, McCalden R, et al. The effect of bracing on varus gonarthrosis. J Bone Joint Surg Am 1999;81:539-548.
10. Cochrane DJ, Stannard SR. Acute whole body vibration training increases vertical jump and flexibility performance in elite female field hockey players. Br J Sports Med 2005;39:860-865.
11. Bogaerts A, Verschueren S, Delecluse C, Claessens AL, Boonen S. Effects of whole body vibration training on postural control in older individuals: a 1 year randomized controlled trial. Gait Posture 2007;26:309-316.
12. Fagnani F, Giombini A, Di Cesare A, Pigozzi F, Di Salvo V. The effects of a whole-body vibration program on muscle performance and flexibility in female athletes. Am J Phys Med Rehabil 2006;85:956-962.
14. Cardinale M, Lim J. The acute effects of two different whole body vibration frequencies on vertical jump performance. Med Sport 2003;56:287-292.
15. Trans T, Aaboe J, Henriksen M, Christensen R, Bliddal H, Lund H. Effect of whole body vibration exercise on muscle strength and proprioception in females with knee osteoarthritis. Knee 2009;16:256-261.
18. Bae SC, Lee HS, Yun HR, Kim TH, Yoo DH, Kim SY. Cross-cultural adaptation and validation of Korean Western Ontario and McMaster Universities (WOMAC) and Lequesne osteoarthritis indices for clinical research. Osteoarthritis Cartilage 2001;9:746-750.
19. Bosco C, Cardinale M, Tsarpela O, Colli R, Tihanyi J, von Duvillard SP, et al. The influence of whole body vibration on jumping ability. Biol Sport 1998;15:157-164.
20. Bosco C, Colli R, Introini E, Cardinale M, Tsarpela O, Madella A, et al. Adaptive responses of human skeletal muscle to vibration exposure. Clin Physiol 1999;19:183-187.
21. Torvinen S, Kannu P, Sievanen H, Jarvinen TA, Pasanen M, Kontulainen S, et al. Effect of a vibration exposure on muscular performance and body balance: randomized cross-over study. Clin Physiol Funct Imaging 2002;22:145-152.
23. De Gail P, Lance JW, Neilson PD. Differential effects on tonic and phasic reflex mechanisms produced by vibration of muscles in man. J Neurol Neurosurg Psychiatry 1966;29:1-11.
25. Lundstrom RJ. Responses of mechanoreceptive afferent units in the glabrous skin of the human hand to vibration. Scand J Work Environ Health 1986;12(4 Spec No):413-416.
26. Talbot WH, Darian-Smith I, Kornhuber HH, Mountcastle VB. The sense of flutter-vibration: comparison of the human capacity with response patterns of mechanoreceptive afferents from the monkey hand. J Neurophysiol 1968;31:301-334.
30. Ford KR, Myer GD, Hewett TE. Valgus knee motion during landing in high school female and male basketball players. Med Sci Sports Exerc 2003;35:1745-1750.
32. Knapik JJ, Bauman CL, Jones BH, Harris JM, Vaughan L. Preseason strength and flexibility imbalances associated with athletic injuries in female collegiate athletes. Am J Sports Med 1991;19:76-81.
33. Thomas KS, Muir KR, Doherty M, Jones AC, O'Reilly SC, Bassey EJ. Home based exercise programme for knee pain and knee osteoarthritis: randomised controlled trial. BMJ 2002;325:752.
34. Ben Salah Frih Z, Fendri Y, Jellad A, Boudoukhane S, Rejeb N. Efficacy and treatment compliance of a home-based rehabilitation programme for chronic low back pain: a randomized, controlled study. Ann Phys Rehabil Med 2009;52:485-496.
35. Kawasaki T, Kurosawa H, Ikeda H, Takazawa Y, Ishijima M, Kubota M, et al. Therapeutic home exercise versus intraarticular hyaluronate injection for osteoarthritis of the knee: 6-month prospective randomized open-labeled trial. J Orthop Sci 2009;14:182-191.
38. Hulshof C, van Zanten BV. Whole-body vibration and low-back pain: a review of epidemiologic studies. Int Arch Occup Environ Health 1987;59:205-220.
39. Cochrane DJ, Legg SJ, Hooker MJ. The short-term effect of whole-body vibration training on vertical jump, sprint, and agility performance. J Strength Cond Res 2004;18:828-832.
A woman stands on the vibrating platform of whole body vibration (TurboSonic) with a slight flexion of both knees.
Fig. 2
The graph shows changes in physical function over time. The changes of (A) Korean Western Ontario McMaster score (KWOMAC) and (B) Lysholm Scoring Scale (LSS) were significantly different between baseline and 2 months in both groups. But there was no significant differences study between study group and control group. Asterisk (*) indicates statistical significance between baseline and 2 months (p<0.05).
Fig. 3
The graph shows changes of knee extensor muscle strength: (A) isokinetic torque (60°/sec) and (B) isometric torque in both groups. (A) Isokinetic torques of right knee extensor increased significantly over time during training period in both groups and there were no significant differences between study group and control group. Isokinetic torques of left knee extensor was not significantly different during training period in each group and between groups. (B) Isometric torques of both knee extensors increased significantly over time during training period and there were no significant differences between groups during training period. Asterisk (*) indicates statistical significance between baseline and 1 month (p<0.05) and double asterisk (**) indicates statistical significance between baseline and 2 months. ISK, isokinetic; ISM, isometric; Rt, right; Lt, left.
Fig. 4
The graph shows changes in dynamic balance over time in both groups. Anterior-posterior (AP) index and medial-lateral (ML) index significantly improved at 1 month and 2 months, respectively, but there was no significant difference between study group and control group. Asterisk (*) indicates statistical significance between baseline and 1 month (p<0.05) and double asterisk (**) indicates statistical significance between baseline and 2 months (p<0.05).
Table 1
Clinical characteristics of the subjects
Values are presented as mean±standard deviation.
KL score, Kellgren-Lawrence system score.
Table 2
Pain intensity (Numeric Rating Scale) of knee
Values are presented as mean±standard deviation.
Time effect, the difference between subjects of each group according to the change of time; Interaction, for analytic significant interaction between time and group.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA. *p<0.05.
Table 3
Change of physical functions
Values are presented as mean±standard deviation.
KWOMAC, Korean Western Ontario McMaster score; LSS, Lysholm Scoring Scale; Time effect, the difference between subjects of each group according to the change of time.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA (time effect). *p<0.05.
Table 4
Change in muscle strength
Values are presented as mean±standard deviation.
Time effect, the difference between subjects of each group according to the change of time; ISK, isokinetic torque of knee extensor (angular velocity, 60°); ISM, isometric torque of knee extensor.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA (time effect). *p<0.05.
Table 5
Change in dynamic balance
Values are presented as mean±standard deviation.
AP, anterior-posterior; ML, medial-lateral; Time effect, the difference between subjects of each group according to the change of time.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA (time effect). c)Significant differences (p<0.05) are identified. *p<0.05.
Figure & Data
References
Citations
Citations to this article as recorded by
Effects of whole body vibration versus wobble board balance exercises on muscle activity, dynamic balance, pain, function, and quality of life in individuals with knee osteoarthritis Tahseen Anjum, Tarushi Tanwar, Mosab Aldabbas, Iram Iram, Zubia Veqar Sport Sciences for Health.2025; 21(1): 453. CrossRef
Effects of whole-body vibration training as an adjunct to conventional rehabilitation exercise on pain, physical function and disability in knee osteoarthritis: A systematic review and meta-analysis Yan Peng, Qi Qi, Chai Li Lee, Yan Ling Tay, Siaw Chui Chai, Mohd Azzuan Ahmad, Slavko Rogan PLOS ONE.2025; 20(2): e0318635. CrossRef
Improving pain, function and quality of life in end-stage knee osteoarthritis: a patient-preference cohort study on whole-body vibration and exercise as bridging therapies for total knee replacement Kendrew Yu-Hei Choi, Wai-Wang Chau, Linda Man-Kuen Li, Sammie Yuk-Lam Ng, Boie Po-Yee Lo, Michael Tim-Yun Ong, Patrick Shu-Hang Yung Arthroplasty.2025;[Epub] CrossRef
Vertical whole body vibration for treatment of knee osteoarthritis: a pilote monocentric prospective, randomized trial Jan P. Hockmann, Kourosh Zarghooni, Gregor Stein, Kortessa Tersudi, Peter Knöll, Sebastian G. Walter Archives of Orthopaedic and Trauma Surgery.2025;[Epub] CrossRef
Acute and Long-Term Effects of Stretching with Whole-Body Vibration on Young’s Modulus of the Soleus Muscle Measured Using Shear Wave Elastography Hayato Miyasaka, Bungo Ebihara, Takashi Fukaya, Hirotaka Mutsuzaki Sports.2024; 12(6): 165. CrossRef
Client-based evaluation of the effects of localized vibration therapy on pain and mobility scores in dogs with radiographic bilateral hip dysplasia Kristal F. Turner, Sherman O. Canapp, Debra A. Canapp, Angela M. Sutton, Allyson Canapp, Isabel A. Jimenez, Joyce Gerardi Frontiers in Veterinary Science.2024;[Epub] CrossRef
Low-frequency whole-body vibration can enhance cartilage degradation with slight changes in subchondral bone in mice with knee osteoarthritis and does not have any morphologic effect on normal joints Haiming Wang, Chi Zhang, Siyi Zhu, Chengfei Gao, Qiang Gao, Ridong Huang, Sijia Liu, Xiangyang Wei, Huakai Zhang, Quan Wei, Chengqi He, Lin Han PLOS ONE.2023; 18(8): e0270074. CrossRef
Whole-Body Vibration Impacts on the Degree of Toe Angle and Its Correlation to the Knee Osteoarthritis Index during Level Walking among Female University Students: A Randomized Controlled Trial Amany E. Abd-Eltawab, Asmaa M. Elbandrawy, Heba B. Ghanem, Hasnaa A. Ebrahim, Mohamed El-Sherbiny, Ateya Megahed Ibrahim, Mohamed Ahmed Eladl, Dalia Mahmoud Abdelmonem Elsherbini Journal of Clinical Medicine.2023; 12(17): 5735. CrossRef
Arthrogenic Muscle Inhibition: Best Evidence, Mechanisms, and Theory for Treating the Unseen in Clinical Rehabilitation Grant Norte, Justin Rush, David Sherman Journal of Sport Rehabilitation.2022; 31(6): 717. CrossRef
The application of whole-body vibration training in knee osteoarthritis Zheng Wang, Xinan Zhang, Mingli Sun Joint Bone Spine.2022; 89(2): 105276. CrossRef
Mechanical-based therapies may reduce pain and disability in some patients with knee osteoarthritis: A systematic review with meta-analysis Sofia Oliveira, Renato Andrade, Cristina Valente, João Espregueira-Mendes, Filipe Silva, Betina B. Hinckel, Óscar Carvalho, Ana Leal The Knee.2022; 37: 28. CrossRef
An overview of the effects of whole-body vibration on individuals with cerebral palsy Logan Ruhde, Ryan Hulla, Deborah Gaebler-Spira, Michael Green, Heakyung Kim Journal of Pediatric Rehabilitation Medicine.2022; 15(1): 193. CrossRef
Effects of surface variability in whole-body vibration platform on knee osteoarthritis: A scoping review Priyanka Choursiya, Tarushi Tanwar, Zubia Veqar Journal of Bodywork and Movement Therapies.2022; 32: 120. CrossRef
Rehabilitation Melissa R. King Veterinary Clinics of North America: Equine Practice.2022; 38(3): 557. CrossRef
Comparison of whole-body vibration training and quadriceps strength training on physical function and neuromuscular function of individuals with knee osteoarthritis: A randomised clinical trial Zhangqi Lai, Seullee Lee, Yiyang Chen, Lin Wang Journal of Exercise Science & Fitness.2021; 19(3): 150. CrossRef
A comparison between whole-body vibration and conventional training on pain and performance in athletes with patellofemoral pain Najmeh Shadloo, Fahimeh Kamali, Nasrin Salehi Dehno Journal of Bodywork and Movement Therapies.2021; 27: 661. CrossRef
A Comparison of the Effect of Two Types of Whole Body Vibration Platforms on Fibromyalgia. A Randomized Controlled Trial José Antonio Mingorance, Pedro Montoya, José García Vivas Miranda, Inmaculada Riquelme International Journal of Environmental Research and Public Health.2021; 18(6): 3007. CrossRef
Effect of the Combined Intervention with Passive Whole-Body Vibration and Auriculotherapy on the Quality of Life of Individuals with Knee Osteoarthritis Assessed by the WHOQOL-Bref: A Multi-Arm Clinical Trial Marcia Cristina Moura-Fernandes, Eloá Moreira-Marconi, Alexandre Gonçalves de Meirelles, Ana Paula Ferreira de Oliveira, Aline Reis Silva, Luiz Felipe Ferreira de Souza, Adriana Lírio Pereira da Silva, Carmen dos Santos-Fernandes, Bruno Bessa Monteiro de Applied Sciences.2020; 10(6): 1956. CrossRef
Whole-body vibration and stretching enhances dorsiflexion range of motion in individuals with chronic ankle instability Feland JB, Thalman Lesley, Hunter I, Cochrane DJ, Hopkins JT Physical Therapy in Sport.2020; 44: 1. CrossRef
Isokinetic testing of muscle strength in older adults with knee osteoarthritis: An integrative review Bradley J. Myers, Richard Bohannon Isokinetics and Exercise Science.2020; 28(3): 269. CrossRef
Effects of Vibration Training in Interstitial Lung Diseases: A Randomized Controlled Trial Andreas Rembert Koczulla, Tobias Boeselt, Janina Koelpin, Fabian Kaufhold, Martina Veith, Christoph Nell, Inga Jarosch, Marc Spielmanns, Peter Alter, Christian Kähler, Timm Greulich, Claus F. Vogelmeier, Rainer Glöckl, Tessa Schneeberger, Klaus Kenn, Nico Respiration.2020; 99(8): 658. CrossRef
Whole Body Vibration Exercise for Chronic Musculoskeletal Pain: A Systematic Review and Meta-analysis of Randomized Controlled Trials Yulin Dong, Wu Wang, Jiejiao Zheng, Su Chen, Jun Qiao, Xueqiang Wang Archives of Physical Medicine and Rehabilitation.2019; 100(11): 2167. CrossRef
Whole Body Vibration Training on Muscle Strength and Brain-Derived Neurotrophic Factor Levels in Elderly Woman With Knee Osteoarthritis: A Randomized Clinical Trial Study Adriano Prado Simão, Vanessa Amaral Mendonça, Núbia Carelli Pereira Avelar, Sueli Ferreira da Fonseca, Jousielle Márcia Santos, Ana Carolina Coelho de Oliveira, Rosalina Tossige-Gomes, Vanessa Gonçalves César Ribeiro, Camila Danielle Cunha Neves, Cláudio Frontiers in Physiology.2019;[Epub] CrossRef
Early Post-Operative Intervention of Whole-Body Vibration in Patients After Total Knee Arthroplasty: A Pilot Study Yu-Hsuan Hsiao, Song-Hsiung Chien, Hung-Pin Tu, Jimmy Chun-Ming Fu, Shih-Ting Tsai, Ying-Shan Chen, Yi-Jen Chen, Chia-Hsin Chen Journal of Clinical Medicine.2019; 8(11): 1902. CrossRef
Effects of the Whole-Body Vibration and Auriculotherapy on the Functionality of Knee Osteoarthritis Individuals Cristiane Ribeiro Kütter, Eloá Moreira-Marconi, Ygor Teixeira-Silva, Marcia Cristina Moura-Fernandes, Alexandre Gonçalves de Meirelles, Mario José dos Santos Pereira, Shyang Chang, José Alexandre Bachur, Laisa Liane Paineiras-Domingos, Redha Taiar, Mario Applied Sciences.2019; 9(23): 5194. CrossRef
Treatment of chronic back pain using indirect vibroacoustic therapy: A pilot study Einly Lim, Renly Lim, Anwar Suhaimi, Bee Ting Chan, Ahmad Khairi Abdul Wahab Journal of Back and Musculoskeletal Rehabilitation.2018; 31(6): 1041. CrossRef
Long-Term and Immediate Effects of Whole Body Vibration on Chronic Lameness in the Horse: A Pilot Study Bart Tom Halsberghe Journal of Equine Veterinary Science.2017; 48: 121. CrossRef
Whole-body vibration of mice induces articular cartilage degeneration with minimal changes in subchondral bone M.R. McCann, C. Yeung, M.A. Pest, A. Ratneswaran, S.I. Pollmann, D.W. Holdsworth, F. Beier, S.J. Dixon, C.A. Séguin Osteoarthritis and Cartilage.2017; 25(5): 770. CrossRef
Different doses of strontium ranelate and mechanical vibration modulate distinct responses in the articular cartilage of ovariectomized rats A.G.H. Mierzwa, J.F. Campos, M.F. Jesus, H.B. Nader, M. Lazaretti-Castro, R.D. Reginato Osteoarthritis and Cartilage.2017; 25(7): 1179. CrossRef
C57BL/6 mice are resistant to joint degeneration induced by whole-body vibration G.J. Kerr, M.R. McCann, J.K. Branch, A. Ratneswaran, M.A. Pest, D.W. Holdsworth, F. Beier, S.J. Dixon, C.A. Séguin Osteoarthritis and Cartilage.2017; 25(3): 421. CrossRef
Effect of low-magnitude different-frequency whole-body vibration on subchondral trabecular bone microarchitecture, cartilage degradation, bone/cartilage turnover, and joint pain in rabbits with knee osteoarthritis Wang Junbo, Liu Sijia, Chen Hongying, Liu Lei, Wang Pu BMC Musculoskeletal Disorders.2017;[Epub] CrossRef
Effects of whole body vibration exercise on neuromuscular function for individuals with knee osteoarthritis: study protocol for a randomized controlled trial Zhangqi Lai, Xueqiang Wang, Seullee Lee, Xihe Hou, Lin Wang Trials.2017;[Epub] CrossRef
The influence of trait anxiety and illusory kinesthesia on pain threshold Ryota Imai, Michihiro Osumi, Tomoya Ishigaki, Shu Morioka Journal of Physical Therapy Science.2017; 29(7): 1236. CrossRef
Effects of whole-body vibration training with quadriceps strengthening exercise on functioning and gait parameters in patients with medial compartment knee osteoarthritis: a randomised controlled preliminary study P. Wang, L. Yang, H. Li, Z. Lei, X. Yang, C. Liu, H. Jiang, L. Zhang, Z. Zhou, J.D. Reinhardt, C. He Physiotherapy.2016; 102(1): 86. CrossRef
In Patients with Established RA, Positive Effects of a Randomised Three Month WBV Therapy Intervention on Functional Ability, Bone Mineral Density and Fatigue Are Sustained for up to Six Months Alessandra Prioreschi, Mohamed A. Makda, Mohammed Tikly, Joanne A. McVeigh, Gordon Fisher PLOS ONE.2016; 11(4): e0153470. CrossRef
Effect of whole body vibration training on quadriceps muscle strength in individuals with knee osteoarthritis: a systematic review and meta-analysis Shahnawaz Anwer, Ahmad Alghadir, Hamayun Zafar, Einas Al-Eisa Physiotherapy.2016; 102(2): 145. CrossRef
Effects of Whole Body Vibration Exercise associated with Quadriceps Resistance Exercise on functioning and quality of life in patients with knee osteoarthritis: a randomized controlled trial Pu Wang, Lin Yang, Chuan Liu, Xiaofei Wei, Xiaotian Yang, Yujing Zhou, Hua Jiang, Zhongjie Lei, Jan D. Reinhardt, Chengqi He Clinical Rehabilitation.2016; 30(11): 1074. CrossRef
Association Between Physical Therapy and Risk of Coronary Artery Disease and Dyslipidemia Among Osteoarthritis Patients: A Nationwide Database Study Huan-Jui Yeh, Yiing-Jenq Chou, Nan-Ping Yang, Chi-Chia Cheng, Nicole Huang Archives of Physical Medicine and Rehabilitation.2016; 97(1): 8. CrossRef
The modern view on the problem of joint pathology rehabilitation Nailya Sheveleva, Larissa Minbayeva Journal of Clinical Medicine of Kazakhstan.2016; 2(40): 6. CrossRef
The application of whole-body vibration in physiotherapy – A narrative review M Stania, G Juras, K Słomka, D Chmielewska, P Król Acta Physiologica Hungarica.2016; 103(2): 133. CrossRef
Therapeutic Effects of Whole-Body Vibration Training in Knee Osteoarthritis: A Systematic Review and Meta-Analysis Hamayun Zafar, Ahmad Alghadir, Shahnawaz Anwer, Einas Al-Eisa Archives of Physical Medicine and Rehabilitation.2015; 96(8): 1525. CrossRef
Laboratory-based measurement of standing balance in individuals with knee osteoarthritis: A systematic review Tyler Lawson, Adam Morrison, Stephen Blaxland, Matthew Wenman, Curtis G. Schmidt, Michael A. Hunt Clinical Biomechanics.2015; 30(4): 330. CrossRef
Effects of whole body vibration on pain, stiffness and physical functions in patients with knee osteoarthritis: a systematic review and meta-analysis Pu Wang, Xiaotian Yang, Yonghong Yang, Lin Yang, Yujing Zhou, Chuan Liu, Jan D Reinhardt, Chengqi He Clinical Rehabilitation.2015; 29(10): 939. CrossRef
Effects of an exercise therapy protocol on inflammatory markers, perception of pain, and physical performance in individuals with knee osteoarthritis Grazielle Cordeiro Aguiar, Marcela Rêgo Do Nascimento, Aline Silva De Miranda, Natalia Pessoa Rocha, Antônio Lúcio Teixeira, Paula Luciana Scalzo Rheumatology International.2015; 35(3): 525. CrossRef
Whole-Body Vibration Exercise for Knee Osteoarthritis: A Systematic Review and Meta-Analysis Xin Li, Xue-Qiang Wang, Bing-Lin Chen, Ling-Yan Huang, Yu Liu Evidence-Based Complementary and Alternative Medicine.2015; 2015: 1. CrossRef
Repeated Exposure to High‐Frequency Low‐Amplitude Vibration Induces Degeneration of Murine Intervertebral Discs and Knee Joints Matthew R. McCann, Priya Patel, Michael A. Pest, Anusha Ratneswaran, Gurkeet Lalli, Kim L. Beaucage, Garth B. Backler, Meg P. Kamphuis, Ziana Esmail, Jimin Lee, Michael Barbalinardo, John S. Mort, David W. Holdsworth, Frank Beier, S. Jeffrey Dixon, Cheryl Arthritis & Rheumatology.2015; 67(8): 2164. CrossRef
Osteoarthritis Year in Review 2014: rehabilitation and outcomes M.R. Maly, S.M. Robbins Osteoarthritis and Cartilage.2014; 22(12): 1958. CrossRef
Low magnitude high frequency vibration accelerated cartilage degeneration but improved epiphyseal bone formation in anterior cruciate ligament transect induced osteoarthritis rat model J. Qin, S.K.-H. Chow, A. Guo, W.-N. Wong, K.-S. Leung, W.-H. Cheung Osteoarthritis and Cartilage.2014; 22(7): 1061. CrossRef
Therapeutic Effect of Whole Body Vibration on Chronic Knee Osteoarthritis
Fig. 1 A woman stands on the vibrating platform of whole body vibration (TurboSonic) with a slight flexion of both knees.
Fig. 2 The graph shows changes in physical function over time. The changes of (A) Korean Western Ontario McMaster score (KWOMAC) and (B) Lysholm Scoring Scale (LSS) were significantly different between baseline and 2 months in both groups. But there was no significant differences study between study group and control group. Asterisk (*) indicates statistical significance between baseline and 2 months (p<0.05).
Fig. 3 The graph shows changes of knee extensor muscle strength: (A) isokinetic torque (60°/sec) and (B) isometric torque in both groups. (A) Isokinetic torques of right knee extensor increased significantly over time during training period in both groups and there were no significant differences between study group and control group. Isokinetic torques of left knee extensor was not significantly different during training period in each group and between groups. (B) Isometric torques of both knee extensors increased significantly over time during training period and there were no significant differences between groups during training period. Asterisk (*) indicates statistical significance between baseline and 1 month (p<0.05) and double asterisk (**) indicates statistical significance between baseline and 2 months. ISK, isokinetic; ISM, isometric; Rt, right; Lt, left.
Fig. 4 The graph shows changes in dynamic balance over time in both groups. Anterior-posterior (AP) index and medial-lateral (ML) index significantly improved at 1 month and 2 months, respectively, but there was no significant difference between study group and control group. Asterisk (*) indicates statistical significance between baseline and 1 month (p<0.05) and double asterisk (**) indicates statistical significance between baseline and 2 months (p<0.05).
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Therapeutic Effect of Whole Body Vibration on Chronic Knee Osteoarthritis
Clinical characteristics of the subjects
Values are presented as mean±standard deviation.
KL score, Kellgren-Lawrence system score.
Pain intensity (Numeric Rating Scale) of knee
Values are presented as mean±standard deviation.
Time effect, the difference between subjects of each group according to the change of time; Interaction, for analytic significant interaction between time and group.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA. *p<0.05.
Change of physical functions
Values are presented as mean±standard deviation.
KWOMAC, Korean Western Ontario McMaster score; LSS, Lysholm Scoring Scale; Time effect, the difference between subjects of each group according to the change of time.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA (time effect). *p<0.05.
Change in muscle strength
Values are presented as mean±standard deviation.
Time effect, the difference between subjects of each group according to the change of time; ISK, isokinetic torque of knee extensor (angular velocity, 60°); ISM, isometric torque of knee extensor.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA (time effect). *p<0.05.
Change in dynamic balance
Values are presented as mean±standard deviation.
AP, anterior-posterior; ML, medial-lateral; Time effect, the difference between subjects of each group according to the change of time.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA (time effect). c)Significant differences (p<0.05) are identified. *p<0.05.
Table 1 Clinical characteristics of the subjects
Values are presented as mean±standard deviation.
KL score, Kellgren-Lawrence system score.
Table 2 Pain intensity (Numeric Rating Scale) of knee
Values are presented as mean±standard deviation.
Time effect, the difference between subjects of each group according to the change of time; Interaction, for analytic significant interaction between time and group.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA. *p<0.05.
Table 3 Change of physical functions
Values are presented as mean±standard deviation.
KWOMAC, Korean Western Ontario McMaster score; LSS, Lysholm Scoring Scale; Time effect, the difference between subjects of each group according to the change of time.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA (time effect). *p<0.05.
Table 4 Change in muscle strength
Values are presented as mean±standard deviation.
Time effect, the difference between subjects of each group according to the change of time; ISK, isokinetic torque of knee extensor (angular velocity, 60°); ISM, isometric torque of knee extensor.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA (time effect). *p<0.05.
Table 5 Change in dynamic balance
Values are presented as mean±standard deviation.
AP, anterior-posterior; ML, medial-lateral; Time effect, the difference between subjects of each group according to the change of time.
a)p-value between-subject effects from repeated measures analysis of variance (RMANOVA). b)p-value within-subject effects from RMANOVA (time effect). c)Significant differences (p<0.05) are identified. *p<0.05.
