This study was funded by Guangzhou Medical University (Grant Number 2018A053).

The clinical project was approved by the Medical Ethics Association of the Fifth Affiliated Hospital of Guangzhou Medical University and has been registered at the China Clinical Trial Registration Center (No. ChiCTR1800017677 and entitled &#8220;Effect and Mechanism of Anti-gravity Treadmill on Lower Limb Motor Function in Patients with Knee Osteoarthritis&#8221;).
1. Recruitment
<ol>
	<li>Recruit patients presenting with radiographic evidence of mild-to-moderate (Kellgren &#38; Lawrence gr...

<ol>
	<li>McAlindon, T. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=OARSI+guidelines+for+the+non-surgical+management+of+knee+osteoarthritis.">OARSI guidelines for the non-surgical management of knee osteoarthritis.</a> Osteoarthritis Cartilage. 22, 363-388 (2014).</li><li>Luyten, F. P., Denti, M., Filardo, G., Kon, E., Engebretsen, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Definition+and+classification+of+early+osteoarthritis+of+the+knee.">Definition and classification of early osteoarthritis of the knee.</a> Knee Surgery Sports Traumatology Arthroscopy. 20, 401-406 (2012).</li><li>Lankhorst, G. J., Van de Stadt, R. J., Van der Korst, J. 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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+quadriceps+strength+and+proprioception+on+risk+for+knee+osteoarthritis.">Effect of quadriceps strength and proprioception on risk for knee osteoarthritis.</a> Medicine &amp; Science in Sports &amp; Exercise. 42, 2081 (2010).</li><li>Linda, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EULAR+recommendations+for+the+non-pharmacological+core+management+of+hip+and+knee+osteoarthritis.">EULAR recommendations for the non-pharmacological core management of hip and knee osteoarthritis.</a> Annals of the Rheumatic Diseases. 72, 1125-1135 (2013).</li><li>Watanabe, S., Someya, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Body+Weight-supported+Walking+on+Exercise+Capacity+and+Walking+Speed+in+Patients+with+Knee+Osteoarthritis:+A+Randomized+Controlled+Trial.">Effect of Body Weight-supported Walking on Exercise Capacity and Walking Speed in Patients with Knee Osteoarthritis: A Randomized Controlled Trial.</a> Journal of the Japanese Physical Therapy Association. 16, 28-35 (2013).</li><li>Takacs, J., Anderson, J. E., Leiter, J. R., MacDonald, P. B., Peeler, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lower+body+positive+pressure:+an+emerging+technology+in+the+battle+against+knee+osteoarthritis?.">Lower body positive pressure: an emerging technology in the battle against knee osteoarthritis?.</a> Clinical Interventions in Aging. 8, 983-991 (2013).</li><li>Ruckstuhl, H., Kho, J., Weed, M., Wilkinson, M. W., Hargens, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparing+two+devices+of+suspended+treadmill+walking+by+varying+body+unloading+and+Froude+number.">Comparing two devices of suspended treadmill walking by varying body unloading and Froude number.</a> Gait &amp; Posture. 30, 446-451 (2009).</li><li>Peeler, J., Christian, M., Cooper, J., Leiter, J., MacDonald, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Managing+Knee+Osteoarthritis:+The+Effects+of+Body+Weight+Supported+Physical+Activity+on+Joint+Pain,+Function,+and+Thigh+Muscle+Strength.">Managing Knee Osteoarthritis: The Effects of Body Weight Supported Physical Activity on Joint Pain, Function, and Thigh Muscle Strength.</a> Clinical Journal of Sport Medicine. 25, 518-523 (2015).</li><li>Patil, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anti-gravity+treadmills+are+effective+in+reducing+knee+forces.">Anti-gravity treadmills are effective in reducing knee forces.</a> Journal of Orthopaedic Research. 31, 672-679 (2013).</li><li>Nicolas-Alonso, L. F., Gomez-Gil, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brain+computer+interfaces,+a+review.">Brain computer interfaces, a review.</a> Sensors (Basel). 12, 1211-1279 (2012).</li><li>Webber, S. C., Horvey, K. J., Yurach Pikaluk, M. T., Butcher, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiovascular+responses+in+older+adults+with+total+knee+arthroplasty+at+rest+and+with+exercise+on+a+positive+pressure+treadmill.">Cardiovascular responses in older adults with total knee arthroplasty at rest and with exercise on a positive pressure treadmill.</a> European Journal of Applied Physiology. 114, 653-662 (2014).</li><li>Dolphin, N. W., Crue, B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pain:+Clinical+Manual+For+Nursing+Practice.">Pain: Clinical Manual For Nursing Practice.</a> Clinical Journal of Pain. 5, 363 (1989).</li><li>Lavernia, C., D'Apuzzo, M., Rossi, M. D., Lee, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+Knee+Range+of+Motion+Assessment+After+Total+Knee+Arthroplasty.">Accuracy of Knee Range of Motion Assessment After Total Knee Arthroplasty.</a> The Journal of Arthroplasty. 23, 85-91 (2008).</li><li>Bellamy, N., Buchanan, W. W., Goldsmith, C. H., Campbell, J., Stitt, L. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+study+of+WOMAC:+a+health+status+instrument+for+measuring+clinically+important+patient+relevant+outcomes+to+antirheumatic+drug+therapy+in+patients+with+osteoarthritis+of+the+hip+or+knee.">Validation study of WOMAC: a health status instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee.</a> Journal of Rheumatology. 15, 1833-1840 (1988).</li><li>Collins, N. J., Misra, D., Felson, D. T., Crossley, K. M., Roos, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measures+of+knee+function:+International+Knee+Documentation+Committee+(IKDC)+Subjective+Knee+Evaluation+Form,+Knee+Injury+and+Osteoarthritis+Outcome+Score+(KOOS),+Knee+Injury+and+Osteoarthritis+Outcome+Score+Physical+Function+Short+Form+(KOOS-PS)+Knee+O.">Measures of knee function: International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Knee Injury and Osteoarthritis Outcome Score (KOOS), Knee Injury and Osteoarthritis Outcome Score Physical Function Short Form (KOOS-PS) Knee O.</a> Arthritis Care &amp; Research. 63, S208-S228 (2011).</li><li>Rabin, R., De-Charro, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EQ-5D:+a+measure+of+health+status+from+the+EuroQol+Group.">EQ-5D: a measure of health status from the EuroQol Group.</a> Annals of Medicine. 33, 337-343 (2001).</li><li>Wirz, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effectiveness+of+automated+locomotor+training+in+patients+with+chronic+incomplete+spinal+cord+injury:+a+multicenter+trial.">Effectiveness of automated locomotor training in patients with chronic incomplete spinal cord injury: a multicenter trial.</a> Archives of Physical Medicine and Rehabilitation. 86, 672-680 (2005).</li><li>Shumway-Cook, A., Baldwin, M., Polissar, N. L., Gruber, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Predicting+the+probability+for+falls+in+community-dwelling+older+adults.">Predicting the probability for falls in community-dwelling older adults.</a> Physical Therapy. 77, 812-819 (1997).</li><li>Iii, R. B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+gait+analysis+data+collection+and+reduction+technique.">A gait analysis data collection and reduction technique.</a> Human Movement Science. 10, 575-587 (1991).</li><li>Peeler, J., Ripat, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+low-load+exercise+on+joint+pain,+function,+and+activities+of+daily+living+in+patients+with+knee+osteoarthritis.">The effect of low-load exercise on joint pain, function, and activities of daily living in patients with knee osteoarthritis.</a> Knee. 25 (1), 135-145 (2018).</li><li>Escamilla, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Knee+biomechanics+of+the+dynamic+squat+exercise.">Knee biomechanics of the dynamic squat exercise.</a> Medicine &amp; Science in Sports &amp; Exercise. 33, 127-141 (2001).</li><li>Linschoten, R. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+PEX+study+&#8211;+Exercise+therapy+for+patellofemoral+pain+syndrome:+design+of+a+randomized+clinical+trial+in+general+practice+and+sports+medicine+[ISRCTN83938749].">The PEX study &#8211; Exercise therapy for patellofemoral pain syndrome: design of a randomized clinical trial in general practice and sports medicine [ISRCTN83938749].</a> BMC Musculoskeletal Disorders. 7, 31 (2006).</li></ol>

The authors have nothing to disclose.

We proposed an LBPP treadmill intervention protocol, which includes both clinical assessment and treatment models, for the rehabilitation of lower extremity motor function in knee OA. Meanwhile, in response to the clinical symptoms and knee OA dysfunction, the treatment model includes not only a training section for walking in the LBPP protocol but also an innovative squatting training section, which aims to solve the daily dysfunction due to thigh muscle weakness and squatting difficulties in knee OA patients. To the be...

Knee osteoarthritis (OA) is a progressive degenerative joint condition and a major cause of pain and locomotor disability in people all over the world1. Knee OA is characterized by osteophyte and cyst formation, narrow joint spacing, and subchondral bone sclerosis2. These pathological changes make it difficult to perform essential activities of daily living such as walking, squatting, and going up and down stairs3. However, physical activity is recommended as an essential component of first-line knee OA management4. Exercise intervention for knee OA rehabilitation is affected by several factors: (1) limited knee joint movement caused by pain and minor knee structural changes; (2) muscle atrophy associated with maintaining knee stability and a decrease in muscle strength5; and (3) the above reasons lead to a reduction in exercise and an increase in body mass index (BMI), which further increases the burden on the knees, thus creating a vicious cycle6.
In response to the above mentioned issues, the body weight-supported training system (BWSTT) has gradually addressed bone and joint disease-related rehabilitation7. In recent years, one of the emerging body weight-supported training technologies is called the lower body positive pressure (LBPP) treadmill7. This technology uses a waist-high inflatable balloon to achieve positive lower limb pressure and accurately adjust the air pressure to regulate body weight with the aim of achieving weight reduction. The system is also equipped with a running platform that can concurrently perform treadmill-related activities under the control of body weight8. Meanwhile, the pressure generated in the inflated enclosure provides a lifting force against the body. Because the pressure is only slightly above atmospheric pressure and is evenly distributed, the force on the lower body is almost imperceptible. Thus, the LBPP running platform provides a higher level of comfort and is more suitable for long-term training compared with the traditional BWSTT9. Peeler et al. performed an LBPP treadmill intervention on 32 knee OA patients and showed that the LBPP treadmill can effectively relieve knee pain, improve daily life functions, and produce an increase in thigh muscle strength10. The potential mechanism might be related to achievement of effective knee joint activity while reducing knee joint torque11. On the other hand, since the age of onset of knee OA patients is mostly over 45 years old12, onset may also be associated with cardio-pulmonary diseases. Studies have shown that LBPP allows people to achieve walking as exercise with relatively low heart rate, blood pressure, and oxygen consumption and achieve safer and more effective aerobic exercise than full-weight flat walking; this type of walking is another advantage of LBPP when compared with traditional BWSTT13.
However, due to the relatively new application of this system to knee OA intervention, the relatively few existing studies have greatly limited the clinical application of this technology in knee OA rehabilitation. The LBPP protocol proposed in this article aimed to explore the clinical non-drug and surgical knee OA treatment using the LBPP treadmill.

<table>
	<tbody>
		<tr>
			<td>AlterG Anti-Gravity Treadmill M320</td>
			<td>AlterG Inc, Fremont, CA, USA</td>
			<td>1</td>
			<td>LBBP training</td>
		</tr>
		<tr>
			<td>BTS Smart DX system</td>
			<td>Bioengineering Technology System, Milan, Italy</td>
			<td>2</td>
			<td>Temporospatial data collection</td>
		</tr>
		<tr>
			<td>BTS FREEEMG</td>
			<td>Bioengineering Technology System, Milan, Italy</td>
			<td>3</td>
			<td>Surface EMG data collection</td>
		</tr>
		<tr>
			<td>BTS SMART-Clinic software</td>
			<td>Bioengineering Technology System, Milan, Italy</td>
			<td>4</td>
			<td>Data processing</td>
		</tr>
	</tbody>
</table>

the lower body positive pressure treadmill for knee osteoarthritis rehabilitation

Here, based on a clinician&rsquo;s point-of-view, we propose a two-model lower body positive pressure (LBPP) protocol (walking and squatting models) in addition to a clinical, functional assessment methodology, including details for further encouragement of the development of non-drug surgical intervention strategies in knee osteoarthritis patients. However, we only present the effect of LBPP training in improvement of pain and knee function in one patient through three-dimensional gait analysis. The exact, long-term effects of this approach should be explored in future studies.

We show results from a knee OA patient, who was a 60-year-old female (BMI = 22.9) undergoing &#8220;more than 3 years of knee osteoarthritis&#8221; and severe pain when she was walking (visual analog scale [VAS] = 8/10) and participated in a 2-week LBPP training program at our facility. During the entire intervention, the patient did not take any painkillers to relieve knee pain. The radiological image of her knee joints and the results of clinical function assessments are shown in Figure 3 ...

Watch this Scientific Journal Video about The Lower Body Positive Pressure Treadmill for Knee Osteoarthritis Rehabilitation at JoVE.com

The Lower Body Positive Pressure Treadmill for Knee Osteoarthritis Rehabilitation

Here, based on a clinician&#8217;s point-of-view, we propose a two-model lower body positive pressure (LBPP) protocol (walking and squatting models) in addition to a clinical, functional assessment methodology, including details for further encouragement of the development of non-drug surgical intervention strategies in knee osteoarthritis patients. However, we only present the effect of LBPP training in improvement of pain and knee function in one patient through three-dimensional gait analysis. The exact, long-term effects of this approach should be explored in future studies.

Here, based on a clinician&rsquo;s point-of-view, we propose a two-model lower body positive pressure (LBPP) protocol (walking and squatting models) in ...

Pain and the resulting gait are the main problems of patients with knee osteoarthritis. Here, we propose The Lower Body Positive Pressure Treadmill Intervention Protocol, which includes both clinical assessment and treatment models for the rehabilitation of lower extremity motor functions in knee osteoarthritis. The LBPP treadmill protocol allows people to achieve exercises with relatively low heart rate, blood pressure and oxygen consumption, so it is safer and more effective than full-weight exercises for knee OA patients with cardiopulmonary disease.Visual demonstration of this method is critical for safe operation of the LBPP training system and understanding of our protocol. Demonstrating the procedure will be Dr.Junjie Liang, Dr.Qiang Lin, PT Hongxin Chen, and Dr.Shijuan Lang from my lab. Begin the clinical assessment by asking the patient to describe their pain intensity from zero to 10 where zero is no pain and 10 is the worst pain.Then conduct the active/passive knee joint range of motion assessment using a handheld two arm goniometer. Then conduct the Western Ontario and McMaster Universities Osteoarthritis Index or WOMAC by asking the patient to mark the corresponding position of pain or limited function on a straight line for five pain-related items, two stiffness items, and 17 functional items. Zero indicates no pain or no function limitation.10 indicates severe pain or extreme limited function. Following the WOMAC, conduct two optional assessments:the Knee Injury and Osteoarthritis Outcome Score or KOOS, and/or the European Five Dimensional Health Scale, EQ-5D, to assess pain symptoms and quality of life. Then for the 10-meter walk test ask the patient to perform three consecutive 10-meter walk test trials at a self-selected pace for safety and comfort.Ask the patient to walk without assistance for 10 meters and measure the time taken for the middle six meters. Next, to conduct The Timed Up and Go test ask the patient to perform three consecutive trials at a self-selected pace. Stand up, walk three meters, turn, walk back and sit down.Lastly, perform a 3D gait analysis. To do this, position 22 spherical markers on the patient's anatomical landmarks based on the Davis Protocol. Then position six surface EMG electrodes on the bilateral rectus femoris, semitendinosus and long head biceps femoris of the patient.Ask the patient to hold an orthostatic position for at least three to five seconds with the feet aligned in order to avoid having one foot in the more anterior or posterior position with respect to the other. Instruct the patient to walk with a self-selected speed along the fiver-meter walkway five times. Finally, remove all the spherical markers and EMG electrodes from the patient and save all the collected data for later processing.Begin by introducing the lower body positive pressure or LBPP treadmill training process and related precautions to the patient. Next, check the patient's blood pressure and heart rate. Determine the size of the air seal shorts according to the waist circumference of the patient and ask the patient to put on the shorts.Turn on the treadmill by operating the switch located on the front cover of the system and run the self-testing of the antigravity treadmill. Lower the cockpit. And have the patient step into the fabric enclosure of the antigravity treadmill.Lift the cockpit to the appropriate height according to the LBPP training model such that the cockpit height is at the anterior superior iliac spine with a walking model, and slightly below the femur's great trochanter for the squatting model. Once the cockpit is in place, zip the patient into the antigravity treadmill. Use the safety lanyard supplied with the machine to secure the clip onto the patient's clothing, which is essential for emergency stopping during the training process.Then instruct the patient to stand still on the surface of the treadmill belt to allow the system to hold and weigh the patient's a full body weight without any support from any part of the system, and then press the start button to perform an antigravity treadmill system calculation for accurate unweighting. Lastly, adjust the positions of three cameras supplied with the machine to obtain the synchronized video feedback during the training process to help the patient correct abnormal movement patterns. For the training session, start the warm-up with the following settings:five minutes with the speed zero to two miles per hour, BW 65%incline 0%Increase speed by 4 miles per hour and body weight support in 7%increments per minute.Then perform the walking model session with the following settings:15 minutes with the speed at two miles per hour, BW at 65%and incline at 0%Perform the cool down session with the following settings:five minutes with the speed at two to zero miles per hour, BW 65 to 100%incline at 0%Decrease speed by 4 miles per hour, and body weight support in 7%decrements per minute. End up with the squatting model session with the following settings:five minutes with the speed at zero miles per hour, BW 50%incline 0%AROM zero to 50 degrees or the maximum tolerable joint range of motion within 50 degrees, 30 seconds of squatting followed by a 30-second rest period. Finally after two weeks of the LBPP training session, reevaluate the patient using the standardized tests and 3D gait analysis.These results indicate that the 10-minute walk test decreased from 4.1 seconds at pre-training to 3.3 seconds at post-training. The TUG test decreased from 9.1 seconds at pre-training to 8.2 seconds at post-training. After two weeks of LBPP training, patients showed an improvement in total WOMAC scores, pain subscales, stiffness subscales, and function subscales.The total VAS pain scores did not change after two weeks of treatment. The right swing phase increased. And left swing phase decreased from pre-training to post-training.The right side length decreased, but the left side stride length increased from pre-training to post-training. Further, the mean velocity and cadence increased from pre-to post-training, but the step width decreased. Our LBPP training session consists of the walking and squatting modules.The walking module focuses on improving walking function and the squatting module focuses on enhancement of the tight muscles'joints. If the patient can not tolerate the squatting training module, only perform the walking module.

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10.3K Views.  The Fifth Affiliated Hospital of Guangzhou Medical University. Pain and the resulting gait are the main problems of patients with knee osteoarthritis. Here, we propose The Lower Body Positive Pressure Treadmill Intervention Protocol, which includes both clinical assessment and treatment models for the rehabilitation of lower extremity motor functions in knee osteoarthritis. The LBPP treadmill protocol allows people to achieve exercises with relatively low heart rate, blood pressure and oxygen consumption, so it is safer and more effective than full-weigh...