Anti Gravity Treadmill Research Papers


Rehabilitation after total knee arthroplasty (TKA) is an essential component of treatment. Various protocols and methodologies have evolved to enhance the effect of rehabilitation in the postoperative period. We prospectively evaluated the effect of using an antigravity treadmill as an alternative to routine postoperative physical therapy.


Twenty-nine patients undergoing unilateral primary TKA were randomized to either gait training (standard outpatient physical therapy) or to the use of an AlterG® antigravity device for gait training for 2 days/week for 4 weeks for a total of 8 therapy sessions. Average age was 68 and 55% were female. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and Timed Up and Go (TUG) test were collected at baseline (first therapy session), at final therapy session and at 3 months postoperatively. The numerical rating scale (NRS) for pain was measured at baseline and at end of therapy. Adverse events and complications were recorded.


All patients completed standard therapy and antigravity treadmill protocol without adverse events. KOOS, TUG and NRS scores improved in both groups but no statistically significant difference was apparent between groups. Overall, the greatest improvement was seen in the Sports/Recreation and Quality of Life subscales of the KOOS; scores improved from 23 and 32 to 67 and 69 at 3 months, respectively. TUG scores improved from 14 seconds to 7 seconds at 3 months. Pain, as measured on the NRS, improved from 2.8 to 1.1. Subjectively, therapists reported 100% satisfaction with the antigravity treadmill for use in postoperative TKA rehabilitation.


This initial study demonstrated that an antigravity treadmill device was safe and effective for outpatient postoperative TKA rehabilitation. Further studies are warranted to better define the role of this device as an alternative or adjunct to currently established TKA rehabilitation protocols.

Webber S, Horvey K, Yurach Pikaluk M, Butcher S. Cardiovascular responses in older adults with total knee arthroplasty at rest and with exercise on a positive pressure treadmill. Eur J Appl Physiol. 2014 Mar;114(3):653-62.

This study investigated cardiovascular responses at rest and during submaximal exercise on a lower body positive pressure treadmill in older adults with total knee arthroplasty (TKA). At rest there were no differences in blood pressure across different treadmill pressures, but heart rate was significantly lower when 30 mmHg was applied compared to ambient pressure conditions (P < 0.05). Participants averaged 5.1 exercise test stages with 0% body weight support (maximum speed 2.5 mph, 0% incline) and 6.4 stages with 40% body weight support (maximum speed 3.0 mph, 10% incline). During exercise, heart rate, systolic blood pressure, oxygen consumption, and minute ventilation were lower when 40% body weight support was provided for a given test stage (P < 0.01). Diastolic blood pressure, knee pain and perceived exertion did not differ with body weight support but increased with increasing exercise test stages (P < 0.05). Provision of body weight support allowed TKA patients to walk at faster speeds and/or to tolerate greater incline with relatively lower levels of heart rate, blood pressure, and oxygen consumption.


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