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Lower body positive pressure treadmills (LBPP-TM) provide assistive body weight support to the user by forcing air into an inflatable chamber in which the user is secured. The result of this positive pressure can be experienced as a lift to the user. The degree of chamber air pressure (CAP) determines the amount of supportive lift provided with greater and lesser CAP producing more and less lift, respectively. Exercise studies consistently report lower effort perceptions with greater CAP which suggest a reduced physiological and mechanical strain on the body. What is less well known is the effect on resting perceptions of standing weight (SWP). The purpose of this investigation was to examine the perception of resting standing weight across four different weighted conditions in a LBPP-TM. Nine participants (6 female; overall age: 21.3±1.9 years) stood in a LBPP-TM under the following order of body weight set (BWset) conditions: 100%BWset, 70%BWset, 35%BWset, 90%BWset. A portable Davis Vantage weather station barometer measured CAP inside the inflatable chamber and a 10-cm visual analogue scale measured SWP. Repeated measures analysis of variance evidenced significant changes across CAP (100%BWset: 767.5±4.9 mmHg; 70%BWset: 780.0±3.0 mmHg; 35%BWset: 793.5±3.0 mmHg; 90%BWset: 776.4±7.0 mmHg; all ps ≤ 0.001) except for the 70%BWset and 90%BWset conditions (p = 0.486) and within SWP (90%BWset: 8.8±1.4 cm vs. 70%BWset: 5.8±2.9 cm, p = 0.011; and 35%BWset: 4.6±3.2 cm, p = 0.007) experimental conditions. LBPP-TMs appear to provide robust manipulations of perception across different experimental contexts. Similar to findings from exercise studies, greater CAP and its resultant lift produced significant reduced perceptions of standing weight while at rest.
Lower body positive pressure treadmills, LBPP-TM, Chamber air pressure, standing weight perception, Kinesiology, Transformations