Maximal Physiological Parameters during Partial Body-Weight Support Treadmill Testing

1Sports Medicine Unit, University Hospital Center and University of Lausanne, Lausanne, SWITZERLAND
Medicine and science in sports and exercise (Impact Factor: 3.98). 04/2012; 44(10):1935-41. DOI: 10.1249/MSS.0b013e31825a5d1f
Source: PubMed


This study investigated maximal cardiometabolic response while running in a lower body positive pressure treadmill (antigravity treadmill (AG)), which reduces body weight (BW) and impact. The AG is used in rehabilitation of injuries but could have potential for high-speed running, if workload is maximally elevated.
Fourteen trained (nine male) runners (age 27 ± 5 yr; 10-km personal best, 38.1 ± 1.1 min) completed a treadmill incremental test (CON) to measure aerobic capacity and heart rate (V˙O2max and HRmax). They completed four identical tests (48 h apart, randomized order) on the AG at BW of 100%, 95%, 90%, and 85% (AG100 to AG85). Stride length and rate were measured at peak velocities (Vpeak).
V˙O2max (mL·kg·min) was similar across all conditions (men: CON = 66.6 (3.0), AG100 = 65.6 (3.8), AG95 = 65.0 (5.4), AG90 = 65.6 (4.5), and AG85 = 65.0 (4.8); women: CON = 63.0 (4.6), AG100 = 61.4 (4.3), AG95 = 60.7 (4.8), AG90 = 61.4 (3.3), and AG85 = 62.8 (3.9)). Similar results were found for HRmax, except for AG85 in men and AG100 and AG90 in women, which were lower than CON. Vpeak (km·h) in men was 19.7 (0.9) in CON, which was lower than every other condition: AG100 = 21.0 (1.9) (P < 0.05), AG95 = 21.4 (1.8) (P < 0.01), AG90 = 22.3 (2.1) (P < 0.01), and AG85 = 22.6 (1.6) (P < 0.001). In women, Vpeak (km·h) was similar between CON (17.8 (1.1) ) and AG100 (19.3 (1.0)) but higher at AG95 = 19.5 (0.4) (P < 0.05), AG90 = 19.5 (0.8) (P < 0.05), and AG85 = 21.2 (0.9) (P < 0.01).
The AG can be used at maximal exercise intensities at BW of 85% to 95%, reaching faster running speeds than normally feasible. The AG could be used for overspeed running programs at the highest metabolic response levels.

Download full-text


Available from: Boris Gojanovic, Jul 25, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Knee osteoarthritis (OA) is the most prevalent medical condition in individuals over the age of 65 years, and is a progressive joint degenerative condition with no known cure. Research suggests that there is a strong relationship between knee pain and loss of physical function. The resulting lifestyle modifications negatively impact not only disease onset and progression but also overall health, work productivity, and quality of life of the affected individual. The goal of this investigation was to examine the feasibility of using an emerging technology called lower body positive pressure (LBPP) to simulate weight loss and reduce acute knee pain during treadmill walking exercise in overweight individuals with radiographically confirmed symptomatic knee OA. Prospective case series. Twenty-two overweight individuals with knee OA completed two 20-minute treadmill walking sessions (one full weight bearing and one LBPP supported) at a speed of 3.1 mph, 0% incline. Acute knee pain was assessed using a visual analog scale, and the percentage of LBPP support required to minimize knee pain was evaluated every 5 minutes. Knee Osteoarthritis Outcome Scores were used to quantify knee pain and functional status between walking sessions. The order of testing was randomized, with sessions occurring a minimum of 1 week apart. A mean LBPP of 12.4% of body weight provided participants with significant pain relief during walking, and prevented exacerbation of acute knee pain over the duration of the 20-minute exercise session. Patients felt safe and confident walking with LBPP support on the treadmill, and demonstrated no change in Knee Osteoarthritis Outcome Scores over the duration of the investigation. Results suggest that LBPP technology can be used safely and effectively to simulate weight loss and reduce acute knee pain during weight-bearing exercise in an overweight knee OA patient population. These results could have important implications for the development of future treatment strategies used in the management of at-risk patients with progressive knee OA.
    Full-text · Article · Jul 2013 · Clinical Interventions in Aging
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Body weight (BW) support during running can be accomplished using deep water running (DWR) (100% BW support) and Lower Body Positive Pressure (LBPP) treadmill. Purpose: The purpose of this study was to compare lower extremity muscle activity during DWR and running on a LBPP treadmill at matched stride frequency. Methods: Eight subjects (40(6.5) yrs; 173(7.2) cm; 66.9(11.7) kg) completed four running conditions all at a preferred stride frequency which was determined while running with no support. Two conditions were running on the LBPP treadmill at 60% and 80% of body weight and the remaining two conditions were different DWR styles: High knee, Cross-country. Average (AVG) and root mean square (RMS) electromyography (rectus femoris, biceps femoris, gastrocnemius, tibalis anterior) were each compared among conditions (repeated measures analysis of variance). Results: Results for AVG and RMS variables were identical for statistical test for each muscle. Rectus femoris electromyography during DWR-High Knee was lower than that of DWR-Cross Country (p<.05) but not different than either 60%BW or 80%BW (p>.05). Biceps femoris electromyography was less during DWR-High Knee vs. DWR-Cross Country (p<.05) but greater during DWR-High Knee vs. either BW60% or BW80% (p<0.05). Neither gastrocnemius nor tibialis anterior electromyography were different between conditions (p>.05). Conclusion: The mechanism of BW support nor style of DWR influenced gastrocnemius or tibialis anterior muscle activity during running at the same stride frequency. However, rectus femoris and biceps femoris muscle activity were influenced not only by the mechanism of BW support but also the style of DWR.
    No preview · Article · Aug 2013 · Journal of Sport Rehabilitation
  • [Show abstract] [Hide abstract]
    ABSTRACT: We investigated cardiovascular responses at rest and during submaximal exercise on a lower body positive pressure treadmill in older adults with total knee arthroplasty (TKA). Twenty-four adults (mean age 64.6 ± 7.9 SD) with unilateral TKA participated (median time since surgery 8.0 weeks). Heart rate and blood pressure responses were measured at rest standing on the positive pressure treadmill with 0, 10, 20, and 30 mmHg applied. Heart rate, blood pressure, oxygen consumption, minute ventilation, knee pain and perceived exertion were measured during submaximal exercise tests (0 and 40 % body weight support) conducted 1 week apart. 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.
    No preview · Article · Dec 2013 · Arbeitsphysiologie
Show more