title: Maximal physiological parameters during partial body-weight support treadmill testing.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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 (VO(2max) and HR(max)). 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 (V(peak)).
  
  
  RESULTS
  VO(2max) (mL.kg(-1).min(-1)) 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 HR(max), except for AG85 in men and AG100 and AG90 in women, which were lower than CON. V(peak) (km.h(-1)) 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, V(peak) (km.h(-1)) 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Sports Medicine Unit, University Hospital Center and University of Lausanne, Lausanne, Switzerland. boris.gojanovic@chuv.ch
authors.forename: Boris
authors.initials: B
authors.lastname: Gojanovic
authors.forename: Phil
authors.initials: P
authors.lastname: Cutti
authors.forename: Rebecca
authors.initials: R
authors.lastname: Shultz
authors.forename: Gordon O
authors.initials: GO
authors.lastname: Matheson
mesh_terms: D000328:Adult; D001835:Body Weight; D005080:Exercise Test / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D012420:Running / Q000502:physiology*; D055815:Young Adult
chemical_list: D019344:Lactic Acid