title: To establish whether McKenzie lumbar flexion and extension mobility exercises performed in lying affect central as well as systemic hemodynamics: a crossover experimental study.
abstract: OBJECTIVE
  Examine systemic and central hemodynamic responses following McKenzie lumbar flexion and extension mobility exercises performed in lying (FIL and EIL).
  
  
  METHODS
  Crossover experimental study.
  
  
  METHODS
  Clinical laboratory.
  
  
  METHODS
  Healthy male volunteers (n=25) (mean(SD) age: 28(3)years; range 21 to 34).
  
  
  METHODS
  Based on alternating assignment of either FIL or EIL to participants, three sets of the first exercise (10, 15, 20 repetitions) were performed with 5-minute rest between sets; after 15-minute rest, the protocol was repeated for the other exercise.
  
  
  METHODS
  Systemic hemodynamic parameters included heart rate (HR), and systolic and diastolic blood pressures (SBP, DBP). Central hemodynamic parameters included abdominal aortic diameter (AD), peak systolic velocity (PSV/AD), end diastolic velocity (EDV/AD) and resistive index (RI). Measures recorded after each exercise set.
  
  
  RESULTS
  FIL RPP at baseline was 9.1 (1.4), after 20 repetitions 18.3 (2.5), mean difference 8.9 (95% confidence interval (CI) 7.9 to 9.8) compared to EIL at baseline 9.1 (1.5), after 20 repetitions 13.0 (3.1), mean difference 4.1 (95% CI 3.3 to 5.0). FIL RI at baseline was 0.78 (0.03), after 20 repetitions 0.87 (0.03), mean difference 0.08 (95% CI 0.06 to 0.10) compared to EIL at baseline 0.78 (0.03), after 20 repetitions 0.83 (0.03), mean difference 0.05 (95% CI 0.04 to 0.07).
  
  
  CONCLUSIONS
  Although 10 repetitions of FIL and EIL may be regarded as safe, our findings support screening patients with lifestyle risk factors, and cautioning about adhering to recommended repetition number given associated increased work of the heart. The extent of AD mechanical perturbation remains unclear.
authors.affiliation: Department of Physical Therapy, Faculty of Allied Health Sciences, Kuwait University, Kuwait. dralobaidi@hsc.edu.kw
authors.forename: Saud M
authors.initials: SM
authors.lastname: Al-Obaidi
authors.forename: Akram
authors.initials: A
authors.lastname: Asbeutah
authors.forename: Nowall
authors.initials: N
authors.lastname: Al-Sayegh
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Dean
mesh_terms: D000328:Adult; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D018592:Cross-Over Studies; D005081:Exercise Therapy / Q000379:methods*; D064368:Healthy Volunteers; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology*; D008161:Lumbosacral Region / Q000502:physiology*; D008297:Male; D026741:Physical Therapy Modalities; D011187:Posture / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D012146:Rest / Q000502:physiology; D016683:Supine Position / Q000502:physiology; D014463:Ultrasonography; D055815:Young Adult