Short Term Bed Rest Study: Evaluation of the Use of Artificial Gravity, Induced by Short-arm Centrifugation
Condition: Bone Diseases, Metabolic; Acid-Base Imbalance; Muscular Atrophy; Sprains and Strains; Protein Metabolism; Body Weight Changes; Cardiovascular Abnormalities
MeSH terms: Bone Diseases; Bone Diseases, Metabolic; Muscular Atrophy; Cardiovascular Abnormalities; Metabolic Diseases; Acid-Base Imbalance; Body Weight; Body Weight Changes; Sprains and Strains
Study type: Interventional

Summary: 
      Randomized cross-over design with 10 male subjects and 3 campaigns to test whether the
      negative effects of bed rest (6º head-down tilt) on the various systems of the body and the
      consequences to health of simulated weightlessness can be counteracted by the use of a
      defined training programme.
    

Detailed description: 
      The SAG study was a single center, open-label crossover trial with healthy men conducted in
      three campaigns at the Institute of Aerospace Medicine, Cologne, Germany.

      The subjects were quasi randomized alternatively by enrolment to undertake the different
      training interventions or to be in the control group during 5 days of immobilisation in 6°
      head down tilt position. The subjects were quasi randomized either to the one of the training
      programs or the non-training group depending on the arrival at the Institute of Aerospace
      Medicine.

      The study started November 01st, 2010 and was finished May 29th, 2011. The first campaign
      lasted from November 01st to November 21sh, 2010, the second campaign from January 10th to
      January 30th, 2011 and the third campaign from May 09th to May 29th, 2011.

      Each campaign comprised a 5 day adaptation-, a 5 day intervention phase in HDT bed rest, and
      a 5 day recovery phase (15 days in total) in-house at the Metabolic Ward of the Institute of
      Aerospace Medicine.

      Baseline Data were collected during the adaptation phase (BDC Baseline Data Collection) when
      subjects could move free inside the lab. The intervention was administered during the bed
      rest phase where the subjects had to lie in bed in 6° head down tilt (HDT Head Down Tilt)
      position and were not allowed to get up. Recumbency was to be adhered to at all times
      including all activities (hygienic procedures, leisure activities). The bed rest phase was
      followed by a recovery phase (R+).
    

Intervention name(s): Defined Training Programme
Intervention type(s): Other
Intervention description(s): A Smith Machine with fixed rails was used to guide the heel raise and squat exercises in the vertical axis. A metronome was used to direct the subjects during the performance of the exercises. Squats and heel raises were performed against body weight plus the additional weight of the barbell (15 kg). The heel raises were performed with straight knees and without ankle dorsiflexion. The shallow squats were performed continuously for 3 minutes. The hopping and the cross-hopping exercises were performed without Smith Machine. The bilateral hops were performed at ~ 3 repetitions per second with 15-s rest insertions between each set. Cross-hopping was performed continuously for 3 minutes against ~ 1.3 repetitions per second. Except for the duration of the static squat, with progressed from 45 s at HDT1 to 70 s at HDT5, none of the exercises were progressed during the study. Including the scheduled rest pauses, the LRT sessions were completed in 24 minutes.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: bone metabolism; acid base balance; bed rest