title: High-Intensity Jump Training Is Tolerated during 60 Days of Bed Rest and Is Very Effective in Preserving Leg Power and Lean Body Mass: An Overview of the Cologne RSL Study.
abstract: OBJECTIVE
  Space agencies are looking for effective and efficient countermeasures for the degrading effects of weightlessness on the human body. The aim of this study was to assess the effects of a novel jump exercise countermeasure during bed rest on vitals, body mass, body composition, and jump performance.
  
  
  METHODS
  23 male participants (29±6 years, 181±6 cm, 77±7 kg) were confined to a bed rest facility for 90 days: a 15-day ambulatory measurement phase, a 60-day six-degree head-down-tilt bed rest phase (HDT), and a 15-day ambulatory recovery phase. Participants were randomly allocated to the jump training group (JUMP, n = 12) or the control group (CTRL, n = 11). A typical training session consisted of 4x10 countermovement jumps and 2x10 hops in a sledge jump system. The training group had to complete 5-6 sessions per week.
  
  
  RESULTS
  Peak force for the reactive hops (3.6±0.4 kN) as well as jump height (35±4 cm) and peak power (3.1±0.2 kW) for the countermovement jumps could be maintained over the 60 days of HDT. Lean body mass decreased in CTRL but not in JUMP (-1.6±1.9 kg and 0±1.0 kg, respectively, interaction effect p = 0.03). Resting heart rate during recovery was significantly increased for CTRL but not for JUMP (interaction effect p<0.001).
  
  
  CONCLUSIONS
  Participants tolerated the near-daily high-intensity jump training and maintained high peak forces and high power output during 60 days of bed rest. The countermeasure was effective in preserving lean body mass and partly preventing cardiac deconditioning with only several minutes of training per day.
authors.affiliation: Sensorimotor Performance Lab, University of Konstanz, Konstanz, Germany.
authors.forename: Andreas
authors.identifier: http://orcid.org/0000-0002-2586-5508
authors.initials: A
authors.lastname: Kramer
authors.affiliation: Sensorimotor Performance Lab, University of Konstanz, Konstanz, Germany.
authors.forename: Jakob
authors.initials: J
authors.lastname: Kümmel
authors.affiliation: Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
authors.forename: Edwin
authors.initials: E
authors.lastname: Mulder
authors.affiliation: Department of Sports and Sports Science, University of Freiburg, Freiburg, Germany.
authors.forename: Albert
authors.initials: A
authors.lastname: Gollhofer
authors.affiliation: Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Frings-Meuthen
authors.affiliation: Sensorimotor Performance Lab, University of Konstanz, Konstanz, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Gruber
mesh_terms: D000328:Adult; D001510:Bed Rest; D015992:Body Mass Index; D015444:Exercise / Q000502:physiology*; D018475:Head-Down Tilt / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D053580:Muscle Strength / Q000502:physiology*