Reliability of a new test battery for fitness assessment of the European Astronaut corps.
BACKGROUND
To optimise health for space missions, European astronauts follow specific conditioning programs before, during and after their flights. To evaluate the effectiveness of these programs, the European Space Agency conducts an Astronaut Fitness Assessment (AFA), but the test-retest reliability of elements within it remains unexamined. The reliability study described here presents a scientific basis for implementing the AFA, but also highlights challenges faced by operational teams supporting humans in such unique environments, especially with respect to health and fitness monitoring of crew members travelling not only into space, but also across the world. The AFA tests assessed parameters known to be affected by prolonged exposure to microgravity: aerobic capacity (VO2max), muscular strength (one repetition max, 1 RM) and power (vertical jumps), core stability, flexibility and balance. Intraclass correlation coefficients (ICC3.1), standard error of measurement and coefficient of variation were used to assess relative and absolute test-retest reliability.


RESULTS
Squat and bench 1 RM (ICC3.1 = 0.94-0.99), hip flexion (ICC3.1 = 0.99) and left and right handgrip strength (ICC3.1 = 0.95 and 0.97), showed the highest test-retest reliability, followed by VO2max (ICC3.1 = 0.91), core strength (ICC3.1 = 0.78-0.89), hip extension (ICC3.1 = 0.63), the countermeasure (ICC3.1 = 0.76) and squat (ICC3.1 = 0.63) jumps, and single right- and left-leg jump height (ICC3.1 = 0.51 and 0.14). For balance, relative reliability ranged from ICC3.1 = 0.78 for path length (two legs, head tilted back, eyes open) to ICC3.1 = 0.04 for average rotation velocity (one leg, eyes closed).


CONCLUSIONS
In a small sample (n = 8) of young, healthy individuals, the AFA battery of tests demonstrated acceptable test-retest reliability for most parameters except some balance and single-leg jump tasks. These findings suggest that, for the application with astronauts, most AFA tests appear appropriate to be maintained in the test battery, but that some elements may be unreliable, and require either modification (duration, selection of task) or removal (single-leg jump, balance test on sphere) from the battery. The test battery is mobile and universally applicable for occupational and general fitness assessment by its comprehensive composition of tests covering many systems involved in whole body movement.
Wyle GmbH, Cologne, Germany ; Space Medicine Office (HSO-AM), European Astronaut Centre Department (ESA), Directorate of Human Spaceflight and Operations (D/HSO), European Space Agency, Geb. 12, Linder Höhe, PO Box 906096, 51147 Cologne, Germany ; Institute of Training Science and Sport Informatics, German Sport University Cologne (DSHS), Am Sportpark Muengersdorf 6, 50933 Cologne, Germany.
Nora
N
Petersen
Institute of Physiology and Anatomy, German Sport University Cologne (DSHS), Am Sportpark Muengersdorf 6, 50955 Cologne, Germany.
Lutz
L
Thieschäfer
Universities Space Research Association, NASA Johnson Space Center, B261, SK3, Houston, TX 77058 USA.
Lori
L
Ploutz-Snyder
Space Medicine Office (HSO-AM), European Astronaut Centre Department (ESA), Directorate of Human Spaceflight and Operations (D/HSO), European Space Agency, Geb. 12, Linder Höhe, PO Box 906096, 51147 Cologne, Germany.
Volker
V
Damann
Institute of Training Science and Sport Informatics, German Sport University Cologne (DSHS), Am Sportpark Muengersdorf 6, 50933 Cologne, Germany.
Joachim
J
Mester
Astronaut fitness assessment; Intraclass correlation coefficients (ICC); Reliability; Space flight; Test battery