Physical fitness was assessed pre- and post- bed rest to guide individual physical training and to determine individual responses to training countermeasures. Functional Fitness pre- and post- bed rest testing captured a subject’s flexibility, endurance, and strength in absolute numbers.
APPROACH:
Functional fitness evaluations were performed by each subject before and after bed rest. Lower back and hamstring flexibility were tested by a sit and reach exercise immediately following a brief warm up and stretching exercises. Upper body strength was measured using a Smith Bench Press and lower body strength was measured using a leg press. Both measures used the 1 repetition maximum (RM) protocol. The 1 RM is typically achieved within 3 to 5 trials. The 1-RM value was recorded as the maximum weight lifted for the last successful trial.
Endurance of the latissimus dorsi, elbow flexors, and pectorals was assessed by the number of pull-ups the subject was able to complete. Endurance of the pectoral and shoulder muscles was assessed by the number of push-ups the subject was able to complete in 2 minutes, and abdominal muscle endurance was assessed by the number of sliding crunches the subject was able to complete in 2 minutes.
RESULTS:
This experiment has concluded in ground-based studies sponsored by the National Aeronautics and Space Administration's (NASAs) Human Adaptation and Countermeasures Division. This experiment was conducted during Bed Rest Campaigns 1 and 3, 5, Artificial Gravity (AG), and Head Down Tilt - 30 day (HDT30).
There was no significant change in flexibility when comparing pre- bed rest day 2 to post- bed rest day 1. This may be due to the fact that subjects followed a daily stretching routine during the bed rest. Both genders had reduced endurance after bed rest. Both male and female subjects showed a significant reduction in strength between pre- and post- bed rest scores. The biceps and muscles of the back are used very little during bed rest, which leads to a reduction in muscular endurance. The tests of the leg press show a significant change from the pre- and post. During bed rest the subjects are not permitted to use their lower bodies; this provides the best representation to space flight that the investigators could record with Functional Fitness testing. Subjects lost substantial percentages of lower body strength from pre- bed rest day 2 to post- bed rest day 1. Strength returned to nearly the original pre- bed rest score on the final day of post-testing.