Neuromuscular Power: Vertical Jump is one of eleven International Bedrest Standard Measures conducted on healthy subjects at the :envihab facility in Cologne, Germany. Vertical jump is used as an assessment of whole-body-power output and is a highly reliable measure that is free of any learning effect. The objective is to assess muscle power in the legs before and after bedrest. The purpose of the standard measures project is to populate a repository with data that enables high-level monitoring of countermeasure effectiveness and meaningful interpretation of health and performance outcomes. These standard measures will support future, hypothesis-driven research that enables planetary missions by providing an optimized minimal set of measures captured from subjects. These measures will be available to other studies under data sharing agreements as well as undergo analysis to understand risk posture.
APPROACH:
Neuromuscular Power will be assessed by having subjects perform the vertical jump test on a ground-reaction platform. Subjects will perform a warm-up session and three warm-up squats. Subjects will then be instructed to perform two to three practice countermovement jumps at 50% of maximum effort to ensure that proper technique is understood. Countermovement jump begins by anchoring the hands on the waist while standing with erect posture. The movement is performed by the subjects quickly dropping into a squat then reversing the direction by pressing into the platform with maximum force and jumping as high as possible. This motion does not allow pause during the movement and always requires the hands to be anchored to the hips to remove moments of inertia contributed by arms swinging.
After the subjects have warmed-up and proper technique is observed, subjects will attempt three maximum effort jumps. Prior to jumping, body mass will be measured during quiet stance assuming acceleration due to Earth’s gravity to be 9.8 meters per second squared. Subjects will then be instructed to jump and elevate their head as high as possible. Subjects rest 60-90 seconds between jumps or longer if the subjects desire more time.
The sum of the vertical ground reaction forces collected from the force plate are divided by body mass to determine subjects’ acceleration profiles. Subjects’ jump height is calculated through a double integration of the acceleration profile. Instantaneous power is calculated as the product of the acceleration and velocity. Variables of peak acceleration (Apeak), peak velocity (Vpeak), jump height (Hpeak), and peak power are then assessed as the maximum of these respective curves.
The scheduled days of collection are as follows:
- Five days prior to mission
- The day mission ends
RESULTS:
The :envihab International Bedrest Standard Measures Test Battery is not a hypothesis-driven study, but rather a collection of data made available to future researchers and for trend analysis. As such, there are no specific hypotheses, outcome measures, or statistical analyses associated with the skeleton of the project. The questionnaire will capture a "snapshot" of optimized data that can be investigated by researchers in the future.
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