Title: Investigating force transmission during repeated jumping in microgravity
Funder: UK Space Agency

Abstract: Spending a prolonged period of time in space causes a reduction in physical fitness including a loss of muscle and bone strength. For this reason, astronauts on the International Space Station spend a considerable proportion of their working day training to ameliorate these losses. This is known as countermeasure exercise. However, because exercising in microgravity is a challenge, current devices are bulky and countermeasure exercise does not always entirely mitigate losses in physical fitness. We have designed and built a novel exercise device called 'High Frequency Impulse for Microgravity' (HIFIm) which allows astronauts to perform jumping and hopping exercises in space. Jumping activities are thought to be a highly effective form of exercise countermeasure as they require large muscle forces and these forces are transmitted to the skeleton. Equally, the effectiveness of jumping has been demonstrated in a long-term bed-rest study carried out by the European Space Agency (bed-rest is considered to be the 'gold-standard' method for replicating the deconditioning effect of microgravity on Earth). Despite this, jumping is not currently used as an exercise countermeasure. One reason for this is that exercise countermeasures cannot be allowed to transmit substantial forces or vibrations to the spacecraft. HIFIm is engineered to reduce this loading to a minimal value. The design is inspired by modern pilates equipment, and the resistance is provided by high tensile springs. We have recently demonstrated that repeated jumping is possible in microgravity using HIFIm. This was achieved by the successful use of HIFIm in a parabolic flight campaign. Parabolic flights, where an aircraft performs a series of steep dives and climbs can be used to simulate microgravity. During this parabolic flight campaign we also provided a proof of the engineering concept and showed that force transmission was reduced in microgravity. However, a small force was seen during each landing from a jump. A primary aim of this research is therefore to perform a series of tests in order to optimise the engineering of HIFIm to reduce this impact force to a minimal value. The second aim of this project is to study the range of jumping and landing strategies that might be required for an effective exercise countermeasure programme to understand the differential effects of them on the user of HIFIm and the impact of jumping and landing strategies on force transmission

Lay abstract: Spending a prolonged period of time in space causes a reduction in physical fitness including a loss of muscle and bone strength. For this reason, astronauts on the International Space Station spend a considerable proportion of their working day training to ameliorate these losses. This is known as countermeasure exercise. However, because exercising in microgravity is a challenge, current devices are bulky and countermeasure exercise does not always entirely mitigate losses in physical fitness. We have designed and built a novel exercise device called 'High Frequency Impulse for Microgravity' (HIFIm) which allows astronauts to perform jumping and hopping exercises in space. Jumping activities are thought to be a highly effective form of exercise countermeasure as they require large muscle forces and these forces are transmitted to the skeleton. Equally, the effectiveness of jumping has been demonstrated in a long-term bed-rest study carried out by the European Space Agency (bed-rest is considered to be the 'gold-standard' method for replicating the deconditioning effect of microgravity on Earth). Despite this, jumping is not currently used as an exercise countermeasure. One reason for this is that exercise countermeasures cannot be allowed to transmit substantial forces or vibrations to the spacecraft. HIFIm is engineered to reduce this loading to a minimal value. The design is inspired by modern pilates equipment, and the resistance is provided by high tensile springs. We have recently demonstrated that repeated jumping is possible in microgravity using HIFIm. This was achieved by the successful use of HIFIm in a parabolic flight campaign. Parabolic flights, where an aircraft performs a series of steep dives and climbs can be used to simulate microgravity. During this parabolic flight campaign we also provided a proof of the engineering concept and showed that force transmission was reduced in microgravity. However, a small force was seen during each landing from a jump. A primary aim of this research is therefore to perform a series of tests in order to optimise the engineering of HIFIm to reduce this impact force to a minimal value. The second aim of this project is to study the range of jumping and landing strategies that might be required for an effective exercise countermeasure programme to understand the differential effects of them on the user of HIFIm and the impact of jumping and landing strategies on force transmission

Research activity codes: 6.3 MEDICAL DEVICES;6.7 PHYSICAL
Health categories: MUSCULOSKELETAL