Space Physiotherapy

Original Editor - Srishti Banerjee

Top Contributors - Srishti Banerjee and Kim Jackson  

One Page Owner - Srishti Banerje as part of the One Page Project 

Introduction[edit | edit source]

Physiotherapy continues to expand horizons and physiotherapy in space is one such example. When exposed to microgravity , the astronauts experience physiological changes similar to detraining athletes or senile bedridden patients. A physiotherapist works with a sports scientist and prepares and conditions the astronaut for the space flight and reconditions the astronaut after their return. The role of physiotherapy begins with aiding the pre flight stress relief, counteracting in-flight symptoms , design a well curated exercise regime during the space station stay.[1]

Adaptions of Human Body to Microgravity[edit | edit source]

The physiological adaptations of the human body depends on the duration of the flight. The space flight can be a short space flight which ranges from one day to 14 days whereas long space flight is up to 14 days. The physiological adaptations occur because of two major factors :

  1. reduced hydrostatic gradient
  2. reduced ground reaction force.


These factors lead to unloading and disuse of weightbearing structures[2].

Cardiovascular System Adaptations[edit | edit source]

As the hydrostatic gradient reduces , there is an upward shift of the blood and fluids in the thoraco-cephalic region and there is shift of the fluid from the extracellular space to intracellular space leading to puffy face. The total cardiac work reduces. When the astronaut is continuously exposed to microgravity the volume of the left ventricle reduces. There is evidence of cardiac atrophy on magnetic resonance imaging resulting from prolong exposure to microgravity. It has been found that while returning to earth there is reduction in orthostatic tension which results in postural hypotension while returning to the earth[3].

Pulmonary System Adaptations[edit | edit source]

During the first 3 days in microgravity , the carbon monoxide diffusing capacity increases in standing and sitting which returns to baseline i.e pre flight levels after 3 days. Exposure to microgravity leads to a reduced maximal exercise capacities[4],[5].

Adaptations in body fluids[edit | edit source]

Both during short as well as long space flight plasma and red cell mass decreases. The hemoglobin levels increases in short space flight where is reduces in long space flight because of increased potassium intake. The weight can change from a gain of 0.1kg to loss of 5.9 Kg [4]

Fluid loss accounts for 50 % of weight loss and rest is due to fats and proteins. Inadequate energy intake leads to fat loss[4].

Neurological Adaptations[edit | edit source]

Neuro-vestibular effects are very commonly experienced by about 70 percent astronauts which includes immediate reflex motor response where the astronauts experience postural illusions, rotation ,dizziness, vertigo , space motion sickness which includes pallor, cold sweating, nausea and vomiting. The symptoms of motion sickness also occur during the flight but subsides after 2-7 days. However even though these symptoms can endanger the overall health of the astronaut , currently there are no counter measures for the same.

In addition to this the post flight neurological symptoms includes vertigo while standing and walking, clumsiness, difficulty in walking on straight line, nausea, vomiting, difficulty in maintaining concentration and difficulty in maintaining postural equilibrium. These changes are common in both long and short flight[5],[6].

Musculoskeletal Adaptations[edit | edit source]

In the earth's gravitational field the line of gravity passes ventral through L3 vertebrae , however when exposed to microgravity astronauts assumes a more flexed position and the center of mass shifts posteriorly leading to a greater recruitment of the flexor muscles and loss of extensor muscles. Exposure to microgravity leads to shift from type 1 ( tonic) to type 2 (phasic) occurs. Gravitoreceptors which carry sensations for neural representation of direction of gravity with respect to the direction of gravity lose their function in microgravity making the astronaut less aware of their posture , therefore they have to rely more on vision and feedback from dynamic receptors.

Exposure to microgravity leads to excessive absorption of water in the intervertebral disc ( hyperhydration) causing back pain , however this is short lived.

Prolong exposure to microgravity results in muscle atrophy which eventually leads to reduced muscle strength and function. Bones under go demineralization[7].

Physiotherapy in space[edit | edit source]

Training differs depending on the whether the astronaut is in the pre-flight, in-flight or post-flight stage[8][9]

[10]

Pre Flight Stage[edit | edit source]

Goals of pre flight training

  • Prepare and familiarize the astronaut for in flight situations
  • Treat any pre existing musculoskeletal and neurological disorders
  • Conduct pre flight measures

The pre flight assessment includes examination of any pre- existing conditions , posture, motor control , functional movements and examination of joints. Ultrasound imaging for from previous missions can be used to study the voluntary ability of the abdominal and paraspinal muscles to contract.

In the pre flight stage , exercise protocol focuses on keeping the astronaut's cardiovascular abilities at their best. Aerobic exercise program begins with the use of treadmill, bicycle ergometer, aquatic exercises , walking in horizontal position.

Advance resistive exercise device(AERD) is a form of strengthening done on international space station can be used which focuses on the posture, pelvic tilt and the spine while performing resistance exercises.

Aerobic conditioning and adaptation should be done in pre flight stage. Ground level micro gravity stimulation can be done by 5 basic strategies.

  1. Head down position with head tilt of 3 to 12 degrees.
  2. Water immersion where the astronaut lies supine in a water tank for about 24 hours and performs complex eye hand coordination tasks, mimicking skills required for space flight.
  3. Immobilization and bed confinement similar to bedridden patients
  4. Short parabolic flights for brief periods of weightlesness

In Flight Stage[edit | edit source]

Effective inflight workouts includes treadmill, cycle ergometer, leg rowing ergometer , dynamic resistance exercises for upper and lower body have proven to be effective in maintaining joint range of motion and muscles strength.

AERD stimulates free weight exercises using piston driven vacuum cylinders along with flywheel system to exercises all the major muscle groups. These exercises includes squats , deadlift , calf raises etc.

In addition to this space cycle can be used.

Post Flight Reconditioning[edit | edit source]

The post flight reconditioning is implemented within 24 hours after the return.

The major goals here are:

  • Prevention of any short term or long term painful conditions such as low back pain
  • Addressing any mission related, physical health issues
  • Return to pre flight physical fitness level

The principles of reconditioning includes:

  • Recover postural control , muscle control and balance
  • Normalization of muscle recruitment using strategies of motor control
  • Retraining the postural control with the alignment with the line of gravity
  • Once the posture is corrected , implement strength training

The reconditioning protocol is as follows :

Return + 1-2 days

The initial examination includes , assessment of the musculoskeletal system. Begin with voluntary isolated muscle contraction of large ,antigravity muscles such as paraspinal , abdominal and vastus medialis. The program should always begin with training trunk control, ultrasound imaging can be used here to look for muscle recruitment and contraction. While training for upper limb movements it is essential to look for any compensation and trick movements.

While retraining posture , it is important to train movements in all the planes ,as in micro gravity sagittal plane movements are predominant.

The training begins with eyes open and should be progressed to eyes closed , as the astronaut heavily relies on vision in microgravity. To restore movement patterns and proprioception , motor control strategies should be implemented.

Return + 3-4 days (R+3-R+4)

A progression can be made in motor control and postural exercises. TheraBands can be used to implement strength training. Functional training such as sit to stand activities can be implemented. Endurance training can be done by holding a particular position.

Return + 4-5 (R+4-R+5)

From here exercises are curated along with a sports scientist. Aquatic exercises are very helpful in this phase. Following which patterns of movement are improved on a standard treadmill and bicycle ergometer. Balance and coordination are assessed in this phase and motor control strategies can be progressed from here.

Resources[edit | edit source]

How Do Astronauts Exercise in Space?

Train Like an Astronaut: Adapted Physical Activity Strategies


References[edit | edit source]

  1. Das S. Physiotherapy for Astronauts in Zero/micro Gravitational Environments. Available from https://www.practo.com/healthfeed/physiotherapy-for-astronauts-in-zero-micro-gravitational-environments-39184/post [Last accessed 4 December 2021]
  2. Sneha, K. R., Hiral, M. S., Chhaya, V. V., Jaimala, S., Swati, S., & Amita, M. (2013). Exercise Training for Astronauts-A Review. Indian Journal of Physiotherapy and Occupational Therapy, 7(4), 62.
  3. Convertino V.A. et al. Changes in the size and compliance of the calf after 30days of stimulated microgravity. Journal of Applied physiology 1989,66,1509-1512.
  4. 4.0 4.1 4.2 Jack H Willmore. Physiology of sport and exercise. 3rd edition.chap 11 exercise in hypobaric, hyberbaric and microgravity environment. Pg 360- 374. Editor: lori Garrett.
  5. 5.0 5.1 Mc kardel.chapter: microgravity: Last frontier.pg 665-719
  6. Bacal K, Billica R, Bishop S: Neurovestibular symptoms following space flight. J Vestib Res 2003;3:93–102
  7. Lambrecht G, Petersen N, Weerts G, Pruett C, Evetts S, Stokes M, Hides J. The role of physiotherapy in the European Space Agency strategy for preparation and reconditioning of astronauts before and after long duration space flight. Musculoskeletal Science and Practice. 2017 Jan 1;27:S15-22.
  8. Kale, Sneha & Master, Hiral & Verma, Chhaya & Shetye, Jaimala & Surkar, Swati & Mehta, Amita. (2013). Exercise Training for Astronauts - A Review. Indian Journal of Physiotherapy and Occupational Therapy - An International Journal. 7. 62. 10.5958/j.0973-5674.7.4.123.
  9. Lambrecht G, Petersen N, Weerts G, Pruett C, Evetts S, Stokes M, Hides J. The role of physiotherapy in the European Space Agency strategy for preparation and reconditioning of astronauts before and after long duration space flight. Musculoskeletal Science and Practice. 2017 Jan 1;27:S15-22.
  10. . National Space Centre. Astronaut Training Exercises with ClaireAvailable from:https://www.youtube.com/watch?v=XLuIDYuv1UY [last accessed 4/12/2021]