FOOT REACTION FORCES DURING SPACEFLIGHT (FOOT)
Research Area: Bone and Muscle Physiology
Expeditions: 6, 8, 11 and 12
Principal Investigator(s): ● Peter R. Cavanagh, PhD, DSc, University of
Washington, Seattle, Washington
RESEARCH OBJECTIVES
The Foot/Ground Reaction Forces During Spaceflight (Foot) experiment studies the load on the
lower body and muscle activity in crew members while working on the International Space
Station (ISS). This study will provide a better understanding of the bone and muscle loss in the
lower extremities experienced by astronauts in microgravity.
EARTH BENEFITS
The human body is designed to bear weight. Without the
stimulation caused by placing weight on lower
extremities, whether because of the microgravity
environment or lack of use on Earth, bones lose mass, and
muscles lose strength. The results of this experiment will
help in future spaceflights as well as have significance for
understanding, preventing, and treating osteoporosis on
Earth.
SPACE BENEFITS
The loss of bone mineral in the lower extremities is widely
viewed as one of the critical factors that may limit long-
term human habitation of space (upper extremity
changes in bone mineral density [BMD] appear to be
minimal or to increase). Deficiencies in lower extremity
muscle function as a result of prolonged exposure to
microgravity also have implications for performance and
safety during space missions. The information derived
from this study is expected to shed new light on possible
solutions to bone mineral loss and drops in muscle
function of the lower extremities. These results will lay an
important foundation for the further development of
countermeasures for lower extremity muscle and bone
loss.
RESULTS
The Foot investigation collected foot reaction forces data from four crew members during
exercise with the Treadmill with Vibration Isolation and Stabilization (TVIS), Cycle Ergometer with
Vibration and stabilization (CEVIS), and Interim Resistance Exercise Device (iRED) over their 6-
month missions over the period from Increments 6-12 (November 2002 and April 2006) on the
ISS. A ground-based study collected baseline data from crew members performing prescribed
ISS006E11018 – Expedition 6 Mission
Commander Kenneth Bowersox,
wearing a body harness, runs on the
Treadmill Vibration Isolation System
(TVIS) while conducting the
Foot/Ground Reaction Forces During
Spaceflight (Foot) experiment in the
Zvezda/Service Module.