Motor Control of Landing from a Jump in Simulated Hypergravity

PLoS One. 2015 Oct 27;10(10):e0141574. doi: 10.1371/journal.pone.0141574. eCollection 2015.

Abstract

On Earth, when landing from a counter-movement jump, muscles contract before touchdown to anticipate imminent collision with the ground and place the limbs in a proper position. This study assesses how the control of landing is modified when gravity is increased above 1 g. Hypergravity was simulated in two different ways: (1) by generating centrifugal forces during turns of an aircraft (A300) and (2) by pulling the subject downwards in the laboratory with a Subject Loading System (SLS). Eight subjects were asked to perform counter-movement jumps at 1 g on Earth and at 3 hypergravity levels (1.2, 1.4 and 1.6 g) both in A300 and with SLS. External forces applied to the body, movements of the lower limb segments and muscular activity of 6 lower limb muscles were recorded. Our results show that both in A300 and with SLS, as in 1 g: (1) the anticipation phase is present; (2) during the loading phase (from touchdown until the peak of vertical ground reaction force), lower limb muscles act like a stiff spring, whereas during the second part (from the peak of vertical ground reaction force until the return to the standing position), they act like a compliant spring associated with a damper. (3) With increasing gravity, the preparatory adjustments and the loading phase are modified whereas the second part does not change drastically. (4) The modifications are similar in A300 and with SLS, however the effect of hypergravity is accentuated in A300, probably due to altered sensory inputs. This observation suggests that otolithic information plays an important role in the control of the landing from a jump.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acceleration
  • Adult
  • Ankle / physiology
  • Biomechanical Phenomena
  • Electromyography
  • Female
  • Hip / physiology
  • Humans
  • Hypergravity*
  • Joints / physiology
  • Knee / physiology
  • Male
  • Middle Aged
  • Muscles / physiology*
  • Musculoskeletal System*
  • Sports
  • Weight-Bearing

Grants and funding

This work was supported by ESA-Prodex (4000103291, Belgium) and co-funded by the Government of Luxembourg (Ministry of Higher Education and Research) through an ESA Contract in the Luxembourg Third Party Programme (4000107923/13/NL/KML). The view expressed herein can in no way be taken to reflect the official opinion of the European Space Agency. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.