TY - JOUR
T1 - Hyperthermia-induced Neural Alterations Impair Proprioception and Balance
AU - Mtibaa, Khouloud
AU - Thomson, Athol
AU - Nichols, David
AU - Hautier, Christophe
AU - Racinais, Sebastien
N1 - Publisher Copyright:
© 2017 by the American College of Sports Medicine.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Purpose: Hyperthermia has been shown to affect both central and peripheral nervous systems. However, the consequences of these alterations on the proprioceptive mechanisms underlying human movement control remain unclear. The aim of this study was to investigate the effect of passive hyperthermia on various measures of proprioception and balance, two key components of injury prevention and movement efficiency. Methods: After a familiarization session, 14 volunteers (8 males, 6 females) completed two experimental sessions in temperate (CON, 24-C) and hot (HOT, 44-C-50-C) conditions, in a counterbalanced order. Participants were tested for neural function (electrically evoked M-wave and Hoffman reflex, Soleus), active movement discrimination (five positions, 50 trials, dorsiflexion), dynamic balance (Star Excursion Balance Test, three directions), and static balance (single-leg stance). Results: Both rectal (39.0-C T 0.3-C vs 36.9-C T 0.6-C) and mean skin (37.9-C T 1.0-C vs 32.0-C T 2.7-C) temperatures were significantly higher in HOT than CON (P G 0.05). Hyperthermia significantly reduced the Hoffman reflex (P G 0.05) but not the M-wave (P 9 0.05) amplitudes, increased the mean error for active movement discrimination (0.58-T 0.13- vs 0.50- T 0.11-, +17%, P G 0.05), decreased the average distance reached in the posteromedial direction during dynamic balance (88.6 T 7.9 cm vs 90.9 T 6.1 cm, P G 0.05), and increased the contact area of the foot (126 T 14 cm2 vs 122 T 13 cm2, +2.7%, P G 0.05) and the center of pressure excursion (64 T 14 vs 57 T 9 cm, +11.1%, P G 0.10) during single-leg stance. Conclusions: The current study suggests that hyperthermia impairs the proprioception and balance parameters measured. These observations might be due to heat-induced alterations in efferent and afferent signals to and from the muscle.
AB - Purpose: Hyperthermia has been shown to affect both central and peripheral nervous systems. However, the consequences of these alterations on the proprioceptive mechanisms underlying human movement control remain unclear. The aim of this study was to investigate the effect of passive hyperthermia on various measures of proprioception and balance, two key components of injury prevention and movement efficiency. Methods: After a familiarization session, 14 volunteers (8 males, 6 females) completed two experimental sessions in temperate (CON, 24-C) and hot (HOT, 44-C-50-C) conditions, in a counterbalanced order. Participants were tested for neural function (electrically evoked M-wave and Hoffman reflex, Soleus), active movement discrimination (five positions, 50 trials, dorsiflexion), dynamic balance (Star Excursion Balance Test, three directions), and static balance (single-leg stance). Results: Both rectal (39.0-C T 0.3-C vs 36.9-C T 0.6-C) and mean skin (37.9-C T 1.0-C vs 32.0-C T 2.7-C) temperatures were significantly higher in HOT than CON (P G 0.05). Hyperthermia significantly reduced the Hoffman reflex (P G 0.05) but not the M-wave (P 9 0.05) amplitudes, increased the mean error for active movement discrimination (0.58-T 0.13- vs 0.50- T 0.11-, +17%, P G 0.05), decreased the average distance reached in the posteromedial direction during dynamic balance (88.6 T 7.9 cm vs 90.9 T 6.1 cm, P G 0.05), and increased the contact area of the foot (126 T 14 cm2 vs 122 T 13 cm2, +2.7%, P G 0.05) and the center of pressure excursion (64 T 14 vs 57 T 9 cm, +11.1%, P G 0.10) during single-leg stance. Conclusions: The current study suggests that hyperthermia impairs the proprioception and balance parameters measured. These observations might be due to heat-induced alterations in efferent and afferent signals to and from the muscle.
KW - AMEDA
KW - ENVIRONMENT
KW - HEAT STRESS
KW - TEMPERATURE
UR - http://www.scopus.com/inward/record.url?scp=85038253899&partnerID=8YFLogxK
U2 - 10.1249/MSS.0000000000001418
DO - 10.1249/MSS.0000000000001418
M3 - Article
C2 - 28863075
AN - SCOPUS:85038253899
SN - 0195-9131
VL - 50
SP - 46
EP - 53
JO - Medicine and Science in Sports and Exercise
JF - Medicine and Science in Sports and Exercise
IS - 1
ER -