title: Non-invasive measurement of tibialis anterior muscle temperature during rest, cycling exercise and post-exercise recovery.
abstract: We introduce a non-invasive and accurate method to assess tibialis anterior muscle temperature (Tm) during rest, cycling exercise, and post-exercise recovery using the insulation disk (INDISK) technique. Twenty-six healthy males (23.6  ±  6.2 years; 24.1  ±  3.1 body mass index) were randomly allocated into the 'model' (n = 16) and the 'validation' (n = 10) groups. Participants underwent 20 min supine rest, 20 min cycling exercise at 60% of age-predicted maximum heart rate, and 20 min supine post-exercise recovery. In the model group, Tm (34.55  ±  1.02 °C) was greater than INDISK temperature (Tid; 32.44  ±  1.23 °C; p < 0.001) and skin surface temperature (Tsk; 29.84  ±  1.47 °C; p < 0.001) throughout the experimental protocol. The strongest prediction model (R(2) = 0.646) incorporated Tid and the difference between the current Tid temperature and that recorded four minutes before. No mean difference (p > 0.05) and a strong correlation (r = 0.804; p < 0.001) were observed between Tm and predicted Tm (predTm) in the model group. Cross-validation analyses in the validation group demonstrated no mean difference (p > 0.05), a strong correlation (r = 0.644; p < 0.001), narrow 95% limits of agreement (-0.06  ±  1.51), and low percent coefficient of variation (2.24%) between Tm (34.39  ±  1.00 °C) and predTm (34.45  ±  0.73 °C). We conclude that the novel technique accurately predicts Tm during rest, cycling exercise, and post-exercise recovery, providing a valid and cost-efficient alternative when direct Tm measurement is not feasible.
authors.affiliation: FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece. Institute of Research and Technology Thessaly, Centre for Research and Technology Hellas, Trikala 42100, Greece.
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Flouris
authors.forename: Petros C
authors.initials: PC
authors.lastname: Dinas
authors.forename: Kiriakos
authors.initials: K
authors.lastname: Tsitoglou
authors.forename: Ioanna
authors.initials: I
authors.lastname: Patramani
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Koutedakis
authors.forename: Glen P
authors.initials: GP
authors.lastname: Kenny
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000502:physiology*; D012146:Rest / Q000502:physiology*; D016683:Supine Position / Q000502:physiology; D062125:Thermometry / Q000295:instrumentation / Q000379:methods*; D055815:Young Adult