3. Results 3.3. Thermographic Data of the Thoracic Region 3.1. Horse Inclusion All eight horses were in competitive work (Foxhunter or above, British Show Jumping), ranged in height at the withers from 1.60 to 1.70 m with (mean ± SD) of 1.65 ± 0.03 m, had a body mass between 490 and 603 kg (561 ± 23 kg) and were aged nine to 12 years (10 ± 2 years). Each horse underwent a visual lameness evaluation on the day preceding the experiment, performed by an experienced veterinary surgeon. All horses were deemed to be non-lame and did not show any signs of back discomfort. From the objective move ment asymmetry measures, horses had (mean ± SD) asymmetry values (mm): HDmin, 4.0 ± 1.4 and HDmax, 5.5 ± 1.0, PDmin 1.3 ± 1.0 and PDmax 4.0 ± 1.1, and HHD 2.4 ± 2.2. 3.2. Saddle Fit Saddles were all jumping type and wool focked. From the static and dynamic assessment, following the SMS guidelines, n = 3 saddles were found to be too narrow, n =3 too wide and n = 2 assessed as a correct ft. 3.3.1. Minimum Temperatures (.C) Time point fixed factor: differences between the minimum temperatures were found for the right cranial region (p = 0.05) and left caudal region (p = 0.04). For the right cranial region, post hoc analysis showed an increase in minimum temperatures post lunge estimated marginal mean (EMM) and standard error (SE), (21.7 .C, (0.8), (p = 0.05)) compared to baseline (18.7 .C (0.8)) temperatures. For the left caudal region, an increase in minimum temperatures (23.4 (0.9)), (p = 0.04) compared to baseline (20.6, (0.9)) was found. Post hoc analysis did not identify any differences between post lunge and post ridden exercise (p = 0.51). Saddle ft fixed factor: no differences were found between saddle conditions (p = 0.29) (Table 1). 3.3.2. Maximum Temperatures (.C) Time point fixed factor: differences were found between the maximum temperatures of the left cranial region (p = 0.0001) and right cranial region (p = 0.0001). Differences between the maximum temperatures for the left caudal region (p = 0.001) and the right caudal region (p = 0.001) were found. In all areas, temperatures were higher post lunge and post ridden when compared to the baseline. No differences were found in either the cranial (p = 0.12) or caudal (p = 0.38) symmetry parameters. Saddle ft fixed factor: differences in the maximum temperatures were found for saddle widths (p = 0.05) however, post hoc analysis did not identify any differences between saddle widths (Table 1). 3.3.3. Mean Temperatures (.C) Time point fixed factor: differences were found between the mean temperatures of the left cranial region (p = 0.003) and right cranial region (p = <0.0001). Differences between the mean temperatures for the left caudal region, (p = 0.003) and right caudal region (p = 0.006) were found. In all areas, temperatures were higher post lunge and post ridden when compared to the baseline. No differences were found in either the cranial (p = 0.14) or caudal (p = 0.32) symmetry parameters. Table 1. Minimum, maximum and mean thermal temperatures of the cranial and caudal regions of the thoracic spine. EMM: Estimated marginal means; SE: standard error. Correct Saddle Width (◦ C) EMM (SE) Narrow Saddle Width (◦ C) EMM (SE) Wide Saddle Width (◦ C) EMM (SE) Saddle Width Main Effects p Value - 20.3 (0.9) 20.6 (0.7) 22.2 (0.7) 0.28 - BL < PL, p = 0.05 20.4 (1.1) 19.1 (0.8) 21.2 (0.8) 0.29 - 0.04 BL PR, p = 0.04 0.3 (0.3) −0.6 (0.2) 0.6 (0.2) 0.05 - Difference between cranial and caudal 0.12 Mean Temperatures (◦ C) Left Cranial Region 23.1 (0.6) 26.3 (0.6) 25.2 (0.6) Right Cranial Region 22.1 (0.6) 26.1 (0.6) 24.9 (0.6) 0.003 BL < PL, p = 0.003 BL < PR, p = 0.03 24.4 (0.9) 24.5 (0.8) 25.7 (0.8) 0.53 - <0.0001 BL < PL, p ≤ 0.0001 BL < PR, p = 0.006 24.6 (0.9) 23.3 (0.8) 25.3 (0.8) Left Caudal region 23.3 (0.6) 26.1 (0.6) 26.2 (0.6) 0.29 - 0.003 BL < PL, p = 0.008 BL < PR, p = 0.006 24.2 (1.1) 25.1 (0.8) 26.2 (0.8) Right Caudal Region 23.3 (0.8) 25.8 (0.8) 26.0 (0.8) 0.40 - 0.006 BL < PL, p = 0.01 BL < PR, p = 0.01 24.5 (1.4) 24.7 (1.1) 26.0 (1.1) 0.67 Cranial Region Symmetry (left–right) - 0.9 (0.3) 0.1 (0.1) 0.3 (0.30 0.14 - −0.1 (0.6) 1.2 (0.5) 0.4 (0.5) 0.29 - Caudal Region Symmetry (left–right) −0.0 (0.2) 0.2 (0.2) 0.2 (0.2) 0.32 - −0.2 (0.4) 0.4 (0.3) 0.2 (0.3) 0.45 - Difference between cranial and caudal 0.7 (0.3) −0.2 (0.3) 1.0 (0.3) 0.006 BL > PL, p = 0.02 PL < PR, p = 0.008 −0.1 (0.4) 0.9 (0.3) 0.6 (0.3) 0.22 - 17