## 2 Materials and Methods
Lower body kinematics during both tasks were captured using a 12-camera, three-dimensional, high-speed motion analysis system (Raptor-E System, Motion Analysis Corporation, Rohnert Park, CA, USA) sampling data at 500 Hz. Subsequently, participants entered the climate chamber (Votsch Industritekin Climatic walk-in chamber series VCZ, Beethovenstrasse, Germany) where they remained seated for 40 min at 0 \({}^{\circ}\)C while wearing a standardised cotton jumper. The cooling protocol adopted was based on work by [PERSON] and colleagues [21]. At the end of the cooling period, participants exited the chamber and repeated the exercise testing protocol by performing five DL and five CMJ. The climate chamber was housed within the motion capture laboratory and participants only had a 10 s walk to the testing area limiting the amount of re-heating. Individual testing sessions were conducted, and retro-reflective markers were left attached to the participants during cooling and quickly visually inspected for correct placement prior to the post-cooling test. Figure 1: Garments used in this study: (**A**) control garment, (**B**) thermal garment, (**C**) compression garment. Subjective ratings of the participant's thermal sensation were recorded immediately prior to and every ten minutes during the cooling protocol and five minutes post-exercise testing completion using a linear, 17-point, 0.0 to 8.0 scale that was graduated in a 0.5 increment. This scale used the terms of 0.0 = \"Unbearable Cold\", 1.0 = \"Very Cold\", 2.0 = \"Cold\", 3.0 = \"Cool\", 4.0 = \"Comfortable\", 5.0 = \"Warm\", 6.0 = \"Hot\", 7.0 = \"Very Hot\" and 8.0 = \"Unbearably Hot\" and was previously used in a cooling experiment [22]. Raw kinematic data from each CMJ and DL were processed with manufacturer-supplied software (Cortex version 3.1, Motion Analysis, Santa Rosa, CA, USA). Marker trajectories were smoothed using a low-pass Butterworth filter with a cut-off frequency set at 9 Hz following residual analysis of the data [20]. Manufacturer-supplied modelling software (Kintools RT, Motion Analysis, Santa Rosa, CA, USA) converted the processed kinematic data into 3-dimensional angular data for knee frontal plane angle for each trial [20]. As ground reaction force data were not collected, initial contact with the ground could not be accurately determined, and thus knee kinematic histories or knee varus-valgus ranges upon landing could not be calculated. As such, only the maximum knee frontal plane angle was obtained for each landing trial [20]. This value was used to judge the effect of cooling on the knee frontal plane angle by calculating the absolute difference prior to and after cooling in the three garment conditions. CMJ height was calculated as the difference in the vertical trajectory of the sacral marker from the initial standing position to the maximal vertical displacement. An average value from the five DL and CMJ performed pre- and post-cooling was obtained. Changes in these dependent variables pre- and post-cooling were used to investigate the association between cooling and garment type. Statistical analysis was undertaken using SPSS (version 22, IBM, Armonk, NY, USA). Data were inspected for normality using the Shapiro-Wilk test where normality was confirmed. A two-way repeated measures ANOVA (garment \(\times\) time) was performed to determine if thermal sensation changed over time and between garments. When significant changes were identified between the two factors (time \(\times\) garment), paired sample \(t\)-tests (with Bonferroni correction and significance accepted at 0.017) were used to identify for which garments the significant differences lay. Linear mixed models were used to assess the association of conditions on the dependent kinematics variables. Percent change in jump height due to cooling was assessed with fixed effects of condition (control, compression, thermal) and sex. The random effect was a participant. Change in peak knee valgus angle was assessed with fixed effects: condition (control, compression, thermal) and sex.