## 1 Introduction  
Exposure to the cold has been shown to negatively affect muscle performance with a reduction of up to 5% in performance for every 1 \({}^{\circ}\)C drop in muscle temperature [1]. The decrement in performance has been attributed to altered neuromuscular function such as changes in neural drive and muscle mechanics [1, 2]. This can have a profound effect on high-intensity athletic tasks such as jumping, where maximal recruitment of the available muscle fibres happens at high velocities [1, 3].  
Alpine skiing and snowboarding are the most popular disciplines of winter sports and these are performed in open environments with undulating terrain and steep slopes requiring the athlete to assume a squat-like position [4]. This posture not only lowers the centre of gravity to allow for better balance but also encourages dissipation of force upon landing, permits sharper and greater acceleration out of turns and increases jump height, all common manoeuvres in skiing and snowboarding [4, 5]. Thus, it is unsurprising that physiological profiles have identified lower limb power production as the main determinant of skiing and snowboarding success [6, 7].  
Apart from the varied terrain, skiing and snowboarding are performed in relatively cold environments (\(-20\) to 10 \({}^{\circ}\)C) [8]. Considering the cold has been shown to reduce muscle power [3], strength [9], proprioception [10] and rate of force development [11], the combination of these reductions with the physical demands of skiing and snowboarding may leave the athlete's musculoskeletal system in a very vulnerable state [8]. In fact, the cold has been associated with an increased risk of knee injury in female skiers [8]. Some of these knee injuries occur whilst landing thus maintaining good landing biomechanics is important for injury prevention [12]. Maintaining appropriate muscle temperature is thought to be an important factor and this is usually achieved from a combination of appropriate warm-up before activity and by wearing appropriate thermal insulating garments.  
Garments used by skiers and snowboarders consist of multiple layers which typically comprise an outer layer designed to allow transfer of moisture to the air, a middle layer that is the primary insulating layer and a base layer or next-to-skin garment that is tight fitting [13]. Commonly, next-to-skin garments with thermal insulating properties are worn; however, anecdotal evidence suggests skiers and snowboarders are switching to compression garments as their next-to-skin garment of choice with manufacturers of compression garments introducing a range, especially for snow sports.  
In winter racing sports, compression garments have been shown to reduce surface drag and help with muscle function through reduced vibration during high impact [14]. In laboratory testing of simulated skiing, compression garments have been shown to lower perceived exertion in a deep tuck [15], reduce muscle activity in the lower limb [16], and improve centre-of-pressure measures [17]. In other sports, compression garments have been shown to increase skin temperature but not improve running performance while athletes were tested in cool (10 \({}^{\circ}\)C) environments [18], as well as lower levels of (simulating skiing) in a laboratory. This leaves a gap in the knowledge of the usefulness of compression garments in changing kinematics in dynamic movements when these movements are performed in the cold. Therefore, the aim of our study was to compare two different next-to-skin garments on thermal sensation as well as countermovement jump height and knee valgus upon landing against a control garment following exposure to the cold. We hypothesised that cold exposure would reduce thermal sensation scores and vertical jump height and induce knee valgus upon landing. In addition, both next-to-skin garments would be associated with ameliorating these effects. The null hypothesis was that old exposure would not reduce thermal sensation score and vertical jump height and induce knee valgus upon landing.