Asymmetry in Elite Snowboarders : A Study comparing Range of Motion in the Hip and Spine, Power in Lower Extremities and Circumference of Thigh

Abstract: Snowboarding is a relatively young sport and has grown since the birth in the 1960-70. Today, snowboarding still is a lifestyle to many, but also an accepted mainstream sport and has been an Olympic sport since the Olympic Winter Games in Nagano, Japan 1998 (18,35,36). The movement pattern and body position is asymmetric, since you stand sideways with the front foot ahead of the rear foot in the line of direction (14,18,28). Several studies that have investigated the biomechanics of snowboarding have showed that the loading of the lower extremities are different in the front leg compared to the rear leg during riding (14,18, 22,23,28). The purpose of this study was to investigate if the asymmetric body position in snowboarding causes differences between front and rear leg considering; circumference of thigh, range of motion (ROM) in the hip joints, power in lower extremities, or causes asymmetrical ROM in the spine in the test group compared to the control group. Two groups were used, one test group consisting of ten elite snowboarders (n=10) with an average age of 18 years, and one control group consisting of eight high level skiers (n=8), average age 17,25 years. All subjects were students at Malung/Sälen Alpine Elite Gymnasium. Measurements of ROM in hip and spine were made with a myrin incline goniometer and universal plastic goniometer. A one leg countermovement jump (CMJ) was made as a test of power in the lower extremities using Ivar ump & speed analyzer. Measurements of circumference of thighs were made using a soft tape measure. The results show significant differences in four of the ten measurements in test group and in two of the ten measurements in the control group. There are significant differences in hip passive flexion (P<0,05) and adduction(P<0,05) in both groups (Tables 2,3) suggesting that in these movements there are individual differences. The one leg CMJ and circumference of thigh shows significant differences, (P>0,05) and (P<0,001), between front and rear leg in the test group (Table 2), but no such differences can be seen in the control group (Table 3) suggesting that these differences may be caused by the asymmetrical body position during snowboarding.