The elite cross-country skier : clinical and sports related functional tests, dance training, injuries and self-related health

The general aim of this thesis was to study cross-country skiers regarding the effect of dance training on joint mobility and muscle flexibility of the spine, hip and ankle and on speed and agility. Another aim was to perform test-retests of joint mobility and muscle flexibility of the hip and of sports related functional tests. A further aim was to compare high school students with age matched cross-country skiers concerning physical health, activity and location for possible symptoms/injuries. Finally, the aim was to study back pain regarding influence on skiing in high school cross-country skiers. Athletes aged 11 years (8 boys, 3 girls) completed four different test sessions for two sports related functional tests, emphasising speed and agility, the slalom-test and the hurdle-test. No significant differences were found between testing sessions for either the slalom-test (p=0.99) or the hurdle-test (p=0.96). Healthy athletic volunteers (5 males, 5 females) on average 30±16 years performed four joint motion and muscle flexibility tests at three times with one day intervals. The results using intra class correlation coefficients showed the following values 0.99 (knee flexion with hip extended), 0.88 (hip extension with knee extended), 0.93 (hip flexion with knee extended), and 0.53 (a combination of abduction and external rotation of the hip). Subsequently, three out of the four tests showed a good reliability. A group of young (aged 12-15 years) cross-country skiers (n=10) performed dance training during 8 months. Another aged matched group of cross-country skiers (n=10) served as a reference group. Before, during and after the intervention period joint mobility and muscle flexibility of the spine, hip and ankle as well as sports related functional tests were performed in all skiers from both groups. The results showed improvements in speed, agility and range of motion of the spine in most of the studied parameters. A group of elite cross-country skiers (aged 19±3.9 years) either performed additional preseason dance training for 3 months (n=16) or served as a reference group (n=10). Before and after the intervention period joint mobility and muscle flexibility of the spine, hip and ankle and sports related functional tests were performed in all skiers. Prior to dance training the intervention group showed a slight impairment of range of motion of the spine and the relationship between kyphosis of the thoracic and lordosis of the lumbar spine compared with the reference group. After dance training these parameters were improved and a tendency towards a positive effect on back pain was also found. Using a questionnaire cross-country skiers from ski high schools (n=120) were found to be considerably more physical active in as well other sports as skiing when compared with age matched ordinary high school students (n=993). In comparison with controls a higher number of ski high school students described themselves to be physically healthy. Half of the cross-country ski students complained of back problems, mainly low back pain, while skiing and above all during diagonal skiing