Spörri Jörg, Kröll Josef, Fasel Benedikt, Aminian Kamiar, Müller Erich
Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria.
Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
Orthop J Sports Med. 2018 Jan 8;6(1):2325967117747843. doi: 10.1177/2325967117747843. eCollection 2018 Jan.
In alpine ski racing, typical loading patterns of the back include a combined occurrence of spinal bending, torsion, and high peak loads. These factors are known to be associated with high spinal disc loading and have been suggested to be attributable to different types of spine deterioration. However, little is known about the effect of standing height (ie, the distance between the bottom of the running surface of the ski and the ski boot sole) on the aforementioned back loading patterns.
To investigate the effect of reduced standing height on the skier's overall trunk kinematics and the acting ground-reaction forces in giant slalom (GS) from an overuse injury prevention perspective.
Controlled laboratory study.
Seven European Cup-level athletes skied a total of 224 GS turns with 2 different pairs of skis varying in standing height. Their overall trunk movement (frontal bending, lateral bending, and torsion angles) was measured based on 2 inertial measurement units located at the sacrum and sternum. Pressure insoles were used to determine the total ground-reaction force.
During the turn phase in which the greatest spinal disc loading is expected to occur, significantly lower total ground-reaction forces were observed for skis with a decreased standing height. Simultaneously, the skier's overall trunk movement (ie, frontal bending, lateral bending, and torsion angles) remained unwaveringly high.
Standing height is a reasonable measure to reduce the skier's overall back loading in GS. Yet, when compared with the effects achievable by increased gate offsets in slalom, for instance, the preventative benefits of decreased standing height seem to be rather small.
To reduce the magnitude of overall back loading in GS and to prevent overuse injuries of the back, decreasing standing height might be an efficient approach. Nevertheless, the clinical relevance of the current findings, as well as the effectiveness of the measure "reduced standing height," must be verified by epidemiological studies before its preventative potential can be judged as conclusive.
在高山滑雪比赛中，背部的典型负荷模式包括脊柱弯曲、扭转和高峰负荷的综合出现。已知这些因素与高椎间盘负荷有关，并被认为可归因于不同类型的脊柱退变。然而，关于站立高度（即滑雪板运行表面底部与滑雪靴鞋底之间的距离）对上述背部负荷模式的影响知之甚少。
从预防过度使用损伤的角度，研究降低站立高度对大回转（GS）滑雪者整体躯干运动学和作用地面反作用力的影响。
对照实验室研究。
7名欧洲杯级别的运动员使用2双站立高度不同的滑雪板总共滑行了224个大回转转弯。基于位于骶骨和胸骨处的2个惯性测量单元测量他们的整体躯干运动（前屈、侧屈和扭转角度）。使用压力鞋垫确定总地面反作用力。
在预计会出现最大椎间盘负荷的转弯阶段，观察到站立高度降低的滑雪板的总地面反作用力明显更低。同时，滑雪者的整体躯干运动（即前屈、侧屈和扭转角度）仍然保持在很高的水平。
站立高度是降低大回转滑雪者整体背部负荷的合理措施。然而,与例如在回转中增加旗门偏移可实现的效果相比，降低站立高度的预防益处似乎相当小。
为了降低大回转中整体背部负荷的程度并预防背部过度使用损伤，降低站立高度可能是一种有效的方法。然而，在其预防潜力被判定为确凿之前，当前研究结果的临床相关性以及“降低站立高度”措施的有效性必须通过流行病学研究来验证。
