IMPROVED SKIING PERFORMANCE THROUGH ALIGNMENT AND EQUIPMENT OPTIMIZATION

Harald R. HARB, Diana ROGERS and Robert A. HINTERMEISTER

Harb Ski Systems, Dumont, CO, USA

INTRODUCTION

In order to ski effectively and efficiently, alpine skiers must perform the specific tasks of rolling their skis on edge and balancing on one edged ski to engage the ski’s sidecut. Large variation in lower extremity skeletal alignment greatly influences how an individual accomplishes these tasks. Some natural alignments assist in performing the requisite edging and balancing tasks, while others are detrimental and make performing the tasks extremely difficult. Additionally, the geometric and functional differences that exist between manufacturers and their models of ski equipment influence skiing performance. For more optimal skiing performance, it is critical that skiers undergo evaluation of their alignment along with assessment of equipment to match their particular characteristics.

The authors have developed a method that helps both recreational and competitive skiers use their skis in a most effective and efficient manner. The presumption is that an optimal skeletal alignment exists for each skier that improves his or her effectiveness of movement and decreases the muscular effort required for skiing. Two procedures, a static lower extremity alignment assessment and a dynamic balance assessment while skiing, are used to configure ski equipment for the specific balance needs of each skier. While both procedures are instrumental, the dynamic balance assessment is critical for optimizing a skier’s equipment. It has been designed to minimize the influence of a skier’s technique on his or her apparent alignment, while also demonstrating the skier’s reaction to the inertial loads of skiing. The goal of the method is to find an equipment configuration that enables the skier to ski in a more optimal alignment.

METHODS

The alignment assessment and equipment optimization are performed as either a three- or six-hour session. The three-hour session is sufficient for skiers who do not change equipment. A six-hour session is often required when a skier changes equipment such as boots or skis. A typical session begins with the dynamic on-snow balance assessment, then moves indoors for the static lower extremity alignment assessment. After both assessments, equipment changes or modifications are implemented on a preliminary basis. Another dynamic on-snow balance assessment follows to assess the efficacy of the equipment modifications. Finally, fine-tuning of the equipment occurs if needed.

The dynamic on-snow balance assessment consists of exercises that isolate and test one-legged balance. High-performance skiing requires that a skier can balance comfortably on each leg, and engage and modulate the edge angle of each ski. Four exercises simulate these fundamental requirements. First is a straight run down the fall line on a gentle slope with the skier balancing on one ski. Second is a straight traverse with the skier balanced on the downhill ski. Next is a straight traverse with the skier balanced on the uphill ski. Last is a straight run down the fall line on a gentle slope, with inversion of the lifted foot. Each exercise is performed with each foot.

The indoor assessment measures anatomical parameters of consequence in skiing. These include forefoot to hindfoot relationship, nominal calcaneal angle, nominal position of the knee joint in a skiing stance, tracking of the knee during flexion in a skiing stance, range of motion (ROM) of calcaneal inversion and eversion, and ROM of dorsiflexion. Measurements taken in ski boots include nominal position and tracking of the knee joint.

Depending on individual needs, equipment modifications may include the following: footbeds; footbed ramp angle; varus or valgus of the boot board and shims under the binding; boot cuff angles; and new equipment, including boots, skis, and risers.

RESULTS

The method has been used, directly by or with close supervision of the authors, on approximately 1000 skiers over 4 years. Our results are primarily qualitative and are based on our observations and those of the skiers. They range from remarkable improvement to those of little change, with the majority of skiers experiencing obvious improvement. The authors’ criteria for determining improvement are several performance standards. These include the skier’s ability to keep both skis tipped to the same edge angle, the extent of body adjustments that are required to maintain balance, and the ability of the skier to engage the ski.

The skiers’ criteria for determining improvement are more widely ranging. They include comfort; ease in achieving one-footed balance; better success with the on-snow skiing tasks; better control of the skis; improved speed control; and enjoyment. Most skiers cite improved one-legged balance and diminished effort in skiing as a result of the procedure.

Several generalizations can be made from our observations. Skiers who are moderately misaligned and have a well developed sense of balance are likely to benefit most from the procedure. Skiers with poor balance are likely to experience less than average improvement. Equipment can also influence skiing performance. Narrow-waisted skis and risers are beneficial for the bowlegged skier, while the same equipment combination for a knock-kneed skier can be detrimental to balance and edging.

The importance of the dynamic assessment is revealed by the results. For many skiers, the equipment configuration that produces more optimal alignment is different than that suggested by the static assessment. In fact, the dynamic solution can even be opposite than expected from the static measurements. Two case studies will be presented: a "typical" case, where the static and dynamic assessments concur, and a contradictory case, where the static and dynamic assessments indicate different alignment solutions.

DISCUSSION

This method of assessing skeletal alignment and balance, and configuring equipment to help skiers use their skis properly is effective. For most skiers, a half- or full-day session yields tangible improvement. Achieving more optimal alignment can produce significant improvement in skiing performance. The dynamic balance assessment is crucial for accuracy in alignment. Static measurements alone can vary from accurate to contradictory.

The importance of the dynamic assessment does require a high level of competence from the on-snow technician. However, the simplicity of the on-snow exercises helps the technician by minimizing the influence of technique, while revealing important clues about fundamental balance.

Optimal alignment alone does not determine skiing performance. Poor technique can overpower good alignment. Despite equipment optimization, skiers may not improve as much as they desire without appropriate coaching to eliminate inefficient movements.

Assessment and modification of skeletal alignment and ski equipment can improve skiing performance remarkably, leading to a more enjoyable skier experience.

REFERENCES

Harb, H.R. (1997). Anyone can be an Expert Skier. Harb Ski Systems, Dumont, CO.

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