Diederick Hol is a Dutch mechanical engineer who developed a revolutionary application based upon the 'clap' speed skate in 1996. This technology is now standard in the manufacture of the equipment used in the sport of speed skating. Athletes using this type of skate have lowered the existing world records in both men's and women's competition at every race distance since 1997.
Hol was a graduate mechanical engineering student in 1995 at Delft University when he first began to experiment with an old speed skating technology, the clap skate. The first clap skates were patented in Holland in the late nineteenth century, but the invention had not ever been pursued to the extent of manufacturing a commercially saleable product.
In 1995, speed skates had undergone very little by way of technological improvement for over 100 years, other than refinements in the construction of the boots. The essence of the speed skate was its long blade, capable of assisting the skater in generating greater speeds that those skates used for ice hockey. The longer the skate blade, the greater amount of ice that can be covered by an athlete in one stride (shorter blades are used in hockey due to their greater maneuverability, in a game where the athlete changes direction frequently).
Conventional speed skates were constructed of a boot, attached to the long blade in a fixed position. The clap skate was designed with a hinge positioned at the ball of the foot, so as to permit the skater's heel to become detached from the blade with each stride. The clap mechanism replicates the motion of the foot observed in sports such as running and cross country skiing, where the power produced in each stride is culminated with an extension of the toes pushing of from the surface.
Speed skating is a very popular sport in many parts of Europe, particularly in the Netherlands (Holland) where it is the national winter sport.
In reviewing the clap technology, Hol reasoned that the skater could develop a greater amount of force to be exerted with every stride, as the entire musculoskeletal structure of the lower leg would be engaged in the action. In particular, the extension motion of the knee and the plantar flexors, including the gastrocnemius (calf muscles) could be better utilized with the clap technique.
Hol also observed that with the clap mechanism, the forceful push off with the toe did not cause the blade to be forced deeper into the ice surface, creating additional drag between the blade and the ice. The forces of the stride continued to be directed along the axis of the skate blade, making it more efficient. The skater is also able to generate a more natural stride and cadence.
Hol constructed a spring mechanism to permit the skater the skate boot and the hinge operated at the same angle as the skater's body in the turn. By permitting the skate to move with the motion of each turn, the skater expends less wasted energy (i.e., any energy not directed to forward motion).
In 1997, the Dutch national speed skating team were the first elite athletes equipped with the new technology, amid significant controversy that the clap skates were a mechanical advantage as opposed to improved equipment. The International Skating Union (ISU), the governing body of the sport, ultimately ruled that the clap skate was legal, as the athlete was required to use their own power to perform.
The impact of the clap skate upon speed skating competitions was profound. Elite athletes were able to reduce their times by as much as one second for every 400 m (440 yd); 14 world records were broken in the first year of the international use of the clap skate.
Hol has also played a significant role in the developing of in line skate technologies, particularly the Dual Box frame. This construction is designed to produce a better transfer of energy from the inline skater to the skate through modifications in the degree of elasticity in the inline skate frame construction.