Inline speed skating
Roller speed skating is the roller sport of racing on inline skates. The sport may also be called inline racing or speed skating by participants. Although it primarily evolved from racing on traditional roller skates, the sport is similar enough to ice speed skating that many competitors are known to switch between inline and ice speed skating according to the season.
Skate
An inline speed skate is a specialized shoe version of the inline skate. The boot or shoe is close-fitting, without much padding and usually made of leather, carbon fiber, and/or fiberglass composites. For best performance, the boot must conform closely to the shape of the foot, so most inline speed skating boots are custom-fitted or else heat-moldable.Speed skating boots are low-cut and offer little ankle support, allowing the skater extra ankle movement. Skin blisters due to friction can be a problem, and common solutions include neoprene or silicone "ankle bootee" such as "Ezeefit" or "Bunga Pads"; double thin synthetic socks; smaller boots; improving technique; re-moulding the boots; sports tape; and use of "advanced healing" plasters to help recovery.
The frame that holds the wheels may be made of aircraft-quality aluminum, magnesium, or possibly carbon fiber. Frames flex during skating, and the amount of flex can be a personal factor in which frame choice to use. Very "stiff" frames may be favored by heavy skaters. A frame that is too stiff for a particular skater may feel unstable on corners, while a frame that is not stiff enough will be slower. Frame stiffness also works along with boot and wheel stiffness, so there are many possible variations. Nevertheless, a light frame is desirable. Ideal frame length is affected by foot size and wheel size. A slightly shorter frame may be preferred for the tight curves of smaller tracks; a longer frame may be preferred for longer distance events.
The frame position can usually be adjusted with respect to the skate to adjust for a skater's individual foot, ankle and leg characteristics. Frame positioning is very critical as even a minor change from the skater's actual frame position can lead to severe foot pain. Also, many times it leads to 'locking' of the skater's ankle and/or calf muscle, thereby restricting its movements. It may take a skater several days to weeks to test and adjust the frame position of his new skates. The common inline mounting is 195mm, which is different from the ice mounting of 165mm. The frame usually mounts three, four, or five polyurethane wheels. The three wheel frames are used by skaters with small feet, otherwise four-wheel frames are commonly used, with 90 mm to 110 mm diameter wheels. Five-wheel frames with smaller wheel have lost favor. Each wheel contains two ball bearings with an aluminum spacer, held in place with an axle screwed into the frame.
Larger wheels require better skating technique, so skaters generally progress upwards in wheel size as they gain experience. "Hi-Lo" arrangements are also available, which usually have three larger wheels and one smaller wheel under the ball of the foot, allowing a lower and shorter overall frame design.
In 2014 Powerslide introduced a 125mm wheel for use on a three-wheeled frame varying in sizes from 11.8" to 13.0". Much controversy surrounded this development since FIRS did not allow 125mm wheels at the 2014 and 2015 world championships. On January 18 of 2016 FIRS released a press release that stated: "Dear Friends, Considering the evolution and growth that our sport has attained in the last years, the FIRS and the Speed Technical Committee have decided to allow, starting from February 1, 2016, the use of the wheels up to a maximum size of 125mm but only for the Marathons and the MASTER Category. We will be grateful for the spread of this information and we take this opportunity to send you. Kind regards, Jorge Roldan, FIRS Speed Technical Committee, Chairman & Robert Marotta FIRS Secretary General."Harder wheels minimize elastic hysteresis energy absorption, due to skater's weight deforming the solid polyurethane "tyre". So, speed skaters tend to select the hardest possible wheels, with the highest polyurethane durometer for their skating condition, limited by either wheel slip or surface roughness. Durometer selection is also affected by skater weight, and temperature. Wheels for indoor use are hardest with a durometer of 88–97. They tend to last well, but can be easily damaged if used outdoors. Wheels for outdoor use are softer with a durometer of 82–87, and tend to wear more quickly. Harder outdoor wheels can also be used effectively indoors. Skaters sometimes combine different hardness wheels on the same skate in an attempt to achieve the best combination.
Skaters also consider wheel "rebound". This refers to the relative height to which a dropped wheel rebounds. It is a reasonable comparative indicator of the relative energy absorbed by elastic hysteresis of a wheel during skating.
Bearing sizes have been standardized around the popular 608 series. A smaller and lighter 688 series has had limited acceptance. Bearing manufacturing precision generally run from ABEC-1 to ABEC-11, and some skate bearings are additionally designed to be "loose" to minimize ball rolling friction.
Various grades of steel offer better hardness, rust resistance etc. Bearings with ceramic balls have been available since the late 1990s. They are lighter and longer lasting, however significantly more expensive. Black silicon nitride ceramic is superior to white zirconium dioxide ceramic, since it is considerably harder and tougher. At the modest rotational speeds encountered in skates, manufacturer data suggests negligible difference in friction performance between the various bearing materials. At these speeds, ball bearing friction tends to be dominated by seals and lubricants.
Bearing shields reduce the entry of dirt into the bearing. Metal and rubber non-contact shields are commonly used, of which rubber shields are slightly more effective. Neither shield type is totally effective, often resulting in the need for bearing maintenance. The ball retainer is usually made of either metal, plastic, or glass. Plastic types are preferred since they are quieter.
Bearing lubrication is usually either light oil or grease. Synthetic types last longer before breaking down. Grease assists in holding dirt away, and stays in the bearing longer, reducing maintenance and increasing bearing life. The lifetime of bearings used for outdoor speed skating is often quite limited due to damage caused by dirt ingress. These bearings are usually cleaned by soaking them in petrol overnight and then cleaning the dirt.
In search of the maximum speed the principal goal is to minimize wind resistance, hence the use of skinsuits, special helmets and techniques. The second issue is elastic hysteresis energy absorption in the wheel. The distant third is bearing internal friction, a set of bearings in good condition, properly inserted and lubricated is normally enough.
Technique and control
Mechanically, strokes in speed skating are deeper and faster than recreational skating but not as deep or as fast as in ice speed skating. This is because of the greater frictional forces in the direction of travel and lesser ability to apply friction without slipping of wheels on a hard surface compared to a blade on ice.Speedskaters move each foot across the center line of travel, leading to the double push, a method named by United States skater Chad Hedrick. The technique allows two pushes in each stroke of the skate. However, it can be tiring for inexperienced skaters who have improper technique, and they will often save it until needed, such as the latter stages or final sprint of a distance race. With proper execution, the double push is an energy saver. The double push is mostly used in outdoor racing and the straightaways of indoor skating.
During sprints, skaters need to initially push their body with force to get a jump start. For this they tend to take quick and sharp strides. Once they have achieved a good pace, they move to taking comparatively longer strides. Speedskaters usually bend from their knees to maintain a low posture. This has two advantages. First of all, it increases the reach of the skater's legs, which results into even more powerful strides. Secondly, a low posture reduces the total surface area of the skater's body that comes in contact with the resistive air, thus providing an aerodynamic advantage.
Turning is significantly more difficult with inline speed skates than recreational skates because of more and larger wheels, creating a longer wheelbase. The wheel profile, that is, the cross-section, is parabolic, with a sharper shape than recreational or aggressive wheels, allowing the skater to essentially skate on a smaller, and hence more agile, wheel when leaned over in a turn.
Brakes are not used on speed skates, so various other techniques to slow down are used, such as slaloming or v-plowing, where the heels are pushed outward and the toes inward. The v-plow is often the stop used in situations where there is little lateral and forward room to stop. One technique is the T-stop, essentially dragging one foot perpendicular to and behind the other, however this wears the wheels of that skate quickly. Another stop involves picking up one foot and setting it down quickly and repeatedly somewhat perpendicular to the forward motion while keeping weight on the other foot. Hockey stops are possible on speed skates, but require a very deep lean in order to cause the wheels to lose traction and slide, also the fact that wheels are sliding means that the wheels are also wearing down very quickly. Grass runouts are always a last option, given an adjacent grassy area.
When switching over to ice, speed skaters are generally faster. While there are some small differences in technique, speed skaters already have the muscle they need to skate on ice.
An inline speedskater takes much time to stop and often has few options in an emergency. It typically takes several hundred feet on a level surface to come to a stop at a full, controlled deceleration. Thus, a skater should be familiar with and proficient in stopping techniques before attempting difficult situations such as heavily travelled roads or hills.