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Ken Roberts - - Skating what's here
earlier in 2007:
see also: other Years | public discussion | Skating home low hip in main push 207nov9 I looked at some more speedskating videos after my previous analysis of low pushing-side hip, and saw something different. Especially middle-distance ice speedskaters and inline skaters doing double-push have the non-pushing-side hip lower than the pushing-side hip during the main Extension push. The advantage of this configuration is that it allows fuller use of the big well-developed hip-extension muscles. The big drawback is that dropping the non-pushing hip lower requires more flex of the non-pushing knee joint, and more force and strain on the knee-extension muscles. One strategy for dealing with this is not to allow the non-pushing hip to drop so low. Another strategy is to drop it lower but only briefly, and then make it easier to rise up out of that position. For "classic" normal-push (including "pivot-aim style"), the trick for this strategy is to drop the shoulders soon after the previous leg finishes its Extension push and lifts up -- so that little force is needed to extend the knee joint of the next leg -- because they raising of the mass of the buttocks and abdomen (around the hips) is offset by the lowering of the mass of the chest and head (around the shoulders) -- so the knee-extension move requires little or no positive work. For double-push, there is little need for a "trick", because the lower position of the hip of the next-pushing leg is already in a good configuration for engaging the hip-extension muscles for direct propulsive work in its inward-push (whose reactive force also raises the hips some). Then after the inward-push, the shoulders are dropped (also other body parts), during the Aim-switch phase. Seem like the situation where the pushing-side hip is dropped lower is with high turnover frequency (usually high-force situations, like sprints and climbing steep hills), because then there isn't time in stroke-cycle for the trick of dropping the shoulders -- because need to quickly get to the Extension push by the next leg. This looks like the more general principle for hip-pelvis tilt:
Kim Perkins article on climbing hills07nov2 I saw an article by Kim Perkins on "How to Climb", which had some helpful advice and mental images. "stroke light and short" makes sense as a good overall strategy, and the article offers a strong mental image for this. Finding non-obvious ways to help move up is good, and the article gives some. Response to some of the article's specific points. 1. Setting down foot between the hips. This strikes me as good advice for classic normal-push skating on the flat -- not a techique specific for climbing hills. On sustained steep hills I think most people are going to find it difficult to execute it literally. But still it can be helpful as an aspirational mental image for playing with getting more work from the out-sweeping moves of hip-abduction and medial hip-knee rotation. 2. Adding work from recovery moves. From the physics this strikes me as not likely to add enough net propulsive work to be worth the distraction (see this detailed discussion). But recovering the foot more inward might help emphasize an initiate the outward-sweep moves in the main push -- or at least help prevent inward collapsing during the main push. 4. Emphasize falling from side to side. Good imagery for many skaters. More helpful for climbing than than the typical "quiet upper body" and "stability" concepts. Of course in the objective physics what's important for adding propulsive work is the side-to-side acceleration and deceleration, not the "falling" (and excess up-and-down motion is likely to be counter-productive for climbing hills). And actually this side-to-side motion does use muscles, but different non-obvious muscles. Leaning forward? Seems like this ought to be unnecessary for climbing up a steep hill, since aerodynamics are much less important. And for sure there's no point in leaning forward as far as in flat skating. But still in the "Monte Brutalo" video I see significant forward lean by the better climbers. Perhaps it's good biomechanics to better engage the big hip-extension (e.g. gluteus) muscles -- or perhaps it's an unconscious mistake? low pushing-side hip in main push07nov1 One thing I notice in several videos of elite speedskaters in their main outward push is that in the second half of their leg-push they move the pushing-side hip just a little lower than the non-pushing hip. I might have thought they would drop the non-pushing hip, because that would keep the hip-hip-knee angle closer to perpendicular, which would seem to be more effective for engaging the big gluteus muscles (like in bicycling). There are two big advantages to dropping the pushing hip lower:
Seems like these two benefits outweigh the apparently less-effective angle for the big gluteus muscles. Seems like the training strategy for elite speedskaters is to develop those muscles for pushing partly out toward the side. See lots more detail in this note. A related move that helps get the hip lower . . . stepping forward in normal-push07nov1 Setting the foot down further forward in classic normal-push allows the ankle joint to be less flexed (dorsi-flexion) at set-down. The implies that for a given angle of knee-flexion, the hip will be lower. If the foot is set down move behind, the ankle is flexed forward more, which tends to bring the hip higher. Unless the knee joint is flexed more. But if the knee joint is flexed more with the force of body weight on it, there is much more strain on the knee joint and knee-extension muscles. So it's often better to set down the foot farther forward while the other leg's extension push is finishing with a lower hip. Then move the foot backward (using some combination of ankle-flexion, knee-flexion, and possibly hip-flexion muscles) -- which has the effect of moving the knee down and forward relative to the ankle, and moving the hip forward and upward relative to the ankle. This move of driving the foot backward is simultaneous with sweeping the feet outward toward the side. A combination which feels strange to me at first. Thus during the first half of the leg-push there is ankle-flexion and knee-flexion (and perhaps hip-flexion), while the second half of the leg-push is the opposite: knee-extension and then ankle-extension (or plantar-flexion). why pushing back works07nov1 Lots of coaches say to practice pushing toward the side. A theoretical idea is to push perpendicular to the aiming direction of the foot. But most videos of elite racers show them pushing their foot diagonally more backward -- not perpendicular to the aiming of the foot. I think pushing diagonally more backward works better because it uses more of the big hip-extension muscles (e.g. gluteus). Pushing more directly out to the side uses more hip-abduction muscles and less hip-extension. But the hip-abduction muscles are usually smaller and weaker in most skaters. Using more of the hip-extension muscles requires pushing more backward, because that simply is the direction of that (articulation) move. The result of pushing backward more is that the component of distance the foot travels which is perpendicular to the aiming-direction is shorter than it would be if the pushing motion were perpendicular to the aiming-direction of the foot. This tends to reduce the propulsive work from the push. But there is another factor . . . Work = Force * Distance: so Force is also important. Not only are the hip-abduction muscles usually weaker, but in the second half of the push they are not well-aimed to add a propulsive component of force. The hip-extension muscles are stronger and better-aimed for propulsion, so it makes sense to emphasize them more in the second half of the leg-push. Therefore the second half must have a substantial backward component. So the direction of the foot's pushing motion is not the same as the direction of the propulsive component of its force. The more general principle is to let the muscles push the way they best push, and allow the mechanical constraints to convert that into the appropriate propulsive force. Similarly in pedaling a bicycle, the pedal moves in a circle, but there is no need to worry about pushing the foot in a circular path. Or in a piston combustion engine for a car, the piston only pushes linearly back-and-forth, and allows the mechanics of the linkage to convert into circular motion of the car's wheels. Lausanne, SwitzerlandAugust 2007 I found two major different sections in my daytime mid-week skating: the hilly main city, and the gentle stuff in the park by the big lake. The main city had mostly nice sidewalk surfaces, but the most of the streets I saw had too much vehicle traffic for the lane width to be inviting for daytime skating. I was able to handle the hills with my Gatorleash and braking skill, but I didn't find them much fun. The lake-front park had pretty good surfaces and sights, and by using one of the park roads I was able to skate a nice loop toward the west side. ankle twist and in-push errors in Double-pushthread: ankle twist on the underpush Mikeyb wrote: I'd like to avoid ankle twists and wonder if there might be any common errors in underpush technique that I might look to correct? All my ankle-twist injuries have been from some obvious and single unexpected traumatic move, never just from overuse in repeated motion -- and none of those injuries during skating. So I guess the only lesson for avoiding ankle-turning injuries from my experience is to stay away from stones - (see below for an idea for strengthening ankle muscles). Common errors with the inward push: I suspect the most frequent error is to get good at tracing a nice S-curve arc, but without effectively pushing much toward the inside. Feels good, looks good, but doesn't make you faster. I have a feeling that's not your problem. A subtle variation on this is to try to really push thru the foot toward the inside, but simultaneously "absorb" most of it in the upper body (by allowing the upper body to "collapse" sideways toward the inside, instead of holding stable). This problem is tricky to diagnose without a good coach or careful video analysis (but not likely to cause an ankle injury). Lazy transition to the main outward push is something which I think reduces power and speed, and I've been working on it lately. I think my pattern has been to make a nice inward push, pivot the skate to aim toward the outside, but then enjoy gliding on it a little before starting my outward sweep. I think this passive-glide time reduces my turnover frequency and thus my rate of effective power output. I'm thinking that an exercise which might help fight that lazy pivot transition would be Eddy Matzger's drill to make propel myself forward by making alternate pushes to different sides with the same skate, while dragging the toe wheel of the other skate behind for balance. I bet this drill also helps strengthen some ankle muscles to help resist injury. (but I don't think this drill helps develop the Pascal Briand / Joey Mantia style of making a significant extension of the whole leg in the inward push.) Ken Germany skating visitAugust 13 I had fun skating in some places in Germany in July -- see selected photos | map
I also checked some other places that looked promising for skating:
Overall my impression was that Germany (especially Düsseldorf and south) is one of the most promising countries for my style of skating. Here's more detail on skating in several places . . . Frankfurt am MainOne day I bicycled around Frankfurt city, and another day I skated around Frankfurt and east and west of it along the Main river and over several bridges across the Main river.
drawbacks
Rhein river gorgeI started just north of Boppard and skated south along the west side of the Rhein river to St Goar and the Loreley statue, then return north the same way to Boppard. Since I live near the Hudson river valley, I was not expecting to be impressed with the Rhein gorge, but I was. The hills alongside the Rhein were not as big as those along the lower Hudson, and the river is not as wide -- but the hills in the Rhein gorge tend to be steeper, and I did like the villages and castles, and the more frequent activity of barges on the Rhein. Skating surface on the path on the west side between Boppard and St Goar was sometimes a bit coarse, other times very smooth. Next time I might try:
other observations:
StuttgartI skated during the day on a weekday, first around the main shopping streets and the Schloss plaza. Then I tried to follow the Thursday Night Skate route, which worked pretty well. Then I drove out to the Langes Feld area outside the city and bicycled much of route #1 on the UHU skate route maps. good points:
concerns:
Langes Feld area north of the city:
useful links
more placesHere's some places where I did not actually skate, but I visited and thought if they were likely or not to be good for future visits for my preferred style of skating:
what makes for good city skating?July 2007 daytime work-day skating -- no organized groupNormally during the working days there's lots of vehicle traffic on the streets, so you need to either do a substantial amount of skating on the sidewalks or on bicycle paths -- or you need wide streets with a traffic patterns that somehow make them reasonable for skating (depends on skill level and risk preferences of each skater). To me the whole point of being in a city is to visit places near the active life of the city, or famous tourist sites or view areas -- or interesting spaces for skating -- I like skating across bridges.
"smooth surface" -- best is good asphalt. Acceptable is large tiles whose shortest width is at least 20cm, but 30cm is better, and grooves betweeen tiles are small, say less than 0.5cm. Standard-size bricks are acceptable only if the grooves between them are very small and the bricks are at a continuous very even level. evening or night-time skating - no organized groupAfter working and commuting hours, often there is less vehicle traffic on the streets -- so there's more freedom to skate on the streets. Usually this makes it easier to enjoy city skating at night. Also lots of cities just look better at night.
organized night skateThe two keys to a good organized night-skate are the organization and the skaters. Also key is surface quality, but you sort of hope that the organizers would not put in the work if they did not know a route with mostly good surface quality. Skaters -- all depends on what sorta people you want to hang out with and compatibility of your speed and style with theirs. Note that some night skates skate kinda fast, or "aggressive" in handling vehicle traffic or tricky terrain situations -- often you can find this out if you ask in advance. Organizers -- Do not assume this will be good. Skaters are usually complex, flexible people with lots of other interesting things going on their varied and dynamic lives. In modern city life, actually showing up at a specific place at a specific time fixed long in advance puts a major cramp on their lifestyle. So don't be surprised if the weekly skate gets cancelled and nobody told you (especially if the weather is questionable). Or if there's a few skaters there on time, but the leader does not show up until half an hour later. Or the leader who knows the route never arrives, so some a couple of the other skaters sorta "make something up". Note also that some skate leaders are great skaters who know lots of places to show off their greatness, but have no idea how to make it a fun and safe time for most other skaters. Tips
multi-day skating visitI'm not much into confining myself to the boundaries of one city for multiple days. I'd only do it if it were a rather large city (e.g. New York). Normally my preference is to use transportation to also explore skating (or bicycling) that is well outside the city -- or in another different city. For me "transportation" usually means a rental car, and then I choose my lodging place to be convenient for parking and access to major roads. The other strategy is to know in advance where there are other good skating places which you know you can use trains or buses or ferries to get there and back. |
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Netherlands skating visitJune 2007 post to SkateLog forum I had fun skating in several places in the Netherlands in June and early July -- see selected photos | map
I was a bit unlucky with rain + clouds on most days -- and a couple of times I was glad I had hiking poles with me to me help push while skating against high winds. But it's a special place for skating, and I'd gladly go back for more. Here's more detail on skating in several places in the Netherlands . . . Rotterdam cityI joined the alternate informal ROW skate [ website ] for two hours [ photos ]. (Thanks to recommendation by "janneman" on SkateLog forum). Had a great time skating over all the bridges, thru the tunnel, and visited the world-famous container-ship harbor. Mostly on bicycle paths and lanes (except for the container-ship area). Lotsa nice asphalt. About the nicest skating over bridges I've ever done. Also some nice skating alongside the big river. Hope I get a chance to skate there again on my own -- and also again with ROW. The start point for the ROW skate was about one block southwest from the Oude Haven parking garage. I think I remember we skated first east along north side of Mass river, then south across the A16 bridge (Van Brienenoordbrug), then west, then north across Willemsbrug, then west, then south thru the Maas tunnel (under the Mass river). Then west (some on streets with no bike lane or path) to Waalhaven to see the container facilities, back east, then northwest over Erasmusbrug, and east back to start. KinderdijkThis village near Rotterdam has a collection of old-style windmills just outside it next to some canals and open fields -- which turned out to be a nice place to skate [ photos ]. (Thanks to recommendation by "janneman" on SkateLog forum). I found there was an asphalt path from the main car parking area through the windmills -- so I started skating on it. After a ways I saw another asphalt path with a painted arrow on it branching away, so I tried that and it led me to just outside another village called Ablasserdam, and I kept going and found more asphalt that led me back to the original path and back to the parking area. Trying this would have been safer if I'd had a local map -- and having a map could have helped me to feel free to skate a longer tour. Windmills -- My image of the Netherlands had lots of these old-style windmills everywhere. But actually most of the windmills nowadays are sleek and tall with a "tri-propeller". A few places I visited had a single old-style windmill for show, but this was the only area which had lots of them together. Hoge Veluwe national parkSharon and I heard this park was an interesting "nature" area, so we tried visiting during a dry break on an otherwise rainy day [ photos ]. One thing that makes it different is that it has some hills -- though they were gentle. We got some good advice and maps at the Otterlo VVV tourist office, then parked our car by the museum. I skated some on the main bike trails and some on the park roads. I made a loop visiting the other two Park entrances, Schaarsbergen and Hoenderloo. The main bike trail was narrower than most paved trails I've seen -- but I found it was just wide enough for enjoyable skating -- at least with my style. Perhaps it helped that it was a cloudy weekday, and might have felt too cramped if I had to share it with lots of bicycles on a crowded weekend. Some of the paved path surface was a bit slow and some of the park road surfaces were coarse, but some were smoother. My favorites were sections of the main bike trail between Schaarsbergen and Hoenderloo, and some of the park road in the southwest corner. I saw a sign by Otterlo for a skating trail, but the VVV said that was closed for maintainance work. Lots of free bicycles available in the Park near each entrance. I think the park is roughtly northwest from Arnhem, about 85km east from Rotterdam or 60km from Amsterdam. AfsluitdijkThis is a big long dike in the midst of the sea. There's a 4-lane highway (A7) the whole way across, and a bicycle path parallel to the highway. There's an earthen ridge on the ocean side, which protected me some from the wind -- but mostly I could only view toward the inland sea -- except for several observation points where I could get up on the ridge. The inland sea is pretty big, so other than some dots on the distant horizon, all I saw was wide water to the horizon -- and lots of cars and trucks whizzing past close. All flat, and mostly pretty straight. [ photos ] I skated back and forth on a section in the center. Boredom was a factor for me, but even more so the wind. Fortunately I had my metal-tipped walking poles with me to help me push against the wind (which is the direction I did first). Then when I turned around it was very fun to go fast and easy back to my starting point. That was interesting to do once. Might have been worth skating the whole thing one-way: (a) if I had a tail-wind; (b) if somebody else had driven a car ahead to meet me at the end; (c) if I hadn't seen it already in a car. I think the southwest end of the dike is about 50km north of Amsterdam. Friesland (around Bolsward + Workum)Friesland (or Fryslan) is the northern area of the Netherlands. I started from the village Tjerkwerd (just south of Bolsward and the A7 highway) and skated more or less south -- on a secondary road with little car traffic alongside a canal -- to the large village (or small city) of Workum and on its main street. I found a bakery there and had a couple of pastries and called Sharon on my mobile. Then I skated around on some of the other streets of Workum and then went back on the same road. [ photos ] I found it enchanting (despite the wind): cows and sheep and horses, boats on the canal, windmills and farm buildings. Fortunately I had my metal-tipped walking poles to use to help push to fight the wind on the way out. Main drawback was that both Tjerkwerd and Workum had lots of bricks on their streets and sidewalks -- so perhaps a lesson for selection of routes skating tours is to avoid villages -- or find a list of skating-friendly villages. Encounter: For a short section on the quiet road the surface was coarser on the right side, so I moved over and started skating on the left side. A minute later one of the rare cars pulled alongside. The driver rolled down his window, and told me that it was incorrect to skate on the left side, better that I should skate on the right side of the road. I'd be glad to try some more skating in Friesland -- and other rural areas of the Netherlands. I think where I skated was about 90km driving north from Amsterdam. Southwest cornerAnother area I visited which looked promising for skating was around Sluis + in the far southwest corner of the Netherlands. Actually the better skating surfaces were on public roads in the country of Belgium just southwest from Sluis. I didn't skate it, but from Sharon and I riding on our bicycle, seemed like many (but not alll) of the quiet roads on the pretty "Maerlant" bicycle route (from the village of Damme in Belgium) looked skatable -- but that would need more exploration. (I think this area is about 135km driving from Rotterdam). Amsterdam cityAmsterdam didn't work for me skating. I started near the Vondelpark, skated in thru the old city to Centraal Station, then back out to Vondelpark, then more or less followed one of the Friday Night Skate routes out to the northwest section of the city and back to near Vondelpark. [ photos ] I had two problems with my skating in Amsterdam:
My impression was confirmed by another visitor's report on the web, and by what the Rotterdam skaters told me. The sense I get is that the Friday Night Skate is good (if it doesn't rain), but otherwise it's tricky to find good skating unless you're with an experienced local skater. Otherwise, if I wanted to have a fun time exploring the the city on wheels, I'd rent a bicycle. Yes I found lots of bicycle paths and lanes all around Amsterdam, and lots of cyclists riding on them (though I saw no skaters on them outside of myself). But many of those paths and lanes were covered with bricks, not asphalt. The brick surface tended to be nicer further away from the center city -- and the probability of finding asphalt was higher farther out -- much of the asphalt was good quality, but some was not. I think there's lots of other "brick cities" in northern Europe, but Amsterdam is bigger so its brick section is bigger. Vondelpark is a pretty park, but the loop for skating and bicycling was not very long, not very wide, and had two-way traffic. (Contrast with New York City's Central Park and Prospect Park loops). I've heard there is some good skating somewhere around Amsterdam, but I would have done better to follow the advice and example of some other experienced skaters: do the Friday Night Skate, but otherwise skate there only with a local. Leiderdorp near LeidenA pleasant town with streets and bike paths and sidewalks and canals and water ditches. Some of the bike paths and sidewalks were asphalt, some were brick. Fortunately many of the streets were asphalt. Some intersections had special traffic signals for cyclists and walkers -- which (based on my skating experience from New York + New Jersey) I found confusing at first. Europe cities ranking on skate tourismSkateLog
Forum -- Main forum Which cities are good for "seeing the tourist sites" on skates? Here's my first try at an answer for western Europe. Lots of room for more opinions, and corrections -- and different ways to ask the question. A -- good for my kind of skate tourism even in daytime on working days:
B -- good for my kind of skate tourism in evenings or quieter weekend hours:
C -- local knowledge needed to find substantial good skating tourism, or the good skating is somewhere away from the tourist sites:
D -- not a good bet for non-locals to find much good skating:
By "skate tourism" I mean the ability to skate to obvious tourist sites like interesting buildings + views + shopping streets + waterfront, and into interesting skating spaces like over bridges and thru narrow passageways. Of course every city is going to have some difficult spots, and have some inevitable navigational confusion for a first-time visitor. These ratings assume that I have a detailed city map, and skating maps or routes publicly available on websites easily found by obvious Google searches, and that I have solid competence in handling light to moderate traffic on public streets. And there are lots of other ways to "rate" cities, like skating community and special events (e.g. Amsterdam has a well-regarded Friday night skate) -- which will produce different rankings. Details on some cities:
See also more detail in other notes. I'm looking forward to getting corrections -- and more ideas for fun skating in European cities. Ken skating with cars: how to?SkateLog
Forum -- Main forum I like skating out on the public roads and streets used by cars and trucks. More better surface, interesting terrain, bigger audience. But it's a different game with different risks. How to play it? I haven't found much about how to skate with car traffic in books or articles or websites -- not much more than a page with a list of ideas like "Wear a helmet" and "Look both ways". Know any interesting resources for How to Skate with Cars? Bicycling has several books and websites with some detail and depth about this, so that's what I've been depending on so far. I found one that seems especially useful for skating: The Art of Cycling, by Robert Hurst. Globe Pequot Press, 2007. [ Amazon | B&N ] The first reason Hurst's book is helpful for skating is just that it's got lots of specific suggestions for interacting with cars. Second, the book emphasizes city streets and traffic more than rural. And it's got a sense of humor. The book also conveys an overall "mental paradigm" for interacting with motor vehicle traffic which I like. The first paradigm for skating on the streets is to do your best to stay out of the way. The other side is the "in your face": I'm doing my cool thing and it's up to you drivers (and walkers) to deal with it. Robert Hurst gives a third way. What else can I check out? Providence RI -- skate Rhode Island07jun11 I skated the East Bay Bike Path (www.eastbaybikepath.com) on a mid-week day and it was great. Nice views of water, sometimes on both sides. Mostly good pavement. Often nice design of road-crossings. Food places near the trail in some places. It's about 14.5 miles long, and I skated the whole thing in both directions -- not the sort of thing I usually do with rail trails. Earlier in the day I skated for an hour on the streets of the city of Providence -- I found it skatable but nothing outstanding. more . . .see also
concept words: ski skiing snow roberts report reports learn learning skating: skate skates skater skaters push glide inline inlines ice speed speedskate speedskating speedskater speedskaters roller technique: techniques technical theory theories theoretical physics physical biomechanics biomechanical mechanics mechanical model models concept concepts idea ideas |
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