Sprinting

Discussion in 'Silvio' started by JonB, Jul 21, 2008.

  1. Robert Stewart

    Robert Stewart Active Member

    A previous thread produced a very interesting discussion about riding position and technique on the Silvio:

    http://www.cruzbike.com/forums/viewtopic.php?f=3&t=231&st=0&sk=t&sd=a

    I would like to focus here on the specific issue of maximum power delivery for sprinting. It seems to be fairly generally accepted that you can get an increase in power delivery by pulling your chest closer to the handlebars, but I don't think that is how to get maximum power delivery. In the final post of the thread linked to above, Flasharry said this:

    I would like to suggest folks give this technique a try. I have tested it on steep hills and flat roads and in both cases it allows me to accelerate faster than I can using any other riding position. It is a difficult position to maintain though, so it's most useful for sprints imho. I woud like to hear other people's experiences with this method. Try It, You Might Like It. :)

    Cheers,
    Rob
     
  2. JonB

    JonB Well-Known Member

    If you proceed with this kind of thinking, then imagien standing in the pedals and hold yourself up with your arms. Not vertical, but less.
     
  3. keithkling

    keithkling Member

    I have done this same thing with similar results on my Rans VRex. It seems to be a natural position for putting out a lot of power(shoulders, hips and feet aligned). I have often wondered what it would be like to have a seat which you could switch to that position so you wouldn't have to hold yourself up during maximum output.
     
  4. Peder Torgersen

    Peder Torgersen Well-Known Member

    I have used that technique in the winter for better traction up hills. I have also tested it for better speed up hills under normal road conditions it does work you are able to increase your speed. The other method by sitting on the seat and leaning forward and using your upper body is for me even faster.

    Peder
     
  5. John Tolhurst

    John Tolhurst Well-Known Member

    Sprinting and Hill Climbing are different because of the air.

    This method of leaning back introduces some fresh muscles and reduces aero drag. So it might be best for sprints.

    Working the front of the bike and leaning forward slightly (depending on how reclined your seat is) seems to generate greater maximum power, but with more drag. I think the cross over is about 30 to 35 kph.
     
  6. Lief

    Lief Well-Known Member

    I had read this post back before I got my Silvio and had tried it early on but since forgotten the technique.
    ...until a couple weeks ago.

    I had some recumbent-butt-pain going on and during a somewhat fast flat section (about 25mph/40kph) I lifted my hips for some relief.
    I was amazed to find myself feeling a springing forward sensation - it seemed to smooth out my pedal stroke (or it felt like that) such that, as JT says, it introduced some new/different muscles and there was a bunch more pulling through the bottom of the pedal stroke. I was immediately going faster. It is hard to hold that position for more than a few seconds but I found nearly the same feeling just arching my lower back, which I can hold for quite a bit longer, minutes even.

    I am pretty happy to have "discovered" this since I will be giving everything I have in a 200M flying start sprint at the Human Power Challenge in Portland OR on May 30th (10 mile TT on the 29th).
    Running compact double SRAM Rival 50/34 with 165MM cranks which should also help with the crank turnover.

    We'll see how it goes.
     
  7. Manalive

    Manalive Member

    Was pressing hard in a similar fashion some days ago, with backside clear of the seat, and the (non-suspension) conversion hit a speedbump. Heart-in-mouth moment as the bike dances under me: I now make sure I'm well-seated for any bumps...
     
  8. kidneyboy

    kidneyboy Active Member

    this is a technique that fast freddy markham has been recommending for years for hillclimbing/sprinting/quick bursts of power. i believe you can still find his discussions about this on the easy racer forums.
     
  9. Lief

    Lief Well-Known Member

    I did this once too...
    ...even with my suspended Silvio the front wheel did a two-step to the right and then the left.

    Never felt out of control - I like steering with my legs too.
    Certainly lost some forward momentum skipping my wheel like that tho. :eek:
     
  10. Mark B

    Mark B Well-Known Member

    I had to think about my sprinting technique. I guess I'm a butt-lifter, but not clear off the seat. I think it's more putting the full leg and hips into action spinning the pedals as opposed to fully lifting my butt off the seat. I do know that I am seriously working the bars AND throwing the bike side to side. This might be good cause for a video!

    Mark
     
  11. Doc Reyman

    Doc Reyman Member

    Hello Blief.z,

    Here is good luck and safe racing to you this weekend.
    Let us know how it goes.

    Enjoy yourself. I did about a month ago here in Indiana. See #340 "Larry Reyman" -stock class.

    http://www.recumbents.com/wisil/racing2010/indy2010_results.htm

    There were no other high racers in my race--all low racers! But honestly, that would not have mattered, the field was small but loaded with super strong riders.

    http://www.recumbents.com/wrra/records.asp

    Good Luck, again. Larry
     
  12. gannet

    gannet Member

    Interesting list...
    Maria is on here twice - now just a matter of time before 'Cruzbike Vendetta' starts to fill the slots ??!! ;)
     
  13. Lief

    Lief Well-Known Member

    Thanks Larry, I will report back early next week.
    In the meantime here is some bike pr0n of my CBSV-086 AllBlackSilvio (except for the eggbeaters [sigh])

    Some points:
    * my computer is in the windshadow of the headset (took about 2 hours to work this all out.)
    * JT will be proud of the level of...well...the levelness of the handlebars. The brifters will not push any *more* wind than they must. ;)
    [​IMG]
    [​IMG]
     
  14. Gromit

    Gromit Well-Known Member

    Nice, neat job Lief :)

    Though you've forgotten to remove the valve cap off the rear tube to save weight. I see that you've already taken the front one off. ;) :)
     
  15. Lief

    Lief Well-Known Member

    Perfect, I will do that.
    I'm also working on a technique whereby I exhale and remain exhaled for the duration of the 200M sprint so as not to have to drag along that extra 100g* of air.

    * assuming I have a 6.0L lung capacity, I can exhale all of it, and air weighs 1lb / 13cuft...just an estimate.
    :ugeek:
     
  16. Doc Reyman

    Doc Reyman Member

    Hello Blief.z,
    AllBlackSilvio does look good and the cables appear more carefully routed along the TFT than I have done. Good Job.

    There are no mirrors in those 2 pics and before your race day this weekend, you should check for a mirror requirement. That existed in my HPV race, but it was a field of bikes on a circuit course for 20 laps. A TT event or a timed Flying 200M might not have the requirement since you would not be subject to being overtaken and passed.

    Larry
     
  17. Lief

    Lief Well-Known Member

    Thanks Larry, and Man! CruzBikers are observant. ;)
    I have intentionally been running with a messenger mirror on my glasses in case the mirror requirement exists for my events.
    I saw that it did, at least for some races, and I didn't want to take the chance.
    I will bring a back-up in case for some reason my messenger mirror isn't sufficient.

    This is my first real "race" so I haven't internalized things like that - I appreciate checking up on me.

    at first I thought it wouldn't work for me but after a couple of weeks, I find it works fine. Slightly convex, subtends the same amount of my vision as my regular blackburn mirror - just not quite as much light gathering power (F-stop?)
    I recommend it.

    http://www.messengermirror.com/

    And not that you have much choice (my profile name is blief.z after all), but I prefer to be on a "normal name" basis with you all. :)

    Lief
     
  18. Mark B

    Mark B Well-Known Member

    Lief,

    I've not seen that mirror before. I don't care for the bike mounted mirrors, but personally favor the Take A Look mirrors.
    They're a little more expensive ($15-$16 US), but they last forever.
    [​IMG]

    Mark
     
  19. defjack

    defjack Well-Known Member

    At one time I was using both handlebar mirror and a Take A Look and found the Take A Look worked much better so thats all I use now. Jack.
     
  20. Mark B

    Mark B Well-Known Member

    Getting back on topic:

    I analyzed my sprinting technique a litte closer this weekend. I'm definitely a "pull forwarder" as opposed to a "lean back and lift your butter". Everything goes into the legs in a full spin, working the bar and throwing the bike side to side. I can actually feel the seat back brushing against my back as it swings side to side.

    Mark
     
  21. Doc Reyman

    Doc Reyman Member

    Staying on topic of SPRINTING, I tried 2 techniques tonight.

    The group ride was 30 miles and the front pack tends to average around 24mph. I led out to be a rabbit for them to chase and holding 21-22mph, they needed 6-8 miles to catch me, so I had quite a time trial leading up to the sprint technique test. I did this test after an hour into the ride and about 22 miles complete, so I was far from fresh.

    It seems that a rider has their choice with a sprint effort, either pull up into the handlebars or push away and wedge against the seatback for power.

    I tried both and the sprint speed when I pulled forward got into the 28+mph range and I could feel I was pulling back on the pedals a lot to get my power. "Think of pedaling full circles." I have ridden 15+ years using fixed gear bikes so spinning like this is natural for me and I was maintaining that speed for several hundred yards-- maybe over a quarter of a mile.
    Later after resting, I repeated the sprint effort (much to the disgust of the 2 DF riders who were still with me), but pushed into the handlebars and tried to unweight the seatpan by lifting my hips. This effort engaged the anterior thigh muscles like hill climbing (or lunge exercises) and caused rapid exhaustion, but the speed went to 31+ mph.

    Therefore those riders who are strong at hill climbs out-of-the-saddle, may get the better sprint results by pushing into the bar and lifting the hips. Whereas, the spinners that climb hills by staying in the saddle longer may find the better results with the pull up technique.

    Of course, this has only been a one time test and I still have less than 500 miles on SILVIO.

    Good riding to everyone.

    Larry
     

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