On May 1, 2:36 pm, Simon Brooke <
[email protected]> wrote:
> in message <[email protected]>,
>
>
>
> [email protected] ('[email protected]') wrote:
> > On Apr 30, 12:03 pm, Simon Brooke <[email protected]> wrote:
> >> I'm a cyclist of limited performance. I have bad circulation problems in
> >> my left leg, which means I can't pump much blood round it anyway; and
> >> I'm on warfarin to prevent clotting, so the blood I can pump doesn't
> >> carry as much oxygen as normal. So if I'm going to improve my time trial
> >> performance I essentially need to improve my aerodynamics (and get
> >> weight off, but that's a different problem).
>
> >> Let's be clear about this: we're not talking great performance. I want
> >> to break 30 minutes for a ten. I know everyone else can do that while
> >> eating their sandwiches, but my lifetime personal best is 30:06[1].
>
> >> I've been out this morning working on my tuck. I find that in full tuck
> >> I can manage 40Km/h on the flat at 90rpm, without any feeling of strain
> >> - which is great, far more than I need. But I can't hold full tuck for
> >> long, and as soon as I sit up the speed at what feels like the same
> >> level of power output drops to 25Km/h. What's happening is that the
> >> muscles along the front of my thighs get very tight. It doesn't feel
> >> like a lactic acid problem - there's no sensation of burn or cramping.
>
> >> So I'm assuming it's a stretching problem. Am I right, and if so, can
> >> anyone suggest exercises which will help? Also, should I keep going when
> >> it starts to really hurt in full tuck, or could I be doing damage?
>
> > Can you be more specific about where this discomfort is?
>
> It feels like it's a muscle on the front of the thigh from the middle of
> the knee to the outside of the pelvis.
>
> > Is it
> > constant, or does it appear at a specific point in each pedal
> > rotation?
>
> It's not at any specific point in the rotation. It doesn't start
> immediately I get into the tuck - the first two or three minutes are easy
> and I can spin well, with plenty of power. Then the tightness begins to
> build and after about five minutes it really feels painfully tight.
>
> > Also how agressive is your position? Bar position, etc. When
> > you are in your tuck, what attitude do your arms have?
>
> My saddle is about 70mm higher than my forearm rests; the tribars are up at
> about 25 or 30 degrees to the horizontal; from the nose of the saddle to
> the forearm rests is 580mm and from the rests to the grips of the tribars
> is another 290mm.
>
> Pictures (not very good ones) here:http://www.jasmine.org.uk/~simon/album/kitchenpr0n/
Nice bike! I think however your problem is due to inappropriate choice
of hydration, as indicated in some of the other pics.
>
> In the tuck my elbows are considerably forward of my shoulders, and my
> wrists are a bit higher - not much higher - than my elbows. Upper arm
> angle say 60 degrees to the horizontal, forearms about 10 degrees to
> horizontal. Back certainly no more than ten degrees above horizontal.
>
> Minor problem with legs hitting belly, but like most masters fattie I have
> a bit of an airobelly.
>
> > I was on a long ride the other day, and my seatpost binder bolt wasn't
> > adequately tightened (and since I am a Paris-Roubaix sceptic, I didn't
> > have a set screw as a backup.) and my seat slid down about 5cm during
> > the course of the ride. It happened very gradually and as I had been
> > making seat adjustments, I was expecting things to feel weird. Anyway,
> > it took quite a while for me to figure out what happened, and one of
> > the things that tipped me off was a very strange sensation (not unlike
> > pain!) in the front of my thighs about 1/3 of the way up from my knee
> > toward the inside when the pedals were at about 2 o'clock. This
> > discomfort was worse with a greater upper body lean. Perhaps you have
> > a seat that is low, but didn't cause problems because you have not
> > been using a tuck recently?
>
> Seat is pretty damn high - I actually have it about 25mm higher when I've
> got tribars on the bike than without, presumably because of the rotated
> pelvis. But I'm going pretty much to the edge of the straight leg point.
> If I push it any higher my pelvis starts to rock.
>
> --
> [email protected] (Simon Brooke)http://www.jasmine.org.uk/~simon/
>
> ;; Life would be much easier if I had the source code.
I am not an authority by any means, but I think the 25mm seat height
change is extreme if it results in more than usual leg extension.
Unless you give yourself plenty of time to get used to it, and perhaps
even then it may be a bit much.
I don't think a seat height change by itself is desirable for a TT
setup. Rather, keep the thigh-torso angle the same, and rotate the
whole position forward about the BB. This means the saddle must
usually come up and forward, but the idea is to keep the leg extension
the same as you are used to, and the thigh-torso-pelvis attitude the
same, just all tilted forward to ge the back more parallel to the
ground to reduce frontal area.
It's hard to say with knowing about your fore-aft seat position, but
maybe 70mm diff between seat and bars is a bit much? Judging by the
pics we a roughly the same height and have our seats pretty far back,
and I have my bars 60mm lower than the saddle. (road bars) And when I
try to do my impression of a pro cyclist and rest my forearms on the
tops, my chest and aerobelly get in the way too much, and I feel much
to "folded-up" and it is not a maintainable position. But when I have
my bike set up for TT with the seat up and forward, the aerobar
armrests are 10-12 cm below the seat, and I feel much more open. This
is from the forward seat position:
http://arbitrary.org/pinarello.jpg
So my thoughts in short are the seat is too high (without compensating
forward placement), and you have too acute a torso-thigh angle all of
which you are unaccustomed to, and which is perhaps made worse by
being less than optimally limber. Try moving the seat forward to open
up your torso angle, and then adjsut bar height accordingly.
Joseph
. You might want to start with a class aimed at beginners, which should be gentler than more aggressive classes for more experienced practitioners.
