I’m fine for the first hour. Then…


A phrase that I hear a lot is “I’m fine for the first hour.  Then I start to get…” followed by some symptom that kicks in at around that point.

You might be familiar with some of them:

  • sore hands, 
  • tired arms,
  • neck ache,
  • shoulder ache,
  • back ache,
  • saddle soreness…

Typically these symptoms spoil the rest of the ride.  

If there’s quite a lot of the ‘rest of the ride’ they can spoil the rest of the day and sometimes they persist beyond.

So what is it that happens after ‘about an hour’?  Why is everything OK until then?

It normally takes about this long for you to run low on glycogen and for your muscles to fatigue.   

Obviously muscles can keep going for much longer than this – but it only if they’re doing what they’re good at.  Phasic muscles (mobilisers) are good at keeping you moving and postural muscles (stabilisers) are good at holding you still.   However stabilisers are not good at holding you still in unusual positions, which means that you tend to use your mobilisers to hold you still instead.  A double whammy.

  • think about the Wall Sit exercise where you ‘sit’ against a wall with no chair,   supporting yourself with your legs bent at 90 degrees.  Quadriceps don’t like being postural muscles!
  • think about the Plank exercise.  Hell after just a few seconds if you use your (phasic) rectus abdominis muscles, easy for a few minutes if you use your (stabiliser) core muscles, but still not something that you can do for hours like sitting or standing upright, which require you to carry exactly the same weight, but which only require your core stabilisers to hold a neutral posture.

Riding a bike isn’t as extreme as the wall sit or the plank, but can easily have elements of both.

If, for instance, your position on the bike means that the act of pedalling causes you to slide forwards on the saddle, you will slide off the front of the saddle unless you push yourself back with an equal amount of force. 

Isaac Newton ‘discovered’ a long time ago that:

  • a body continues in its state of motion until acted on by an external force
  • for every action there is an equal and opposite reaction

So you prevent yourself sliding off the saddle by pushing on the handlebars, and the force must go through your arms and your back.   If your elbows are bent you have to use your triceps (phasic muscles) to stop them bending more, and if your back is bent (a non-neutral position) you have to use the erector spinae muscles in your back (postural) to stop it bending more, however you also have to use the muscles your shoulders (phasic) stop them from collapsing – effectively you’re holding a weight at arms length in front of you.  It’s not quite the car battery of  The World’s Strongest Man…

Screenshot 2019-07-09 at 10.16.11

…but try holding any battery, even a watch battery, out there for an hour.  

After pushing you back onto the saddle for an hour those muscles in your arms, your shoulders and your back get tired.   

A good bike set up doesn’t put these muscles under any stress.  If the act of pedalling doesn’t move you forward on the saddle there’s no need for your arms and back to do any work at all, other than support a little of the weight of your upper body – which is more akin to standing up or sitting at a table.

What about the soreness in your hands and your nether regions?  Why does that seem to get worse after an hour too?  For the same reason.  When the big muscles in your arms and legs are full of glycogen they hold you up.  Pressing hard on the pedals lifts you off the saddle.  Once the energy has gone you sit much more heavily.  If your setup is bad your weight is on your perineum (your ‘taint), and your hands.  Unlike muscles, which can respond positively to overload over time, nerves don’t, and the effects of compression in the hands and perineum can last well beyond the end of the ride.

Again, if your set up is good your weight is on your sit bones which will quite happily take it for for hours with no lasting ill effects.

Bike set up isn’t just about angles and aerodynamics.  If you’re going to be riding for more than an hour it matters where your bodyweight is and how it is supported.  Fitting systems that ignore this, by simplifying real human beings to stick figures, statistics and heuristics, miss this key aspect completely.  They also don’t know anything about handling and braking.

4 thoughts on “I’m fine for the first hour. Then…

  1. Jacek Ratajczyk May 9, 2023 — 3:32 am

    Hello Tim
    I found your Blog by accident. I had two bike fit sessions in past – but was not happy. Because of situation, I had to change my bike I was fit on. Changed to endurance geometry – canyon endurace. First I was surprise how so small size with short TT, short stem could be for my 169cm height (it has 25mm setback seat post). I tried to replicate my previous position – moved seat forward, almost slammed stem, tried 5 different saddles and I couldn’t find myself. I’m rather athletic built with some belly – 45yo, 3 shift work pattern, mostly in front of desktop. I ride about 10k km for year since 4 years. After redfing your Blog I realised that maybe it’s not the way with my bike, maybe I should try to move my saddle back, raise stem, move cleats all the way back and start from the beginning ? I bought also SMP saddle – because was curious about it – some say it’s very comfortable once you find sweet spot. I was wondering if you have some knowledge to share to start with that saddle – setup in the rail center and levelled from two highest point or with some “slope” ? It has very strange shape, just centered it moves my butt to be more rerward regard to standard saddle. Hope it’s good direction to be comfortable. I don’t race, I need bike ride to get some fresh air and keep shape. Kind regards.

    1. Hi Jacek, thanks for reading and commenting. The ‘fit’ is the positions of the saddle and the handlebars relative to the bottom bracket so, depending on the geometry of the frame, you might find that you want the saddle at the front or the back of the rails, and the stem flipped up with spacers or flipped down and slammed. If the bike allows, it’s easy enough to swap the stem for a longer or a shorter one, and the seat post for one with more or less setback. It’s not always easy to experiment, however :-(. SMP make saddles with longer rails than most other manufacturers, so their saddles allow a good range of adjustment. This is particularly handy if you can’t swap the seat post. Their range of saddles is huge and very diverse (which doesn’t necessarily make it easy to find a suitable one, though they have an on-line selection tool). I’m afraid I can’t give a more personal answer.

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