Jynx

1. Anyone have the animation that was a leg on a crank doing the pedal stroke listing each muscle that was used in each part of the stroke?

2. Also on a side note, I always see it mentioned that people who ride A LOT develop like 3 out of 4 of the leg muscles and one of them doesnt get "worked out" which leads to a tightness or something like that. Anyone know what muscle is the one that gets left out on a bike?

Thanks

Machka 

2. Yes, cycling develops 3 of the 4 quad muscles (you've got a number of other muscles in your leg too). The muscle in question is the Vastus Medialis ... the quad muscle on the inside of the leg.

That muscle doesn't become tight, what happens is that the knee doesn't track correctly, which can lead to knee problems, particularly patello-femoral syndrome.

https://www.ultracycling.com/training/centuries3.html

Enthalpic

Enjoy

Enthalpic

Good point, one thing to add is that standing cycling can work this muscle. It is only used in the final few degrees of leg extension.

Jynx

Man you both are good. Thanks!

Garfield Cat

I find that a rider can "trick out" the muscles by doing what you say, standing. Other things a rider can do is to work the "recovery phase" of that diagram. By concentrating on that part, a rider can develop that part of the pedal stroke and use it under certain riding situations.

Giro

One study of ten different muscles used (compared upright vs. recumbent, but recumbent was not very recumbent): Functional roles of the leg muscles when pedaling in the recumbent versus the upright position. LINK
Sample graph for the rectus femoris (RF) from the study: LINK

For a fairly recent review of cycling science in general see:
The science of cycling: physiology and training - part 1. LINK
The science of cycling: factors affecting performance - part 2. LINK

The "Related Links" feature of PubMed should retrieve additional relevant references.

Giro

From Faria, Parker & Faria. The Science of Cycling: Factors Affecting Performance – Part 2. Sports Med 2005; 35 (4): 313-337.
"In summary, shifting from a seated to standing posture while cycling changes the magnitude and activity of several key muscle groups whose function is to provide maximum force to the pedals. When standing, the magnitude and activity of the gluteus maximus is higher. Activation of the vastus lateralis is earlier and its duration of activity is longer. Likewise, the rectus femoris increases its duration of activity and the soleus increases ankle plantar flexion. However, similar activity is observed for the biceps femoris, gastrocnemius and tibialis anterior for the saddle and standing position. Nonetheless, in well trained cyclists and within the limitations of current investigations, economy and gross-external efficiency in seated uphill cycling are not different than in uphill standing cycling. Further research is needed in order to expand our knowledge ..."