What are the different muscle groups I use when I bike vs when I run? As a followup question to that: What can I do in my bike fit to optimize using different muscle groups on the bike. (different than run muscles)
I have been making small adjustments on my new bike to find a comfortable position and I notice that I use different muscles even with seemingly small adjustments.
This is probably a vague question, but any input is appreciated.
What are the different muscle groups I use when I bike vs when I run? As a followup question to that: What can I do in my bike fit to optimize using different muscle groups on the bike. (different than run muscles)
I have been making small adjustments on my new bike to find a comfortable position and I notice that I use different muscles even with seemingly small adjustments.
This is probably a vague question, but any input is appreciated.
You use all the same muscles for both activities. The difference is simply one of degree and timing. The differences you are experieincing are probably simply slightly different timing or extent of contraction from a different fit.
Lefty…I have to agree and disagree with Frank. I agree in that you are using the same muscles because it is the same body and all the muscles are being used, but you are using them differently. While you bike you are mostly seated, while you run you are mostly standing with a slight lean forward. The spine and body are at a different angle. After longer time in the saddle your base of your spine gets the crap beat out of it (all the way down to the coccyx and the hips with the ischial tuberosities -bone you feel when you sit), and if you are in the aerobars, your neck is held more perpendicular to the ground–whole different muscle strength needed to hold that up (why else would the RAAMers have to build devices to hold the head up where as ultra runners just need massage).
When you cylcle it is more up and down at an angle, when you run there is more rotation and freedom added into the process. Sprung pelvis is more likely to happen (and often happens) in a cyclist versus a runner. Shin splints are more likely to happen in a runner not a cyclist.
From the obvious–I know I am leaving out some important ones, just going off of a burnt memory right now…
Psoas and Hip Flexors ares more shortened when you cycle, elongated when you run.
ITB gets a little bit of a break more with cycling than running (angle of force and power of glutes) —but a weakness in the anatomical chain will put more force on the ITB to work harder–especially if the counter adductors are weak on the bike.
Hamstrings go through a significantly further stretch when you cycle (especially when you are in the aerobars) both activities can tear the hamstring from the ischial tuberosity -enjoyable sensation, and recovery blows. Squats/lunges/stairclimbs will help build these (lower weight higher reps–not the heavy stuff) kind of simultating being on the bike and climbing a hill.
Quads get abused in both like the hams, but angle plays a huge factor. If you sit for a long time the quads aren’t getting stretched out enough at the origin (up at the top) and the attachment down under the knee (of the rectus femoris) can take a beating from being over powered. When you cycle you are stuck in a position, when you run the pounding is different and more open to injury (adjustments from rolls, ect).
Low back muscles are worked different because of bending in aerobars and of course the abs --those just better be strong no matter what. Quadratus lumborum fibers are more taxed from being in the aerobars and more rotational when running.
Calves and counter anterior tib and peroneus muscles just get abused. On the bike you are less likely to feel the ache/pain because you are on a machine, on the ground, you get a cramp, nothing to compensate and you are going down.
Neurological weaknesses/impingements can mess you up with being able to lift your foot which you will notice more on the run than the bike, because once again you are clipped in on the bike. On the run, not being able to get foot clearance you will be on your face before you know it.
Piriformis just gets beat up ugly on both. Sitting is worse on the piriformis but long term pounding can shut down the butt too.Don’t forget to strengthen your anterior tib (pumping the gas pedal motion) because often the calf muscles are so strong.
LATTS!!! Be sure these babies are strong. The muscle has fibers that attach to your sacrum and courses in front to the front of the arm–very powerful muscle needed. Usually more outstretched in the aerobars and the power is actually used when you run.
The easy answer is all around fitness 
adding in Pilates/Yoga to help with flexability. There is more, but those muscles are the keys to address.
WOW great stuff. Thx for taking the time to write all that down. Very interesting.
tom
Eileen, awesome info, do you have any specific excercises you do to strengthen your lats, especially outside of the gym.
I understand that you use all muscle groups when you run. But I have read and heard before that you use more quads when you bike, and more hamstrings when you run. Is this generalization totally unfounded, or is there some merit to this idea?
I completely forgot to mention sartorius and a bunch of others -sartorius is REALLY important! Balance is key, one side too strong setting yourself up for injury.
Make the latts stronger outside of the gym: Swimming with paddles and no legs, wide arm pushups/pullups (if you are weak like me can do wall pushups with holding halfway). If you want to get creative, wall handstand pushups, might I suggest having a partner hold your legs first couple of times (this is a very advanced move btw). Stretching is just as important as strength. To stretch the latts…arm up at an angle in a door jam and lean back, better if you go across the body–no way that makes sense in writing. You lose your flexability other muscles take over. I haven’t done a search on here…but I bet if you do there are probably plenty of articles addressing the different muscles and how to make them strong.
Ben depends on how you cycle. SO individual (which is why I agree with Frank-same body different angles of force). If you are primarily pushing down you are using all quads, if you pull up then hams really get used/abused (and of course a shift in the other muscles too).
In general you will use more quads for bike and hams for run. Set-up will dictate differently. I am sure you have heard the standby to spin before you get to the run, your body will thank you. I don’t spin, I grind, so ultimately I always come out of T2 and walk for a little then pick up the feet. I am NOT qualifying for Kona so the walking is a luxury I am allowed.
Which brings it full circle to Lefty…no clue how to tell you to make adjustments…I only work muscles and could probably figure it out by looking at someones position, the whole angles and degree of seat…man I am lost, that is why I pay Patrick at All3Sports–he puts my body on the bike how it belongs, I then do micro adjustments depending on how the body shifts hrs/days into a race. He is however, not currently responsible for the angle of my bars, he was horrified by them.
Bottom line…BALANCE between strength and flexability and knowing your body enough to alter how you move when something is injured, other muscles are willing to work if you allow them.
Make the latts stronger outside of the gym: … wide arm pushups/pullups (if you are weak like me can do wall pushups with holding halfway). If you want to get creative, wall handstand pushups, might I suggest having a partner hold your legs first couple of times (this is a very advanced move btw).
Pullups yes. But pushups?
wide arm pushups yes…close in arm…no. BUT the muscles of the pecs and coracobrachials and hopefully serratus anterior that gets worked with close arm are still needed as a triathlete.
Wide arm pushups squeeze when you are down and hold, you will feel it in the latts. If you don’t, you might not be wide enough. A move that simulates this in the gym is when you do latt pull downs at a 45 degree angle and hold, same sensation with wide arm pushups.
There are more efficient ways to work the latts, was just giving a quick example of something you can do at home.
wide arm pushups yes…close in arm…no. BUT the muscles of the pecs and coracobrachials and hopefully serratus anterior that gets worked with close arm are still needed as a triathlete.
Wide arm pushups squeeze when you are down and hold, you will feel it in the latts. If you don’t, you might not be wide enough. A move that simulates this in the gym is when you do latt pull downs at a 45 degree angle and hold, same sensation with wide arm pushups.
There are more efficient ways to work the latts, was just giving a quick example of something you can do at home.
Sure you’re not confusing transverse flexion with transverse extension?
Eileen,
Thank you! You have provided some great info, more than I hoped for, and I appreciate you taking the time to do so.
As for my question regarding body position and how that relays to different muscles, I suppose I am specifically referring to seat position as it relates to bottom bracket. If I am very forward (0 cm behind bottom bracket), I wonder if I am putting more strain on my quads. And maybe that doesn’t matter as long as I am comfortable?
So much to learn, so little brain power…
Thanks again!