The ones that hurt the most when you do a lot of uphill running.
The muscles that hurt the most might be an indication of weakness not necessarily the ones most used.
What does most used even mean? In relation to what?
If training to 100% capacity running on flat ground yields totally balanced physical adaptations, then no muscle is weak in relation to the others for their primary function (running on flat ground). If running uphill yields sore muscles, it's because those muscles are receiving a new stimulus. This may be good if there is a new primary function (running uphill), but may cause an imbalance to running on flat ground.
I don't know what the answer is to the OP. I never have sore glutes/hamstrings after hill sprints, long hill reps, or even mountain running. I'll get sore quads from downhill running, or after a marathon, and I get sore hamstrings from sprinting on flat ground.
In college we sometimes had all our runners (mid-distance and true distance guys) workout together (or at least have a bunch of overlapping work. This was particularly true during cross country.
Interestingly, us middle distance guys seemed to be stronger on the hills than the distance guys. These were highly trained guys in all cases, and there were exceptions, but something about the musculature of mid distance types did better on the hills.
Running uphill should target more muscles on the backside of your body, the glutes, hamstrings and calves as hip extension should be driving you up. This will only be true of people who are biomechanically sound though as muscle dominance is at play. A lot of people will rely on the hip flexors/quads too much so you will get people who will tell you the quads are the most important because that is the sensation they feel when running up hill when in reality, if they had strong glutes and hamstrings, they wouldn't feel that way and would be more efficient.
Downhill hits the quads the hardest because of the eccentric contractions and loading from almost falling down a hill and having a more limited range of hip extension out the backside. If you tried to run at the same angle of the ground on a steep hill, your balance would be comprised. Just like you lean into an uphill slightly, you lean back slightly on a downhill.
When you walk up a flight of stairs, taking two at a time, where do you feel the strain most? It's your quads.
Running uphill is a similar action, which is more of a concentric contraction of the quadriceps compared to running on the flat (where you have an eccentric load when bracing for ground contact). As a result, uphill running more closely resembles the action of a step-up or single leg squat, which are exercises that specifically target the quads.
However, you likely feel sore in your hamstrings because of the elongated position your hamstring will be in when running fast uphill (people lean forward slightly). Due to the fact that muscles tend to be weakest when at full stretch, you're much more likely to experience DOMS under these circumstances.
Running uphill should target more muscles on the backside of your body, the glutes, hamstrings and calves as hip extension should be driving you up. This will only be true of people who are biomechanically sound though as muscle dominance is at play. A lot of people will rely on the hip flexors/quads too much so you will get people who will tell you the quads are the most important because that is the sensation they feel when running up hill when in reality, if they had strong glutes and hamstrings, they wouldn't feel that way and would be more efficient.
Downhill hits the quads the hardest because of the eccentric contractions and loading from almost falling down a hill and having a more limited range of hip extension out the backside. If you tried to run at the same angle of the ground on a steep hill, your balance would be comprised. Just like you lean into an uphill slightly, you lean back slightly on a downhill.
When you walk up a flight of stairs, taking two at a time, where do you feel the strain most? It's your quads.
Running uphill is a similar action, which is more of a concentric contraction of the quadriceps compared to running on the flat (where you have an eccentric load when bracing for ground contact). As a result, uphill running more closely resembles the action of a step-up or single leg squat, which are exercises that specifically target the quads.
However, you likely feel sore in your hamstrings because of the elongated position your hamstring will be in when running fast uphill (people lean forward slightly). Due to the fact that muscles tend to be weakest when at full stretch, you're much more likely to experience DOMS under these circumstances.
Good post. Also no matter how fit you are, walking up stairs seems to blow you up a bit. It’s because you’re using some type 2 quad fibers which don’t have much aerobic capacity.