Question From Maureen
Can you shed light on why some runners overuse Rectus Femoris rather than Psoas, and how they may be re-educated?
Response From Coach James Dunne
Thanks for the great question Maureen. This is something I’ve been considering a lot over the past few months.
N.B. I’d be interested in the opinion of others in the Sports Injury industry… The following are simply my thoughts and simple rationalisations of what I see coaching on a daily basis.
If anybody has any research to back these points up, or prove me wrong – I’d gladly welcome the input either way!
If you consider the following factors in combination, I feel it could be fairly easy to explain why distance runners have a tendency become so overactive through Rec.Fem.
Different Hip Flexors for Different Ranges
In terms of the muscles making up the hip flexor complex, and their individual lever-arms / muscle actions; Iliopsoas really comes into its own in producing inner range hip flexion (knee up near hip height, and above). In this inner range, Iliopsoas is far more mechanically effective in flexing the hip than Rec.Fem. could ever be.
Conversely, when the hip is in a mid and outer range flexed position, Rec.Fem. has a far more effective lever-arm to create hip flexion, than that of Iliopsoas. The body tends to favour the path of least resistance, thus Rec.Fem. picks up most of the load in flexing the hip through outer and mid range.
Running Pace Dictates Range of Hip Flexion Used
Most of us recreational athletes don’t run much running (if at all) at paces requiring inner range (~90o) hip flexion as part of our running gait. Put simply, we don’t run the majority of our milage with our knees coming up near hip height. Most of us aren’t running at paces requiring that kind of stride length.
Instead, during swing phase of most running paces below a sprint, most of us work the hip through from outer to mid-range of flexion, and back again during stance phase.
This whole cycle keeps the hip in the sagittal range-arc that favours Rec.Fem. as the go-to hip flexing muscle, due to its mechanical lever arm. That’s not to say that Iliopsoas isn’t involved – of course it is, partially assisting in hip flexion, but also in its role as a lumbro-pelvic stabiliser.
Another Long Lever-Arm
Consider also the lever arm not of the relatively small Tensor Fascia Lata (TFL) muscle in isolation, but of TFL and the ITB in combination. The ITB acts kind of like a super-long tendon for TFL, providing it with a massive lever arm in comparison to its muscular size. Perhaps this enables it to assist in hip flexion (as well as abduction) due to it’s anterior positioning relative to the axis of the hip joint.
When Rec.Fem. fatigues, I often see TFL kicking in more in an attempt to assist hip flexion – the problem is that it simply isn’t mechanically efficient in doing this, so it just becomes overactive and tight – directly affecting tension in the ITB.
Rehab & Re-education
The way I see it, there are a number of rehab and gait re-education factors to be considered here.
1) Strengthening Iliopsoas
As alluded to above, if a runner does very little training in a range of hip flexion that really challenges Iliposoas, chances are it will be significantly weak in comparison to Rec.Fem., creating an imbalance. To improve muscle balance, it will almost certainly benefit the athlete to work on specific Iliposoas strengthening as part of a consolidated rehab plan. This is so often omitted.
Article on Iliopsoas Strengthening to follow soon!
2) Gait Re-education
I often find that increasing hamstring activation in early swing phase, flexing the knee slightly more through swing to the point of recovery (heel under the body), helps to reduce the torque of the swing leg acting on the hip in the sagittal plane. This reduces the effort required from Rec.Fem. to flex the hip.
This often has to come with a regime of hip flexor and quad stretching, to accommodate the increased knee flexion in swing phase.
I find this means of taking the load off the hip flexors through shortening the lever-arm of the swinging limb (essentially a third class lever) particularly effective.
As I said… simply some thoughts I’ve been having recently. Comments both for and against are very welcome!
I will definitely be looking forward to the future article on Iliopsoas Strengthening. My TFL is always so sore when rolling and balling!
A thought. With the common finding of poor abdominal strength, illiopsoas changes function from hip flexor to lumbar stabilizer, demanding more hip flexor activity from rectus femoris. The runners may have less knee raise, with limited knee flexion during the swing phase, compounding the load on rectus femoris.
Completely agree with these sentiments. The quad dominance in the general population coupled with the lumbar biased inhibition of Iliopsoas leads to so many runners reliant on Rectus Femoris as their primary hip flexor. Most recreational runners do not achieve high levels of hip flexion as you say, but sprint intervals are a nice way to utilise inner range hip flexion to remind the brain what it feels like to use Iliopsoas over Rectus Femoris.
Quire rufhtly, TFL is a prime contributor to hip flexion, as is Adductor Longus, both of which are a problem as they cause adverse femoral motion in the sagital plane, contributor to so many running related injuries. A well functioning Iliopsoas csn help you avoid this movement pattern that plagues so many runners.
Runners should focus on promoting true hip extension with dynamic mobility exercises whilst controlling pelvic rotation, alongside strengthening Iliopsoas, which can prove tricky. It is important to remember that Iliopsoas is the only hip flexor with a lever arm capable of producing hip Flexion beyond 90 degrees, hence the only way to isolate it independent of Rectus Femoris to to reach inner range hip flexion.
Totally agree with your thoughts James. From a personal point of view, I find this an interesting area and a difficult balance to strike when considering running efficiency for ultras.
Well written explanation. I agree with what you have said and believe regardless of your preferred running distance all runners should incorporate hills and sprints into their program. I’d add poor motor control of the posterior fibers of the gluteus medius which is extremely common especially in those who are desk bound and simply can’t position the pelvis in neutral when upright. In this case the TFL/ITB is at a mechanical advantage and works overtime not just to facilitate hip flexion but to stabilise against hip ADDuction in single leg stance. This is commonly referred to as synergistic overload ie when a synergistic muscle has to work overtime to compensate for a weak agonist. In this case the TFL is a synergist in hip flexion and ABduction and has to work overtime due to postural and dysfunctional movement that leaves the Agonists of hip flexion and abduction weak.
But that’s just a localised assessment of what’s occuring. Most often there’s a tension imbalance between the “core” (rubbish term but I’ll use it for brevity) and the hips as touched on by another reader
I’m loving your blog, wish I came across it earlier
Simple rec fem is trying to do the hip flexion job of the psoas as well as doing the job of knee flexion, or it is doing the hip flexion job and then the tibialis and calf are trying to do the job of the quad and hamstrings, or the foot is driving all the actions, but then the same thing can happen with the arm driving hip flexion, all which can have an effect on the rec fem.
Simple activations get the muscles to starting doing their own jobs instantly, so instead of the muscles being drawn into the centre imploding on themselves they, when activated, now fire with explosive energy and ease as you are no longer fighting with the muscle going but I do several jobs instead of that one I am designed to do! Easily shown by muscle tests on the muscles to the before and after patterns.
I wondered if you ever did create an article / film on Iliopsoas Strengthening…. hip flexors constantly tight particularly on one side…..I need to be more flexible across the front of the hip ie TFL and re fem…..suggestions for exercises / stretching / rolling in this area are welcome. Thanks!