The Return of the Leg Curl
When it comes to functional training rarely do people have any kind of leg curl come to mind. I’ll be the first to admit that I fell into the camp of rarely ever doing active knee flexion exercises. Instead, I would squat, hinge, lunge, bridge, etc. and let my hamstrings get worked from that.
While that’s all fine and dandy, its tends to neglect the hamstrings to a capacity. In particular, one of your hamstrings – the short head of the biceps femoris – gets greatly ignored by this type of training. You see our hamstring group is composed of 3 muscles - the semitendinosus, semimembranosus, and biceps femoris. The biceps femoris however has two heads, much like the biceps in your arm, and one of them is unique. You see the semitendinosus, semimembranosus, and long head of the biceps femoris all cross both the hip joint and knee joint. This allows them to be worked in movements like hip extension (much of what I listed above). Unfortunately for the short head of the biceps femoris, it is only a knee flexor – not crossing the hip joint.
Why does this matter? I work with a lot of athletes, in particular strength athletes – weightlifters and powerlifts specifically – and many of them complain of having knee aches and pains. One thing I noticed was when testing these athletes, their hip and knee extension strength is through the roof, but their knee flexion strength was very limited.
I would recommend a number of changes to their training program (not being discussed in this article), one being the addition of more knee flexion strengthening work. These seemed to make a big change for a lot of the athletes who dealt with knee issues and since my implementation of them in more athletes programs I’ve dealt with less complaints from athletes having knee issues.
Knee flexion exercises come in a variety of forms and today I’ll share a few of my favorites:
Ball leg curl – supine
In this variation we are focusing on knee flexion without hip extension, allowing the hips to flex as we go through knee flexion. You can also keep the hips extended throughout (more challenging) which will increase the demand on the glutes.
Laying leg curl
This is an exercise that’s great at the tail end of a workout to pump out some isolated work on the hamstrings. Here we have the hips passively extended, putting full emphasis on knee flexion. The limitation to this exercise is once you get to 90* of knee flexion, the exercise is not challenging due to weight falling into flexion instead of having to be pulled into flexion. Due to this, I usually add in an incline version with it, where we do the flat first, then go into the incline to finish things off.
Back raise into leg curl
In this exercise we challenge the individual to maintain hip extension while performing the leg curl motion. This can be progressed over time, starting by adding weight and then eventually moving to something like the Nordic leg curl.
Consider adding some of these into your training sessions and get those hammies strong!
Move well, lift heavy, stay health,
The Strength Therapist