Anatomy Review: Hamstrings

by David Lauterstein, LMT

Origin: Ischial tuberosity; medial 1/3 linea aspera (short head of biceps femoris) Insertion: Semimembranosus: medial condyle of tibia, Semitendonosus: proximal, antero-medial aspect of tibia, Biceps Femoris: head of fibula Action: Extention of hip, flexion of knee, medial or lateral rotation of lower leg, (Excessive: Hyperextended knee) Antagonist: Quadriceps

These interesting muscles (which were no doubt named by a very primitive culture which used to make strings out of ham!) illustrate nicely the distinction between postural and structural kinesiology. AS far as I know, “Structural” kinesiology is what you find in most books. It basically describes what happens to the movable body part on which a given muscle inserts when that muscle contracts. For example, when you contract the pectoralis major, you wack somebody upside the head if they’re unfortunate enough to be standing in front of you. Contract the anterior deltoid and biceps and you hit yourself in the head unless you duck. Pretty straightforward, eh?

But what if the body part on which a muscle inserts is stabilized? For instance if you lift one leg and contract the hamstrings, the knees will bend and the hip, extend. But if you keep both feet on the floor and contract the hamstrings, the knees will lock back and the pelvis shift forward. Pretty neat, eh? This is because if the hip is to extend, i.e. thighs move behind the pelvis, while the feet remain on the floor, the knees have to lock back. Stand up and try it…So, from the postural kinesiological standpoint, the hamstrings can have the exact opposite action, namely knee hyperextention, from their structural kinesiological action, knee flexion. This grasp of the impact of muscle contraction on posture is an essential part of structural approaches to the body.

So what if a person locks their knees? It is a tension-producing, rigid and potentially dangerous way of standing. It’s again as if we would like to ignore our lower half, just lock it into place and go about business. But anytime we disown a part of ourselves, we diminish ourselves by that much. Would you walk in goose-steps or dance or fight that way? It’s interesting, isn’t it, how even rigidity or Nazi culture didn’t escape the legacy of four-leggedness. Remember the straight-armed salute? It’s exactly the same as their goose-step, only hyperextending the hinge joint of the elbow in addition to the knee. It’s quite an image, isn’t it – hateful soldiers, hell-bent, limbs rigid in furious denial of their own animality.

Locking the knees will compress the knee and the hip. By immobilizing the legs, it will reduce circulation and give rise to congestion and undernourishment of tissues. Locked knees also leave us more susceptible to injury as we cannot then well absorb any sudden impact or motion.

So from the standpoint of both spirit and structure, I would say it makes sense not to lock the knees! Therefore, hamstring lengthening is the order of the day. The hamstrings are broad and strong. Often they can absorb a fair amount of pressure. Feel free to use forearm, fist or flat of knuckle wherever you need to. Usually, the musculo-tendinous junction of the biceps femoris is particularly tight because this muscle is the only one which pulls up on the fibula while eight muscles pull down. Additionally, it is the only lateral rotator of the lower leg.

Often times, lengthening the hamstrings will not remedy knee hyperextension. It is a habit and at least initially, most people have consciously let go of this habit again and again.

Help by explaining that unlocking the knees doesn’t mean squatting: it means just unlocking a little, leaving a bit of play in the knee joint that one can come to enjoy.

After all, as Elvis Presley, our rock and roll mentor, implied – you can’t really love without getting a little weak in the knees.