THE HAMSTRINGS

(The Leg Bicep) The Hamstring Muscles (Biceps Femoris)

The muscle that flexes your leg every time you walk, run or jump for joy. An intensely active muscle who does a dance with others in the leg, keeping you from falling forward on your face (if you've ever leaned forward too far and "caught" yourself, then thank your B.F. for keeping you from kissing the pavement.)

The B.F. originates on the ischial tuberosity (the bottom of the pelvis that you sit on). It also has a second origin (like his cousin in your arm) the back of the femur (leg bone). It inserts into the top of the fibula (the "outer" of the two lower leg bones) and the lateral (outside) part of the tibia. In short, it flexes the knee. The knee was designed for ONLY this (despite our misguided desires), flexion.

While running the hamstrings slow down the leg at the end of its forward swing and prevents the trunk from flexing at the hip joint (falling on your face). Here's the challenge. His cousin on the other side of town (the Quadriceps boys) are far stronger from birth (3:2 ratio). By the time we get to adulthood, we find ourselves doing far more exercises for the quads than hams, and that imbalance turns into 2:1. Since B.F. does most of the work (he initiates the movement of flexion, with his little brothers the semimembrinosus and semitendinosus coming in to help AFTER B.F. starts). So B.F. is very, very vulnerable to tearing during the first 15 degrees (and last) of an exercise like the leg extension. He's far away from your center of gravity and is going to hurt something bad, unless you "spot" him (have your training partner assist the first and last 15 degrees). This can prevent unnecessary strain and injury. Also, since he works all day keeping you from falling, he deserves LOTS of careful stretching.

Hamstrings tend to get "tight" from working a lot, but also sitting all day at a desk can take its toll. Give him a good, careful stretch. And be sure to keep him strong so his bigger cousin the Quads don't overwhelm him. Train him carefully, and watch the first and last 15 degrees most of all. And one exercise note; seated leg curls, although not "harmful" are the least effective exercise because...you're SITTING on the MUSCLE your supposed to be working!!! Imagine a trainer asking you to do curls for your arm bicep, while he jams his fist into the muscle at the same time! Sitting on the B.F. causes the nervous system to "shut down" motor activity to the muscle (to keep it from being damaged). This is a great muscle who serves us well every day - literally standing by us in the most important way.