Any NBA fan reading this will probably best understand the hamstring in relation to the following observation. The hamstring is like Derrick Rose; it’s always the one getting injured. If that’s relatable enough for you, though, then suffice it to say that the hamstring is like the butler in any classic who-done-it. It’s the most common muscle to be fraught with injuries in sports, and it’s the muscle that plagues the careers of the most athletes across a wide variety of sports. We often refer to it as a muscle, but this is technically a misnomer; in reality, the hamstring is comprised of four separate muscles grouped together in the back of the thigh. It’s most prominent when you stretch to touch your toes should you also run your hand up the back of your leg, and if there’s any group of muscles most adamant about enforcing the rule that you stretch before doing anything, it’s the hamstring.
The true hamstring muscles account for only three of the four, but they are considered “true hamstring” muscles because they each actually cross the knee joint as well as the hip. These are the semimembranosis, the semitendinosis, and the long head of the bicep femoris. The ischial tuberosity, however, is a bone at the base of the pelvis, and it cornices all three of these muscles whereas the tibia and fibula are bones below the knee to which the tendons of the aforementioned muscles also attach. These muscles essentially stretch from the ischial tuberosity to these two bones below the knee to form the bulk of the hamstring. The short head of the bicep femoris only crosses the knee and is, therefore, often times not considered to be a true hamstring muscle; however, it is, indeed, the fourth muscle.
The injuries that plague the hamstring and make it such a problem muscle for so many people stem from a myriad of training errors and misconceptions about how to use it in activities as basic as running and cycling. The hamstring gets injured in two most common ways, and these constitute just one of the hamstring pitfalls. The issue with these types of basic activities is straining the hamstring, and it typically occurs on the ischial tuberosity at the tendinous insertion, which is on the pelvis. This type of hamstring injury frequents marathon runners but also triathletes. The complaint with which they usually consult a physician of any kind in this scenario is of a lower-buttock pain of increasing severity that seems to have a reactionary relationship with the foot of the hurt leg hitting the ground whether running or walking. Needless to say, it can make walking a cumbersome and perhaps laborious process.
The other main problem for young athletes is typically the result of abrupt movements like a sudden leap or kick or even an explosive sprint. These actions strain the hamstring differently such that the back of the thigh stretches a pain up the middle. This can also make it painful to walk, but in addition, it can swell and, in some cases, bruise as days go by after the initial strain occurs. This is usually the kind of hamstring injury that also that manifests in a way that induces an ostensible limp to such an extent that one may be given crutches to take weight off the leg and allow it to heal due to the process of walking actually being quite a hindrance to the healing process.
Chiropractic tells us that running has two gait phases that are repeated throughout the process, and they are the stance phase and the swing phase. The former is all about the foot striking the ground, transitioning through a brief “midstance” in which that foot is flat-footed, and then what they call a “toe-off” wherein the same foot shoves the body forward with the toes and the ball of the foot. The swing phase, on the other hand, has to do with the follow-through, what they refer to as hip flexion, and then the leg descent. The two phases toggle each other simultaneously on either side such that immediately following foot-strike on the left is follow-through on the right, swinging the right leg forward so to speak.
The point of it all is that there is, believe it or not, a correct way to run to protect yourself from injury. They refer to the elongation of muscle fibers, which occurs to decelerate a motion during the gait, as an eccentric contraction. It is when the eccentric load becomes more than the strength of these muscle fibers can bear that the hamstring tears. This is what constitutes the infamous straining of the hamstring.