Whether you are physically active or relatively sedentary, you are vulnerable to overly tight quadriceps that create imbalanced muscle tension at the hips. If left unaddressed, too-tight quadriceps can effect posture and body mechanics, leading to back pain and making you predisposed to injuries of the hip and knees.
The quadriceps are a group of four muscles located at the front of your thigh, the rectus femoris, vastus lateralis, vastus medialis and sartorius. All four muscles influence movement at the knee. The rectus femoris, the largest of the four, crosses over the hip and works with the iliopsoas muscle, located in the pelvic floor, to produce hip flexion. When quadriceps muscles are overworked from athletic movements like jumping, running or weight training, they can become tight and inelastic and exert imbalanced tension at the joints. Sitting, and standing with the knees hyper-extended, can also produce tightness in the quadriceps. When tight quadriceps are accompanied by weak hamstrings, you have all the ingredients for an ACL injury.
Hip Flexor Tightness
Your skeleton is a kinetic chain, meaning that the position of a single joint will effect the position of its neighbor. When one joint is out of alignment, it can have a domino effect on other joints. According to strength coach and human movement expert Mark McGrath, when hip flexor muscles become too tight, they exert force on the pelvis, causing it to tilt forward, or anteriorly, throwing the hips out of alignment. An anterior pelvic tilt increases the lordotic curve of the low back, causing the vertebrae to become compressed, and hyperextending the knees. Tight hip flexors can lead to back and knee pain, and can promote inefficient movement during sports that can lead to injury.
Tight quadriceps can also lead to misalignment of the patella, or knee cap, causing a painful condition known as patello femoral pain syndrome, or PFPS. In addition to overuse during sports, the "Sports Injury Bulletin" points to aggravating factors such as prolonged sitting, squatting, stair climbing and running. PFPS is often caused by imbalanced muscle tension at the knee joint that forces the patella to be pulled "off-track." Typically, the rectus femoris and the vastus lateralis exert lateral forces on the knee cap that need to be offset by strengthening the vastus medialis and stretching the tighter muscles.
Daily stretching of the quadriceps is important to improve muscle balance at the hip and knee. A classic quadriceps stretch is done by standing erect next to a wall or chair. Using one arm to balance, grasp the ankle of the outside leg and pull the heel to your buttocks. Point your knee straight down to the floor and fully extend your hip. Hold your stretch for 30 to 60 seconds. It is also important to strengthen opposing muscles, especially the hamstrings and gluteal muscles. The Sports Injury Clinic notes that inadequately warming muscles up before engaging in sports can make tight quadriceps more vulnerable to injury.