When sitting for longer periods, the hips are continuously kept in a bent position. Due to these prolonged times of non-movement, the muscles and tendons shrink , so it is not surprising that hip flexor tightness is a very common complaint. Tight hip flexors can change the tilt of your pelvis, putting stress on the lower back and contribute to low back pain. This will eventually have an impact on your posture and effect your whole body.  Stretching the hip flexors can provide relief. Preventative or regular stretching of the iliopsoas must be part of your daily routine and breaks. Different muscles are causing the tilting of the hips, including one of the quadriceps muscles and muscles in the groin area. An extended stretching program for the hip flexors should take the position of the knee and the orientation of the hip into account.

First: the hip flexors

The hip flexors are a group of muscles that flex the hip joint, or to make if more visible:they preserve the connection and stability between the thigh and torso. The psoas, which originates from the lumbar spine, and the iliacus, which starts from the inside of the pelvis, are attached to the upper femur. The combination of these two forms the iliopsoas, the most powerful hip flexor. Other muscles of the upper leg, such as Sartorius and tensor fasciae latae (related to Gluteus Maximus), also active as hip flexors and last but not least the rectus femoris, one of the quadriceps muscles.

Second: quadriceps

Located on the front of the thigh, the quadriceps or quad, the muscle is named after the four muscles strands it is composed of.  Three of the muscles are attached to the thigh or femur. The fourth (the rectus femoris) -originates from the front of the pelvis above the hip joint. All four muscles are on the other end connected through a common tendon on the kneecap and the upper tibia.  They extend the knee joint. Because the rectus femoris also crosses the hip joint, it works as a hip flexor at the same time.