Why does it tighten down so much when overworking as a spinal stabilizer? Remember that length tension relationship we talked about? Well, if the psoas is tight, it can compress the spine easier, thus providing spinal stability. Plus, it has to work a lot to stabilize the spine. When you don’t have correct functioning of the diaphragm and abdominals, the psoas holds a great deal of tension to do the job. This tightness or tension makes it a very ineffective hip flexor.
You can strain or tear one or more of your hip flexors when you make sudden movements such as changing directions while running or kicking. Sports and athletic activities where this is likely to occur include running, football, soccer, martial arts, dancing, and hockey. In everyday life, you can strain a hip flexor when you slip and fall, for example.