Psoas and External Oblique Test:
Strengthening my weaker left psoas and external oblique really changed my game. It has improved my chronic left low back spasm (quadratus lumborum), it improved my movement mechanics, and it's even made it possible for me to do more advanced gymnastics movements.
The psoas is a powerful hip flexor and it also flexes your trunk. It is the base of the IT chain pyramid. The 2nd layer of the pyramid is your external obliques, low abs and transversus abdominals. If your left psoas is weak, then typically the left external oblique is also weak. And your left quadratus lumborum probably has a history of going into spasm. Yes, they are related. The QL is likely the antagonist of the psoas.
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