Below is a very good YouTube video on hip thruster exercise which instructs about the importance of pelvic tilting during the exercise to maximise the contraction of gluteal muscles.
Here lies the crux of why hip thruster can make your back stiffer and more painful if low back pain is a recurring issue for you.
When you hip thrust with insufficient posterior pelvic tilt, gluteal contraction is reduced and not maximised. Therefore, there is more load on spinal extensors. This is because when you are hip thrusting, you are also extending your trunk relative to your legs (see below).
Your pelvis may already be anteriorly tilted most of the time when standing, which make you vulnerable to tense up your low back region’s spinal extensors.
It will likely become tenser when you hip thrust, resulting in cramping pain.
Gluteal muscles are bulky while spinal extensors are a bunch of lanky muscles. Those muscles on your bum will go to waste if you don’t utilise them.
When one become over-reliant on spinal extensor, they may develop a lordosis or swayback posture.
These postures are associated with tense lumbar spinal extensor and low back pain.
This posture is akin to a single-use space rocket… It can only thrust up/forward but not return safely.
Our pelvis needs to be like the rocket boosters that Elon Musk’s company Space X has successfully trialled.
The launched rocket boosters landed back intact so that they can be reused and make space travel more cost-effective. Watch the video below to see it in action.
If you regularly experience stiff or painful lower back that is recurring, you need to learn to pelvic tilt or else avoid the hip thruster exercise and practice gluteus exercises with minimal spinal extension. If you are doing a squat or lunge with weights and your back muscles are seizing, it is a sign that you need to recondition your back muscles.
This is not rocket science but consider seeking professional guidance if you need a kickstart.
The article is written by Dan Chan (PhD, AEP, ESSAM) and it is his perspective as an exercise physiologist. Consult the appropriate exercise professional if you are uncertain in performing any movement or exercise mentioned.