Right, so you have taken a video of yourself running and found that indeed you do twist at the shoulders, or your arms come across the midline, when you run. Remember this will be worse when you complete a longer run and fatigue plays its part.
What do you do? Well firstly assess your pec minor and make sure you are addressing the right restriction. If this is tight then get to work on some release work, however if it is normal then I would suggest you look to get a professional opinion to understand where your specific shoulder restriction is coming from.
The get rolling, and roll before your run for a short period to help you maintain more control over your technique when out running.
Regular work is required to maintain the improvement and if you sit a desk then make sure this becomes part of your weekly training routine.
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