English to Polish Medical Sports / Fitness / Recreation

Widzę z internetu, że inni też maja problem z tym terminem. Spotkałam się z "głąboka partią mieśni" oraz z "mięśniami środka" w tłumaczeniu "core muscles".
Kontekst: sprawność fizyczna po wyprowadzeniu stomii:
Build up core stability
...These muscles have many functions, important in core stability...
...work on your core stability and abdominal muscles...
All three (joga, tai chi, pilates) involve controlling movement, which is also referred to as core stability, and people with good core stability move better, look better, have stronger backs ...