Glossary · Physiology & Health
The early stage before overload becomes a fracture
Bone density describes the mineral content of bone and is an important factor in its mechanical load-bearing capacity. A stress reaction is the earliest stage of bone overload injury: a precursor to a stress fracture, in which imaging already shows swelling inside the bone (known as bone marrow edema) without a complete fracture line through the bone.
Bone overload is now understood as a continuum: from stress reaction to stress fracture to complete fracture if load is not adjusted. Studies in adolescent ballet dancers have found site-specific reductions in bone density, particularly in the arms, compared with age-matched controls – a finding of particular concern during a life stage when bone should still be accruing. A stress reaction initially often causes only vague, activity-related pain that eases with rest and is therefore easily dismissed as temporary overload. If load is not adjusted at this stage, a pronounced stress fracture can develop. Risk factors such as low energy availability, delayed puberty, and low body weight, as described in the context of relative energy deficiency in sport (RED-S), further increase the likelihood of reduced bone density.
Because a stress reaction is still reversible and usually resolves without consequence once load is adjusted, this early stage is a key focus of CENIT e.V.'s prevention work. Taking activity-related pain seriously early, rather than ignoring it, while also keeping bone health and energy supply in view, can often prevent progression to a true fracture.
This entry serves to convey knowledge in a prevention context and is not a substitute for medical diagnosis or advice. For persistent activity-related pain, we recommend consulting professionals experienced in dance medicine – for example through ta.med's referral network or the resources provided by IADMS.
Hoenig T, Hollander K, Popp KL et al. International Delphi consensus on bone stress injuries in athletes. Br J Sports Med. 2025;59(2):78–90. doi.org/10.1136/bjsports-2024-108616 · Wewege MA, Ward RE. Bone mineral density in pre-professional female ballet dancers: A systematic review and meta-analysis. J Sci Med Sport. 2018;21(9):878–884. doi.org/10.1016/j.jsams.2018.02.006
