RED-S Research: Bones and Ballet

BJSM Blog 26/8/2019

Dr Nicky Keay

BJSMThere are many areas of RED-S (relative energy deficiency in sport) that are currently being researched. Whilst there is animated discussion about scientific evidence for energy availability thresholds in men and women, in the clinical setting what are the most effective ways to identify and support these athletes and dancers at risk of the health and performance consequences of RED-S?

Bone stress injuries, including stress fractures and other complications of suboptimal bone heath such as compression fractures are some of the most clinically significant sequalae of low energy availability described in the RED-S (relative energy deficiency in sport) clinical model[i]. Suboptimal bone health with associated recurrent stress fractures can be career ending for athletes and dancers.

Therefore early identification of those with suboptimal bone health is crucial. In terms of identifying athletes/dancers at risk of developing bone health consequences due to RED-S, a sport specific questionnaire in male cyclists has been demonstrated to be effective[ii]. The purpose of identifying those at risk of suboptimal bone health is in order to put in place interventions, to prevent progression, and in some cases, improve bone health. Evidence for positive outcomes of these behavioural interventions are reported in male cyclists[iii].

Currently bone mineral density (BMD) is measured using DXA (dual X ray absorptiometry), which although low in dose, nevertheless involves ionising radiation. This limits the frequency of measurement, although bone is metabolically active and often one of first systems to change in response to low energy availability[iv]. The new technology of R.E.M.S. (Radiofrequency Echographic Multi Spectrometry) involves totally safe ultrasound. Furthermore this technology provides information on bone microarchitecture. Currently assessment of bone microarchitecture is only possible with pQCT (peripheral quantitative computerised tomography), which is not only involves a high radiation dose, furthermore is limited to assessment of peripheral skeletal sites. Although BMD is undoubtedly an important factor in determining bone health, nevertheless bone strength and structure also plays an important part.

Therefore the main objective of a forthcoming study[v] is to establish the effectiveness of identifying those at risk of suboptimal bone health with this new specialised ultrasound based technology and correlate with questionnaire and blood markers in both athletic and non athletic populations.

Ballet and other Dance forms

RED-S is more prevalent in sports where being of low body weight confers a performance or aesthetic advantage. Although dance is not a sport, nevertheless this type of activity requires low body weight from both a performance and aesthetic point of view for both male and female dancers. Dance training often starts at a young age[vi] and as with early sport specialisation, there is an increased risk of developing low energy availability during this time of high-energy demand for growth and development[vii]. So much so, that this situation can have a negative impact on accumulation of peak bone mass and adverse potential long-term effects[viii].

Although there is a validated questionnaire LEAF-Q[ix] for assessing low energy availability in female athletes, this excludes half the population and is not sport specific. A questionnaire-based study amongst female athletes was found to be effective at identifying and quantifying the clinical consequences of low energy availability[x]. Our recent study of competitive male road cyclists found that a sport specific energy availability questionnaire combined with interview (SEAQ-I)[xi] was the measured factor most effective in indicating low BMD of the lumbar spine. BMD of the lumbar spine is a quantifiable measure of chronic low energy availability. Other objective measures of low energy availability include indicators of endocrine function. In women menstrual function and in men testosterone, which in turn are clinked to the clinical outcome of impaired bone health and stress fracture in runners[xii]

To date there is a dearth of sport specific questionnaires to assess low energy availability and none that are dance specific. Dance involves both male and female and is certainly a type of activity where individuals are at risk of low energy availability and the clinical consequences of RED-S. Therefore the aim of the current dance study is to use a asses awareness, risk factors and consequences of low energy availability and RED-S. The study is now published

Indicators and correlates of low energy availability in male and female dancers. Keay, Francis, AusDancersOverseas BMJ Open in Sports and Exercise Medicine 2020 doi:

and validated: Nicola Keay, Martin Lanfear, Gavin Francis. Clinical application of interactive monitoring of indicators of health in professional dancers J Forensic Biomech, Vol.12 Iss.5 No:1000380

Nicola Keay, Martin Lanfear, Gavin Francis. Clinical application of monitoring indicators of female dancer health, including application of artificial intelligence in female hormone networks MedRxiv 2021 doi:


[i] Mountjoy M, Sundgot-Borgen J, Burke L et al. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update British Journal of Sports Medicine 2018; 52(11): 687-697 DOI: 10.1136/bjsports-2018-099193

[ii] Keay N, Francis G, Hind K. Low energy availability assessed by a sport-specific questionnaire and clinical interview indicative of bone health, endocrine profile and cycling performance in competitive male cyclists BMJ Open Sport and Exercise Medicine 2018; 4(1) DOI: 10.1136/bmjsem-2018-000424

[iii] Keay N, Francis G, Entwistle I et al. Clinical evaluation of education relating to nutrition and skeletal loading in competitive male road cyclists at risk of relative energy deficiency in sports (RED-S): 6-month randomised controlled trial BMJ Open Sport and Exercise Medicine 2019; 5(1) DOI: 10.1136/bmjsem-2019-000523

[iv] Professor Louise Burke presenting at annual ISENC conference Newcastle 2018

[v] Assessment of Echographic Technology in Measuring Bone Health in the Clinical Setting

[vi] N. Keay. Dancing through adolescence British Journal of Sports Medicine 1998 DOI: 10.1136/bjsm.32.3.196

[vii] N. Keay. The modifiable factors affecting bone mineral accumulation in girls: The paradoxical effect of exercise on bone Nutrition Bulletin 2000 DOI: 10.1046/j.1467-3010.2000.00051.x

[viii] N. Keay, G.Blake, I. Fogleman.  Bone mineral density in professional female dancers British Journal of Sports Medicine 1997; 31(2): 143-147

DOI: 10.1136/bjsm.31.2.143

[ix] Melin A, Tornberg Å, Skouby S et al. The LEAF questionnaire: A screening tool for the identification of female athletes at risk for the female athlete triad British Journal of Sports Medicine 2014: 48 (7)

[x] K. Ackerman, B. Holtzman et al. Low energy availability surrogates correlate with health and performance consequences of Relative Energy Deficiency in Sport British Journal of Sports Medicine 2018; 53(10) 628-633

DOI: 10.1136/bjsports-2017-098958

[xi] N. Keay, G. Francis, K. Hind. Low energy availability assessed by a sport-specific questionnaire and clinical interview indicative of bone health, endocrine profile and cycling performance in competitive male cyclists BMJ Open Sport and Exercise Medicine 2018 4(1) DOI: 10.1136/bmjsem-2018-000424

x Heikura I, Uusitalo A, Stellingwerff T et al. Low energy availability is difficult to assess but outcomes have large impact on bone injury rates in elite distance athletes, International Journal of Sport Nutrition and Exercise Metabolism 2018; 28(4): 403-411 DOI: 10.1123/ijsnem.2017-0313

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