Effects of resistance exercise, collagen ingestion and circulating oestrogen concentration on collagen synthesis in a female athlete: A case report

We investigated the effects of resistance exercise (RE), hydrolysed collagen (HC) ingestion and circulating oestrogen concentration on collagen synthesis in a naturally menstruating female CrossFit athlete. In a double-blind, randomised cross-over design, the participant (36 years; height 1.61 m; mass 82.6 kg) consumed 0 g or 30 g HC prior to performing back-squat RE when endogenous circulating oestrogen concentration was low (onset of menses, OM) and high (late follicular phase, LF) during two consecutive menstrual cycles. Ten 5-mL blood samples were collected during each of the four interventions to analyse concentrations of serum 17β-oestradiol, and biomarkers of type I collagen turnover, i.e. serum procollagen type Ⅰ N-terminal propeptide, (PINP, a biomarker of collagen synthesis) and plasma β-isomerized C-terminal telopeptide of type I collagen (β-CTX, a biomarker of collagen breakdown), as well as the serum concentration of 18 collagen amino acids. 17β-oestradiol concentration was 5-fold higher at LF (891 ± 116 pmol∙L-1) than OM (180 ± 13 pmol∙L-1). The PINP concentration × time area under the curve (AUC) was higher in the 30 g HC OM intervention (201 μg∙L-1∙h) than the 30 g HC LF (144 μg∙L-1∙h), 0 g HC OM (151 μg∙L-1∙h), and 0 g HC LF (122 μg∙L-1∙h) interventions. β-CTX concentration decreased 1.4-fold from pre-RE to 6h post-RE in all interventions. Thus, high circulating oestrogen concentration was associated with lower collagen synthesis following RE in this female athlete. Ingesting 30g HC, however, augmented the collagen synthesis response at LF and particularly at OM.