Is There Evidence for the Development of Sex-Specific Guidelines for Ultramarathon Coaches and Athletes? A Systematic Review

Abstract

Background There is evidence of sex differences in the physiology of endurance exercise, yet most of the advice and guidelines on training, racing, nutrition, and recovery for ultramarathons are based on research that has largely excluded female athletes. The objective was therefore to review the current knowledge of sex differences in ultramarathon runners and determine if sufficient evidence exists for providing separate guidelines for males and females. Methods This systematic review was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three databases were searched for studies investigating differences in elite and recreational male and female ultramarathon runners. Studies were included if they compared males and females and looked at outcomes relating to the performance or health of ultramarathon runners. The quality of the included studies was determined using the Grading of Recommendations Assessment Development and Evaluation (GRADE) approach. Results The search strategy identified 45 studies that met the inclusion criteria. Most studies were observational in design, with only three papers based on randomised controlled trials. The overall quality of the evidence was low. Sex differences in the predictors of ultramarathon performance; physiological responses to training, racing, and recovery; chronic and acute health issues; and pacing strategies were found. There were areas with contradictory findings, and very few studies examined specific interventions. Conclusion The results from this review suggest that the development of sex-specific guidelines for ultramarathon coaches and athletes could have a significant effect on the performance and health of female runners. At present, there is insufficient high-quality evidence on which to formulate these guidelines, and further research is required.

Recommendations for Women in Mountain Sports and Hypoxia Training/Conditioning

“…These authors suggested that, from a performance perspective, the higher running economy may partially compensate for the lower V O 2max in female runners [ 87 ]. However, controversial findings exist on sex differences in fatigue resistance and pacing in road and trail ultra-marathons [ 81 , 88 , 89 ]. Some authors reported greater fatigue resistance and better pacing in female ultra-marathon participants [ 81 , 89 ], whereas others found that women tended to slow down more than men in the later stages of trail running ultra-marathons, despite the terrain (uphill and downhill) [ 88 ].…”

“…However, controversial findings exist on sex differences in fatigue resistance and pacing in road and trail ultra-marathons [ 81 , 88 , 89 ]. Some authors reported greater fatigue resistance and better pacing in female ultra-marathon participants [ 81 , 89 ], whereas others found that women tended to slow down more than men in the later stages of trail running ultra-marathons, despite the terrain (uphill and downhill) [ 88 ]. Further studies are needed to better understand sex differences in the energetics and biomechanics of incline walking and running, and fatigue resistance and pacing strategies in ultra-marathons controlling for fitness levels, anthropometric differences, menstrual cycle effect and the level of relative effort used for testing both sexes.…”

“…Several high-quality reviews have been published on the potential sex differences in ultra-marathons [ 81 , 89 , 202 ]. As they did not focus on mountain ultra-marathons, potential influences of the sex differences in response to altitude/hypoxia were not discussed in those reviews.…”

Can the recent sex-specific evolutions in elite running performances be attributed to advanced footwear technology?

“…Recent upgrades in co-operative drafting strategies during racing ( 54 ) likely benefit women more than men over road racing distances given that they can be paced for the entirety of the race as opposed to only an initial portion, although this does not explain why women are also improving at faster rates on the track. Another consideration is that modern developments in training design and nutritional supplementation strategies which more precisely target female physiology may have also contributed to the latest breakthroughs in performances ( 55 , 56 ).…”

Comment on: “Is There Evidence for the Development of Sex-Specific Guidelines for Ultramarathon Coaches and Athletes? A Systematic Review”

“…We read with great interest the work done by Kelly [ 1 ], who conducted a systematic review (SR) that aimed to review the current knowledge of sex differences in ultramarathon runners and determine if sufficient evidence exists for providing separate guidelines for males and females. First, we want to compliment the author on the relevance of this investigation.…”