Female athletes have garnered considerable attention in the last few years as more and more women participate in sports events. However, despite the well-known repercussions of female sex hormones, few studies have investigated the specificities of elite female athletes. In this review, we present the current but still limited data on how normal menstrual phases, altered menstrual phases, and hormonal contraception affect both physical and cognitive performances in these elite athletes. To examine the implicated mechanisms, as well as the potential performances and health risks in this population, we then take a broader multidisciplinary approach and report on the causal/reciprocal relationships between hormonal status and mental and physical health in young (18–40 years) healthy females, both trained and untrained. We thus cover the research on both physiological and psychological variables, as well as on the Athlete Biological Passport used for anti-doping purposes. We consider the fairly frequent discrepancies and summarize the current knowledge in this new field of interest. Last, we conclude with some practical guidelines for eliciting improvements in physical and cognitive performance while minimizing the health risks for female athletes.

Motor variability is a fundamental feature of developing systems allowing motor exploration and learning. In human infants, leg movements involve a small number of basic coordination patterns called locomotor primitives, but whether and when motor variability could emerge from these primitives remains unknown. Here we longitudinally followed 18 infants on 2–3 time points between birth (~4 days old) and walking onset (~14 months old) and recorded the activity of their leg muscles during locomotor or rhythmic movements. Using unsupervised machine learning, we show that the structure of trial-to-trial variability changes during early development. In the neonatal period, infants own a minimal number of motor primitives but generate a maximal motor variability across trials thanks to variable activations of these primitives. A few months later, toddlers generate significantly less variability despite the existence of more primitives due to more regularity within their activation. These results suggest that human neonates initiate motor exploration as soon as birth by variably activating a few basic locomotor primitives that later fraction and become more consistently activated by the motor system.

Motor variability is a fundamental feature of developing systems allowing motor exploration and learning. In human infants, leg movements involve a small number of basic coordination patterns called locomotor primitives, but whether and when motor variability could emerge from these primitives remains unknown. Here we longitudinally followed 10 neonates (∼4 days old) until walking onset (∼14 months old) and recorded the activity of their leg muscles during locomotor or rhythmic movements. Using unsupervised machine learning, we show that the structure of trial-to-trial variability changes during early development. In the neonatal period, infants own a minimal number of motor primitives but generate a maximal motor variability across trials thanks to variable activations of these primitives. A few months later, toddlers generate significantly less variability despite the existence of more primitives, due to more regularity within their activation. These results suggest that human neonates initiate motor exploration as soon as birth by variably activating a few basic locomotor primitives that later fraction and become more consistently activated by the motor system.

In tennis, both open and square stances are used to produce forehands, although few differences have been found between them in terms of biomechanical or ball speed advantages. Hence, it is currently unclear why expert players decide to change their stance during rallies. The objective of this study was to analyze the influence of the context before the stroke on the players’ stance choice. Based on video analysis of men and women professional tennis matches, 2479 stances chosen by twenty players were recorded, considering contextual factors such as “balance of power” and direction of the ball to be played. Results revealed that open stance was used significantly more than square stance in 83.6% of the forehands, with no difference between women and men. These rates varied based on the balance of power, with fewer open stance during favorable situations (65.4%). The direction of the ball played influenced the choice of stance in favorable situations, with fewer open stance being used to play cross court. Taken all together, these results showed an interaction between factors preceding the forehand stroke when adopting a stance in tennis. When players had little time to make a choice, they overwhelmingly used open stances. This choice can be automated, which reduces the attentional load. On the other hand, when they had more time, they varied their type of stance according to the zone being played, with inter-individual differences. The findings could provide valuable insights for coaches to optimize training and improve players’ decision-making efficiency.

Walking in adults seems to rely on a small number of modules allowing to reduce the number of degrees of freedom effectively regulated by the central nervous system (CNS). However, the extent to which modularity evolves during development remains unknown, particularly regarding the ability to generate several strides in an optimized manner. Here we compared the modular organization of toddlers and adults during several strides of walking. We recorded the electromyographic activity of 10 bilateral (lower limbs) muscles in adults (n=12) and toddlers (n=12) during 8 gait cycles, and used non-negative matrix factorization to model the underlying modular command. While the muscular activity of all strides could be factorized into a consistent low-dimensional modular organization in adults, significantly more computational modules were needed in toddlers to account for their greater stride-by-stride variability. Activations of these modules varied more across strides and was less parsimonious in toddlers than in adults, even when balances constrained were diminished. These findings suggest that the modular control of locomotion of adults evolves as the organism develops and practices. They also suggest that new walker can flexibly activate a higher number of modules and benefit from a higher space of possible action, which could serve motor exploration.