Papers by Stéphane Perrey
Frontiers in Human Neuroscience, Nov 29, 2023
Brain Sciences, Jul 17, 2020
Volition is described as a psychological construct with great emphasis on the sense of agency. Du... more Volition is described as a psychological construct with great emphasis on the sense of agency. During volitional behavior, an individual always presents a volitional quality, an intrapersonal trait for dealing with adverse circumstances, which determines the individual's persistence of action toward their intentions or goals. Elite athletes are a group of experts with superior volitional quality and, thereby, could be regarded as the natural subject pool to investigate this mental trait. The purpose of this study was to examine brain morphometric characteristics associated with volitional quality by using magnetic resonance imaging (MRI) and the Scale of Volitional Quality. We recruited 16 national-level athletes engaged in short track speed skating and 18 healthy controls matched with age and gender. A comparison of a parcel-wise brain anatomical characteristics of the healthy controls with those of the elite athletes revealed three regions with significantly increased cortical thickness in the athlete group. These regions included the left precuneus, the left inferior parietal lobe, and the right superior frontal lobe, which are the core brain regions involved in the sense of agency. The mean cortical thickness of the left inferior parietal lobe was significantly correlated with the independence of volitional quality (a mental trait that characterizes one's intendency to control his/her own behavior and make decisions by applying internal standards and/or objective criteria). These findings suggest that sports training is an ideal model for better understanding the neural mechanisms of volitional behavior in the human brain.
Scientific Reports, Oct 31, 2019
If health can be defined as adaptability, then measures of adaptability are crucial. Convergent f... more If health can be defined as adaptability, then measures of adaptability are crucial. Convergent findings across clinical areas established the notion that fractal properties in bio-behavioural variability characterize the healthy condition of the organism, and its adaptive capacities in general. However, ambiguities remain as to the significance of fractal properties: the literature mainly discriminated between healthy vs. pathological states, thereby loosing perspective on the progression in between, and overlooking the distinction between adaptability and effective adaptations of the organism. Here, we design an experimental tapping paradigm involving gradual feedback deprivation in groups of healthy subjects and one deafferented man as a pathological-limit case. We show that distinct types of fractal properties in sensorimotor behaviour characterize, on the one hand impaired functional ability, and on the other hand internal adaptations for maintaining performance despite the imposed constraints. Findings may prove promising for early detection of internal adaptations preceding symptomatic functional decline. "What is health? The ability to adapt" 1. Consistently, this has also been the basic assumption of a medical and translational research field taking a complex systems approach to medicine and motor behaviour for the past two decades 2-7. However, conceptualizing health as the ability to adapt comes along with an acute need for defining ad hoc measurements of such adaptability 2,8. Given the difficulty to appraise the intricate multiscale organization of complex systems, regardless of their nature, one approach has been to recognize that the manner in which some bio-behavioural variables fluctuate over time contains significant information about the condition of the organism itself. Based on this assumption, mounting evidence showed that unconstrained young and healthy organisms generate variables with highly complex-typically fractal-patterns of fluctuations 5,9-12. In contrast, complexity is lost with pathologies or aging, conditions commonly associated with a loss of the organism's adaptive capacities 5,6,13-15. There are numerous examples, including heart failure 5 , neurodegenerative diseases like Parkinsons's or Huntington's 16 , attention deficit disorders 17 , depression 18 , aging and sensory deficit 19. The convergence of results across such a wide range of clinical situations led researchers to investigate the diagnostic and prognostic power of time series complexity 20-22. It also contributed to ground the idea that fractal complexity in the system observables is a hallmark of its adaptability 5,6,11,12,14. While this idea is inspiring and conceptually plausible in various respects, accumulation of empirical findings is not evidence, and some significant issues remain. Specifically, two interrelated conundrums arise from the literature. Firstly, if time series complexity is indeed a hallmark of organism's adaptability as a cross-cutting factor, then this relationship is necessarily transposable to various circumstances outside of pathology or aging: one could then assume that experimentally-induced constraints mimicking pathology-or age-associated impairments would alter the complexity of functional variables in a similar way. The relative compartmentalization of the literature certainly contributed to leave this point out: on the one hand, clinical approaches mostly addressed the alteration of complexity due to a pathological state or aging via cross-sectional studies, or in relation to the level of impairment (e.g. 16,18,23,24). Outside clinical conditions, only few studies did in fact investigate how fractal properties reflect the organism's internal adaptations under experimental constraints while respecting task equivalence 25-27. Secondly, at a specified functional level, adaptability embraces multiple complementary dimensions, in particular changeableness (the ability to exploit
HAL (Le Centre pour la Communication Scientifique Directe), Jul 9, 2019
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Purpose.-The purpose of this study was to examine the relationships of VO 2 during unloaded arm c... more Purpose.-The purpose of this study was to examine the relationships of VO 2 during unloaded arm cranking and leg cycling exercises to respectively relevant upper and lower limbs anthropometrical characteristics. Method.-Fifteen males completed a 5-min unloaded bout on an arm crank ergometer (60 rpm) and a cycle ergometer (90 rpm). VO 2 corresponding to each unloaded exercise (VO 2 unload), body mass, lengths, and circumferences of upper and lower limbs were measured. Results.-Upper limbs cranking showed a significantly lower (P < 0.001) VO 2 unload than lower limbs cycling (499.0 ± 56.5 and 981.6 ± 126.0 ml min −1). Moreover, upper and lower limbs VO 2 unload values were significantly and positively correlated with circumferences, and length of upper and lower limbs, respectively, with highest correlations obtained between circumferences and VO 2 unload. The amount of VO 2 unload is then principally dependent (i) on the inertia of the limbs, which increased with the circumference of the limb and (ii) on the arm level, which increased with the length of the limb. On the other hand, body mass was not or less correlated with VO 2 unload. This result could be explained by the specificity of the unloaded exercise since only the limb muscles were activated, the entire body mass not being representative of the muscle mass activated.
European Respiratory Journal, Sep 1, 2012
Frontiers in Human Neuroscience, Apr 11, 2023
Frontiers in neuroergonomics, Feb 16, 2023
Sports Medicine - Open
The emergence of the first Fitness-Fatigue impulse responses models (FFMs) have allowed the sport... more The emergence of the first Fitness-Fatigue impulse responses models (FFMs) have allowed the sport science community to investigate relationships between the effects of training and performance. In the models, athletic performance is described by first order transfer functions which represent Fitness and Fatigue antagonistic responses to training. On this basis, the mathematical structure allows for a precise determination of optimal sequence of training doses that would enhance the greatest athletic performance, at a given time point. Despite several improvement of FFMs and still being widely used nowadays, their efficiency for describing as well as for predicting a sport performance remains mitigated. The main causes may be attributed to a simplification of physiological processes involved by exercise which the model relies on, as well as a univariate consideration of factors responsible for an athletic performance. In this context, machine-learning perspectives appear to be valuab...
This study aims to predict individual Acceleration-Velocity profiles (A-V) from Global Navigation... more This study aims to predict individual Acceleration-Velocity profiles (A-V) from Global Navigation Satellite System (GNSS) measurements in real-world situations. Data were collected from professional players in the Superleague division during a 1.5 season period (2019-2021). A baseline modeling performance was provided by time-series forecasting methods and compared with two multivariate modeling approaches using ridge regularisation and long short term memory neural networks. The multivariate models considered commercial features and new features extracted from GNSS raw data as predictor variables. A control condition in which profiles were predicted from predictors of the same session outlined the predictability of A-V profiles. Multivariate models were fitted either per player or over the group of players. Predictor variables were pooled according to the mean or an exponential weighting function. As expected, the control condition provided lower error rates than other models on av...
HAL (Le Centre pour la Communication Scientifique Directe), Oct 15, 2020
The objective of this article is to compare three approaches of missing data management in a clas... more The objective of this article is to compare three approaches of missing data management in a classification context with sequential labels at variable time steps. The data concern the longitudinal monitoring of twenty-seven professional soccer players in terms of training schedules and perceived internal perceived load. One approach without imputation using the age of the data, the other two approaches are based on uncertainty models at the missing data imputation step. The Evidential K-Nearest Neighbors (EKNN) is used for internal load prediction taking into account labels uncertainty, and the K-Nearest Neighbors for the approach without uncertain labels. Results show moderate prediction improvement for models based on imputed data uncertainty.
This study aims to provide a transferable methodology in the context of sport performance modelli... more This study aims to provide a transferable methodology in the context of sport performance modelling, with a special focus to the generalisation of models. Data were collected from seven elite Short track speed skaters over a three months training period. In order to account for training load accumulation over sessions, cumulative responses to training were modelled by impulse, serial and bi-exponential responses functions. The variable dose-response (DR) model was compared to elastic net (ENET), principal component regression (PCR) and random forest (RF) models, while using cross-validation within a time-series framework. ENET, PCR and RF models were fitted either individually (MI) or on the whole group of athletes (MG). Root mean square error criterion was used to assess performances of models. ENET and PCR models provided a significant greater generalisation ability than the DR model (p = 0.012, p < 0.001, p = 0.005 and p < 0.001 for ENETI, ENETG, PCRI and PCRG, respectively...
Scientific Reports, 2022
This study aims to provide a transferable methodology in the context of sport performance modelli... more This study aims to provide a transferable methodology in the context of sport performance modelling, with a special focus to the generalisation of models. Data were collected from seven elite Short track speed skaters over a three months training period. In order to account for training load accumulation over sessions, cumulative responses to training were modelled by impulse, serial and bi-exponential responses functions. The variable dose-response (DR) model was compared to elastic net (ENET), principal component regression (PCR) and random forest (RF) models, while using cross-validation within a time-series framework. ENET, PCR and RF models were fitted either individually ($$M_{I}$$ M I ) or on the whole group of athletes ($$M_{G}$$ M G ). Root mean square error criterion was used to assess performances of models. ENET and PCR models provided a significant greater generalisation ability than the DR model ($$p = 0.018$$ p = 0.018 , $$p < 0.001$$ p < 0.001 , $$p = 0.004$$ p...
Brain Sciences, 2020
Volition is described as a psychological construct with great emphasis on the sense of agency. Du... more Volition is described as a psychological construct with great emphasis on the sense of agency. During volitional behavior, an individual always presents a volitional quality, an intrapersonal trait for dealing with adverse circumstances, which determines the individual’s persistence of action toward their intentions or goals. Elite athletes are a group of experts with superior volitional quality and, thereby, could be regarded as the natural subject pool to investigate this mental trait. The purpose of this study was to examine brain morphometric characteristics associated with volitional quality by using magnetic resonance imaging (MRI) and the Scale of Volitional Quality. We recruited 16 national-level athletes engaged in short track speed skating and 18 healthy controls matched with age and gender. A comparison of a parcel-wise brain anatomical characteristics of the healthy controls with those of the elite athletes revealed three regions with significantly increased cortical thi...
Movement & Sport Sciences - Science & Motricité, 2018
Numéro 100 ! C'est avec beaucoup de plaisir que nous rédigeons cet édito pour le numéro 100 de Sc... more Numéro 100 ! C'est avec beaucoup de plaisir que nous rédigeons cet édito pour le numéro 100 de Science & Motricité-Movement & Sport Sciences, revue de l'ACAPS (Association des Chercheurs en Activités Physiques et Sportives ; www.acaps.asso.fr). Cent numéros et 31 ans d'existence depuis sa création en 1987 qui ont vu se succéder les éditeurs scientifiques principaux ou de section Jacques van
International Journal of Sports Physiology and Performance, 2014
Purpose:This study investigated the effect of training mode on the relationships between measures... more Purpose:This study investigated the effect of training mode on the relationships between measures of training load in professional rugby league players.Methods:Five measures of training load (internal: individualized training impulse, session rating of perceived exertion; external—body load, high-speed distance, total impacts) were collected from 17 professional male rugby league players over the course of two 12-wk preseason periods. Training was categorized by mode (small-sided games, conditioning, skills, speed, strongman, and wrestle) and subsequently subjected to a principal-component analysis. Extraction criteria were set at an eigenvalue of greater than 1. Modes that extracted more than 1 principal component were subjected to a varimax rotation.Results:Small-sided games and conditioning extracted 1 principal component, explaining 68% and 52% of the variance, respectively. Skills, wrestle, strongman, and speed extracted 2 principal components each explaining 68%, 71%, 72%, and...
Frontiers in neuroergonomics, Nov 18, 2022
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Papers by Stéphane Perrey