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Background The net metabolic cost of walking (NCw) and the co-activation of leg muscles are both higher in old adults (OG) than in young adults (YG). Nevertheless, the relation between the two remains unresolved, mainly due to the controversial co-activation measurement method used in previous studies. Research question To compare ankle and knee co-contraction (CCI), calculated using an EMG-driven method, between the groups and to examine their relationship with NCw. Methods Nine young (YG = 25.2 +/- 3.3 years old) and nine older (OG = 68.7 +/5.9 years old) adults walked on a treadmill at five speeds (YG: 1; 1.2; 1.4; 1.6; 1.8 m/s; OG: 0.6; 0.8; 1; 1.2; 1.4 m/s) while electromyography (sEMG) and oxygen consumption were measured. CCI were calculated around the ankle and knee for different parts of the gait cycle (entire gait cycle 0–100 %, stance phase 0–60 %, swing phase 60–100 %). Results NCw was significantly higher (25 %, averaged over the walking speeds) in OG as were Knee_CCI, Knee_CCI_swing and Knee_CCI_stance. Multiple regression models in YG, OG and YG + OG highlighted Ankle_CCI as the main contributor in NCw (β = 0.08−0.188, p Significance The present findings provide a better understanding of the association between muscle co-contraction and metabolic cost in older adults. It may help scientists and clinicians to further develop strategies aimed at neuromuscular rehabilitation as a means of improving mobility and independence among older adults.

BACKGROUND As people age, their physical capacities (eg, walking and balance) decline and the risk of falling rises. Yet, classic fall detection devices are poorly accepted by older adults. Because they often wear eyeglasses as they go about their daily activities, daily monitoring to detect and prevent falls with smart eyeglasses might be more easily accepted. OBJECTIVE On the basis of the Unified Theory of Acceptance and Use of Technology 2 (UTAUT2), this study evaluated (1) the acceptability of smart eyeglasses for the detection and prevention of falls by older adults and (2) the associations with selected fall-related functional physical capacities. METHODS A total of 142 volunteer older adults (mean age 74.9 years, SD 6.5 years) completed the UTAUT2 questionnaire adapted for smart eyeglasses and then performed several physical tests: a unipodal balance test with eyes open and closed, a 10-m walk test, and a 6-minute walk test. An unsupervised analysis classified the participants into physical performance groups. Multivariate ANOVAs were performed to identify differences in acceptability constructs according to the performance group. RESULTS The UTAUT2 questionnaire adapted for eyeglasses presented good psychometric properties. Performance expectancy (β=.21, P=.005), social influence (β=.18, P=.007), facilitating conditions (β=.17, P=.04), and habit (β=.40, PR²=0.73). The unsupervised analysis based on fall-related functional physical capacities created 3 groups of physical performance: low, intermediate, and high. Effort expectancy in the low performance group (mean 3.99, SD 1.46) was lower than that in the other 2 groups (ie, intermediate: mean 4.68, SD 1.23; high: mean 5.09, SD 1.41). Facilitating conditions in the high performance group (mean 5.39, SD 1.39) were higher than those in the other 2 groups (ie, low: mean 4.31, SD 1.68; intermediate: mean 4.66, SD 1.51). CONCLUSIONS To our knowledge, this study is the first to examine the acceptability of smart eyeglasses in the context of fall detection and prevention in older adults and to associate acceptability with fall-related functional physical capacities. The older adults with higher physical performances, and possibly lower risks of falling, reported greater acceptability of smart eyeglasses for fall prevention and detection than their counterparts exhibiting low physical performances.

International audience; This document is a summary of the French intergroup guidelines regarding the nutrition and physical activity (PA) management in digestive oncology. This collaborative work was produced under the auspices of all French medical and surgical societies involved in digestive oncology, nutrition and supportive care. It is based on published guidelines, recent literature review and expert opinions. Recommendations are graded according to the level of evidence. Malnutrition affects more than half of patients with digestive cancers and is often underdiagnosed. It has multiple negative consequences on survival, quality of life and risk of treatment complications. Consequently, in addition to anticancer treatments, supportive care including nutritional support and PA plays a central role in the management of digestive cancers. It is crucial to detect malnutrition (diagnostic criteria updated in 2019) early, to prevent it and to act against it at all stages of the cancer and at all times of the care pathway. In this context, we proposed recommendations for the evaluation and management in nutrition and PA in digestive oncology for each stage of the disease (perioperative setting, during radiation therapy, during systemic treatments, at the palliative phase, after cancer). Guidelines for nutrition and PA management aim at increasing awareness about malnutrition in oncology. They are continuously evolving and need to be regularly updated.

PURPOSE The purpose of this study was to concomitantly investigate the acute and delayed effects of a submaximal eccentric-induced muscle fatigue on the position sense and the neuromuscular function of the right knee extensor muscles. METHODS Thirteen young and physically active participants performed a unilateral isokinetic eccentric exercise of their right lower limb until a decrease in maximal voluntary isometric contraction (MVIC) of 20% was reached. Neuromuscular (i.e., MVIC, voluntary activation (VA) level, and evoked contractile properties [DB100 and DB10]) and psychophysical evaluations (i.e., bilateral position-matching task, perceived muscle soreness, and perceived fatigue) were performed at four time points: before (PRE), immediately after (POST), 24 (POST24), and 48 (POST48) the exercise. RESULTS The acute 20% MVIC reduction (P < 0.001) was associated with both central (i.e., -13% VA decrease, P < 0.01) and peripheral (i.e., -18% and -42% reduction of DB100 and DB10, respectively, P < 0.001) fatigue. In the following days (POST24 and POST48), VA levels had recovered despite the presence of a persisting peripheral fatigue and delayed-onset muscle soreness. Knee position sense, as revealed by position errors, was significantly altered only at POST (P < 0.05) with participants overestimating the length of their knee extensor. Position errors and VA deficits were significantly correlated at POST (r = -0.60, P = 0.03). Position errors returned to nonsignificant control values in the following days. CONCLUSION The acute central fatigue induced by the eccentric exercise contributes to the position sense disturbances. Central fatigue might lead to alterations in the sensory structures responsible for the integration and the processing of position-related sensory inputs.

Context:Firefighters participating in mandatory physical exercise sessions are exposed to a high risk of ankle sprain injury. Although both physiological and psychological risk factors have been identified, few prospective studies considered the complex interaction of these factors in firefighters.Objective:To prospectively determine whether intrinsic physical risk factors and work-related environments predict ankle sprains occurring during on-duty physical exercise in firefighters during an 8-month follow-up period.Design:Prospective.Setting:Fire Department and Rescue Service.Participants:Thirty-nine firefighters were selected based on convenience sampling.Intervention:Participants performed physical tests and completed questionnaires.Main Outcome Measures:Lower Quarter Y-Balance Test, Weight-Bearing Lunge Test, anthropometric measures, postural stability, chronic ankle instability (Cumberland Ankle Instability Tool) scores, previous injuries, and perceived psychosocial work environment (Copenhagen Psychosocial Questionnaire [COPSOQ]).Results:During the follow-up, 9 firefighters sustained an injury. Lower Quarter Y-Balance Test and Weight-Bearing Lunge Test performances, Cumberland Ankle Instability Tool scores, history of previous ankle sprain, and specific dimensions of the COPSOQ significantly differed between injured and uninjured firefighters. Lower-limbs asymmetries of the Lower Quarter Y-Balance Test (ie, anterior, posteromedial, and posterolateral directions) and the Weight-Bearing Lunge Test were predictors of ankle sprains.Conclusions:These findings originally provide evidence that intrinsic factors mainly contribute to ankle sprains, although psychosocial work environment assessment could also characterize firefighters at risk.

The study aims to determine the validity and reproducibility of step duration and step length parameters measured during walking in healthy participants using an accelerometer embedded in smart eyeglasses. Twenty young volunteers participated in two identical sessions comprising a 30 s gait assessment performed at three different treadmill speeds under two conditions (i.e., with and without a cervical collar). Spatiotemporal parameters (i.e., step duration and step length normalized by the lower limb length) were obtained with both the accelerometer embedded in smart eyeglasses and an optoelectronic system. The relative intra- and inter-session reliability of step duration and step length computed from the vertical acceleration data were excellent for all experimental conditions. An excellent absolute reliability was observed for the eyeglasses for all conditions and concurrent validity between systems was observed. An accelerometer incorporated in smart eyeglasses is accurate to measure step duration and step length during gait.

The 6-min walk test (6MWT) is a useful tool for clinicians and researchers to estimate gait performance and fatigue affecting functional mobility. A modified 6MWT administered on a treadmill (TM) can be an efficient, space-saving alternative to perform the 6MWT. The aim of this study was to investigate if a 6MWT on a self-paced (SP) TM produced similar results compared to an overground (OG) 6MWT among healthy participants with the hypothesis that users would demonstrate similar gait parameters. The second aim was to assess the reliability of SP TM sessions with the hypothesis that gait parameters would be reliable. Twelve healthy young adults performed one OG 6MWT and two SP TM 6MWTs, with the TM tests performed on two different testing days. The OG 6MWTs were conducted along a 20 m corridor with a portable optometric system. The SP TM 6MWTs were performed using a dual-belt instrumented TM with speed controlled by feedback from a LIDAR sensor. In the OG condition, participants walked 664.8 m ± 48.9 m when the standard method was used to calculate distance and 721.3 m ± 56.2 m with an average-speed-based estimation of distance, which corrects for U-turns. For the SP TM 6MWT, they covered 729.4 m ± 45.8 m in the first session and 727.4 m ± 56.0 m in the second session. Gait parameters showed good to excellent within- and between-day reliability on the adaptive TM. Gait parameters were similar between modalities. A significant difference in the 6MWT distance was found between modalities. This is attributable to the U-turns, because a comparison between TM 6MWT distance and the average-speed-based estimation of the distance for the OG modality showed no significant difference. However, this system produced similar spatiotemporal gait parameters among participants compared to OG.

International audience; The emergence of RGB-D cameras and the development of pose estimation algorithms offer opportunities in biomechanics. However, some challenges still remain when using them for gait analysis, including noise which leads to misidentification of gait events and inaccuracy.Therefore, we present a novel kinematic-geometric model for spatio-temporal gait analysis, based on ankles’ trajectory in the frontal plane and distance-to-camera data (depth). Our approach consists of three main steps: identification of the gait pattern and modeling via parameterized curves, development of a fitting algorithm, and computation of locomotive indices. The proposed fitting algorithm applies on both ankles’ depth data simultaneously, by minimizing through numerical optimization some geometric and biomechanical error functions. For validation, 15 subjects were asked to walk inside the walkway of the OptoGait, while the OptoGait and an RGB-D camera (Microsoft Azure Kinect) were both recording. Then, the spatiotemporal parameters of both feet were computed using the OptoGait and the proposed model. Validation results show that the proposed model yields good to excellent absolute statistical agreement (0.86≤Rc≤ 0.99). Our kinematic-geometric model offers several benefits: (1) It relies only on the ankles’ depth trajectory both for gait events extraction and spatio-temporal parameters’ calculation; (2) it is usablewith any kind of RGB-D camera or even with 3D marker-based motion analysis systems in absence of toes’ and heels’ markers; and (3) it enables improving the results by denoising and smoothing the ankles’ depth trajectory. Hence, the proposed kinematic-geometric model facilitates the development of portable markerless systems for accurate gait analysis.

Background Many studies have explored spatial and temporal gait parameters in the elderly, and showed that frailty status, fall history, age, and gender may individually strongly influence these parameters. However, it appears necessary to investigate the confounding factors more deeply in order to better know the specific role of each of these factors impacting the evolution of gait with the increase of age. Aim The aim of the present study was to determine the influence of frailty status, fall history, age and gender on spatiotemporal gait parameters. We hypothesized that frailty was the factor that most influence gait parameters. Setting This is a monocentric retrospective study performed at Nice University Hospital Center on older out-patients. Population Older adults were included in the study. This study explored for the first time how frailty status, age, gender and history of falls impact the multiple spatiotemporal parameters of gait using linear mixed models (LMM). Results 479 older adults (360 women and 119 men; 213 non-frail, 228 pre-frail and 38 frail; aged from 65 to 94 years; 403 non-fallers and 73 fallers). Frailty status explained fully: i) the gait speed; ii) the cadence: iii) the initial double contact: DS1; iv) the percentage of the single support phase v) the final double contact: DS2; v) the percentage of the swing phase of the gait cycle. Conclusions The results of this study allow a deeper understanding of the confounding factors since LMM highlighted the importance of frailty status for explaining all the spatiotemporal gait parameters. Clinical rehabilitation impact These results showed that to improve gait, clinical intervention should focus on reducing frailty status. It is also interesting to note that a history of falls explains none of the spatiotemporal gait parameters which suggests that it may be possible to improve gait in all frail subjects irrespective of their history of falls.

Multidisciplinary supportive care, integrating the dimensions of exercise alongside oncological treatments, is now regarded as a new paradigm to improve patient survival and quality of life. Its impact is important on the factors that control tumor development, such as the immune system, inflammation, tissue perfusion, hypoxia, insulin resistance, metabolism, glucocorticoid levels, and cachexia. An increasing amount of research has been published in the last years on the effects of physical activity within the framework of oncology, marking the appearance of a new medical field, commonly known as “exercise oncology”. This emerging research field is trying to determine the biological mechanisms by which, aerobic exercise affects the incidence of cancer, the progression and/or the appearance of metastases. We propose an overview of the current state of the art physical exercise interventions in the management of cancer patients, including a pragmatic perspective with tips for routine practice. We then develop the emerging mechanistic views about physical exercise and their potential clinical applications. Moving toward a more personalized, integrated, patient-centered, and multidisciplinary management, by trying to understand the different interactions between the cancer and the host, as well as the impact of the disease and the treatments on the different organs, this seems to be the most promising method to improve the care of cancer patients.

Walking speed and muscular strength are two main markers of health in adulthood. Previous studies have shown that personality traits may predict these two outcomes. However, little is known about the mechanisms underlying these relationships. Thus, the present study examined whether personality traits are associated with walking speed and muscular strength through the mediating role of subjective age (how young or old individuals experience themselves to be), attitudes toward aging and physical self-perceptions. Community-dwelling older women (N = 243; Mage = 73.0; SDage = 6.5) were recruited. For reasons of recruitment feasibility, participants were only older women. They were requested to complete a questionnaire measuring personality, subjective age, attitudes toward aging and physical self-perceptions. Following this, their walking speed and their muscular strength were investigated. Data were analyzed using structural equation modeling. In line with the literature, we extended the associations between extraversion, neuroticism, conscientiousness and walking speed and between conscientiousness, neuroticism, openness and muscular strength. Physical self-perceptions appear to be a robust mediator between personality traits and walking speed whereas attitudes toward aging and subjective age mediated the personality traits/muscular strength relationship. This study provides evidence, for the first time, that the associations between personality traits and physical capacities are different according to the physical capacities investigated. Based on these results, it could be interesting to adapt physical activity interventions to the psychological profile of older adults.

The present research investigated the effect of the induction of a negative stereotype on older adults’ performance during an endurance task, and how this stereotype influenced older adults’ subjective age. Thirty-four old women were randomly assigned to one of the two conditions: a negative stereotype condition and a nullified-stereotype condition. They performed an endurance task consisting of maintaining 30% of their maximal strength, as long as possible. Then, they answered a questionnaire including subjective age measurement. Contrary to expectations, the induction of the negative stereotype did not influence participants’ endurance performance. However, participants in the negative stereotype condition felt older than participants in the nullified-stereotype condition. As subjective age is relevant to late-life health outcomes, such as walking speed or mortality risk, it seems necessary to implement some strategies to decrease the negative effect of the negative stereotype on subjective age.

Background Lower limb muscle strength is an important determinant of physical function in older adults. However, its measure in clinical settings is limited because of the requirement for large-scale and costly equipment. A new simple protocol based on sit-to-stand test (STS) is developed to measure force velocity (F-v) and power velocity (P-v) profile in the community-dwelling older adults. Objective The objective of this study was to assess the validity of this new methodology for measuring F-v and P-v profile compared to the gold standard isokinetic BIODEX. Participants 46 older people aged 65–85 years (M = 73.7; SD = 7.7). Methods F-v and P-v profiles were assessed in participants on their dominant leg. The concurrent validity of STS was tested using Spearman's rank correlation coefficient and Passing Bablok: maximal power output Pmax, optimal velocity and force Vopt and Fopt, maximal force at null velocity F0, maximal unloaded velocity V0 and coefficient of F-v (SFV) and P-v equation (a_poly, b_poly). Results No proportional difference for F0 and b_poly and a low significant correlation for Pmax (r = 0.314), Sfv (r = 0.229), a_poly (r = 0.335) and b_poly (r = 0.226) whereas the other parameters were non correlated significantly. Conclusion STS method is moderately reliable on force and power parameters whereas further improvements are needing for velocity parameters. However, its feasibility, portability and lower cost compared to other methods makes it very affordable in clinical context and will allow easy investigation of aging population.

Purpose:The aim of the current study was to determine whether the anaerobic performance assessed by a modified Wingate test could account for the 1,500-m rowing ergometer performance in young competitive rowers.Methods:Fourteen national-level adolescent rowers performed on a rowing ergometer i) a 30-s allout exercise (i.e., modified Wingate test) and ii) a 1,500-m all-out exercise (i.e., rowing performance). For each of these two exercises, the mean power output was considered as the main performance criterion (PWIN and P1500, respectively).Results:PWIN was correlated to P1500 (r2 = .83, p < .0001, β = 100%). Furthermore, the estimated total muscle mass was correlated to PWIN and P1500 (r2 = .72 and r2 = .83, p < .0001, β = 100%, respectively). The allometric scaling also indicated that total muscle mass accounts 62% for the relationship between PWIN and P1500.Conclusion:Our results highlight the importance of considering the contribution of total muscle mass and anaerobic energy pathways to 1,500-m rowing performance in competitive adolescent rowers. Therefore, the modified Wingate test could be used by rowing coaches to potentially identify talented young rowers.

Background:Rehabilitation is at the center of the non-medical management of knee osteoarthritis. Concentric muscle strengthening is often preferred, while eccentric contractions play an important role in controlling knee flexion and knee stability and allow the development of a high level of strength with a low energy cost. But few studies have focused on these two techniqueObjectives:To explore the effect of a 6-week-exercise program on function, pain and performance level in symptomatic knee osteoarthritis patientsMethods:An analysis was performed of the data from 60 individuals with symptomatic knee osteoarthritis who were included in the EXART study. The EXART study was a prospective, randomized controlled trial which included patients aged 40 to 85 with KL 2 or 3 responding to the American College of Rheumatology criteria. The first group benefitted from a 6 week eccentric rehabilitation program and the second group from a standard 6 week concentric rehabilitation program. The endpoints were the changes from baseline to week 6 in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), pain, and performance measured with quadriceps power (PMax) and contraction strength (MMax). MRI muscle analysis was performed before and after physical activity.Results:Among 80 patients screened, 60 were included in the study and randomized. 25/30 subjects finished the program in the concentric group and 28/30 in the eccentric group. The mean population age was 74 (+/-8), mean IMC 27.2 (+/-4). The baseline total WOMAC mean was 49.2 (+/-19), VAS pain 5.3 (+/-2). At 6 weeks, both groups showed a significant improvement compared to baseline for the WOMAC without any difference between the two groups (mean difference evolution concentric = 7.5 ± 11.9 (p= pConclusion:Rehabilitation, whether eccentric or concentric, has a beneficial action on function and pain in symptomatic knee osteoarthritis whatever the methods. A gain in muscle performance and vastus medialis volume was found only with the eccentric rehabilitation. This study confirms the importance of any type of rehabilitation in knee osteoarthritis and raises the question of the relation between muscle gain/performance and function or painAcknowledgements:We would like to thank all the patients who took part in the study as well as all the members of the Fragile Platform of the Nice University Hospital.Disclosure of Interests:None declared

Summary Aims The aim of the study was to assess mechanical muscle capacities and profiles of well-trained soccer goalkeepers playing at a national amateur level. Methods Eleven goalkeepers (from 4th French division) performed vertical jump tests and series of loaded half squat and bench throw tests to assess lower and upper limbs force-velocity profiles, respectively. Force, velocity and power produced during each exercise were determined using a guided barbell. Maximal theoretical velocity and maximal theoretical force were determined from the force-velocity profiles. Slopes of those profiles were also calculated. Results Vertical jump performances were 38.5 ± 4.5 cm for the squat jump and 41.6 ± 5.5 cm for the countermovement jump. Lower limbs stiffness was 304.2 ± 55.1 N.m−1.kg−1. Lower limbs force-velocity profile was described by a slope of −11.5 ± 4.0 N.s.m−1.kg−1, with maximal theoretical force and velocity reaching 34.3 ± 5.9 N.kg−1 and 3.2 ± 0.2 m.s−1, respectively. Upper limbs muscular profile was described by a slope of −3.7 ± 1.1 N.s.m−1.kg−1, with maximal theoretical force and velocity of 13.6 ± 3.7 N.kg−1 and 3.7 ± 0.6 m.s−1, respectively. These values reveal that goalkeepers’ muscles profiles are oriented towards velocity. Conclusion This suggests that whatever the goalkeepers’ level, specific and conditioning trainings should mainly focus on velocity to optimize the performance of this specific soccer player.

Maciejewski, H, Rahmani, A, Chorin, F, Lardy, J, Samozino, P, and Ratel, S. Methodological considerations on the relationship between the 1,500-m rowing ergometer performance and vertical jump in national-level adolescent rowers. J Strength Cond Res 33(11): 3000-3007, 2019-The purpose of this study was to investigate whether 3 different approaches for evaluating squat jump performance were correlated with rowing ergometer performance in elite adolescent rowers. Fourteen young male competitive rowers (15.3 ± 0.6 years), who took part in the French rowing national championships, performed a 1,500-m all-out rowing ergometer performance (P1500) and a squat jump (SJ) test. The performance in SJ was determined by calculating the jump height (HSJ in cm), a jump index (ISJ = HSJ·body mass·gravity, in J), and the mean power output (PSJ in W) from the Samozino et al.'s method. Furthermore, allometric modeling procedures were used to consider the importance of body mass (BM) in the relationships between P1500 and jump scores. P1500 was significantly correlated with HSJ (r = 0.29, p ≤ 0.05), ISJ (r = 0.72, p < 0.0001), and PSJ (r = 0.86, p < 0.0001). Furthermore, BM explained at least 96% of the relationships between SJ and rowing performances. However, the similarity between both allometric exponents for PSJ and P1500 (1.15 and 1.04, respectively) indicates that BM could influence jump and rowing ergometer performances at the same rate, and that PSJ could be the best correlate of P1500. Therefore, the calculation of power seems to be more relevant than HSJ and ISJ to (a) evaluate jump performance and (b) infer the capacity of adolescent rowers to perform 1,500-m all-out rowing ergometer performance, irrespective of their body mass. This could help coaches to improve their training program and potentially identify talented young rowers.

Rowing races require developing high level of force and power output at high contraction velocity. This study determined the force-velocity and power-velocity (F-P-V) profiles of lower and upper limbs of adolescent rowers and their relationships with a 1,500-m rowing ergometer performance. The power developed during the 1,500-m (P1500) was evaluated in fourteen national-level male rowers (age: 15.3±0.6 yrs). F-P-V profiles were assessed during bench pull (BP) and squat jump (SJ) exercises. The theoretical maximal values of force (F0), velocity (V0), power output (Pmax) and the F-V relationship slope (S FV ) were determined. The body mass (BM) influence on these relationships was considered using an allometric approach. F0 was 720±144 and 2146±405 N, V0 was 1.8±0.1 and 1.8±0.3 m·s−1, Pmax was 333±83 and 968±204 W and SFV was −391±54 and −1,200±260 N·s·m−1 for BP and SJ, respectively. Upper and lower limb F0 and Pmax were significantly related. P1500 was significantly (P

Introduction Plusieurs etudes ont rapporte des liens entre la vitesse de marche des personnes âgees et certaines caracteristiques psychologiques comme les traits de personnalite [1] ou les stereotypes lies au vieillissement [2] . En revanche, les mecanismes explicatifs de ces relations sont peu connus et la question de leur generalisation a d’autres capacites fonctionnelles reste posee. Cette etude avait pour objet d’examiner les relations entre les traits de personnalite et differentes capacites fonctionnelles par le biais des attitudes vis-a-vis du vieillissement et des perceptions de soi. Methode Cent quarante-neuf personnes âgees (36 ♂ et 113 ♀, 73,8 ± 6,26 ans) presentant differents niveaux de fragilite physique selon les criteres de Fried et al. [3] ont repondu a une batterie de questionnaires valides mesurant leurs traits de personnalite (BFI-FR), attitudes vis-a-vis du vieillissement, âge subjectif, et valeur physique percue (ISP 25). Leurs vitesse de marche (Optogait), force et puissance (Ergometre isocinetique Biodex) ont egalement ete mesurees. Resultats Les analyses de modelisations par equations structurelles avec le logiciel AMOS 21.0 ont montre des indices d’ajustement satisfaisants [vitesse de marche : χ2 (54) = 75,15, TLI = 0,92, CFI = 0,95, RMSEA = 0,051 ; force : χ2 (54) = 81,82, TLI = 0,90, CFI = 0,92, RMSEA = 0,059 ; puissance : χ2 (54) = 75,78, TLI = 0,92, CFI = 0,94, RMSEA = 0,052]. Les traits de personnalite (c.-a-d., agreabilite, extraversion et ouverture aux experiences) apparaissent positivement associes aux differentes capacites fonctionnelles par le biais des attitudes face au vieillissement, de l’âge subjectif et des perceptions de soi. Discussion Ces resultats correlationnels vont dans le sens du caractere protecteur des traits de personnalite « ouverture aux experiences » et « extraversion » a l’egard des limitations fonctionnelles [1] et l’etendent a l’agreabilite et a d’autres capacites fonctionnelles comme la puissance.

International audience; BackgroundThe sit-to-stand movement requires balance control and coordination between the trunk and lower limbs. For these reasons, it is commonly used in clinics for evaluating lower limb muscle function in the elderly. The aim of the present study was to point out re levant biomechanical and neurophysiological sit-to-stand parameters allowing comparison between elderly fallers and non-fallers.MethodsTen elderly fallers and thirty non-fallers performed sit-to-stand movements. Sit-to-stand mechanical (maximal and mean force, impulse) and temporal parameters were measured in the vertical and anteroposterior axes using force platforms. Activity of rectus femoris, vastus lateralis, and gastrocnemius lateralis muscles was bilaterally recorded by surface electromyography.ResultsTime to realize sit-to-stand movements was significantly longer in elderly fallers compared to non-fallers (p < 0.05). In the same way, maximal vertical force and mean posterior force applied on force platform were significantly lower (p < 0.05) in fallers than in non-fallers individual. At muscular activity level, results showed a main statistical difference in gastrocnemius lateralis muscle activity patterns between faller and non-faller groups.ConclusionVertical and anteroposterior data from force platform, and gastrocnemius lateralis muscle activity determined during sit-to-stand movement are the most relevant parameters to differentiate fallers and non-fallers. Moreover, these factors highlight different strategies to rise from a chair between faller and non-faller group, suggesting that fallers would constantly adjust their control balance during the sit-to-stand movement.

Introduction Le depistage des patients âges fragiles est devenu une priorite pour les geriatres. Quelle que soit la methode de detection, la perte de force est l’un des criteres principaux de fragilite physique. De nos jours, il semble bien admis que la puissance musculaire soit un facteur plus important que la force a prendre en compte dans l’alteration des capacites fonctionnelles chez la personne âgee [1] . L’objectif de cette etude etait de determiner si la puissance musculaire pouvait etre un parametre important pour le depistage de la fragilite. Materiels et methode Cent quarante femmes âgees de plus de 65 ans ont participe a cette etude. La fragilite physique a ete evaluee a partir des 5 criteres de Fried et al. [2] . Les parametres spatiotemporels du pas (vitesse, amplitude et frequence) ont ete mesures grâce a un systeme d’analyse de la marche par detection optique. Une evaluation isocinetique des muscles extenseurs du genou a 6 vitesses a permis de calculer la puissance maximale (Pmax), le moment maximal (Mmax), la vitesse maximale (Vmax) et la vitesse optimale (Vopt) a partir de la relation force–vitesse. Resultats Quarante-six patients ont ete detectes fragiles. Pmax, Mmax et le pic de moment a chaque vitesse etaient significativement inferieures (p Conclusion La puissance musculaire semble donc etre un parametre discriminant pour la detection des personnes âgees fragiles. Cependant, ces resultats montrent egalement que ce parametre n’est pas plus sensible que la mesure du Mmax, et que les differences de puissance observees entre les deux populations sont essentiellement dues a une difference de production de force alors que les parametres de vitesse ne different pas.

Sit-to-stand (STS) movement is useful for evaluating lower limb muscle function, especially from force platforms. Nevertheless, due to a lack of standardization of the STS movement (e.g., position, subject’s instructions, etc.), it is difficult to compare results obtained in previous studies. The aim of the present study was to determine the most relevant condition, parameters, and number of trial to perform STS movements. In this study, STS mechanical (maximal and mean force, impulse) and temporal parameters were measured in the vertical, medio-lateral and antero-posterior axes using a force platform. Five STS conditions (i.e., with or without armrests, variation of the height of the chair and the movement speed) were analyzed to evaluate repeatability of different standardized procedures. Most of the mechanical and temporal parameters were influenced by the STS condition (p

Rowing is a strength endurance whole-body activity consisting in achieving 2000 m (Olympic distance) as fast as possible. During those 2000 m, rowers should apply high level of force both to the ha...

It is now recognised that ageing implies a progressive decrease in physical ability leading to dependence (Monod-Zorzi et al. 2007). Timed up and go (TUG) test is a clinical evaluation examining pe...