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The aim of this study was to verify the impact of ethnicity on the maximal power-vertical jump relationship. Thirty-one healthy males, sixteen Caucasian (age: 26.3 ± 3.5 years; body height: 179.1 ± 5.5 cm; body mass: 78.1 ± 9.8 kg) and fifteen Afro-Caribbean (age: 24.4 ±2.6 years; body height: 178.9 ± 5.5 cm; body mass: 77.1 ± 10.3 kg) completed three sessions during which vertical jump height and maximal power of lower limbs were measured. The results showed that the values of vertical jump height and maximal power were higher for Afro-Caribbean participants (62.92 ± 6.7 cm and 14.70 ± 1.75 W∙kg-1) than for Caucasian ones (52.92 ± 4.4 cm and 12.75 ± 1.36 W∙kg-1). Moreover, very high reliability indices were obtained on vertical jump (e.g. 0.95 < ICC < 0.98) and maximal power performance (e.g. 0.75 < ICC < 0.97). However, multiple linear regression analysis showed that, for a given value of maximal power, the Afro-Caribbean participants jumped 8 cm higher than the Caucasians. Together, these results confirmed that ethnicity impacted the maximal power-vertical jump relationship over three sessions. In the current context of cultural diversity, the use of vertical jump performance as a predictor of muscular power should be considered with caution when dealing with populations of different ethnic origins.

Athletes and coaches believe that adequate sleep is essential for peak performance. There is ample scientific evidence which support the conclusion that sleep loss seems to stress many physiological functions in humans. The aim of this study was to determine the effect of one night's sleep deprivation on intermittent exercise performance in the evening of the following day. Ten male Taekwondo players performed the Yo-Yo intermittent recovery test (YYIRT) in three sleep conditions (reference sleep night [RN], partial sleep deprivation at the beginning of night [PSDBN], partial sleep deprivation at the end of night [PSDEN]) in a counterbalanced order, allowing a recovery period ≥q36 hr in between them. Heart rate peak (HRpeak), plasma lactate concentrations (Lac) and rating of perceived exertion (RPE) were measured during the test. A significant effect of sleep restriction was observed on the total distance covered in YYIRT (P

Purpose The aim of this study was to investigate the effect of natural Pomegranate juice supplementation on performance and acute and delayed responses of muscle soreness and biomarkers of muscle damage after a weightlifting training session. Methods Nine elite weightlifters (21±0.5 years) performed two Olympic-Weightlifting-sessions after either placebo (PLA) or natural pomegranate juice (POMj) supplementations. Heart rate, blood pressure and blood samples (hematological parameters, muscle damage and C-reactive protein (CRP)) were collected at rest, 3min and 48h after each session. Weightlifting performance, RPE, and DOMS were also assessed after each training session. Results T-test showed higher performance (+8.30%) and lower RPE values (-4.37%) using POMj supplementation (p0.05). Additionally, during the 48h following the training session, POMj improved the recovery kinetic of SBP (p

Objective During rehabilitation of hemiparetic patients, physiotherapists face a discrepancy between motor skills during analytical exercises and functional abilities observed during gait. A muscle recruitment difference in the two situations could explain this gap. Among pathologic motricity manifestations observed in hemiparetic patients (Gracies 2005), exist the spastic co contraction phenomenon that presently concerned our work. Indeed, the main objective of this study was to compare co-contractions in hemiparetic subjects between an analytical exercise modality and a functional exercise modality, i.e. gait. Our hypothesis was that the co contraction is increased during gait as compared to an analytical exercise and could consequently lead to a decrease of gait ability in patients. Material/Patients and methods Muscular activity of knee flexors and extensors was recorded by surface EMG in analytic exercises and during the swing phase of gait, in a group of hemiparetic subjects (SH) and a group of healthy subjects (SS). Co-contraction index in duration and in magnitude was calculated from EMG data and allowed us the comparison between the 2 exercise modalities. Results Twelve SH and 11 SS were included. ICC differed between analytical and functional modalities in SH ( P Discussion - Conclusion Discussion: the observed results show a significant difference between co-contractions observed analytically and during gait in SH. These results validate the initial hypothesis since in most cases, co-contractions are increased during gait. If the conditions of muscle recruitment differ in analytic conditions and during gait, it seems unsuited to propose analytical exercises with the aim to improve gait parameters. This finding therefore suggests a more functional rehabilitation, according to the concept of task-oriented training: rehabilitate gait by gait.

Background Longitudinal data are data in which each variable is measured repeatedly over time. One possibility for the analysis of such data is to cluster them. The majority of clustering methods group together individual that have close trajectories at given time points. These methods group trajectories that are locally close but not necessarily those that have similar shapes. However, in several circumstances, the progress of a phenomenon may be more important than the moment at which it occurs. One would thus like to achieve a partitioning where each group gathers individuals whose trajectories have similar shapes whatever the time lag between them. Method In this article, we present a longitudinal data partitioning algorithm based on the shapes of the trajectories rather than on classical distances. Because this algorithm is time consuming, we propose as well two data simplification procedures that make it applicable to high dimensional datasets. Results In an application to Alzheimer disease, this algorithm revealed a “rapid decline” patient group that was not found by the classical methods. In another application to the feminine menstrual cycle, the algorithm showed, contrarily to the current literature, that the luteinizing hormone presents two peaks in an important proportion of women (22%).

Aim Very few studies have investigated the temporal specificity of melatonin (MEL) ingestion upon short-term maximal athletic performances. The aim of the present study was to explore the effect of morning MEL ingestion on cognitive and physical performances measured in the afternoon. Methods Twelve soccer players from a Tunisian squad (17.9 ± 1.3 years, 1.74 ± 0.06 m and 62.0 ± 8.8 kg) participated in the present study. They performed two testing sessions at 08:00 h, 12:00 h and 16:00 h after either MEL (5mg) or placebo (PLA) ingestion, in a randomized order. During each period, the participants performed the following cognitive and physical tests: reaction time and vigilance tests, medicine-ball throw (MBT), five jumps, handgrip strength (HG), and agility tests. Results cognitive and physical performances were significantly higher at 16:00 h compared to 08:00 h during the two conditions (p < 0.05). Moreover, performances of MBT and HG were lower in the morning with MEL in comparison to PLA (p < 0.05). However, MEL ingestion did not affect physical and cognitive performances measured at 12:00 h and 16:00 h. Conclusion morning MEL ingestion has no unfavourable effect on afternoon physical and cognitive performances in soccer players.

Single and continuous vertical jumping tests, as well as the Wingate anaerobic test (WAnT), are commonly used to assess the short-term muscle power of female volleyball players; however, the relationship among these tests has not been studied adequately. Thus, the aim of the present study was to examine the relationship of single and continuous vertical jumps with the WAnT in female volleyball players. Seventy adolescent (age 16.0 ˘ 1.0 years, body mass 62.5 ˘ 7.1 kg, height 170.4 ˘ 6.1 cm, body fat 24.2% ˘ 4.3%) and 108 adult female volleyball players (age 24.8 ˘ 5.2 years, body mass 66.5 ˘ 8.7 kg, height 173.2 ˘ 7.4 cm, body fat 22.0% ˘ 5.1%) performed the squat jump (SJ), countermovement jump (CMJ), Abalakov jump (AJ), 30 s Bosco test and WAnT (peak power, Ppeak; mean power, Pmean). Mean power in the Bosco test was correlated (low to large magnitude) with Pmean of the WAnT (r = 0.27, p = 0.030 in adolescents versus r = 0.56, p < 0.001 in adults). SJ, CMJ and AJ also correlated with Ppeak (0.28 ď r ď 0.46 in adolescents versus 0.58 ď r ď 0.61 in adults) and with Pmean (0.43 ď r ď 0.51 versus 0.67 ď r ď 0.71, respectively) of the WAnT (p < 0.05). In summary, the impact of the Bosco test and WAnT on muscle power varied, especially in the younger age group. Single jumping tests had larger correlations with WAnT in adults than in adolescent volleyball players. These findings should be taken into account by volleyball coaches and fitness trainers during the assessment of short-term muscle power of their athletes. Sin financiación No data JCR 2016 No data SJR 2016 No data IDR 2016 UEM

The present study examined the reliability of the force-velocity relationship during cycling and arm cranking exercises in active males and females. Twenty male and seventeen female physical education students performed three-session tests with legs and three-session tests with arms on a friction-loaded ergometer on six different sessions in a randomized order. The reliability of maximal power(Pmax), maximal pedal rate(V0), and maximal force(F0)were studied using the coefficient of variation (CV), the intraclass correlation coefficient (ICC) and the test-retest correlation coefficient(r). Reliability indices were better for men (1.74 ≤ CV ≤ 4.36, 0.82 ≤ ICC ≤ 0.97, and 0.81 ≤r≤ 0.97) compared with women (2.34 ≤ CV ≤ 7.04, 0.44 ≤ ICC ≤ 0.98, and 0.44 ≤r≤ 0.98) and in cycling exercise (1.74 ≤ CV ≤ 3.85, 0.88 ≤ ICC ≤ 0.98, and 0.90 ≤r≤ 0.98) compared with arm exercise (2.37 ≤ CV ≤ 7.04, 0.44 ≤ ICC ≤ 0.95, and 0.44 ≤r≤ 0.95). Furthermore, the reliability indices were high forPmaxandF0whatever the expression of the results (raw data or data related to body dimensions).PmaxandF0could be used in longitudinal physical fitness investigations. However, further studies are needed to judgeV0reliability.

The aim of this study was to examine the impact of emotional eliciting pictures on neuromuscular performance during repetitive supramaximal cycling exercises (RSE). In a randomized order, twelve male participants were asked to perform five 6-s cycle sprints (interspaced by 24 s of recovery) on a cycle ergometer in front of neutral, pleasant or unpleasant pictures. During each RSE, mean power output (MPO) and electromyographic activity [root mean square (RMS) and median frequency (MF)] of the vastus lateralis and vastus medialis muscles were analyzed. Neuromuscular efficiency (NME) was calculated as the ratio of MPO to RMS. Higher RMS (232.17 ± 1.17 vs . 201.90 ± 0.47 μV) and MF (68.56 ± 1.78 vs . 64.18 ± 2.17 Hz) were obtained in pleasant compared to unpleasant conditions (p < 0.05). This emotional effect persisted from the first to the last sprint. Higher MPO was obtained in pleasant than in unpleasant conditions (690.65 ± 38.23 vs . 656.73 ± 35.95 W, p < 0.05). However, this emotional effect on MPO was observed only for the two first sprints. NME decreased from the third sprint (p < 0.05), which indicated the occurrence of peripheral fatigue after the two first sprints. These results suggested that, compared with unpleasant pictures, pleasant ones increased the neuromuscular performance during RSE. Moreover, the disappearance of the beneficial effect of pleasant emotion on mechanical output from the third sprint appears to be due to peripheral fatigue.

The relationships between ankle plantar flexor musculotendinous stiffness (MTS) and performance in a countermovement vertical jump (CMJ) and maximal rate of torque development (MRTD) were studied in 27 active men. MTS was studied by means of quick releases at 20 (S0.2), 40 (S0.4), 60 (S0.6), and 80% (S0.8) of maximal voluntary torque (TMVC). CMJ was not correlated with strength indices but was positively correlated with MRTD/BM,S0.4/BM. The slopeα2and interceptβ2of the torque-stiffness relationships from 40 to 80%TMVCwere correlated negatively (α2) and positively (β2) with CMJ. The different stiffness indices were not correlated with MRTD. The prediction of CMJ was improved by the introduction of MRTD in multiple regressions between CMJ and stiffness. CMJ was also negatively correlated with indices of curvature of the torque-stiffness relationship. The subjects were subdivided in 3 groups in function of CMJ (groups H, M, and L for high, medium, and low performers, resp.). There was a downward curvature of the torque-stiffness relationship at high torques in group H or M and the torque-stiffness regression was linear in group L only. These results suggested that torque-stiffness relationships with a plateau at high torques are more frequent in the best jumpers.

Epub 2013 Aug 28; BACKGROUND: The role of arm motion during the long jump has been well studied. The aim of this study was to quantify the effect of forearm mass on impulse and the kinematics of the flight phase in an upper limb amputee.CASE DESCRIPTION AND METHODS: A world-record paralympic long jumper carried out jumps in three conditions: wearing his usual forearm prosthesis and with 0.3 and 0.4 kg added mass. A motion capture system including force plates was used to record the jump.FINDINGS AND OUTCOME: At take-off, the addition of 0.4 kg to the prosthesis decreased the vertical velocity of the centre of mass but increased horizontal velocity. These modifications were associated with an increase in landing distance and an improvement of the synchronization between arms.CONCLUSION: Increasing forearm mass appears to improve long jump performance. Further studies need to evaluate the optimal prosthetic mass for both training and competition.CLINICAL RELEVANCE: This biomechanical analysis of the long jump highlighted the effects of changing prosthesis mass on performance. This methodological approach may be useful in the context of sport and performance research.

The interests and limits of the different methods and protocols of maximal (anaerobic) power () assessment are reviewed: single all-out testsversusforce-velocity tests, isokinetic ergometersversusfriction-loaded ergometers, measure of during the acceleration phase or at peak velocity. The effects of training, athletic practice, diet and pharmacological substances upon the production of maximal mechanical power are not discussed in this review mainly focused on the technical (ergometer, crank length, toe clips), methodological (protocols) and biological factors (muscle volume, muscle fiber type, age, gender, growth, temperature, chronobiology and fatigue) limiting in cycling. Although the validity of the Wingate test is questionable, a large part of the review is dedicated to this test which is currently the all-out cycling test the most often used. The biomechanical characteristics specific of maximal and high speed cycling, the bioenergetics of the all-out cycling exercises and the influence of biochemical factors (acidosis and alkalosis, phosphate ions…) are recalled at the beginning of the paper. The basic knowledge concerning the consequences of the force-velocity relationship upon power output, the biomechanics of sub-maximal cycling exercises and the study on the force-velocity relationship in cycling by Dickinson in 1928 are presented in Appendices.

Purpose: To investigate changes in diffusion tensor imaging (DTI) measures in limbic system white matter of patients with temporal lobe epilepsy (TLE) using diffusion tensor tractography. Materials and Methods: DTI metrics including fractional anisotropy (FA), λ1, λ2, λ3, and trace (Tr) coefficients were obtained from tractography for bilateral fornix, superior and inferior cingulum fibers in 18 patients and 10 healthy controls. Hippocampal signal-to-noise ratio (SNR) quantitative analysis was performed in order to confirm the magnetic resonance imaging (MRI) hippocampal lesion presence or absence in TLE patients. Results: Nine patients presented unilateral hippocampal sclerosis (TLE+HS) and nine patients had no signal abnormalities on conventional MRI (TLE−HS). On the ipsilateral seizure side, all three investigated tracts showed significant DTI indices abnormalities in both patient groups when compared with controls, most marked on the inferior cingulum. Contralateral to the seizure side, the three tracts presented significant DTI parameters in only the TLE+HS group when compared with controls. Conclusion: The DTI abnormalities found in the TLE−HS group may suggest that in the inferior cingulum the structural integrity is more affected than in the fornix or superior cingulum white matter bundles. The eigenvalues taken separately add complementary information to the FA and Tr metrics and may be useful indices in better understanding the architectural reorganization of limbic system tracts in TLE patients without HS. J. Magn. Reson. Imaging 2012;36:561–568. © 2012 Wiley Periodicals, Inc.

The purpose of the Para-cycling classification is to minimize the impact of impairment on the outcome of competition, so that an athlete’s success in competition relies on training, physical fitness, and personal athletic talent (UCI Cycling Regulations, 2011). Athlete evaluation is done in compliance with the International Paralympic Committee (IPC) Classification Code and International Standard on Athlete Evaluation. A classification panel for athletes with physical impairments in Handbike, Tricycle, and Cycle consists of three International Cycling Union (UCI) accredited classifiers: a medical doctor, physiotherapist, and sports technician. Athletes are classified according to the extent of activity limitation resulting from their impairment. This places athletes according to how much their impairment affects core determinants of performance in cycling. The chapter V of UCI Para-cycling classification guide (UCI Cycling Regulations, 2011) stipulated that the “functional ability of the athletes will decide the final classification” which depends on the nature of spinal cord lesion (complete or incomplete), neurological impairment or amputation. A classification scale is used to include athletes suffering from different pathologies (neurological, amputation) but having comparable multiple functional impairments in the same race category. Since 2010, the UCI included two impairments in the cycling classification: neurological-impairments, with central or peripheral damage, and orthopedic impairments. For example in C1 class, the athletes with hemiplegia, diplegia, athetosis, or ataxia with single above knee and arm amputation. Additionally, a corrective factor essentially based on time – speed relationship is used during Paralympic games “for equity and to be able to compare the podium athlete/medal contenders” (http://www.uci.ch/Modules/BUILTIN/getObject.asp?MenuId=MTI1NjAO Hutzler et al., 1998; Sezer et al., 2004; Ward-Smith, 1985) and our comparison of intergroup performance established in different categories during the last world para-cycling championships (Table ​(Table1),1), it seems the severity of the athlete’s disability is associated with a reduced performance, whatever the duration of effort. One exception was the cycling performance occurred on individual road time trial (TT) and the 1-km Standing Start (1-km Individual TT, i.e., 1-km ITT) events for C4 and C5 categories. This result would reflect, in part, the difference in upper limb response to heterogeneous impairments among C4–C5′ athletes and, therefore, a difference in their gross efficiency (GE), i.e., the ratio between work and energy (Janssen et al., 2001; Leirdal and Ettema, 2011; Stone and Hull, 1993). Previous findings (Crouse et al., 1990; Janssen et al., 2001; Hutzler et al., 1998; Sezer et al., 2004) already suggested that reduced exercise tolerance in amputee and neurological subjects may be due to their reduced GE compared to healthy counterparts. Functional differences in balance, muscle, and motor control between amputees and cerebral palsy suggested that GE and therefore cycling performance are not similar. In a bilateral above knee amputee, Crouse et al. (1990) reported that walking with prostheses requires significant increase in energy expenditure and induces a shorter time to exhaustion compared to controls. Primary effects of stroke on sensorimotor function also include sensory-perceptual dysfunction which could induce technical impairment and a shorter time to exhaustion. However, no significant relationship was found between time to fatigue and motor disability (Corbett, 2009). Sezer et al. (2004) also showed a significant respiratory dysfunction in hemiplegic which could in part explain the difference in time to exhaustion compared with healthy subjects. It has been reported, in valid trained subjects, that maximal oxygen uptake (VO2max) rather than GE explained cycling performance (Capelli et al., 1998; Coyle, 1995). Taken together these previous results suggested that energy expenditure and aerobic capacity rather than motor ability may explain and contribute to cycling performance. During arm-cranking tests, Hutzler et al. (1998) also observed significant differences in aerobic capacity between athletes with different types of impairment (paraplegia, polio, or amputations). They showed that classification accounted for 30 and 38% of the variance in aerobic and anaerobic powers, respectively. This impact of disability was also significant on leg performance (Table ​(Table11). Table 1 Lap time (in seconds) to realize the best performance (±SD) of 1–km standing start for C1–C3 categories and the interclass time difference (delta, s) measured during the UCI World Para-cycling Track championships in 2011. Intermediate times measured during 1-km ITT revealed similar pacing-profiles which were characterized by an initial acceleration followed by a progressive decay in split times (Table ​(Table1).1). Like in valid cyclists, the first 250 m split time was a primary determinant of total 1-km ITT time in para-cyclists. It seems almost certain that the initial acceleration property is limited by the disability level. The 2.4 s separating first and second C1 cyclists after the first 250 m also demonstrated that the nature of disorder (central or peripheral) impacted on performance. Over the remainder of the race, the split time difference between C1–C2 and C1–C3 continuously increased over time whereas it blunted between C2 and C3 athletes. These differences in intergroup responses could be attributable in part to (1) the difference in energy cost between C1 and C2–C3 categories (Capelli et al., 1998) and (2) the adopted pacing strategies. C3 were characterized by a quicker start compared to C2 cyclists. Previously, Corbett (2009) showed that an overly quick start was associated with a concomitant slowing toward the finish. Performance appears to be attributable to faster VO2 responses without a significant change in anaerobic contribution (Bishop et al., 2002). A faster start could also alter the metabolic responses and explain the inability to maintain exercise intensity. Energy requirements may elucidate in part the decrease in time difference from 250 m to 1-km between C2 and C3 and the similar performance between 1-km ITT and 3-km individual pursuit in C2 category during the 2011 world track para-cycling championship (Table ​(Table1).1). The absence of comparative studies on physiological responses between infraclass cyclists makes the task difficult for the IPC to deliver a combined title for the C1–C5 categories during Paralympic Games. Therefore, the question of equity and nation’s strategies remains during a unique race with different final ranking. Based on the metabolic model, cycling performance would be primarily determined by the value of oxygen uptake at the lactate threshold (VO2-LT) and its upper-limit (VO2max; Coyle, 1995; Capelli et al., 1998). Hence, higher VO2max values will increase the time spent at high intensities for less impaired athletes with higher chances of winning. Moreover, the decrease in time difference over the time would promote C2–C3 categories. Finally, the difference in physiological and residual muscle strength between amputated and spinal cord injuries athletes require detailed biomechanical and physiological investigations in order to measure precisely the impact of disability on cycling performance.

International audience; BACKGROUND: This study was designed to evaluate proton magnetic resonance spectroscopy ((1)H-MRS) for monitoring the WHO grade II glioma (low-grade glioma (LGG)) treated with temozolomide (TMZ).METHODS: This prospective study included adult patients with progressive LGG that was confirmed by magnetic resonance imaging (MRI). Temozolomide was administered at every 28 days. Response to TMZ was evaluated by monthly MRI examinations that included MRI with volumetric calculations and (1)H-MRS for assessing Cho/Cr and Cho/NAA ratios. Univariate, multivariate and receiver-operating characteristic statistical analyses were performed on the results.RESULTS: A total of 21 LGGs from 31 patients were included in the study, and followed for at least n=14 months during treatment. A total of 18 (86%) patients experienced a decrease in tumour volume with a greater decrease of metabolic ratios. Subsequently, five (28%) of these tumours resumed growth despite the continuation of TMZ administration with an earlier increase of metabolic ratios of 2 months. Three (14%) patients did not show any volume or metabolic change. The evolutions of the metabolic ratios, mean(Cho/Cr)(n) and mean(Cho/NAA)(n), were significantly correlated over time (Spearman ρ=+0.95) and followed a logarithmic regression (P>0.001). The evolutions over time of metabolic ratios, mean(Cho/Cr)(n) and mean(Cho/NAA)(n), were significantly correlated with the evolution of the mean relative decrease of tumour volume, mean(ΔV(n)/V(o)), according to a linear regression (P

National audience; Un ensemble de recherches récentes suggèrent que les troubles de la personnalité décrits par le DSM-IV peuvent être évalués à partir d’un modèle général de description de la personnalité : le modèle à cinq facteurs (five-factor model: FFM). Dans cet article, nous présentons une méthode permettant de calculer des scores pour les différents troubles de la personnalité à partir du FFM. Sur la base de profils de personnalité prototypiques fournis par des experts pour chacun des troubles décrits par le DSM-IV, il est possible d’identifier, puis d’additionner les scores obtenus pour les traits de personnalité caractéristiques de chacun des troubles et d’obtenir un score de type dimensionnel pour chacun d’eux. Les scores ainsi obtenus pour les différents troubles de la personnalité sont comparés (corrélations et efficacité diagnostique) à des évaluations plus explicites et directes de symptômes décrits par le DSM-IV, réalisées sur deux échantillons de patients. Pour la plupart des troubles de la personnalité, à l’exception des troubles de la personnalité obsessionnelle–compulsive et histrionique, la validité convergente, la spécificité, la sensibilité et le potentiel de prédictivité négative (NPP) varient de « modérés » à « satisfaisants ». La validité discriminante, qui permet l’examen de la comorbidité entre les différents troubles, est équivalente à celle obtenue par des méthodes d’évaluation explicites et directes. Nous envisageons finalement les avantages de cette méthode en pratique clinique : facilité de l’évaluation de la personnalité, facilité de la cotation, existence de données de référence normatives.

Biomedical Engineering section. Directory of Open Access Journals, Google Scholar, CrossRef, Taylor & Francis Online; The first friction-cycle ergometers of the end of the nineteenth century and the beginning of the 20th century are presented before the description of more recent ergometers such as Fleisch ergometer (1954), ErgomécaTM (1985), sinus-balance ergometer, and weight-basket loaded ergometer. The limits of each ergometer are debated. The interest of friction-loaded ergometers was renewed with the proposal of different protocols enabling the assessment of maximal power during short all-out sprints on a cycle ergometer. These protocols are succinctly presented: corrected peak power protocol, force-speed test during repeated all-out sprints against different loads, torque–velocity relationship during a single all-out sprint. The different calibration procedures (static, dynamic, and physiological calibrations) of friction-loaded ergometers are described before the presentation of their results in the literature. Some improvements for the future friction-loaded ergometers are presented at the end of the paper.