Although lots of assistive devices have been studied to fight against caregivers' work-related musculoskeletal disorders, stand-and-turn devices effects on biomechanical constraints are still unknown. The aim of this study is to provide and compare quantitative data on loads in the low back area resulting from the use of a motorless stand-and-turn device and from manual patient handling. Nine caregivers participated to motion capture and ground reaction forces measurement sessions of three cases of handling: manual handling with one caregiver, manual handling with two caregivers, motorless device assisted handling. Forces and torques at the L5/S1 joint were computed through Inverse Dynamics process. Motorless device assisted handling required the smallest loads whereas manual handling with one caregiver required the biggest loads, the latter being in some cases twice as big as the former. Caregivers should use a stand-and-turn device when handling a patient from sitting/standing to standing/sitting position whenever it is possible.

Background: Despite abundant literature, the treatment of iliotibial band syndrome (ITBS) in cyclists remains complicated as it lacks evidence-based recommendations. Purpose: The aim of this study was to develop a musculoskeletal modelling approach that investigates three potential biomechanical determinants of ITBS (strain, strain rate and compression force) and to use this approach to investigate the effect of saddle setback. Design: Cross-sectional Methods: An existing 3D lower-body musculoskeletal model was adapted to cycling and to the computation of three putative pathomechanisms responsible for ITBS: ITB strain, ITB strain rate, and compression force between ITB and the lateral femoral epicondyle (LFE). Lower limb kinematics recorded from ten welltrained healthy cyclists served as input data of the model. Cyclists pedalled at a steady state (90rpm and 200W) on an ergometer, and three different saddle setback conditions were tested. The theoretical combined influence of hip and knee joint angles on ITBS was investigated and analysed through the lens of individual pedalling technique. Results: ITB-LFE compression force was the only parameter significantly affected by saddle setback and supports the hypothesis that compression force is likely to be a determinant factor in ITBS etiology. Furthermore, results showed that ITB-LFE compression force increases in individuals whose pedalling technique exacerbates hip extension-adduction and/or knee extension-internal rotation. Conclusion: This approach has the potential to be advantageously implemented as an additional tool to help diagnose/correct potentially harmful sport techniques and optimize equipment setup/design.

In obstetric science, it is unknown whether the inherent biomechanical features of the squatting position can be achieved and/or transposed to the supine birth position. In this study Biomechanical features of the squatting position were compared with 2 hyperflexed supine positions for giving birth. Thirteen pregnant women past the 32 weeks of gestational age not in labor were assessed first in the squatting position with the feet flat on the floor, then in the hyperflexed supine position, and finally in the optimal supine position "crushing" the hand of the caregiver onto the bed. For each position, the flexion of the spine associated with the plane of the external conjugate (ANGce) and the pelvis, hip flexion, and abduction were quantified using an optoelectronic motion capture system. A non-invasive strain-gauge-based measuring system was used to track the lumbar curve. An optimal position was defined with a flat lumbar spine and a pelvic inlet plane perpendicular to the lumbar spine (ANGce = 0° ± 5°). For the 13 participants, hip flexion, hip abduction, and the lumbar curve did not differ significantly for the three positions (squatting position, hyperflexed supine position, and OS) in the post-hoc analyses. The optimal supine position induced an ANGce closer to the perpendicular plane than the squatting position (p = 0.002). In the squatting position or in hyperflexed supine position positions, none of the subjects fulfilled the two conditions considered necessary to reach the optimal position. The squatting position was not significantly different from the supine hyperflexed supine position with or without voluntary lordosis correction.

The study aimed to assess the associations between the pelvis orientation, lumbar curve and thigh postures throughout pregnancy in a population of healthy women. Additionally, optimal mechanical birth conditions in terms of the pelvic inlet and lumbar curve were researched. The individuals' posture was assessed with three-dimensional motion analysis and the lumbar curve with the Epionics SPINE system. The association between the hip joint angles (flexion and abduction), the pelvis external conjugate, and lumbar curve position was assessed with a generalized linear mixed model (GLMM) adjusted to individuals' characteristics. Joint laxity was assessed with a modified Jobbin's extensometer. For all of the subjects, hip flexion and hip abduction were significantly associated with the angle between the external conjugate and spine, with higher correlation in the multivariate regression model. The association between hip flexion and the lumbar curve was less significant in multivariate than univariate regression analysis. Optimal birth conditions were never reached. The findings contribute to the understanding of the association between the hip position (flexion and abduction), pelvic orientation, and lumbar curve adjusted for joint laxity in healthy pregnant women. They lay the groundwork for future research in the field of obstetrical biomechanics.

This new sensor project has been initiated mainly in order to take measurements in the field of biomechanics during motions of human bodies. For that, it’s necessary to detect the efforts at the contacts with these human bodies in real situation, such as during working, walking, running, biking and so on. Up to now, most of 6 components force sensors which are used, for instance are sensors with each component measuring device as perfectly as possible decoupled from each other’s. This leads to expansive or very expansive sophisticated sensors. The present sensor is a stand-alone wireless, small sized 6-axis force sensor with a powerful and precise conditioning and acquisition system. The sensitive cell is a raw Stewart mechanical structure (strain-gages based) with, conversely to usual multicomponent sensors, force and moment components not decoupled at all, but optimally coupled. Owing to the powerful numerical capabilities of the sensor, the 6 effective components of a given mechanical action are instantaneously computed. Thanks to that, even for small quantity production, the sensor cost price is significantly reduced. This reduction is bigger for larger quantity productions like for: robotics, machine tools, hoisting machines… Added to the sensor design, the project include also a theoretical mechanical research in order to find an accurate calibration method, as easy as possible to be performed. This results in calibration tests needing only a standard traction-compression test machine running with mechanical effects decoupling tools dimensioned so that the calibration relative uncertainty is kept below 1‰. With that, only 6 elementary loading tests have to be applied to the sensor. The whole sequence of calibration is done automatically, completely governed by a powerful calculation and acquisition software. All the raw tests results (strain in µm/m) are automatically collected, converted and analyzed. At the end of the numerical treatment of each set of measurements, all the calibration data attesting the traceability to the International System of units (SI) of the sensor, including : raw calibration results, sensitivities coefficients matrix needed for later data reduction and conversion in solicitation components (force and moment), sensor performances characteristic curves (non-linearity, hysteresis error curve, zero shift error, etc.), calibrations uncertainties, are stored in the computer memory. The calibration matrix is then uploaded on the sensor. So, the measurement results (values of solicitations components) are directly expressed in mechanical units traceable to SI. This sensor is able to perform high data rate wireless streaming with time-synchronization protocol or low data rate transmissions compatible with IOT connectivity. The following paper describes and comments most important engineering job sequences and calibration results. It’s also an example of future connected sensors structures able to gather, not only the staff needed to give accurate high levels measurement results, but also all the key pieces of information’s relative to the measurement traceability proof and quality management, all of them being instantaneously available on the net (IOT). This research and development job got the funding of FEDER-FSE-2014-2020 Nouvelle-Aquitaine program and of CRITT-Sport et Loisirs.

Background: The squatting birth position is widely used for "natural" birth or in countries where childbirth occurs in non-medical facilities. Squatting birth positions, like others, are roughly defined so a biomechanical assessment is required with the availability of noninvasive technology in pregnant women. In practice, we can observe spontaneously two kinds of squatting birth position: on tiptoes and with feet flat. Objective: To compare the impact of foot posture on biomechanical parameters considered essential in obstetrical biomechanics during a squatting birth position: on tiptoes versus with feet flat on the floor. Study design: Thirteen pregnant women beyond 32 weeks of gestational age who were not in labor were assessed during squatting birth position firstly spontaneously and secondly with the foot posture that was not taken spontaneously (on the tiptoes vs with feet flat). For each position, ANGle of flexion on the spine of the plane of the pelvis external conjugate (ANGec), hip flexion and abduction, and lumbar curve were assessed using an optoelectronic motion capture system and a biomechanical model adapted from the conventional gait model as well as a measuring system of the lumbar curve. Results: Spontaneously, 11 out of 13 women squatted on tiptoe at the first test. On tiptoes the hip flexion was lower than with feet flat (p < 0.02), whereas hip abduction was not significantly different (p = 0.28). A lower ANGec angle (p = 0.003) was noticed for the tiptoe position than feet flat. The lumbar curve (lordosis) was more marked for the squatting position on tiptoes than for the position with feet flat (p < 0.001). On tiptoes no woman had a pelvic inlet plane perpendicular to the spine and none had a flat back or kyphosis. No woman on tiptoes fulfilled the two conditions necessary for the position that we consider optimal. Conclusion: In squatting birth position, foot posture has a biomechanical impact on lumbar curve and pelvic orientation. When comparing squatting positions (on tiptoes vs feet flat), feet flat on the ground is closer to optimal birth conditions than on tiptoes.

The thumb’s use is associated with musculoskeletal disorders in many sectors. It plays an essential role in the fulfillment of tasks such as holding. Unlike other upper limb joints, there are insufficient data on comfort angles of the thumb. The purpose of this study was to investigate the thumb joint angles for five order pickers with different anthropometric parameters. A three-dimensional motion analysis system was used with thirty reflective markers attached to each subject skin, allowing an optoelectronic system to track the path of different markers in 3Dimension. The participants performed nine actions such as rear traction, honk and lifting for seven different forklifts and two different movements of abduction/adduction and flexion/extension. As a result of this study, specific forklift type was found as the only type adapted for all participants with their different anthropometric parameters. While the other forklifts need some modifications to be adapted by others. This study can be extended with a larger number of participants working in the same field. The aim should be having a standard angle of the thumb’s comfort for order pickers.

Tethered swimming is a method often used to measure or enhance the physical and technical resources of swimmers. Although it is highlighted that the technique used in tethered swimming is probably different from that used in free conditions, there are few comparative studies on this subject. The current study aims to compare fully tethered and free swimming based on kinematic hand parameters (orientation, velocity and acceleration of the hand, sweepback and angle of attack), which are known to act directly on the generation of propulsive forces. The results show that there are significant differences during the stretch and catch phases but less during the insweep and upsweep phases. Tethered swimming makes it possible to estimate the propelling forces generated by the hand in free swimming at distance and middle-distance paces, but overestimates it at sprint pace. However, in view of the modifications of the kinematic parameters, it should not be used under repeated conditions of use, such as for the development of swimmers’ capacity.

Gyroscopes are now becoming one of the most sold MEMS sensors, given that the many applications that require their use are booming. In the medical field, gyroscopes can be found in Inertial Measurement Units used for the development of clinical tools that are dedicated to human-movement monitoring. However, MEMS gyroscopes are known to suffer from a drift phenomenon, which is mainly due to temperature variations. This drift dramatically affects measurement capability, especially that of cheap MEMs gyroscopes. Calibration is therefore a key factor in achieving accurate measurements. However, traditional calibration procedures are often complex and require costly equipment. This paper therefore proposes an easy protocol for performing a thermal gyroscope calibration. In this protocol, accuracy over the angular velocity is evaluated by referring to an optoelectronic measurement, and is compared with the traditional calibration performed by the manufacturer. The RMSE between the reference angular velocity and that obtained with the proposed calibration was of 0.7°/s, which was slightly smaller than the RMSE of 1.1°/s achieved by the manufacturer's calibration. An analysis of uncertainty propagation shows that offset variability is the major source of error over the computed rate of rotation from the tested sensors, since it accounts for 97% of the error. It can be concluded that the proposed simple calibration method leads to a similar degree of accuracy as that achieved by the manufacturer's procedure.

The aims of this study were to (1) propose a method for evaluating shot-putters mechanical power, (2) investigate the relationship between mechanical work of hand action force (WHAF), peak power output (PPO) of different limbs and shot-put performance and (3) show which of these two parameters (WHAF, PPO) were the most appropriate to characterize the explosive abilities of the shot-putter. Twelve junior right-handed shot-putters, practised glide technique shot-put throwers (personal best = 13.57  ±  1.72 m), participated in this study. Arm and leg force-velocity tests were performed to measure PPO. Kinematic analysis was conducted during a shot-putting event in regular conditions to quantify the WHAF at the release moment and shot-put performance. Significant correlations were found between absolute arm and leg PPO with upper and lower muscle volumes (r = .67; p = .03; r = .76; p = .01; r = .74, p = .01; r = .65, p = .04). Positive relationships were recorded between absolute arm and leg PPO and shot-put performance (r = .67, p = .02; r = .81, p = .004, respectively). Shot-put performance was also closely related to the WHAF (r = .93, p = .0001) and release velocity parameter (r = .86, p = .001). The present results confirm that force-velocity test and WHAF constitute useful tools for assessing mechanical power in throwing. The WHAF could be considered as more suitable than force-velocity test.

Magneto-inertial measurement units (MIMUs) are a promising way to perform human motion analysis outside the laboratory. To do so, in the literature, orientation provided by an MIMU is used to deduce body segment orientation. This is generally achieved by means of a Kalman filter that fuses acceleration, angular velocity, and magnetic field measures. A critical point when implementing a Kalman filter is the initialization of the covariance matrices that characterize mismodelling and input error from noisy sensors. The present study proposes a methodology to identify the initial values of these covariance matrices that optimize orientation estimation in the context of human motion analysis. The approach used was to apply motion to the sensor manually, and to compare the orientation obtained via the Kalman filter to a measurement from an optoelectronic system acting as a reference. Testing different sets of values for each parameter of the covariance matrices, and comparing each MIMU measurement with the reference measurement, enabled identification of the most effective values. Moreover, with these optimized initial covariance matrices, the orientation estimation was greatly improved. The method, as presented here, provides a unique solution to the problem of identifying the optimal covariance matrices values for Kalman filtering. However, the methodology should be improved in order to reduce the duration of the whole process.

The study of biological point-light displays (PLDs) has fascinated researchers for more than 40 years. However, the mechanisms underlying PLD perception remain unclear, partly due to difficulties with precisely controlling and transforming PLD sequences. Furthermore, little agreement exists regarding how transformations are performed. This article introduces a new free-access program called PLAViMoP (Point-Light Display Visualization and Modification Platform) and presents the algorithms for PLD transformations actually included in the software. PLAViMoP fulfills two objectives. First, it standardizes and makes clear many classical spatial and kinematic transformations described in the PLD literature. Furthermore, given its optimized interface, PLAViMOP makes these transformations easy and fast to achieve. Overall, PLAViMoP could directly help scientists avoid technical difficulties and make possible the use of PLDs for nonacademic applications.

The development of codes and power calculations currently allows the simulation of increasingly complex flows, especially in the turbulent regime. Swimming research should benefit from these technological advances to try to better understand the dynamic mechanisms involved in swimming. An unsteady Computational Fluid Dynamics (CFD) study is conducted in crawl, in order to analyse the propulsive forces generated by the hand and forearm. The k-ω SST turbulence model and an overset grid method have been used. The main objectives are to analyse the evolution of the hand-forearm propulsive forces and to explain this relative to the arm kinematics parameters. In order to validate our simulation model, the calculated forces and pressures were compared with several other experimental and numerical studies. A good agreement is found between our results and those of other studies. The hand is the segment that generates the most propulsive forces during the aquatic stroke. As the pressure component is the main source of force, the orientation of the hand-forearm in the absolute coordinate system is an important kinematic parameter in the swimming performance. The propulsive forces are biggest when the angles of attack are high. CFD appears as a very valuable tool to better analyze the mechanisms of swimming performance and offers some promising developments, especially for optimizing the performance from a parametric study.

The purpose of this study was to investigate the evolution of ground reaction force during alpine skiing turns. Specifically, this study investigated how turn phases and slope steepness affected the whole foot normal GRF pattern while performing giant slalom turns in a race-like setting. Moreover, the outside foot was divided into different plantar regions to see whether those parameters affected the plantar pressure distribution. Eleven skiers performed one giant slalom course at race intensity. Runs were recorded synchronously using a video camera in the frontal plane and pressure insoles under both feet's plantar surface. Turns were divided according to kinematic criteria into four consecutive phases: initiation, steering1, steering2 and completion; both steering phases being separated by the gate passage. Component of the averaged Ground Reaction Force normal to the ski's surface([Formula: see text], /BW), and Pressure Time Integral relative to the entire foot surface (relPTI, %) parameters were calculated for each turn phases based on plantar pressure data. Results indicated that [Formula: see text] under the total foot surface differed significantly depending on the slope (higher in steep sections vs. flat sections), and the turn phase (higher during steering2 vs. three other phases), although such modifications were observable only on the outside foot. Moreover, [Formula: see text] under the outside foot was significantly greater than under the inside foot.RelPTI under different foot regions of the outside foot revealed a global shift from forefoot loading during initiation phase, toward heel loading during steering2 phase, but this was dependent on the slope studied. These results suggest a differentiated role played by each foot in alpine skiing turns: the outside foot has an active role in the turning process, while the inside foot may only play a role in stability.

La collaboration entre enseignants d’EPS et de sciences pourrait rendre effective une formation des eleves aux demarches de l’ingenieur.

The impact of pregnancy on pelvic floor disorders remains poorly understood. During pregnancy, an increase in ligamentous laxity and pelvic organ mobility is often reported. Our main objective was to investigate a possible association between peripheral ligamentous laxity and levator hiatus (LH) distension during pregnancy.

In the fields of medicine and biomechanics, MEMS accelerometers are increasingly used to perform activity recognition by directly measuring acceleration; to calculate speed and position by numerical integration of the signal; or to estimate the orientation of body parts in combination with gyroscopes. For some of these applications, a highly accurate estimation of the acceleration is required. Many authors suggest improving result accuracy by updating sensor calibration parameters. Yet navigating the vast array of published calibration methods can be confusing. In this context, this paper reviews and evaluates the main measurement models and calibration methods. It also gives useful recommendations for better selection of a calibration process with regard to a specific application, which boils down to a compromise between accuracy, required installation, algorithm complexity, and time.

Background: The Union Cyclist International (UCI) regulates saddle setback - ‘ the tip of the saddle shall be a minimum of 5 cm to the rear of a vertical plane passing through the crank axis but no maximum is recommended’ - while there is no scientific rational supporting this regulation. Furthermore, the absolute value of 5 cm applies to all cyclists without accounting for cyclist’s anthropometry and, in other disciplines such as track cycling and triathlon that are not subject to this regulation, a smaller setback is often used while there is no higher prevalence of joint overuse injuries.  Purpose: The aim of this study was to investigate the effect of saddle setback on knee joint forces exhibited during cycling. A musculoskeletal modelling approach was developed and, in an attempt to identify the underlined mechanisms responsible for knee joint forces, pedal force, knee kinematics and knee muscle forces were investigated  Methods: Ten well-trained (8.5 ± 6.75 years of experience in competition and average weekly training volume 4.0 ± 0.8 hours) cyclists volunteered to participate in the study. A stationary cycle ergometer was instrumented with two six-load component force sensors that were integrated in the pedals. A 20-camera motion analysis system was used to acquire 3D kinematics. Markers data and pedal forces served as input of the model for the computation of knee joint forces that resulted from the recommended Opensim calculation steps: 1) scaling to participant’s anthropometry, 2) inverse kinematics to compute joint angles, 3) static optimisation to compute muscle forces and 4) joint reaction analysis to compute tibiofemoral forces and patellofemoral forces. Knee joint forces were normalised to pedalling cycle and the mean and peak of the 3 components of each forces were calculated. Three saddle setback conditions were compared: a Recommended condition which included values of saddle height and setback based on individual anthropometric measurements, a Backward (10% more backward) and a Forward (10% more forward) conditions. The setup of all other settings was standardised. For the three conditions, participants were instructed to perform a 3minute trial while keeping cadence (90rpm) and power (200W) constant.  Results: Results showed that the timing (~160° of pedalling cycle) of the peak of tibiofemoral compressive force remained unchanged across saddle setback conditions. Contrary to what some epidemiological studies earlier suggested this study indicates that sitting close to the handlebar (even closer than the 5 cm of the UCI regulation) was not associated with an increase of patellofemoral and tibiofemoral forces. Oppositely, sitting backward may be more detrimental as it leads to higher tibiofemoral forces (Table 1). A 15% increase was found in a ~6 cm change of saddle setback. Those results balance previous findings that reported a mechanical advantage associated with sitting more backward.  Discussion: In a whole, this study brings new insights on the underlying mechanisms of tibiofemoral force in cycling that are of importance for a safe training and for rehabilitation protocols. Indeed, results further explained that the peak joint force was linked neither to the peak of force applied to the pedal nor to the peak of quadriceps force but to the increasing of eccentric hamstring force at the end of the downstroke phase, just before the transition toward the upstroke.  Conclusions: While it was previously reported that sitting more backward increases effectiveness in steady-state pedalling, the present study would oppositely prevent for using an important saddle setback. This underlies the difficult compromise between performance and health and reflects the complexity of defining an “optimal saddle position” and establishing bike fitting guidelines. Subsequently, our results suggest that UCI recommendations (1.3.013), which only regulate the maximal forward saddle position (saddle setback > 5 cm), but neither its backward position nor saddle height, may need to be revised.

This review aims to examine how childbirth position during labour affects maternal, fetal and neonatal outcomes. Epidemiological data suggest that vertical birthing positions have many benefits. But when we consider the players and mechanisms of delivery, including the forces generated to move the fetus and obstacles to its progression, many questions remain about the advantage of one position over another.Thus, childbirth could be considered in a way as an athletic feat that probably requires the choice of optimal positions. These should be individually suited to each woman at different stage of labour to improve its efficiency and effectiveness.Tweetable abstract: Beyond epidemiological data, biomechanical investigations is necessary to assess birth's position.

Background: In the field of biomechanical analysis of pedaling motion, researchers studied the relationship between cost energy and cycling technique for optimal use of the force applied to the pedals, to improve cycling velocity for minimal energy cost or to compute the joint powers according to the resistive load. For that, numerous measuring devices have been developed and investigated to evaluate resultant torque and/or power output. Recently, new pedal sensors I-Crankset (ICS) are sold to measure the forces applied to the pedals and to calculate the torque and/or power output produced during cycling. These pedals’ sensors were calibrated and certificated, but it was essential to check if these devices still measured accurately after their integration on an ergometer. Purpose: The aim of this study was to compare dynamically this new device for measuring crankset’s resultant torque, mechanical power and work outputs.  Methods: A subject (Male, 75 kg, 1.82 m, trained rider) took part to this study conducted ethically according to international standards. The rider adjusted the cycle ergometer according to its personal settings. Figure 1 described the test bench. It was composed of: a chainring (A) was used to connect the ergocycle to the bench through a chain and a flywheel (D) associated with a mechanical braking device (E) composed of a tray with additional masses. The evaluation protocol was implemented to achieve three pedaling conditions and so to cover the usual torque and power ranges (Table 1). For each condition, the subject produced a pedaling torque to overcome that resistive load during one trial of 90 seconds. Feedback of cadence was displayed on the Control SRM bicycle computer. The torque reference sensor (model 1641/1648, Lebow) named RTSL (C) was installed on the axis (B). The scientific version SRM sensor was mounted on the crankset of the ergocycle. The ICS sensors were fixed at each pedal. The relative pedal to crank and the crank to ergometer angles were measured using encoders.  Analyzed parameters: As all the signals are acquired at 200 Hz and synchronized, for each cycle and for each acquisition system, we had the same number of acquisitions samples. According to the sample rate and protocol used, more than 12 000 instantaneous measures will be available for the comparison of several devices. Three power outputs were computed through these equations: (1)  with , k is the reduction coefficient between SRM and bench chainrings, ratio of the two diameters. (2) SRM:,  is the average angular velocity of the crankset over the cycle. (3) ICS: ,  is instantaneous angular velocity of the crankset computed from encoders measures. The mechanical work outputs  were given by integration over the time of the power outputs. By design, the SRM only measures an average angular velocity, so we computed mechanical work firstly considering this constant angular velocity () and secondly considering instantaneous angular velocity provided by ICS encoders (). Statistical analysis: For each condition, the same analysis was performed on torque, power and work outputs obtained from the different sensors. These instantaneous parameters, once pedaling cycles normalized, were compared using a coefficient of multiple correlation inter-protocol (CMC ip ) to appreciate the similarity of the instantaneous measures waveforms given by various sensors in a single acquisition of the same parameter. For each condition (n=30 cycles) and for all conditions (n=90 cycles), the averaged torque and power output were computed over each cycle and then these values were compared pairwise of sensors (A Bland-Altman analysis). A global normalized averaged torque evolution over cycles was also computed for condition 1 and for each sensor using.  Results: Mechanical power output comparisons: Table 2 reports all the data for the comparison of the averaged power output measured by the three sensors, for the each condition and all conditions. Especially for condition 3, we note an increase for the power output of the mean bias and error range between SRM and RTSL against those computed for the torque [mean bias: -4.4 ±2.3% for the power vs -1.20 ±0.53% for the torque; error range: 29 W (9.2%) for the power and 0.79 Nm (1.9%) for the torque]. This is not the case for ICS. The figure 3 confirms these results with a 95% limits of agreement larger for the SRM than ICS [respectively -1.81; 7.37 W and -20.70; 9.48 W for ICS and SRM]. Mechanical work output comparisons: Table 3 shows the difference of cumulative output work over thirty cycles between ICS and RTSL then SRM and RTSL for each condition. The differences are also expressed as the percentage of the total cumulated work. To analyze the influence of the angular velocity, we integrated power output over time to compute the work output in using i) the torque and angular velocity measured by SRM (W SRM ) and ii) the SRM torque multiplied by ICS angular velocity (W SRM* ). These results are presented at the last lines of table 4. The relative error is under 2% whatever the conditions, excepted for condition 3 between SRM and RTSL (5.26%). This error can be reduced by using I‰ ICS provided by ICS to compute the W SRM* (1.44 %).  Discussion: Power output discussion. For the power output, we note high values of  between ICS and RTSL (Table 3). For the steady state condition (C1: 210 W), ICS power mean relative error (0.1 ±0.5%) is better than [1] when comparing Velotron cycle ergometer (-0.8% for constant 250 W trial) with a test bench. For condition 2 (150 – 250 W, 80 rpm), ICS results (1.8 ±0.5%, Table 2) are closed to power mean relative error reported by [4] when comparing Powertap (-1.5 ±0.6% for 50-1000 W at 100 rpm trial) with a test bench. As SRM is considered as a gold standard [5], we will try to position ICS against SRM. Before that, we check that SRM results are consistent with literature. The mean relative errors reported by [1] (0.18%) and [4] (0.1 ±1.1%) are lower than errors of the present study (respectively 0.8 ±1.2% for condition 1 and -0.8 ±2.1% for condition 2). These differences can be related to the possibility of the test bench used by [6] to maintain a constant pace along all the cycle unlike the protocol of this study (mean cadence: 8.3 ±0.2 rad/s for conditions 1 and 2). Indeed, it’s difficult for a rider to produce a constant crankset angular velocity like the motorised test bench used by [1] and [3]. [1] shows that a rapidly increasing angular velocity results in a more inaccurate power measurement (mean relative error: -3.3 %; CI = -8.1 to 1.5 %). This is closer to the results for condition 3 (-4.4 %; CI = -9 to 0.2 %). This condition accentuates the inability of the SRM to record, by design, instantaneous crankset angular velocity. For a similar pedaling cadence and power output, the relative mean error (1.2 %) between Powertap ergometer and SRM reported by [2] is comparable with the relative error between ICS and SRM computed for condition 1 (0.9%, Table 3). However, ICS seems to be more accurate than SRM when looking at the individual results obtained for SRM (-2.4%) and ICS (1.2%) against RTSL for all conditions. Consequently, as for the torque, ICS can be considered sufficiently accurate. Work output discussion: Table 3 show the requirement to precisely measure the instantaneous values of crankset angular velocity to calculate the work as part of an energy study of the pedaling motion. Thus, when pedaling with constant angular velocity, the power output computed by SRM () is enough accurate to calculate the work output (). For the conditions 1 and 2, the error respectively equal to 0.98% and 1.16% is acceptable. But when the angular velocity is variable, the error becomes equal to 5.26% for the SRM while it is still under 2% for ICS. This result confirms those obtained by [1] which indicates that a rapidly increasing angular velocity causes an inaccuracy in calculating the SRM power. This error is reduced to 1.44% when the torque measured by SRM () is multiplied by the instantaneous angular velocity measured by ICS (). So, ICS should be preferred for power and work outputs investigations.  Conclusions: The study showed that ICS sensor was an accurate powermeter comparable to a standard reference sensor and to SRM regardless the pedaling cadence (56 to 90 rpm) and the resistive load (18 to 42 Nm). However, ICS was more efficient than SRM for evaluating the work particularly when the pedaling angular velocity various significantly. This study showed that it was therefore essential to measure both instantaneous torque and angular velocity in order to conduct an energy analysis of the pedaling motion.