Silvio Lorenzetti


Last Name

Lorenzetti

First Name

Silvio

ORCID

0000-0002-8339-8960

Organisational unit

01630 - Lehre HEST

Search Results

Publications 1 - 10 of 43
  • Pilot study: is there an influence of lower limb positioning during magnetic resonance imaging on muscle cross section shape assessment in the thigh?
    Item type: Journal Article
    Oberhofer, Katja; Blum, Matthias; Achermann, Basil; et al. (2023)
    BMC Research Notes
    Positioning in an MRI can influence quantitative measures of the muscle. The goal of this pilot study was to assess the influence of different levels of knee elevation during MRI on the predicted cross-sectional muscle shape in the thigh. Data were acquired in three healthy male participants (age: 29.3 ± 5.1y, height: 181.3 ± 6.4cm, weight: 85.1 ± 3.7kg). For each participant, three MRI scans were taken by a trained radiographer with low, moderate and high knee elevation. The shape of the anatomical cross-sectional areas of the hamstrings and quadriceps in three leg positionings were compared by fitting ellipsoidal functions to the segmented MRI data and calculating the so-called J index for every image slice using the Python scripting language. Different levels of knee elevation resulted in apparent changes in J index for all muscles except vastus medialis. Thereby, the changes were overall more pronounced in the hamstrings compared to the quadriceps. Particularly, by elevating the knee from 8 to 15 degree, the percentage changes in J index were between 7.2 and 13.6% for the hamstrings and between 0.5 and 3.3% for the quadriceps, respectively. For assessing the musculoskeletal properties by means of MRI, a standardized positioning of the leg is required and the knee joint angle should be controlled.
  • Pilot study: validity and reliability of textile insoles used to measure the characteristics of landing tasks during rehabilitation and artistic gymnastics
    Item type: Journal Article
    Schümperlin, Delia; Schärer, Christoph; Kalberer, Luzia; et al. (2023)
    BMC Research Notes
    Objectives: Artistic gymnastics is a sport where most athletes start at an early age and training volumes are high. Hence, overuse and acute injuries are frequent due to the load endured during landing tasks. During landing, the ground reaction force (GRF) is up to 15.8 times the body weight and therefore reliable GRF measurements are crucial. The gold standard for GRF measurements are force plates. As force plates are mostly used in a constrained laboratory environment, it is difficult to measure the GRF in representative training settings. Textile insoles (novel GmbH, Munich, Germany) exist, which can be used to measure dynamic GRF. Hence, the motivation of this study is to test the validity and reliability of these insoles during landing tasks. GRF was measured during four different exercises, in two test subjects and compared to concurrent force plate data. Results: Twelve out of 16 statistical parametric mapping plots showed no significant difference between the measured force curves of insoles and force plates. Across conditions, the root mean square error of the maximal vertical GRF was 21 N/kg and an impulse 0.4 Ns/kg. The intraclass correlation coefficient (ICC 2,1) ranged from 0.02 to 0.76 for maximal vertical GRF and from − 0.34 to 0.76 for impulse. The insoles are a valid measurement tool for GRF curve progression and impulse during landing but underestimate the maximal vertical GRF.
  • Comparison of the kinematics and kinetics of shoulder exercises performed with constant and elastic resistance.
    Item type: Journal Article
    Häberle, Ramona; Schellenberg, Florian; List, Renate; et al. (2018)
    BMC Sports Science, Medicine and Rehabilitation
    Background: Internal and external rotation exercises of the shoulder are frequently performed to avoid injury and pain. Knowledge about the motion and loadings of the upper extremities during these exercises is crucial for the development of optimal training recommendations. However, a comparison of the angles and corresponding moments in the upper extremities that are achieved during internal and external rotation exercises for the shoulder by using different resistance types has not yet been performed. Therefore, the aim of the study was to examine upper extremity kinetics and kinematics in 3D of the internal and external rotation exercises. Methods: The kinematics and kinetics of 12 participants while they performed 10 different exercises with a constant and with an elastic external load corresponding to 2% body mass was assessed. The motion of the upper extremities was recorded three-dimensionally with a motion capture system, using a newly developed marker set and joint coordinate systems with 28 markers. The applied external load was measured with a load cell placed in series with the external resistance, and moments were calculated using an inverse dynamics approach. Results: The range of motion and the joint loading was highly dependent on the exercises. The range of motion in the glenohumeral joint did not differ significantly between the two resistance types, whereas internal/external rotation moments were significantly higher with constant resistance than those with elastic resistance. Conclusions: Larger or lower moments can, therefore, be achieved through selection of the appropriate resistance type, while the range of motion can be altered through the selection of exercise type. Therefore, the loading motion patterns identified in this study can help to choose suitable shoulder exercises dependent on the training objective.
  • A Fast Testing Method to Objectively Quantify the Stiffness of Stability Boots
    Item type: Journal Article
    Bürgi, Simon; Roost, Judith; Hitz, Marco R.; et al. (2015)
    Applied Bionics and Biomechanics
    Stability boots can protect the ankle ligaments from overloading after serious injury and facilitate protected movement in order to aid healing of the surrounding soft tissue structures. For comparing different stability shoe designs and prototypes, a reliable and fast testing method (FTM) is required. The aim of this study was to assess the reliability of a novel custom-built device. Six different stability boots were tested in a novel device that allowed body weight to be taken into account using a pneumatic actuator. The fixation of the boots was controlled using two air pad pressure sensors. The range of motion (RoM) was then assessed during 5 trials at physiological ankle joint torques during flexion/extension and inversion/eversion. Furthermore the intraclass correlation coefficient ICC was determined to assess the repetitive reliability of the testing approach. The measured ankle angles ranged from 3.4° to 25° and proved to be highly reliable (ICC = 0.99), with standard deviations <9.8%. Comparing single trials to one another resulted in a change of 0.01° joint angle, with a mean error of 0.02°. The FTM demonstrates that it is possible to reliably measure the ankle joint RoM in both the sagittal and frontal planes at controlled torque levels, together with the application of body weight force.
  • Dynamic knee valgus in competitive alpine skiers: Observation from youth to elite and influence of biological maturation
    Item type: Journal Article
    Ellenberger, Lynn; Oberle, Felix; Lorenzetti, Silvio; et al. (2020)
    Scandinavian journal of medicine & science in sports
  • Challenges and Opportunities: Addressing Gender Issues in Elite Sports
    Item type: Journal Article
    Nagorna, Viktoriia; Mytko, Artur; Borysova, Olha; et al. (2025)
    Physical Activity Review
    Background. The present study identifies the most critical practical challenges related to gender issues that elite female athletes and their coaches face when utilizing classical methods to monitor and assess general physical preparedness. Material and methods. An innovative approach was taken by conducting experimental studies to assess the practical effectiveness of applying classical scientific methods to gender differences in the overall physical fitness of elite female athletes. This approach, particularly in strength exercises such as the barbell squat, facilitated a multidimensional understanding of the profiles of 41 elite male and female athletes in team sports, including method of expert evaluation, psychophysiological, anthropometric, and biomechanical analyses. Considering the hormonal fluctuations inherent to the female body, we analyzed the results of a specialized Romberg test recorded exclusively during and designed for use with the optimal phases of the menstrual cycle they were subjected to analysis. The results demonstrated that female athletes exhibited an even higher quality of balance function during barbell squats (216 ± 2%) compared to their male counterparts (173 ± 3%). Our research experiment demonstrated that female athletes and their coaches encounter several practical challenges. Most monitoring methods necessitate the use of laboratory equipment, significantly entail considerable financial and time temporal costs, and are challenging to implement. Conclusions. In the context of new evolving technologies, the logistical challenge of developing reliable methodologies to monitor and support women's health in the context of fitness and sport is evident, as optimizing performance and ensuring long-term well-being is of crucial paramount importance.
  • Velocity-Based Strength Training: The Validity and Personal Monitoring of Barbell Velocity with the Apple Watch
    Item type: Journal Article
    Achermann, Basil; Oberhofer, Katja; Ferguson, Stephen J.; et al. (2023)
    Sports
    Velocity-based training (VBT) is a method to monitor resistance training based on measured kinematics. Often, measurement devices are too expensive for non-professional use. The purpose of this study was to determine the accuracy and precision of the Apple Watch 7 and the Enode Pro device for measuring mean, peak, and propulsive velocity during the free-weighted back squat (in comparison to Vicon as the criterion). Velocity parameters from Vicon optical motion capture and the Apple Watch were derived by processing the motion data in an automated Python workflow. For the mean velocity, the barbell-mounted Apple Watch (r = 0.971–0.979, SEE = 0.049), wrist-worn Apple Watch (r = 0.952–0.965, SEE = 0.064) and barbell-mounted Enode Pro (r = 0.959–0.971, SEE = 0.059) showed an equal level of validity. The barbell-mounted Apple Watch (Vpeak: r = 0.952–0.965, SEE = 0.092; Vprop: r = 0.973–0.981, SEE = 0.05) was found to be the most valid for assessing propulsive and peak lifting velocity. The present results on the validity of the Apple Watch are very promising, and may pave the way for the inclusion of VBT applications in mainstream consumer wearables.
  • Material model of the collagen decrease in a single trabecula
    Item type: Conference Paper
    Carretta, Roberto; Lorenzetti, Silvio; Stüssi, Edgar; et al. (2009)
    IFMBE Proceedings ~ Image Processing, Biosignal Processing, Modelling and Simulation, Biomechanics
    Bone is often modeled as an isotropic material, even though it presents a high degree of anisotropy, due to the combination of collagen and hydroxiapatite at the nanoscale level. These two components considerably influence the overall mechanical behavior. Moreover, aging as well diseases influencing the collagen and hydroxyapatite content in bone can cause severe problems in terms of structure stability and fracture risks. According to these assumptions, our investigation is aimed at elucidating the effect collagen has on the elastic properties of bone material at the tissue level. In this sense, we provide a model which, using a numerical simulation software, lets us describe the collagen decrease in a single trabecula. This approach could allow further investigation of the correlation between stiffness reduction and collagen content decrease.
  • Identification of Optimal Movement Patterns for Energy Pumping
    Item type: Journal Article
    Luginbühl, Micha; Gross, Micah; Lorenzetti, Silvio; et al. (2023)
    Sports
    Energy pumping is a way to gain kinetic energy based on an active vertical center of mass movement in rollers in sports like skateboarding, skicross, snowboard cross and BMX. While the principle of the energy transfer from the vertical movement to the horizontal movement is well understood, the question of how to achieve the optimal energy transfer is still unresolved. In this paper, we introduce an inverse pendulum model to describe the movement of the center of mass of an athlete performing energy pumping. On this basis, the problem of identifying the optimal movement pattern is formulated as an optimal control problem. We solve the discretized optimal control problem with the help of a SQP-algorithm. We uncover that the optimal movement pattern consists of a jumping, flying, and landing phase, which has to be timed precisely. We investigate how the maximal horizontal speed depends on parameters like rollers height and maximal normal force of the athlete. Additionally, we present a qualitative comparison of our results with measured results from BMX-racing. For athletes and coaches, we advice on the basis of our results that athlete’s performance is optimized by using maximal force and adopt an exact and proper timing of the movement pattern.
Publications 1 - 10 of 43