Fabian Goell

Background: Fast-jet pilots frequently experience high +Gz forces, leading to cervical musculoskeletal adaptations and performance impairments. The biomechanical mechanisms underlying these effects remain unclear. Understanding these biomechanical adaptations is critical to developing preventive measures and ergonomic guidelines aimed at reducing the risk of injury, maintaining pilot health and ensuring long-term operational readiness, and ultimately improving flight safety. Aims: This study compared cervical muscle properties, kinematics and movement-related pain perception between fast-jet pilots and matched non-pilot controls. Methods: Twenty Eurofighter pilots and 20 near-matched non-pilots participated in a cross-sectional comparative study. Muscle tone, stiffness and elasticity were measured using MyotonPRO. Cervical movements were analysed via 3D motion capture. Pain was measured by the Visual Analogue Scale. Statistical group comparisons were performed. Results: No significant differences in cervical range of motion between groups were found (P > 0.05). Pilots exhibited reduced elasticity in the sternocleidomastoid and trapezius muscles (P < 0.05), suggesting neuromuscular adaptation. Increased muscle tone was observed in non-pilots (P < 0.05). Pain perception did not differ significantly (P > 0.05). Conclusions: Pilots maintain normal cervical mobility, compared to non-pilots, despite high-G exposure, but altered muscle properties suggest long-term adaptations. Occupational medicine approaches, including ergonomic cockpit adjustments, targeted physiotherapy, and preventive exercise protocols, are recommended to address cervical muscle adaptations identified in this study. Such strategies could mitigate musculoskeletal strain, enhance pilot wellbeing, and sustain operational safety throughout pilots’ careers.

The cervical spine of fast jet pilots is exposed to high +Gz accelerations during large range of head movements which may lead to biomechanical impairments. The objective of this study therefore was to quantify and analyze the resulting external cervical spine joint moments experienced by fast jet pilots during standardized head movements in real–flight during +5Gz, +7Gz and +9Gz maneuvers. The in– flight helmet orientation recordings and additional ground based motion capture recordings of isolated head movements of seven Eurofighter pilots were processed using a custom made pipeline. Subsequent inverse kinematics and inverse dynamics simulations of the in–flight head movements using individual OpenSim pilot models showed a significant reduction in the head extension angle with increasing +Gz acceleration. Cervical spine joint moments did not change significantly with increasing +Gz acceleration. However, theory–based model analysis indicated that constant head positions under higher +Gz acceleration would lead to an increase in joint moments. The pilots seemed to exhibit reduced head extension at higher +Gz levels, while external joint moments remained relatively constant. Furthermore, the designed pipeline may support individual cervical spine health assessment and monitoring, as well as to inform strength training or rehabilitation programming.

Neuromuscular training to strengthen leg muscles is an important part of the treatment of musculoskeletal disorders and chronic diseases and preventing age–related muscle loss. This study evaluates different individualization approaches and their real–time implementation for OpenSim musculoskeletal models to estimate the external knee adduction moment during a leg–press exercise. A robotic neuromuscular training platform was utilized to perform isometric and dynamic leg extension exercises. Data were collected for 13 subjects using a 3D motion capture system and force plate measurements from the robotic training platform. Functional joint parameters, determined through dynamic reference movements, were integrated into the OpenSim models, allowing a personalized representation of the hip, knee, and ankle joints. This integration was compared with a conventional scaling method. The results indicate that the incorporation of functional joint axes can significantly enhance the accuracy of biomechanical simulations. These methods provide a real–time and a more precise estimate of the external knee adduction moment compared to conventional scaling approaches and underscore the importance of individualized model parameters in biomechanical research.

Patients with sarcopenia, who face difficulties in carrying heavy loads, may benefit from collaborative robotic assistance that is modeled after human–human interaction. The objective of this study is to describe the kinematics and spatio-temporal parameters during a collaborative carrying task involving both human and robotic partners. Fourteen subjects carried a table while moving forward with a human and a robotic partner. The movements were recorded using a three-dimensional motion capture system. The subjects successfully completed the task of carrying the table with the robot. No significant differences were found in the shoulder and elbow flexion/extension angles. In human–human dyads, the center of mass naturally oscillated vertically with an amplitude of approximately 2 cm. The here presented results of the human–human interaction serve as a model for the development of future robotic systems, designed for collaborative manipulation.

Background: Astronauts have a higher risk of cervical intervertebral disc herniation. Several mechanisms have been attributed as causative factors for this increased risk. However, most of the previous studies have examined potential causal factors for lumbar intervertebral disc herniation only. Hence, we aim to conduct a study to identify the various changes in the cervical spine that lead to an increased risk of cervical disc herniation after spaceflight. Methods: A cohort study with astronauts will be conducted. The data collection will involve four main components: a) Magnetic resonance imaging (MRI); b) cervical 3D kinematics; c) an Integrated Protocol consisting of maximal and submaximal voluntary contractions of the neck muscles, endurance testing of the neck muscles, neck muscle fatigue testing and questionnaires; and d) dual energy X-ray absorptiometry (DXA) examination. Measurements will be conducted at several time points before and after astronauts visit the International Space Station. The main outcomes of interest are adaptations in the cervical discs, muscles and bones. Discussion: Astronauts are at higher risk of cervical disc herniation, but contributing factors remain unclear. The results of this study will inform future preventive measures for astronauts and will also contribute to the understanding of intervertebral disc herniation risk in the cervical spine for people on Earth. In addition, we anticipate deeper insight into the aetiology of neck pain with this research project. Trial registration: German Clinical Trials Register, DRKS00026777. Registered on 08 October 2021.