A Finite Element Model for Estimation of Contact Dynamics During a Jumping Movement on a Trampoline

Abstract

In order to fully understand contact dynamics on a trampoline, a simulation approach using a musculoskeletal model coupled with a dynamic model of the trampoline is essential. The purpose of the study was to examine dynamics and selected lower extremity muscle forces in a landing and jumping movement on a trampoline, using a combination of finite element modeling and musculoskeletal modeling. The rigid frame of the trampoline was modeled in ADAMS and coupled with a finite element model of the elastic trampoline net surface in ANSYS. A musculoskeletal model of an elite trampoline athlete was further developed in LifeMod and combined with the finite element model of the trampoline. The results showed that the peak trampoline reaction forces (TRF) were 3400 N (6.6 BW) and 2900 N (5.6 BW) for the left and right limb, respectively. The right hip, knee and ankle joint reaction forces reached the maximum between 3000-4000 N (5.8 – 7.7 BW). The gluteus maximum and quadriceps reached the maximum muscle force of 380 N (0.7 BW) and 780 N (1.5 BW), respectively. Asymmetric loading patterns between left and right TRFs and lower extremities joint reaction forces were observed due to the need to generate the rotational movement during the takeoff. The observed rigid and erect body posture suggested that the hip and knee extensors played important roles in minimizing energy absorption and maximizing energy generation during the trampoline takeoff.

Effect of jump heights, landing techniques, and participants on vertical ground reaction force and loading rate during landing on three different Korean teeterboards

“…During trampoline jumps, Glitsch and Henrichs 11 used pressure insoles to measure a maximum force of 7.5 BW under one foot for jumps between 1.6 and 2.5 m, whereas a combination of finite element modeling and musculoskeletal modeling estimated the peak force to range between 5.8 and 7.7 BW at one foot contact with the trampoline. 4 If the forces are assumed to be equally distributed under each foot, the total should be approximately 15 BW in trampoline. This value is in agreement with the present results, despite differences in the surface material, jump height and landing technique.…”

“…Trampolinists usually flex their legs during landing and extend their legs during take-off to be fully extended at the lowest point and capture the elastic energy of the trampoline. 3,4 Researchers showed that a strategy to minimize landing impact is to produce a smooth landing through bending of the ankles, knees, and hips. When landing in basketball or volleyball, flexions of the lower extremities can reduce impact forces.…”

The physical determinants of maximal jumping time of flight in elite trampolining

“…During the floor based CMJ the gymnast must perform both flexion and extension of the lower limbs whilst in contact with the ground. In contrast during a trampoline jump, the entire flexion phase occurs exclusively in the downward aerial phase prior to contact with the bed, with hip and knee angles on contact with the being reported between 25° and 40° and 20° and 40°, respectively (Qian et al, 2020; Rupf & Chapman, 2013). Gymnasts also begin to extend the lower limbs prior to contact with the bed as they fall from height, and continue through lower limb extension on contact with the trampoline bed, with both hip and knee angles reported to be less than 10° at the end of the jump cycle (Rupf & Chapman, 2013).…”

“…Conceptually, maximising energy transferral from the gymnast to the bed to achieve maximal ToF could explain why F 0 was identified as the most important determinant in this study and hence the importance of maximal strength in these gymnasts. The quadriceps and gluteus maximus have been suggested to play important roles in maximising energy transferral on the bed (Qian et al, 2020). F 0 as calculated by loaded CMJ's is highly determined by maximal isometric strength and size of the knee extensors (Morales-Artacho et al, 2018).…”

“…Kinematic measures of maximal trampoline jumping highlight that during the contact phase only knee and hip extension is observed (Rupf & Chapman, 2013). This suggests that knee and hip flexion occurs exclusively in the downward aerial phase prior to contact with the bed, with hip and knee angles on contact reported to be between 25° and 40° and 20° and 40°, respectively (Qian et al, 2020; Rupf & Chapman, 2013). At the end of the contact phase, hip and knee angles were both reported to be less than 10° (Rupf & Chapman, 2013).…”