Trampoline Stiffness Estimation by Using Robotic System for Quantitative Evaluation of Jumping Exercises.

Trampolines are recognized as a valuable tool in exercise and rehabilitation due to their unique properties like elasticity, rebound force, low-impact exercise, and enhancement of posture, balance, and cardiopulmonary function. To quantitatively assess the effects of trampoline exercises, it is essential to estimate factors such as stiffness, elements influencing jump dynamics, and user safety. Previous studies assessing trampoline characteristics had limitations in performing repetitive experiments at various locations on the trampoline. Therefore, this research introduces a robotic system equipped with foot-shaped jigs to evaluate trampoline stiffness and quantitatively measure exercise effects. This system, through automated, repetitive movements at various locations on the trampoline, accurately measures the elastic coefficient and vertical forces. The robot maneuvers based on the coordinates of the trampoline, as determined by its torque and position sensors. The force sensor measures data related to the force exerted, along with the vertical force data at X, Y, and Z coordinates. The model's accuracy was evaluated using linear regression based on Hooke's Law, with Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Correlation Coefficient Squared (R-squared) metrics. In the analysis including only the distance between X and the foot-shaped jigs, the average MAE, RMSE, and R-squared values were 17.9702, 21.7226, and 0.9840, respectively. Notably, expanding the model to include distances in X, Y, and between the foot-shaped jigs resulted in a decrease in MAE to 15.7347, RMSE to 18.8226, and an increase in R-squared to 0.9854. The integrated model, including distances in X, Y, and between the foot-shaped jigs, showed improved predictive capability with lower MAE and RMSE and higher R-squared, indicating its effectiveness in more accurately predicting trampoline dynamics, vital in fitness and rehabilitation fields.

Mid-Thoracic Vertebral Compression Fracture after Mini-Trampoline Exercise: A Case Series of Seven Patients.

Background and Objectives: Home-based training exercise gained popularity during the coronavirus disease 2019 pandemic era. Mini-trampoline exercise (MTE) is a home-based exercise that utilizes rebound force generated from the trampoline net and the motion of the joints of the lower extremities. It is known to be beneficial for improving postural balance, stability, muscle strength and coordination, bone strength, and overall health. However, we encountered several patients with mid-thoracic vertebral compression fractures (VCFs) following regular MTE, which was never reported previously, despite having no history of definite trauma. This study aims to report mid-thoracic VCFs after regular MTE and arouse public attention regarding this spinal injury and the necessity of appropriate prior instructions about the correct posture. Patients and Methods: All consecutive patients diagnosed with acute VCFs following regular MTE were included. We collected data on patient demographics, history of MTE, characteristics of symptoms, and radiological findings such as the location of fractures and anterior vertebral body compression percentage. Results: Seven patients (one man and six women) and ten fractures (T5 = 1, T6 = 3, T7 = 2, and T8 = 4) were identified. Symptoms started 2.57 ± 1.13 weeks after the beginning of regular MTE. All patients reported that they were never properly instructed on the correct posture. They also stated that they were exercising with a hunchback posture and insufficient joint motion of the lower extremities while holding the safety bar with both hands, which resulted in increased peak vertical force along the gravity z-axis in the mid-thoracic area and consequent mid-thoracic VCFs. Conclusions: Mid-thoracic VCFs can occur following regular MTE even without high-energy trauma in case of improper posture during exercise. Therefore, public attention on mid-thoracic VCFs following MTE and the appropriate prior instructions are imperative.

Return to competitive gymnastics training in the UK following the first COVID-19 national lockdown.

Following the outbreak of COVID-19 (coronavirus), the UK entered a national lockdown, and all sport was suspended. The study aimed to explore the process of returning to gymnastics training after several months away from the gym, with a particular interest towards training load and injury. Twenty-six, national programmed gymnasts from Men's artistic, Women's artistic and Trampoline gymnastics recorded training load and injury whilst returning to training. At the end of data collection, three coaches were interviewed to further explore the experiences and practices of returning to training. Home-based training during lockdown was seen as beneficial in maintaining a level of fitness. Coaches described a gradual increase in training to reduce the risk of injury, and this partly explains a non-significant association between training load and a substantial injury (p = 0.441). However, week-to-week changes in training load following periods of additional restrictions (additional lockdown, periods of isolation, or substantial restrictions) were not always gradual. There was a significant association between an injury in the preceding week (niggle or substantial injury to a different body part) and a substantial injury in the subsequent week (RR: 5.29, p = 0.011). Monitoring training was described to be a useful practice during the process of returning to training. Coaches believed that although the short-term development of their gymnasts was affected, the long-term development would not be impacted from COVID-19. It is anticipated that learnings from this study can be applied to future practices and situations, particularly when gymnasts are away from the gym for an extended period.

Three-Dimensional Foot Position Estimation Based on Footprint Shadow Image Processing and Deep Learning for Smart Trampoline Fitness System.

In the wake of COVID-19, the digital fitness market combining health equipment and ICT technologies is experiencing unexpected high growth. A smart trampoline fitness system is a new representative home exercise equipment for muscle strengthening and rehabilitation exercises. Recognizing the motions of the user and evaluating user activity is critical for implementing its self-guided exercising system. This study aimed to estimate the three-dimensional positions of the user's foot using deep learning-based image processing algorithms for footprint shadow images acquired from the system. The proposed system comprises a jumping fitness trampoline; an upward-looking camera with a wide-angle and fish-eye lens; and an embedded board to process deep learning algorithms. Compared with our previous approach, which suffered from a geometric calibration process, a camera calibration method for highly distorted images, and algorithmic sensitivity to environmental changes such as illumination conditions, the proposed deep learning algorithm utilizes end-to-end learning without calibration. The network is configured with a modified Fast-RCNN based on ResNet-50, where the region proposal network is modified to process location regression different from box regression. To verify the effectiveness and accuracy of the proposed algorithm, a series of experiments are performed using a prototype system with a robotic manipulator to handle a foot mockup. The three root mean square errors corresponding to X, Y, and Z directions were revealed to be 8.32, 15.14, and 4.05 mm, respectively. Thus, the system can be utilized for motion recognition and performance evaluation of jumping exercises.

Investigation into the Trampoline Dynamic Characteristics and Analysis of Double Bounce Vibrations.

Double bounce is an unusual and potentially very hazardous phenomenon that most trampoline users may have experienced, yet few would have really understood how and why it occurs. This paper provides an in-depth investigation into the double bounce. Firstly, the static and dynamic characteristics of a recreational trampoline are analysed theoretically and verified through experiments. Then, based on the developed trampoline dynamic model, double bounce simulation is conducted with two medicine balls released with different time delays. Through simulation, the process of double bounce is presented in detail, which comprehensively reveals how energy is transferred between users during double bounce. Furthermore, the effect of release time delay on double bounce is also presented. Finally, we conducted an experiment which produced similar results to the simulation and validated the reliability of the trampoline dynamic model and double bounce theoretical analysis.

Seasonal variability and age-related risk in youth trampoline injuries.

BACKGROUND: The aim of this work was to estimate the difference in severity between musculoskeletal trampoline park injuries (TPIs) and home trampoline injuries (HTI) and identify the factors that might mediate or modify that effect. METHODS: The National Electronic Injury Surveillance System database was used to identify musculoskeletal home trampoline injuries and TPIs in pediatric patients occurring in the 2009-2017 period. Injury mechanism and body region were inductively coded. The effect of TPI on risk of admission was estimated using a doubly robust logistic regression model for confounding adjustment. Adjustments were made for date, age, gender, injury mechanism, and body region. The comparative importance of injury mechanism and location and the effect modification of patient characteristics was explored using likelihood ratio tests. RESULTS: Trampoline park injuries were more likely to result in admission even in the model adjusted for injury mechanism and body region (odds ratio (OR) = 2.12 [1.30, 3.45]). Injuries sustained from falling off the trampoline were associated with significantly fewer hospitalizations (OR = 0.119 [0.029, 0.495]) than injuries from falling while on the trampoline. Patient age significantly modified the effect of setting on risk of admission (P = 0.042). Adolescents demonstrated an increased risk at trampoline parks (15 years old OR = 3.23 [1.38, 7.56]), whereas younger children demonstrated a marginally lower risk (5 years old OR = 0.77 [0.44, 1.35]). CONCLUSIONS: Trampoline park musculoskeletal injuries demonstrate an increased risk of admission even after rigorous adjustment for confounding. Injuries to the proximal limbs were associated with a much higher risk of admission than distal injuries. Adolescents face an increased risk of admission after TPI, underscoring the importance of public health interventions that target this age group.

A Measurement of 'Walking-the-Wall' Dynamics: An Observational Study Using Accelerometry and Sensors to Quantify Risk Associated with Vertical Wall Impact Attenuation in Trampoline Parks.

This study illustrates the application of a tri-axial accelerometer and gyroscope sensor device on a trampolinist performing the walking-the-wall manoeuvre on a high-performance trampoline to determine the performer dynamic conditions. This research found that rigid vertical walls would allow the trampolinist to obtain greater control and retain spatial awareness at greater levels than what is achievable on non-rigid vertical walls. With a non-rigid padded wall, the reaction force from the wall can be considered a variable force that is not constrained, and would not always provide the feedback that the trampolinist needs to maintain the balance with each climb up the wall and fall from height. This research postulates that unattenuated vertical walls are safer than attenuated vertical walls for walking-the-wall manoeuvres within trampoline park facilities. This is because non-rigid walls would provide higher g-force reaction feedback from the wall, which would reduce the trampolinist's control and stability. This was verified by measuring g-force on a horizontal rigid surface versus a non-rigid surface, where the g-force feedback was 27% higher for the non-rigid surface. Control and stability are both critical while performing the complex walking-the-wall manoeuvre. The trampolinist experienced a very high peak g-force, with a maximum g-force of approximately 11.5 g at the bottom of the jump cycle. It was concluded that applying impact attenuation padding to vertical walls used for walking-the-wall and similar activities would increase the likelihood of injury; therefore, padding of these vertical surfaces is not recommended.

Detection of Motion on a Trampoline with a Smartwatch.

In this study, we develop a method for detecting the motions performed on a trampoline using an accelerometer mounted on a smartwatch. This method will lead to a system that can be used to promote trampoline exercise using a home trampoline by detecting motions on the trampoline using a smartwatch. We proposed a method based on the convolutional neural network to detect the motions on a trampoline. As a result of the performance evaluation by leave-one-subject-out cross-validation on eight subjects, our method achieves 78.8% estimation accuracy, which is the best estimation accuracy compared to the baseline methods. We also evaluate the inference time and the battery consumption when the model is actually running on a smartwatch. Our method is effective for on-device prediction.

An observational study of trampoline injuries admitted to a Belgian University emergency department between 2011 and 2016.

BACKGROUND: Trampoline injuries are a cause for concern and data from different countries indicate that these are increasing. The aim of this study was to collect data in a Belgian University Hospital emergency department. METHODS: Medical files of patients admitted with a trampoline-related injury between 1st July 2011 and 30th June 2016 were retrospectively analyzed. RESULTS: One hundred and sixty patients, aged between 2 and 64 years old and predominantly males (57%), were admitted most frequently during the months March until September. An increase was observed during the years 2013-2014. Most injuries (76%) occurred during activity on the trampoline. Fractures occurred in 40% of the patients with the extremities most frequently involved. An X-ray examination and a CT scan was performed in 82 and 3% of the cases, respectively. Surgery was carried out in 12% of the patients. 9% of the patients had to be admitted to hospital. CONCLUSIONS: Trampoline injuries are increasingly observed in the emergency department. These injuries are important and further research on the circumstances and causes for the accidents is needed. Preventive measures, as proposed in the literature, should be considered.

Children bouncing to the emergency department: Changes in trampoline injury patterns.

AIM: To compare trampoline injuries and injury costs sustained at a commercial trampoline park versus private homes presenting to a major Australian children's hospital over a 12-month period. METHODS: Children presenting with a trampoline injury to the paediatric emergency department in 2015 were identified using a keyword search of triage information. A comparison of injuries sustained at a commercial trampoline park and private homes was performed. RESULTS: A total of 392 children presented with injuries, and the majority of injuries (68.9%) occurred at a private home; 19.4% were from a commercial trampoline park. Significant differences were seen between patients from a private home and commercial park for median age (5.6 vs. 12.8 years; P < 0.001), gender (48.2 vs. 61.8% female; P = 0.03) and season of injury. Of the injuries, 27.3% occurred when children fell off the trampoline, and fractures (39.5%) were the most common injury; 17.4% required hospital admission, and 12.8% required surgical intervention. Commercial park injuries had a significantly longer median length of stay (37.4 vs. 22.8 h; P = 0.03). The estimated total acute cost for these trampoline injuries in 1 year was $546 786. Commercial trampoline park injuries accounted for 21.7% of the estimated cost and private homes for 68.2%. CONCLUSIONS: Paediatric trampoline injuries remain a common source of hospital presentation and admission, despite the introduction of a Voluntary Australian Standard. Paediatric trampoline injuries usually occur in private homes; however, the increasing popularity of commercial trampoline parks contributes to a change in the profile of trampoline injuries. Commercial park injuries were more expensive to treat.

Buckle fracture of the proximal tibia in children and frequency of association with trampoline and inflatable bouncer use.

BACKGROUND: Proximal tibial buckle fractures are often called "trampoline fractures," but mechanisms are more varied. OBJECTIVE: To assess the frequency of trampoline or bouncer etiology among children with buckle fracture of the proximal tibia, characterizing demographics, alternative etiologies, and fracture patterns. MATERIALS AND METHODS: We performed retrospective chart review of mechanisms, age and gender of children with radiographs interpreted as proximal tibial buckle fracture between 2010 and 2016. Two pediatric radiologists assessed presence of cortical impaction, cortical break, increased anterior scoop deformity, and oblique extension of fracture toward the physis. We studied the associations among demographics, etiology and fracture appearance using analysis of variance and chi-square/Fisher exact tests. RESULTS: We identified 145 exams interpreted as proximal tibial buckle fracture (median age 34 months, 64% girls). Bouncing surface was the most common mechanism (44%), and 80% of those cases reported multiple people on the bouncing surface. Falls were the second most common mechanism (30%). Children injured while bouncing were older (median 41 months) than others (median 21 months, P<0.005) and more likely to have oblique extension of fracture toward the physis (P<0.05). Buckle deformity was associated with a younger age (F=8.67; P<0.01), while oblique extension to the physis and concurrent fibula fracture were associated with older age (F=18.62, P<0.001; and F=8.02, P<0.01, respectively). CONCLUSION: Trampoline use was the most common single mechanism of injury in children with proximal tibial fracture interpreted as buckle deformity. However, non-bouncing mechanisms were overall more common and occurred in a younger age group at risk for "toddler fractures."

The ups and downs of trampolines: Injuries associated with backyard trampolines and trampoline parks.

OBJECTIVE: To compare characteristics associated with backyard trampoline injuries (BTI) and trampoline park injuries (TPI) using records from the electronic Canadian Hospitals Injury Reporting and Prevention Program (eCHIRPP). METHODS: eCHIRPP records for trampoline injuries (2012 to 2016) were extracted using variable codes and narratives, and injuries were examined among individuals 17 years and younger. Descriptive estimates for BTI and TPI, as well as age and sex adjusted odds ratios (OR) for the mechanism, source, body part and type of injury associated with TPIs relative to BTIs, are presented. RESULTS: Trampoline injuries are increasing in Canada (P<0.01). Patients with TPIs were older than those with BTIs. Relative to BTIs, TPIs were more associated with impact as the mechanism (OR 2.6, 95% CI: 2.2 to 3.1), trampoline beds as the source (OR 1.7, 95% CI: 1.4 to 2.1), lower extremity as the body part (OR 3.7, 95% CI: 3.0 to 4.4) and sprains as the type of injury (OR 2.0, 95% CI: 1.6 to 2.4). In contrast, another jumper (OR 0.5, 95% CI: 0.4 to 0.6) or fall (OR 0.4, 95% CI: 0.4 to 0.6) as the mechanism, surface (OR 0.7, 95% CI: 0.5 to 0.9) or another jumper (OR 0.5, 95% CI: 0.4 to 0.7) as the source, face or neck (OR 0.6, 95% CI: 0.4 to 0.7) as the body part, and lacerations (OR 0.6, 95% CI: 0.3 to 0.9) or soft tissue injury (OR 0.7, 95% CI: 0.6 to 0.9) as the type of injury were more associated with BTIs relative to TPIs. CONCLUSION: Trampoline parks result in injuries different than those from backyard trampolines. This examination into the distinct injury characteristics can help to inform future prevention measures.

Effect of 12-Week Rebound Therapy Exercise on Static Stability of Patients With Spinal Cord Injury.

Background: To resolve the impairments associated with spinal cord injury (SCI), such as decreased balance, patients have been recommended to undergo various therapeutic strategies, including the use of different physical exercise methods. The aim of this study was to evaluate the efficiency of using rebound therapy (exercise on a trampoline) on SCI individuals' static stability. Methods: Sixteen people with SCI (American Spinal Cord Association classification: A = 6, B = 6, C = 2, and D = 2) were randomly assigned to an experimental (rebound exercise) group or a control group. The rebound therapy exercise program, lasting 12 weeks, was performed by means of a modified trampoline. During the said period, the experimental group received rebound therapy exercise for 10 to 30 minutes 3 sessions a week. Standing stability parameters (ie, excursion, velocity, and path length of the center of pressure in mediolateral and anteroposterior plane) were assessed before and after the exercise intervention by Kistler force plate (50 × 60 cm). Data were analyzed by repeated measures analysis of variance. Results: Significant interactions were observed for all 6 dependent variables except excursion of the center of pressure in mediolateral and the path length of center of pressure in anteroposterior plane (P < .01). This means that the control group had no progress, whereas the experimental group made a significant improvement in terms of static stability. Conclusion: The results of this study confirmed that rebound therapy could reinforce the static stability of individuals with SCI during motionless standing. It suggests that rebound exercise is a useful sports rehabilitation method for patients with SCI and other wheelchair-bound individuals.

Facial nerve palsy following mild mastoid trauma on trampoline.

We present a case report of a 14-year-old boy who was jumping on a trampoline when he struck his right mastoid on a support pole. The following day, he developed a right-sided facial droop and inability to close his right eye. He presented to the emergency department, where CT of his temporal bone was negative and he was started on prednisone. Over the next month, he had spontaneous recovery of his facial nerve (FN) function. In cases of traumatic FN palsy, urgent referral to otolaryngology is needed, even without a fracture of the temporal bone, as edema within the facial nerve could require decompressive surgery. Steroids, while used in this patient, are of questionable benefit in the limited data available. Patient's with traumatic FN palsies should be instructed to use eye lubricant frequently and tape his eye closed at night, as corneal drying could lead to permanent damage. Proper evaluation, management, and referral are needed in cases of traumatic FN palsy to prevent long-term morbidity.

Mini-trampoline enhances cardiovascular responses during a stationary running exergame in adults.

A new class of video game called exergame (EXG) has been used to promote physical activity and cardiovascular fitness, but EXGs are not as efficient as traditional aerobic exercises. However, auxiliary tools, such as the mini trampoline (MT), may enhance the physiological responses obtained by the EXG. The aim of this study was to compare the metabolic and cardiovascular responses of a stationary running EXG with and without an MT. Nineteen healthy males performed a treadmill test for the determination of VO2max and HRmax. In sequence, the VO2, HR, and METs were measured during the Free Run, a Nintendo Wii's stationary running EXG, according to two distinct protocols. One protocol used the traditional EXG (EXG-PT), and the other protocol used an MT during the EXG (MT-PT). The normalized data were analyzed by statistical software SPSS 20.0 using a t-test and ANOVA for repeated measures (p < 0.05). The results supported that stationary running EXG performed on an MT showed an increased intensity, in all variables analyzed, when compared with the traditional EXG. Furthermore, the MT-PT was classified as a vigorous-intensity exercise and EXG-PT as a moderate to vigorous intensity exercise. In conclusion, these findings support that the MT is a feasible auxiliary tool to enhance physiologic responses during a stationary running EXG.

MR imaging for detection of trampoline injuries in children.

BACKGROUND: The recreational use of trampolines is an increasingly popular activity among children and adolescents. Several studies reported about radiological findings in trampoline related injuries in children. The following publication presents our experience with MRI for detection of trampoline injuries in children. METHODS: 20 children (mean 9.2 years, range: 4-15 years) who had undergone an MRI study for detection of suspected trampoline injuries within one year were included. 9/20 (45%) children had a radiograph as the first imaging modality in conjunction with primary care. In 11/20 (55%) children MR imaging was performed as the first modality. MR imaging was performed on two 1.5 T scanners with 60 and 70 cm bore design respectively without sedation. In 9/20 (45%) children the injury mechanism was a collision with another child. 7/20 (35%) children experienced leg pain several hours to one day after using the trampoline without acute accident and 4/20 (20%) children described a fall from the trampoline to the ground. RESULTS: All plain radiographs were performed in facilities outside the study centre and all were classified as having no pathological findings. In contrast, MR imaging detected injuries in 15/20 (75%) children. Lower extremity injuries were the most common findings, observed in 12/15 (80%) children. Amongst these, injuries of the ankle and foot were diagnosed in 7/15 (47%) patients. Fractures of the proximal tibial metaphysis were observed in 3/15 children. One child had developed a thoracic vertebral fracture. The two remaining children experienced injuries to the sacrum and a soft tissue injury of the thumb respectively. Seven children described clinical symptoms without an overt accident. Here, fractures of the proximal tibia were observed in 2 children, a hip joint effusion in another 2, and an injury of the ankle and foot in 1 child. There were no associated spinal cord injuries, no fracture dislocations, no vascular injuries and no head and neck injuries. CONCLUSIONS: In the majority of children referred for MR imaging with pain after trampoline MR imaging detects injuries. These injuries are often not visible on plain radiographs. Therefore we recommend a generous use of MR imaging in these children after initial negative plain radiography.

Vertebral Artery Dissection in a Bouncy Castle Injury: Case Report and Literature Review.

There is an increased rate of injuries associated with activities on bouncy castles. The purpose of this article was to describe the case of a 6-year-old boy who sustained a brain infarct as a consequence of a left posterior inferior cerebellar artery dissection due to improper landing in a bouncy castle and who required a suboccipital craniotomy. The second goal was to outline the literature review regarding cervical trauma related to trampoline or bouncy castle accidents in pediatric populations. Based on the described case and reviewed studies, bouncy castle or any other activity resulting in hyperflexion or hyperextension of the neck should be carefully evaluated for cervical spine fractures and vascular injuries.

Does trampoline or hard surface jumping influence lower extremity alignment?

[Purpose] To determine whether repetitive trampoline or hard surface jumping affects lower extremity alignment on jump landing. [Subjects and Methods] Twenty healthy females participated in this study. All subjects performed a drop vertical jump before and after repeated maximum effort trampoline or hard surface jumping. A three-dimensional motion analysis system and two force plates were used to record lower extremity angles, moments, and vertical ground reaction force during drop vertical jumps. [Results] Knee extensor moment after trampoline jumping was greater than that after hard surface jumping. There were no significant differences between trials in vertical ground reaction force and lower extremity joint angles following each form of exercise. Repeated jumping on a trampoline increased peak vertical ground reaction force, hip extensor, knee extensor moments, and hip adduction angle, while decreasing hip flexion angle during drop vertical jumps. In contrast, repeated jumping on a hard surface increased peak vertical ground reaction force, ankle dorsiflexion angle, and hip extensor moment during drop vertical jumps. [Conclusion] Repeated jumping on the trampoline compared to jumping on a hard surface has different effects on lower limb kinetics and kinematics. Knowledge of these effects may be useful in designing exercise programs for different clinical presentations.

The effect of modified trampoline training on balance, gait, and falls efficacy of stroke patients.

[Purpose] This research was conducted to investigate the effects of modified trampoline training on the balance, gait, and falls efficacy of stroke patients. [Subjects] Twenty-four stroke patients participated in this study. The subjects were randomly allocated to one of two groups: the trampoline group (n=12) or the control group (n=12). [Methods] Both groups participated in conventional physical therapy for thirty minutes per day, three times a week for six weeks. The trampoline group also took part in trampoline training for thirty minutes per day, three times a week for six weeks. We evaluated balance (Berg balance scale, timed up and go test), gait (dynamic gait index), and falls efficacy (falls efficacy scale-K) to confirm the effects of the intervention. [Results] Both the trampoline and the control group showed significant improvements in balance, gait, and falls efficacy compared to before the intervention, and the improvements were significantly greater in the trampoline group than in the control group. [Conclusion] Modified trampoline training resulted in significantly improved balance, dynamic gait, and falls efficacy of stroke patients compared to the control group. These results suggest that modified trampoline training is feasible and effective at improving balance, dynamic gait, and falls efficacy after stroke.