Skateboarding is an Olympic event with frequent jumping and landing, where the cushioning effect by the foot structure (from the arch, metatarsals, etc.) and damping performance by sports equipment (shoes, insoles, etc.) can greatly affect an athlete\'s sports performance and lower the risk of limb injury. Skateboarding is characterized by the formation of a \"man-shoe-skateboard system,\" which makes its foot cushioning mechanism different from those of other sports maneuvers, such as basketball vertical jump and gymnastics broad jump. Therefore, it is necessary to clarify the cushioning mechanism of the foot structure upon landing on a skateboard. To achieve this, a multibody finite element model of the right foot, shoe, and skateboard was created using Mimics, Geomagic, and ANSYS. Kinetic data from the ollie maneuver were used to determine the plantar pressure and Achilles tendon force at three characteristics (T1, T2, and T3). The stress and strain on the foot and metatarsals (MT1-5) were then simulated. The simulation results had an error of 6.98% compared to actual measurements. During landing, the force exerted on the internal soft tissues tends to increase. The stress and strain variations were highest on MT2, MT3, and MT4. Moreover, the torsion angle of MT1 was greater than those of the other metatarsals. Additionally, the displacements of MT2, MT3, and MT4 were higher than those of the other parts. This research shows that skateboarders need to absorb the ground reaction force through the movements of the MTs for ollie landing. The soft tissues, bones, and ligaments in the front foot may have high risks of injury. The developed model serves as a valuable tool for analyzing the foot mechanisms in skateboarding; furthermore, it is crucial to enhance cushioning for the front foot during the design of skateboard shoes to reduce potential injuries.

Study Design: We designed a cross-sectional epidemiologic study to evaluate the influence of substance use on craniofacial injuries in a population of skateboard and scooter users. Objective: The primary outcome of our study was craniofacial injury. The secondary outcome was hospitalization. Methods: We report a cross-sectional study of patients reported to the National Electronic Injury Surveillance System (NEISS) from January 1, 2019, to December 31, 2020, in the United States. Patients were included in our study if they were evaluated in the emergency department (ED) for a skateboard- or scooter-related injury. Results: There were over 5396 total patients who presented to a NEISS-participating ED after skateboard- or scooter- related trauma during the study period. There were 1136 patients with a craniofacial injury (primary endpoint), and patients under the influence of alcohol or drugs had greater odds of experiencing a craniofacial injury than those not under the influence (odds ratio [OR]: 4.16, 95% confidence interval [CI]: 3.24-5.32, P < .0001). Four hundred-thirty patients were hospitalized (secondary endpoint), and patients under the influence had greater odds of being hospitalized than those not under the influence (OR: 2.83, 95% CI: 2.04-3.91, P < .0001). Conclusions: Alcohol and drug use while skateboarding or scootering drastically increases the likelihood of craniofacial injury and subsequent hospitalization and should be avoided whenever possible. The importance of wearing a helmet while operating these devices cannot be overstated.

BACKGROUND: Falling studies, i.e. assessing what happens when an individual falls, have been conducted in controlled environments but not in field studies for ethical reasons; this potentially limits the validity and applicability of previous studies. We performed field studies on existing YouTube © videos of skateboarders falling. The aims of these studies were to measure the wrist angle at impact on videos of real unprotected falls and to study the dynamics of the upper limbs when falling.
METHODS: Youtube © videos of skateboarders falling were studied assessing the direction of the fall, the positions of both upper limbs and especially the wrists on impact quantitatively and qualitatively. This study would not be ethical by other means.
RESULTS: In study one (the more quantitative study) there were 48 men and 50 falls. The mean elbow flexion was 300 (range 00 to 800) and the mean maximal wrist extension was 800 (range 500 to 1100). The second wrist extended less or the same in > 90%. The second wrist only once (of 31) extended > 900 which should minimise the risk of toppling. Falls onto only one wrist gave significantly greater maximal wrist extension. In the second more qualitative study we observed the \"upper limb falling reflex\" where the response to falling is for the upper limb(s) to align the upper limb with the direction of falling of the body with the elbow mostly but not fully extended. Initially the wrists extend c. 400-500 with the fingers held mildly flexed. Immediately before impact the fingers hyper-extend with some compensatory wrist flexion to c. 300 of extension. The fingertips impact the ground first followed by the hand.
CONCLUSIONS: These studies confirm wrist extension at impact around 800 but the wrist(s) may hyper-extend risking toppling. Falls on both wrists minimise the risk of toppling. The \"upper limb falling reflex\" is defined; it is a rapid dynamic response leading to the fingers impacting the ground first on falling. Abnormalities with the upper limb falling reflex may indicate problems with development in young children and may increase the risk of injury in older people.

UNASSIGNED: Elbow fractures are common in children and occur during daily activities. The aim of this study is to evaluate the epidemiology of paediatric elbow fractures over a two-year period in Okinawa, a southern subtropical island in Japan.
UNASSIGNED: This was a retrospective study of 488 elbow fractures in children younger than 15 years old treated at 11 hospitals in Okinawa. Data included age, gender, calendar month, type of fracture, operation rate, mechanism of injury, and aetiology.
UNASSIGNED: The most frequent age was 6 years old, with 47.5% of all elbow fractures occurring in an age range from 6 to 10 years old. The fracture rate for boys was 1.6 times higher than that for girls. The incidence was the highest in May (56 fractures) and the lowest in August (25 fractures). Supracondylar fractures were the most common type (44%), followed by lateral condyle fractures (22%); 45% of all fractures were treated operatively. Medial epicondyle fractures had the highest rate of operative treatment (91%). In the 6 to 10-year-old group, 19% of all fractures occurred while skateboarding or caster-boarding, the most frequent aetiology.
UNASSIGNED: Supracondylar fractures are the most common fracture type in 4 to 7-year-old boys. In the 6 to 10-year-old group, skateboarding and caster-boarding are the most frequent and increasing cause of elbow fractures. Therefore, some preventive measures are needed.
UNASSIGNED: Level IV, case series.

BACKGROUND: Recreation on longboards is gaining in popularity. The purpose of this study is to detail the injury patterns, treatment and management of children with longboarding injuries seen at a level 1 pediatric trauma center.
METHODS: A retrospective review using our trauma registry from 2006 to 2016 of pediatric patients who sustained injuries while riding a longboard.
RESULTS: Of 12,920 injured children, 64 (0.5%) were treated for injuries that occurred while riding a longboard. Median age was 14.5 years (IQR 13.6, 15.4) and 84% were male. Fifty-one (80%) suffered a traumatic brain injury (TBI) including 32 intracranial hemorrhages (ICH), 17 concussions, and 31 skull fractures. Seven (11%) were wearing helmets. Three patients required neurosurgical intervention. Extremity fractures were the most common reason for surgery. Ninety-six percent of patients were admitted to the hospital with a median length of stay of 1 day (IQR 1, 3). All children survived to discharge. Compared with skateboard injuries during the same period, TBI, ICH, concussion, and skull fractures were all greater.
CONCLUSIONS: TBI ranging from concussion to ICH requiring craniotomy is common in children injured while riding a longboard, and greater than rates after skateboarding injuries. Extremity fracture was the most common reason for operative intervention.
METHODS: III.

Hoverboards pose a significant risk of musculoskeletal injury to pediatric riders. A prospectively enrolled cohort yielded 9 pediatric patients injured while riding hoverboards in 2016. Eight of the injuries involved the upper extremity, and one involved the lower extremity. No riders wore any safety equipment and injury patterns modeled those seen in skateboard riders.

A simple mechanical model of the skateboard-skater system is analysed, in which the effect of human control is considered by means of a linear proportional-derivative (PD) controller with delay. The equations of motion of this non-holonomic system are neutral delay-differential equations. A linear stability analysis of the rectilinear motion is carried out analytically. It is shown how to vary the control gains with respect to the speed of the skateboard to stabilize the uniform motion. The critical reflex delay of the skater is determined as the function of the speed. Based on this analysis, we present an explanation for the linear instability of the skateboard-skater system at high speed. Moreover, the advantages of standing ahead of the centre of the board are demonstrated from the viewpoint of reflex delay and control gain sensitivity.

Bicycle helmets reduce the frequency and severity of severe to fatal head and brain injuries in bicycle crashes. Our goal here was to measure the impact attenuation performance of common bicycle helmets over a range of impact speeds. We performed 127 drop tests using 13 different bicycle helmet models (6 traditional style helmets and 7 BMX-style helmets) at impact speeds ranging from 1 to 10m/s onto a flat anvil. Helmets were struck on their left front and/or right front areas, a common impact location that was at or just below the test line of most bicycle helmet standards. All but one of the 10 certified helmet models remained below the 300g level at an impact speed of 6m/s, whereas none of the 3 uncertified helmets met this criterion. We found that the helmets with expanded polystyrene liners performed similarly and universally well. The single certified helmet with a polyurethane liner performed below the level expected by the Consumer Product Safety Commission (CPSC) standard at our impact location and the helmet structure failed during one of two supplemental tests of this helmet above the test line. Overall, we found that increased liner thickness generally reduced peak headform acceleration, particularly at higher impact speeds.

OBJECTIVE: The aim of this study was to describe trauma in children secondary to the use of wheeled recreational devices (WRDs).
METHODS: This study retrospectively described trauma secondary to use of WRDs sustained by children 16 years or younger over a period of 12 months at two tertiary paediatric hospitals in Brisbane, Queensland. Data were analysed from the Paediatric Trauma Registry at these two facilities. Data were also retrieved from The Commission for Children and Young People and Child Guardian to provide information regarding deaths in Queensland from the use of WRDs for the period January 2004 to September 2013. Outcome measures included age, gender, types of injuries, Injury Severity Scores, admission to Intensive Care, and length of hospital stay for all hospital admissions greater than 24 h.
RESULTS: A total number of 45 children were admitted with trauma relating to WRDs during the 12 months, representing 5.3% of all trauma admissions of greater than 24 h during this time period. Of these, 34 were male with a median age of 11.0 years (IQR = 9-13). Limbs accounted for the majority (54.5%) of injuries, with other common injuries being spine/cranial fractures (14.5%), lacerations (12.7%), internal organ injuries (9.1%), and intracranial bleeds (9.1%). There were six admissions to the Paediatric Intensive Care Unit and one death.
CONCLUSIONS: WRDs contribute significantly to injuries sustained by children. A large proportion of these injuries may be preventable, suggesting that mandating the use of protective equipment in Queensland may be of great benefit.