Pedestrian Safety in Frontal Tram Collision, Part 1: Historical Overview and Experimental-Data-Based Biomechanical Study of Head Clashing in Frontal and Side Impacts.

This article represents the first paper in a two-part series dealing with safety during tram-pedestrian collisions. This research is dedicated to the safety of trams for pedestrians during collisions and is motivated by the increased number of lethal cases. The first part of this paper includes an overview of tram face development from the earliest designs to the current ones in use and, at the same time, provides a synopsis and explanation of the technical context, including a link to current and forthcoming legislation. The historical design development can be characterised by three steps, from an almost vertical front face, to leaned and pointed shapes, to the current inclined low-edged windshield without a protruding coupler. However, since most major manufacturers now export their products worldwide and customisation is only of a technically insignificant nature, our conclusions are generalisable (supported by the example of Berlin). The most advantageous shape of the tram's front, minimising the effects on pedestrians in all collision phases, has evolved rather spontaneously and was unprompted, and it is now being built into the European Commission regulations. The goal of the second part of this paper is to conduct a series of tram-pedestrian collisions with a focus on the frontal and side impacts using a crash test dummy (anthropomorphic test device-ATD). Four tram types approaching the collision at four different impact speeds (5 km/h, 10 km/h, 15 km/h, and 20 km/h) were used. The primary outcome variable was the resultant head acceleration. The risk and severity of possible head injuries were assessed using the head injury criterion (HIC15) and its linkage to the injury level on the Abbreviated Injury Scale (AIS). The results showed increasing head impacts with an increasing speed for all tram types and collision scenarios. Higher values of head acceleration were reached during the frontal impact (17-124 g) compared to the side one (2-84 g). The HIC15 values did not exceed the value of 300 for any experimental setting, and the probability of AIS4+ injuries did not exceed 10%. The outcomes of tram-pedestrian collisions can be influenced by the ATD's position and orientation, the impact speed and front-end design of trams, and the site of initial contact.

The effect of a neuromuscular warm-up on the injury rates in New Zealand amateur futsal players.

OBJECTIVES: To investigate the effectiveness of a futsal-specific warm-up to reduce injuries in amateur teams. DESIGN: Quasi-experimental. SETTING: Two futsal centres followed over one season using a specific report card. PARTICIPANTS: 878 teams (Intervention group, n = 458; Control group, n = 420) of both genders and three age groups (U13, U17, adults). INTERVENTION: A futsal-specific warm-up consisting of cardiovascular exercises, dynamic stretches, and game-related skills. MAIN OUTCOME MEASURES: The incidence rate and severity of all injuries, lower extremity (LE) injuries and contact injuries. A multivariate Poisson regression analysis was used to compare between-group rates. RESULTS: The rate of all injuries was lower in the intervention group (rate ratio (RR) = 0.72, 95% CI = 0.59 to 1.06), yet not significant. There was a significantly lower rate of contact injuries in the intervention group (RR = 0.68, 95% CI = 0.51 to 0.98). Subgroup analysis, based on the warm-up adherence of intervention teams (low, intermediate, high), showed a lower rate of all injuries (RR = 0.52, 95% CI = 0.29 to 0.97), and LE injuries (RR = 0.32, 95% CI = 0.14 to 0.81) in the high compared to low adherence group. CONCLUSION: A futsal-specific warm-up can reduce the rate of contact injuries in amateur players. With high adherence the rate of all injuries and LE injuries may also reduce.

Attitudes, beliefs and factors influencing football coaches' adherence to the 11+ injury prevention programme.

OBJECTIVE: To explore football coaches' beliefs and attitudes about injury prevention and the 11+ injury prevention programme, and to investigate factors that may influence adherence to the 11+ injury prevention programme. METHODS: A total of 538 football coaches who had completed an injury prevention education workshop were invited to participate in a web-based nationwide survey. The survey questions explored beliefs and attitudes about injury prevention and the 11+ injury prevention programme, self-reported adherence to the 11+ programme, as well as perceived barriers and facilitators to the use of the 11+ programme. RESULTS: There were 158 respondents. The majority believe that injury prevention is part of their coaching role (94%) that a structured warm-up is an important part of their team's preparation for training and games (96%), and that the 11+ is effective (92%). While most respondents (95%) use the 11+, modifications are common. Participants with greater coaching experience are more likely to use the programme. Time constraints are the main barriers to adherence, while knowing that the programme enhances performance is seen as a major facilitator. CONCLUSIONS: Coaches who attended an injury prevention workshop have positive attitudes towards injury prevention and the 11+ programme. However, coaches with less coaching experience may be less likely to use the 11+ and could therefore be the target population for future education workshops. Promoting the performance enhancing effects of the 11+ and encouraging modifications could improve acceptability and adherence.

Isokinetic Strength of Rotators, Flexors and Hip Extensors is Strongly Related to Front Kick Dynamics in Military Professionals.

Achieving the maximum possible impact force of the front kick can be related to the isokinetic lower limb muscle strength. Therefore, we aimed to determine the regression model between kicking performance and the isokinetic peak net moment of hip rotators, flexors, and hip extensors and flexors at various speeds of contraction. Twenty-five male soldiers (27.7 ± 7.2 yrs, 83.8 ± 6.1 kg, 180.5 ± 6.5 cm) performed six barefoot front kicks, where impact forces (N) and kick velocity (m∙s-1) were measured. The 3D kinematics and isokinetic dynamometry were used to estimate the kick velocity, isokinetic moment of kicking lower limb hip flexors and extensors (60, 120, 240, 300°âˆ™s-1), and stance lower limb hip internal and external rotators (30, 90°âˆ™s-1). Multiple regression showed that a separate component of the peak moment concentric hip flexion and extension of the kicking lower limb at 90°âˆ™s-1 can explain 54% of the peak kicking impact force variance (R2 = 0.54; p < 0.001). When adding the other 3 components of eccentric and concentric hip internal and external rotations at 30°âˆ™s-1, the internal and external hip rotation ratios at 30°âˆ™s-1 on the stance limb and the concentric ratio of kicking limb flexion and extension at 300°âˆ™s-1 that explained the variance of impact force were 75% (p = 0.003). The explosive strength of kicking limb hip flexors and extensors is the main condition constraint for kicking performance. The maximum strength of stance limb internal and external rotators and speed strength of kicking limb hip flexors and extensors are important constraints of kicking performance that should be considered to improve the front kick efficiency.