Event-specific impact test protocol for ice hockey goaltender masks

Investigation of Head Kinematics and Brain Strain Response During Soccer Heading Using a Custom-Fit Instrumented Mouthguard

Association football, also known as soccer in some regions, is unique in encouraging its participants to intentionally use their head to gain a competitive advantage, including scoring a goal. Repetitive head impacts are now being increasingly linked to an inflated risk of developing long-term neurodegenerative disease. This study investigated the effect of heading passes from different distances, using head acceleration data and finite element modelling to estimate brain injury risk. Seven university-level participants wore a custom-fitted instrumented mouthguard to capture linear and angular acceleration-time data. They performed 10 headers within a laboratory environment, from a combination of short, medium, and long passes. Kinematic data was then used to calculate peak linear acceleration, peak angular velocity, and peak angular acceleration as well as two brain injury metrics: head injury criterion and rotational injury criterion. Six degrees of freedom acceleration-time data were also inputted into a widely accepted finite element brain model to estimate strain-response using mean peak strain and cumulative strain damage measure values. Five headers were considered to have a 25% concussion risk. Mean peak linear acceleration equalled 26 ± 7.9 g, mean peak angular velocity 7.20 ± 2.18 rad/s, mean peak angular acceleration 1730 ± 611 rad/s2, and 95th percentile mean peak strain 0.0962 ± 0.252. Some of these data were similar to brain injury metrics reported from American football, which supports the need for further investigation into soccer heading.

Upper Limb Strikes Reactive Forces in Mix Martial Art Athletes during Ground and Pound Tactics

Athletes of mixed martial arts use a ground and pound strategy with the strikes in the dominant ground position. The aim of this study was to compare the average peak force (F_peak) among three punches and to estimate the probability of achieving a skull bone fracture force of 5.1 kN for each type of strike in male and female athletes. A total of 60 males and 31 females (26 ± 8 years, 75 ± 20 kg, 177 ± 11 cm) practicing professional self-defense at the advanced and professional levels performed 15 strikes on a force plate. The analyses of 1360 trials showed significant differences among the strikes F_peak in females (p < 0.01) and males (p < 0.01). Straight punches had lower F_peak than palm strikes and elbow strikes in both genders, and palm strikes had higher F_peak than elbow strikes in females. No difference was observed between palm strikes and elbow strikes in males (p = 0.09). The ground and pound strikes resulted in higher impacts than previously reported strikes in the standing position. Male athletes can deliver a F_peak above 5.1 kN with a probability of 36% with elbow and palm strikes. Such forces can cause head injury; therefore, the use of these strikes in competition should be carefully considered.

Force and velocity of impact during upper limb strikes in combat sports: a systematic review and meta-analysis

Upper limb strikes are frequent movements in combat sports and self-defence systems, in which numerous types of strikes can be applied. Therefore, the aim of this systematic review and meta-analysis was to summarise and compare the mechanical consequences of different types of upper limb strikes among various sports disciplines. A literature search was conducted in Scopus and Web of Science, with the following search formula: (impact force) AND (strike) AND (taekwondo) OR (karate) OR (self-defence) OR (combat sport) OR (boxing). The search resulted in 28 studies describing 9 kinds of strikes, where straight punches and reverse punches have larger mean impact forces than the kung fu punch (p < 0.001) and that a palm strike had a lower strike velocity (p < 0.001) than a reverse punch, straight punch, or junzuki punch. The highest recorded mean force was found for a straight punch (3427 N). Athletes in mixed martial arts, trainers of self-defence or tactical coaches can expect that straight punches and reverse punches should be performed at high speeds (over 10 m/s) and provide similar or larger impacts than other upper limb strikes; therefore, those punches should favour a combat athlete to win a competition or succeed in self-defence.