A novel equestrian helmet testing method: helmet liner performance in highly realistic simulation.

OBJECTIVE: Employ a novel testing method to assess Multi Directional Impact Protection System (MIPS) helmet technology on rotational velocity and acceleration during head impact. METHODS: An optimization study was completed utilizing a 50th percentile male Hybrid III anthropomorphic test device (ATD). Helmets included expanded polystyrene foam (EPS) and two different MIPS helmets (MIPS 1, MIPS 2). A 24.38-m-long elevated track with rails and a motorized sled was utilized to replicate a fall from approximately 2.13 m. The sled was set to a speed of 20.92 kph, where a tripping mechanism induced rotation in the ATD from the sled and onto a sand surface. During impact of the ATD with the sand surface, head kinematics were measured using resultant acceleration (peak G's), duration of impact (ms), and rotational velocity (rad/s). RESULTS: A total of three trials for each helmet did not demonstrate a significant difference between the EPS vs. MIPS 1 group with, peak (G's) for resultant acceleration (p = 0.100), duration (ms) for resultant acceleration, (p = 0.100), peak (G's) for rotational velocity, (p = 0.700), and duration (ms) for rotational velocity (p = 0.700). Similarly, the EPS vs. MIPS 2 testing demonstrated no significant differences between the MIPS 2 helmet compared to the EPS helmet, with resultant acceleration (p = 0.400), duration acceleration (p = 0.200), rotational velocity (p = 0.400) and duration velocity (p = 0.400). However, when the MIPS helmet data were pooled, and the EPS helmet data were compared, a statistically significant difference in the duration of acceleration was found (p = 0.048). CONCLUSIONS: Current testing uses a helmeted head form which is dropped or rolled from a prescribed height. These methods discount the loading placed on the neck and head through the angular momentum of the body. Our novel testing method did not find significant differences between the helmet types in diminishing peak rotational forces to the brain; however, our data suggests that MIPS helmet liners may reduce duration of impact. The reduction of acceleration duration could indicate less rotation of the neck, due to the dampening of these forces by the MIPS liners.

Validation of the Polar Team Pro System for Sprint Speed With Ice Hockey Players.

ABSTRACT: Conners, RT, Whitehead, PN, Dodds, FT, Schott, KD, and Quick, MC. Validation of the polar team pro system for sprint speed with ice hockey players. J Strength Cond Res 36(12): 3468-3472, 2022-Commercially available player tracking sensors such as the Polar Team Pro system (PTPS) have been used to monitor athlete performance. Use during ice hockey practices and games has resulted in seemingly plausible and valid values for internal metrics (heart rate); however, external metrics (distance, speed, and acceleration) seem sporadic and counterintuitive. To determine the validity of the PTPS for measuring sprint speed with collegiate hockey players, 15 NCAA Division I male athletes (21.86 ± 1.04 years, 175.86 ± 6.78 cm, 80.58 ± 4.44 kg) participated in the study. Subjects wore a PTPS strap, at the level of the xiphoid process, and performed 2 sprints of 15.24 m (blue line to blue line) and 35.05 m (red line to the far blue line) in 3 conditions: indoor ice skating, indoor running, and outdoor running. Timing gates (TG) were used to determine sprint times, which allowed for manual calculation of speed. Speed values from the PTPS and TG were compared using paired-samples t -tests, and an alpha level of 0.05, 2-sided, was set a priori as a significance level. For indoor ice skating, PTPS significantly underestimated speeds at both distances ( p < 0.001). However, PTPS significantly overestimated speeds for indoor and outdoor sprints at both distances ( p ≤ 0.001). The PTPS is not accurate for measuring short-distance linear sprint speed or linear sprint speed during indoor ice skating. The inconsistency in speed values needs to be taken into consideration when using the system for science-based training because inaccurate speed values may negatively affect other external performance metrics provided by PTPS.

Shoulder Strength and Range of Motion Between Collegiate Pitchers and Position Players in Baseball.

Baseball is a sport that places excessive strain on the shoulder complex caused from repetitive overhead throws. In the sport of baseball, shoulder strength and range of motion (ROM) are paramount for success on the field. The purpose of this study was to determine strength and ROM differences between collegiate baseball pitchers and position players. It was hypothesized that pitchers would have higher strength and ROM values, due to the volume of throwing a pitcher performs. A total of nine collegiate baseball pitchers and position players (n = 18) volunteered for the study (age = 20.94 ± 1.21 years, height = 183.42 ± 4.74 cm, and mass = 89.56 ± 10.76 kg). Shoulder strength was measured using a Humac Norm isokinetic dynamometer at 180ºsec-1 and 300ºsec-1 and ROM was measured using a goniometer. All participants completed a five-minute warm-up at 50 rpm on an upper body ergometer. Following the warm-up, passive internal and external ROM were measured for the throwing (dominant) arm. No statistical differences were found in external ROM (p = 0.319), internal ROM (p = 0.258), external peak torque @180ºsec-1 (p = 0.467), internal peak torque @180ºsec-1 (p = 0.156), external peak torque @300ºsec-1 (p = 0.225), or internal peak torque @300ºsec-1 (p = 0.137). The findings indicate similar isokinetic strength and flexibility in the throwing shoulder of collegiate athletes who perform repeated overhead throwing motions. Thus, in this study the player's baseball position (pitchers vs. position player) did not influence throwing shoulder strength and ROM characteristics.