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Simon J. MacLeod, Chris Hagan, Mikel Egaña, Jonny Davis, and David Drake

in team sports. Importantly, to obtain a global view of the overall training load, valid measurements of both the volume and the intensity of collisions are essential as collisions provide a greater subjective, physical, and physiological load than noncontact rugby training or high

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Jonathan P. Norris, Jamie Highton, and Craig Twist

possessing acceptable validity and reliability for locomotive demands, previous attempts to simulate the match demands of rugby league have resulted in similar heart rate (HR) responses but greater relative distance and high-speed running compared with match play. 5 The replication of collisions in the

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Megan Nye and Paul A. Cacolice

Clinical Scenario Sport-related concussions are at the forefront of media and public attention, especially for those who participate in high school collision sports. As clinicians are uncertain of optimal diagnostic and treatment strategies, 1 it is suggested that prevention is a preferable

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Corey P. Ochs, Melissa C. Kay, and Johna K. Register-Mihalik

Clinical Scenario Concussions are one of the most common sports-related injuries affecting athletes of all ages. Collision sports, such as football and ice hockey, are often at a higher risk of concussion due to the physical nature and style of play. Incidence ranges from 6.61/1000 athlete

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Billy T. Hulin, Tim J. Gabbett, Rich D. Johnston, and David G. Jenkins

specifically for rugby league, which can be used to quantify collision counts. 4 This algorithm is sensitive to detect 97.6% of collision events during professional rugby league match-play, and the typical error associated with measuring these events is 7.8%. 4 Accurately quantifying collision workloads is

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Matthew J. Major, José L. Zavaleta, and Steven A. Gard

would theoretically increase collision work above that observed with rigid pylons, but also generate some energy return to mediate that increased work loss. Depending on the mechanical energy exchange, this may affect the energetics of walking 29 , 30 and could partially explain results indicating that

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John J. McMahon, Jason P. Lake, Nicholas J. Ripley, and Paul Comfort

performances ( r  = .56–.62, P  < .05) 2 and better tackling ability ( r  = .38, P  < .05) 3 in high-level players. These attributes are considered important because RL match play is composed of many high-intensity running, collision, and tackling actions. 4 Sprint momentum (body mass × velocity) has been

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Tim J. Gabbett and Aaron J. Wheeler

Purpose:

To investigate the relationship between repeated high-intensity-effort (RHIE) ability and selected physical qualities in rugby league players.

Methods:

Sixteen rugby league players underwent measurements of upper-body strength (4-repetition-maximum [4RM] bench press, weighted chin-up, weighted dips), upper-body muscle endurance (body-mass maximum-repetition chin-up, body-mass maximum-repetition dips), lower-body strength (4RM squat), estimated maximal aerobic power (multistage fitness test), and RHIE ability. The RHIE-ability test consisted of 1 × 10-m sprint, 3 × full-contact 1-on-1 tackling efforts, and a 30-m jog recovery. Players performed 4 repetitions of the test, with each repetition completed in 40 second. During the RHIE test, player speed was evaluated with a 10-m sprint effort while the movement of players was recorded using a wearable microtechnology device. 2D Player Load was used to quantify the collision component of the test.

Results:

Speed decrement was lower for the first- (−2.4% ± 1.0%) than the second-grade (−4.7% ± 2.1%) players. Players with greater initial speed had a higher average speed over the 4 sprints (r = .75), while players with greater maximum-repetition dips maintained a higher 2D Player Load (r = .76).

Conclusions:

These findings demonstrate a relationship between well-developed acceleration and upper-body muscle-endurance qualities and RHIE ability in rugby league players. Training programs designed to develop acceleration and upper-body muscle endurance are likely to improve RHIE ability.

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Cloe Cummins and Rhonda Orr

Objective:

To investigate the impact forces of collision events during both attack and defense in elite rugby league match play and to compare the collision profiles between playing positions.

Participants:

26 elite rugby league players.

Methods:

Player collisions were recorded using an integrated accelerometer in global positioning system units (SPI-Pro X, GPSports). Impact forces of collisions in attack (hit-ups) and defense (tackles) were analyzed from 359 files from outside backs (n = 78), adjustables (n = 97), wide-running forwards (n = 136), and hit-up forwards (n = 48) over 1 National Rugby League season.

Results:

Hit-up forwards were involved in 0.8 collisions/min, significantly more than all other positional groups (wide-running forwards P = .050, adjustables P = .042, and outside backs P = .000). Outside backs experienced 25% fewer collisions per minute than hit-up forwards. Hit-up forwards experienced a collision within the 2 highest classifications of force (≥10 g) every 2.5 min of match play compared with 1 every 5 and 9 min for adjustables and outside backs, respectively. Hit-up forwards performed 0.5 tackles per minute of match play, 5 times that of outside backs (ES = 1.90; 95% CI [0.26,3.16]), and 0.2 hit-ups per minute of match play, twice as many as adjustables.

Conclusions:

During a rugby league match, players are exposed to a significant number of collision events. Positional differences exist, with hit-up and wide-running forwards experiencing greater collision events than adjustables and outside backs. Although these results may be unique to the individual team’s defensive- and attacking-play strategies, they are indicative of the significant collision profiles in professional rugby league.

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Richard P. Wells, Patrick J. Bishop, and Malcolm Stephens

Spinal cord trauma due to head-first collisions is not uncommon in vehicle accidents, shallow water diving, football, or ice hockey. Two approaches to evaluating potential protective devices for ice hockey are described: an evaluative tool based upon an anthropometric test dummy, and a computer simulation of axial head-first collisions. Helmets reduced the peak cervical spine loads during low velocity head-first collisions by up to 8%. It is shown that large thicknesses of appropriate padding are necessary to hold the cervical spine loads to noninjurious levels. A head-first impact of 3.0 m • sec−1 required padding deformations on the order of 94 mm to hold cervical spine loads below 2,000 N.