Nathan Elsworthy

Physical and Decision-Making Demands of Australian Football Umpires During Competitive Matches

Abstract Elsworthy, N, Burke, D, Scott, BR, Stevens, CJ, and Dascombe, BJ. Physical and decision-making demands of Australian football umpires during competitive matches. J Strength Cond Res 28(12): 3502–3507, 2014—This study examined the physical and decision-making requirements of elite Australian football (AF) umpires during match play. Twenty-nine field umpires were assessed across 20 AF League matches. Physical demands were monitored using global positioning system devices to record the total distance covered and high-speed running (HSR; >14.4 km·h−1) demands across each quarter. Decision-making performance was assessed through video by 3 elite umpire coaches who reviewed free-kick accuracy during each match. These data were further analyzed according to the position (mid-zone or end-zone) of the umpire when each decision was made. The average distance covered was 10,563 ± 608 m, of which 1,952 ± 494 m was HSR. Significant reductions in distance covered were observed during the third (p = 0.006) and fourth (p = 0.001) quarters, compared with the first. An average of 44 ± 8 free kicks awarded per match with a decision accuracy of 84 ± 6%; however, there were no significant differences (p > 0.05) in these measures across a match. Significantly (p ⩽ 0.05) higher physical (HSR; relative distance) and decision-making requirements were observed within the mid-zone. The current data quantify the physical and decision-making demands of AF umpiring and demonstrated that despite a high physical workload, free-kick accuracy is maintained across a match. This suggests that decision making may not be directly compromised by the intermittent running demands of AF umpires. Positional rotations between the mid-zone and end-zone position allow for the demands to be shared among all field umpires during a match.

Factors relating to the decision-making performance of Australian football officials

Team sport officials are charged with the responsibility to enforce the laws of the game and their performance is based upon the quality of their decisions during a match. The current investigation examined the effects of positioning and retrospective physical demands had on the decision-making accuracy of Australian football officials. Match decision-making statistics and time motion data from 20 elite Australian football matches and the factors related to improved decision-making during match play were examined. Most decisions were made from a distance between 11-15 m, however distance from play had no significant effect on accuracy. There was no significant effect of movement velocity at the time of a decision on accuracy. There was a significant (P<0.05) difference between correct and incorrect decisions in the running speed across the 5 s prior to the decision being made. These findings determine that there is no effect of distance from play or instantaneous velocity on decision-making accuracy during match play. However, higher relative running speeds prior to a decision increases the likelihood of a decisional error. Superior anticipatory skill may reduce the running demands immediately prior to a decision, and therefore possibly improve the decision-making accuracy of umpires.

The validity and reliability of a customized rigid supportive harness during Smith machine back squat exercise.

Abstract Scott, BR, Dascombe, BJ, Delaney, JA, Elsworthy, N, Lockie, RG, Sculley, DV, and Slattery, KM. The validity and reliability of a customized rigid supportive harness during Smith machine back squat exercise. J Strength Cond Res 28(3): 636–642, 2014—Although the back squat exercise is commonly prescribed to both athletic and clinical populations, individuals with restricted glenohumeral mobility may be unable to safely support the bar on the upper trapezius using their hands. The aims of this study were to investigate the validity and reliability of a back squat variation using a rigid supportive harness that does not require unrestricted glenohumeral mobility for quantifying 1 repetition maximum (1RM). Thirteen young men (age = 25.3 ± 4.5 years, height = 179.2 ± 6.9 cm, and body mass = 86.6 ± 12.0 kg) with at least 2 years resistance training experience volunteered to participate in the study. Subjects reported to the lab on 3 occasions, each separated by 1 week. During testing sessions, subjects were assessed for 1RM using the traditional back squat (session 1) and harness back squat (HBS; sessions 2 and 3) exercises. Mean 1RM for the traditional back squat, and 2 testing sessions of the HBS (HBS1 and HBS2) were 148.4 ± 25.0 kg, 152.5 ± 25.7 kg, and 150.4 ± 22.6 kg, respectively. Back squat and mean HBS 1RM scores were very strongly correlated (r = 0.96; p < 0.001). There were no significant differences in 1RM scores between the 3 trials. The test-retest 1RM scores with the HBS demonstrated high reliability, with an intraclass correlation coefficient of 0.98 (95% confidence interval [CI] = 0.93–0.99), and a coefficient of variation of 2.6% (95% CI = 1.9–4.3). Taken together, these data suggest that the HBS exercise is a valid and reliable method for assessing 1RM in young men with previous resistance training experience and may be useful for individuals with restricted glenohumeral mobility.

Physical and psychomotor performance of Australian football and rugby league officials during a match simulation

Abstract The onset of exercise facilitates an improvement in psychomotor performance until the second ventilatory threshold, after which performance is reduced. This inverted-U relationship appears valid for incremental and steady-state exercise, however, not for intermittent exercise. This study examined changes in psychomotor performance of team sport officials during a laboratory-based match simulation. Twelve elite Australian football (n = 5) and rugby league (n = 7) officials (32.5 ± 5.5 years; 180.0 ± 6.8 cm; 78.8 ± 7.6 kg) completed the match simulation on a non-motorised treadmill. Physiological measures were routinely taken, while psychomotor performance was assessed using the Eriksen flanker task (multiple-choice response time). Significant reductions (P < 0.05) were observed in distance covered and high-speed running during the second half when compared to the first. No significant differences (P > 0.05) in psychomotor performance at different time points were observed. Response time was significantly improved when running above 65% of maximal sprinting speed (P < 0.01). This data questions the application of the inverted-U hypothesis for intermittent exercise and suggests that the short high-intensity efforts may not result in the same physiological events that limit psychomotor performance during sustained high-intensity exercise. More so, the high-intensity efforts during the match protocol appeared to promote psychomotor performance during the intermittent exercise.

Examining the skill involvements of under-16 rugby league players during a small-sided game and match-play:

This study investigated the correlations between the skill demands of an ‘on-side’ small-sided game (SSG) and match-play in under-16 junior rugby league players. Fifteen Harold Matthews players undertook a SSG (10 vs. 10 on a 68 m by 40 m playing surface for 3 min) in the week leading up to round 6 of their competitive season. The frequency of skill involvements (i.e. offensive, defensive and total) was manually coded using a specific criterion. The defensive and total skill involvements were significantly higher per minute of play in the SSG when compared to match-play. A significant, very large, positive correlation was observed between offensive and total skill involvements during a SSG and offensive skill involvements during a match (r(s) = 0.80, p < 0.01; r(s) = 0.71, p < 0.01, respectively). No significant correlations were evident for defensive skill involvements during SSG and match-play. Overall, it appears that the selected SSG provided players with ample opportunity to practice match-specific skills. In addition, the transfer of these opportunities seems confined to offensive rather then defensive skills.