Relationships between reactive agility movement time and unilateral vertical, horizontal, and lateral jumps
- Authors: Henry, Greg , Dawson, Brian , Lay, Brendan , Young, Warren
- Date: 2016
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 30, no. 9 (2016), p. 2514-2521
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- Description: Henry, GJ, Dawson, B, Lay, BS, and Young, WB. Relationships between reactive agility movement time and unilateral vertical, horizontal, and lateral jumps. J Strength Cond Res 30(9): 2514-2521, 2016 - This study compared reactive agility movement time and unilateral (vertical, horizontal, and lateral) jump performance and kinetics between dominant and nondominant legs in Australian rules footballers (n 31) to investigate the role of leg strength characteristics in reactive agility performance. Jumps involved jumping forward on 1 leg, then for maximum height or horizontal or lateral distance. Agility and movement time components of reactive agility were assessed using a video-based test. Correlations between each of the jumps were strong (r -0.62 to -0.77), but between the jumps and agility movement time the relationships were weak (r -0.25 to -0.33). Dominant leg performance was superior in reactive agility movement time (4.5%; p 0.04), lateral jump distance (3%; p 0.008), and lateral reactive strength index (4.4%; p 0.03) compared with the nondominant leg. However, when the subjects were divided into faster and slower performers (based on their agility movement times) the movement time was significantly quicker in the faster group (n 15; 12%; p < 0.001), but no differences in jump performance or kinetics were observed. Therefore, although the capacity for jumps to predict agility performance seems limited, factors involved in producing superior lateral jump performance in the dominant leg may also be associated with advantages in agility performance in that leg. However, because reactive strength as measured by unilateral jumps seems to play a limited role in reactive agility performance and other factors such as skill, balance, and coordination, and also cognitive and decision-making factors, are likely to be more important. © 2013 National Strength and Conditioning Association.
Agility and change-of-direction speed are independent skills: Implications for training for agility in invasion sports
- Authors: Young, Warren , Dawson, Brian , Henry, Greg
- Date: 2015
- Type: Text , Journal article
- Relation: International Journal of Sports Science & Coaching Vol. 10, no. 1 (2015), p. 159-169
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- Description: This review explores the differences between agility in invasion sports (defined as including reactive decision-making) and change-of-direction speed (CODS), and highlights the implications for training. Correlations between agility tests and CODS tests indicate that they represent independent skills. Agility tests discriminate higher-from lower-standard athletes better than CODS tests, indicating that the cognitive element of agility is important to performance. Training studies have shown that the development of strength qualities can transfer to gains in CODS, but this has never been shown for agility. There is some evidence that the importance of physical qualities is greater for CODS than for agility. It was concluded that the reactive element should be included in agility training, testing and research. While there appears to be no research evidence for the benefits of strength and power training, there is some support for the use of small-sided games for improving agility.
Decision-making accuracy in reactive agility: Quantifying the cost of poor decisions
- Authors: Henry, Greg , Dawson, Brian , Lay, Brendan , Young, Warren
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 27, no. 11 (2013), p. 3190-3196
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- Description: Decision-making accuracy and the time cost of incorrect responses was compared between higher- (n = 14) and lowerstandard (n = 14) Australian footballers during reactive agility tasks incorporating feint and nonfeint scenarios. Accuracy was assessed as whether the subject turned in the correct direction to each stimulus. With skill groups pooled, decision accuracy at the first (or only) stimulus (decision time 1) was 94 6 7%, and it decreased to 83 6 20% for the second stimulus (decision time 2; p = 0.01; d = 0.69). However, with skill groups separated, decision accuracy was similar between groups at decision time 1 (higher 95 6 6% vs. lower 92 6 7%; p = 0.6; d = 0.42), somewhat better in the higher-standard group at decision time 2 (88 6 22% vs. 78 6 17%; p = 0.08; d =0.50). But the decrease in accuracy from decision time 1 to 2 was significant in the lower-standard group only (92 6 7% to 78 6 17%; p = 0.02; d = 1.04). However, with skill groups pooled but agility times examined exclusively in trials involving correct or incorrect decisions, incorrect decisions at decision time 1 during feint trials resulted in a shorter agility time (1.73 6 0.24 seconds vs. 2.03 6 0.39 seconds; p = 0.008; d =0.92), whereas agility time was significantly longer in feint (incorrect at decision time 2 only; 2.65 6 0.41 seconds vs. 1.97 6 0.36 seconds; p , 0.001; d = 1.76) and nonfeint trials (1.64 6 0.13 seconds vs. 1.51 6 0.10 seconds; p = 0.001; d = 1.13). Therefore, although decision-making errors typically worsen reactive agility performance, successful anticipation of a feint can produce performance improvements. Furthermore, higher-standard footballers are less susceptible to such feints, perhaps because of superior anticipation. Training to improve decision-making accuracy, particularly involving feint movements, may therefore principally benefit lesser-skilled players and should be practiced regularly. © 2013 National Strength and Conditioning Association.
- Description: C1
Effects of a feint on reactive agility performance
- Authors: Henry, Greg , Dawson, Brian , Lay, Brendan , Young, Warren
- Date: 2012
- Type: Text , Journal article
- Relation: Journal of Sports Sciences Vol. 30, no. 8 (2012), p. 787-795
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- Description: This study compared reactive agility between higher-standard (n = 14) and lower-standard (n = 14) Australian footballers using a reactive agility test incorporating a life-size video image of another player changing direction, including and excluding a feint. Mean agility time in the feint trials was 34% (509 ± 243 ms; p < 0.001; effect size 3.06) longer than non-feint trials. In higher-standard players, agility time was shorter than for lower-standard players in both feint (114 ± 140 ms; p = 0.18; effect size 0.52; likely beneficial) and non-feint (32 ± 44 ms; p = 0.22; effect size 0.47; possibly beneficial) trials. Additionally, the inclusion of a feint resulted in movement time increasing over three times more in the lower-standard group (197 ± 91 ms; p = 0.001; effect size 1.07; almost certainly detrimental) than the higher-standard group (62 ± 86 ms; p = 0.23; effect size 0.66; likely detrimental). There were weak correlations between the feint and non-feint trials (r = -0.13-0.14; p > 0.05), suggesting that reactive agility involving a feint is a unique skill. Also, higher-standard players are more agile than their lower-standard peers, whose movement speed deteriorates more as task complexity increases with the inclusion of a feint. These results support the need for specific training in multi-turn reactive agility tasks. © 2012 Copyright Taylor and Francis Group, LLC.
Validity of a reactive agility test for Australian football
- Authors: Henry, Greg , Dawson, Brian , Lay, Brendan , Young, Warren
- Date: 2011
- Type: Text , Journal article
- Relation: International Journal of Sports Physiology and Performance Vol. 6, no. 4 (2011), p. 534-545
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- Description: Purpose: To study the validity of a video-based reactive agility test in Australian footballers. Methods: 15 higher performance, 15 lower performance, and 12 nonfootballers completed a light-based reactive agility test (LRAT), a video-based reactive agility test (VRAT), and a planned test (PLAN). Results: With skill groups pooled, agility time in PLAN (1346 ± 66 ms) was significantly faster (P = .001) than both reactive tests (VRAT = 1550 ± 102 ms; LRAT = 1572 ± 97 ms). In addition, decision time was significantly faster (P = .001; d = 0.8) in LRAT (278 ± 36 ms) than VRAT (311 ± 47 ms). The correlation in agility time between the two reactive tests (r = .75) was higher than between the planned and reactive tests (r = .41-.68). Higher performance players had faster agility and movement times on VRAT (agility, 130 ± 24 ms, d = 1.27, P = .004; movement, 69 ± 73 ms, d = 0.88, P = .1) and LRAT (agility, 95 ± 86 ms, d = 0.99, P = .08; movement, 79 ± 74 ms; d = 0.9; P = .08) than the nonfootballers. In addition, higher (55 ± 39 ms, d = 0.87, P = .05) and lower (40 ± 57 ms, d = 0.74, P = .18) performance groups exhibited somewhat faster agility time than nonfootballers on PLAN. Furthermore, higher performance players were somewhat faster than lower performance for agility time on the VRAT (63 ± 85 ms, d = 0.82, P = .16) and decision time on the LRAT (20 ± 39 ms, d = 0.66, P = .21), but there was little difference in PLAN agility time between these groups (15 ± 150 ms, d = 0.24, P = .8). Conclusions: Differences in decision-making speed indicate that the sport-specific nature of the VRAT is not duplicated by a light-based stimulus. In addition, the VRAT is somewhat better able to discriminate different groups of Australian footballers than the LRAT. Collectively, this indicates that a video-based test is a more valid assessment tool for examining agility in Australian footballers. © 2011 Human Kinetics, Inc.
Effects of static stretching in warm-up on repeated sprint performance
- Authors: Sim, Aaron , Dawson, Brian , Guelfi, Kym , Wallman, Karen , Young, Warren
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 23, no. 7 (2009), p. 2155-2162
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- Description: Sim, AY, Dawson, BT, Guelfi, KJ, Wallman, KE, and Young, WB. Effects of static stretching in warm-up on repeated sprint performance. J Strength Cond Res 23(7): 2155-2162, 2009-The aim of this study was to examine the effects of static stretching during warm-up on repeated sprint performance and also to assess any influence of the order in which dynamic activities (i.e., run-throughs and drills) and static stretching are conducted. Thirteen male team sport players completed a repeated sprint ability test consisting of three sets of maximal 6 3 20-m sprints (going every 25 seconds) after performing one of three different warm-up protocols in a within-subjects counterbalanced design. Each warm-up protocol involved an initial 1000-m jog, followed by either dynamic activities only (D), static stretching followed by dynamic activities (S-D), or dynamic activities followed by static stretching (D-S). First (FST), best (BST) and total (TST) 20-m sprint times were determined for each individual set of the repeated sprint ability test and overall (3 sets combined). Although consistent significant differences were not observed between trials for TST, BST, and FST, the mean values for TST in all individual sets and overall were generally slowest in the D-S condition (D = 60.264 +/- 1.127 seconds; S-D = 60.347 +/- 1.774 seconds; D-S = 60.830 +/- 1.786 seconds). This trend was supported by moderate to large effect sizes and qualitative indications of "possible'' or "likely'' benefits for TST, BST, and FST for the D and S-D warm-ups compared to D-S. No significant differences or large effect sizes were noted between D and S-D, indicating similar repeated sprint ability performance. Overall, these results suggest that 20-m repeated sprint ability may be compromised when static stretching is conducted after dynamic activities and immediately prior to performance (D-S).
- Description: 2003008195
Physiological and anthropometric characteristics of starters and non-starters and playing positions in elite Australian Rules football : A case study
- Authors: Young, Warren , Newton, Robert , Doyle, Tim , Chapman, Dale , Cormack, Stuart , Stewart, Glenn , Dawson, Brian
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 8, no. 3 (Sep 2005), p. 333-345
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- Description: A purpose of this study was to determine if pre-season anthropometric and physiological measures were significantly different for the players from one Australian Football League (AFL) club selected to play in the first game of the season compared to the players not selected. Another purpose was to compare fitness test results for defenders, forwards and mid-fielders in the same AFL club. Thirty-four players were tested for isolated quadriceps and hamstrings strength, leg extensor muscle strength and power, upper body strength, sprinting speed, vertical jump (VJ), endurance, skinfolds and hamstring flexibility. The starters who were selected to play the first game were a significantly older and more experienced playing group, and were significantly better (p < 0.05) in measures of leg power, sprinting speed and the distance covered in the Yo Yo intermittent recovery test compared to the non-starters. Although there were trends for the superiority of the starters, the differences in lower and upper body strength, VJ and predicted VO(2)max were nonsignificant. The forwards generally produced the worst fitness scores of the playing positions with the midfielders having significantly lower skinfolds and the defenders possessing better hamstring strength and VJ compared to the forwards. It was concluded that some fitness qualities can differentiate between starters and non-starters, at least in one AFL club. Comparisons of playing positions and the development of fitness norms for AFL players require further research.
- Description: C1
- Description: 2003001187