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Sean J. Maloney, Anthony N. Turner and Stuart Miller

It has previously been shown that a loaded warm-up may improve power performances. We examined the acute effects of loaded dynamic warm-up on change of direction speed (CODS), which had not been previously investigated. Eight elite badminton players participated in three sessions during which they performed vertical countermovement jump and CODS tests before and after undertaking the dynamic warm-up. The three warm-up conditions involved wearing a weighted vest (a) equivalent to 5% body mass, (b) equivalent to 10% body mass, and (c) a control where a weighted vest was not worn. Vertical jump and CODS performances were then tested at 15 seconds and 2, 4, and 6 minutes post warm-up. Vertical jump and CODS significantly improved following all warm-up conditions (P < .05). Post warm-up vertical jump performance was not different between conditions (P = .430). Post warm-up CODS was significantly faster following the 5% (P = .02) and 10% (P < .001) loaded conditions compared with the control condition. In addition, peak CODS test performances, independent of recovery time, were faster than the control condition following the 10% loaded condition (P = .012). In conclusion, the current study demonstrates that a loaded warm-up augmented CODS, but not vertical jump performance, in elite badminton players.

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Gerald T. Mangine, Jay R. Hoffman, Jose Vazquez, Napoleon Pichardo, Maren S. Fragala and Jeffrey R. Stout

The ultimate zone-rating extrapolation (UZR/150) rates fielding performance by runs saved or cost within a zone of responsibility in comparison with the league average (150 games) for a position. Spring-training anthropometric and performance measures have been previously related to hitting performance; however, their relationships with fielding performance measures are unknown.

Purpose:

To examine the relationship between anthropometric and performance measurements on fielding performance in professional baseball players.

Methods:

Body mass, lean body mass (LBM), grip strength, 10-yd sprint, proagility, and vertical-jump mean (VJMP) and peak power (VJPP) were collected during spring training over the course of 5 seasons (2007–2011) for professional corner infielders (CI; n = 17, fielding opportunities = 420.7 ± 307.1), middle infielders (MI; n = 14, fielding opportunities = 497.3 ± 259.1), and outfielders (OF; n = 16, fielding opportunities = 227.9 ± 70.9). The relationships between these data and regular-season (100-opportunity minimum) fielding statistics were examined using Pearson correlation coefficients, while stepwise regression identified the single best predictor of UZR/150.

Results:

Significant correlations (P < .05) were observed between UZR/150 and body mass (r = .364), LBM (r = .396), VJPP (r = .397), and VJMP (r = .405). Of these variables, stepwise regression indicated VJMP (R = .405, SEE = 14.441, P = .005) as the single best predictor for all players, although the addition of proagility performance strengthened (R = .496, SEE = 13.865, P = .002) predictive ability by 8.3%. The best predictor for UZR/150 was body mass for CI (R = .519, SEE = 15.364, P = .033) and MI (R = .672, SEE = 12.331, P = .009), while proagility time was the best predictor for OF (R = .514, SEE = 8.850, P = .042).

Conclusions:

Spring-training measurements of VJMP and proagility time may predict the defensive run value of a player over the course of a professional baseball season.

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Norikazu Hirose and Chikako Nakahori

Purpose:

To describe cross-sectional age differences in change-of-direction performance (CODp) in female football players and investigate the relationship between CODp and linear-sprint speed, muscle power, and body size.

Methods:

A sample of 135 well-trained female football players was divided into 8 age groups. Anthropometry (height, body mass, and lean body mass) and athletic performance (10-m sprint speed, 10-m × 5-CODp, and 5-step bounding distance) were compared to determine interage differences using ANOVA. Then, the participants were divided into 3 age groups: 12- to 14-y-olds, 15- to 17-y-olds, and ≥ 18 y-olds. Simple- and multiple-regression analyses were conducted to determine the correlation between CODp and the other measurement variables in each age group.

Results:

Age-related differences were found for CODp (F = 10.41, P < .01), sprint speed (F = 3.27, P < .01), and bounding distance (F = 4.20, P < .01). Post hoc analysis revealed that the CODp of 17-y-old players was faster than that of 16-y-old players (P < .01), with no interage differences in sprint speed and bounding distance. Sprint speed and bounding distance were weakly correlated with CODp in 15- to ≥18-y-old players, but only sprint speed was correlated with CODp in 12- to 14-y-old players.

Conclusions:

CODp improves from 16 to 17 y of age in female players. Linear-sprint speed, muscle power, and body size were weakly correlated with the age differences in CODp.

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Olfa Turki, Wissem Dhahbi, Sabri Gueid, Sami Hmaied, Marouen Souaifi and Riadh Khalifa

Purpose: To explore the effect of 4 different warm-up strategies using weighted vests and to determine the specific optimal recovery duration required to optimize the repeated change-of-direction (RCOD) performance in young soccer players. Methods: A total of 19 male soccer players (age 18 [0.88] y, body mass 69.85 [7.68] kg, body height 1.75 [0.07] m, body mass index 22.87 [2.23] kg·m−2, and body fat percentage 12.53% [2.59%]) completed the following loaded warm-up protocols in a randomized, counterbalanced cross-over, within-participants order and on separate days: weighted vest with a loading of 5% (WUV5%), 10% (WUV10%), 15% (WUV15%) body mass, and an unloaded condition (control). RCOD performance (total time, peak time, and fatigue index) was collected during the preintervention phase (5 min after the dynamic stretching sequence) for baseline values and immediately (at 15 min), at 4- and 8-minute postwarm-up intervention. Results: For each postwarm-up tested, recovery times (ie, 15 s, 4 min, and 8 min), of both total and peak times were faster following WUV5%, WUV10%, and WUV15%, compared with the unloaded condition (P ≤.001–.031, d = 1.28–2.31 [large]). There were no significant differences (P = .09–1.00, d = 0.03–0.72 [trivial–moderate]) in-between recovery times in both total and peak times following WUV5%, WUV10%, and WUV15%. However, baseline fatigue index score was significantly worse than all other scores (P ≤.001–.002, d = 1.35–2.46 [large]) following the loaded conditions. Conclusions: The findings demonstrated that a dynamic loaded warm-up increases an athlete’s initial RCOD performance up to the 8-minute postwarm-up intervention. Therefore, strength coaches need to consider using weighted vests during the warm-up for trained athletes in order to acutely optimize RCODs.

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Julia Kathrin Baumgart and Øyvind Sandbakk

Purpose:

To investigate on-ice repeated-sprint and sports-specific-technique abilities and the relationships to aerobic and anaerobic off-ice capacities in world-class ice sledge hockey players.

Methods:

Twelve Norwegian national team players performed 8 repeated maximal 30-m sprints and a sports-specific-technique test while upper-body poling on ice, followed by 4 maximal upper-body strength tests and 8-s peak power and 3-min peak aerobic-capacity (VO2peak) tests while ergometer poling.

Results:

The fastest 30-m sprint time was 6.5 ± 0.4 s, the fastest initial 10-m split-time 2.9 ± 0.2 s, and the corresponding power output 212 ± 37 W. Average 30-m time during the 8 repeated sprints was 6.7 ± 0.4 s, and the sprint-time decrement was 4.3% ± 1.8%. Time to execute the sport-specific-technique test was 25.6 ± 2.7 s. Averaged 1-repetition-maximum strength of the 4 exercises correlated with the fastest 30-m sprint time (r = –.77), the fastest initial 10-m split time (r = –.72), the corresponding power output (r = .67), and the average 30-m sprint time (r = –.84) (all P < .05). Peak power of the 8-s ergometer sprint test correlated with the highest initial 10-m power (r = .83, P < .01) and the average 30-m sprint time (r = –.68, P < .05). Average 3-min ergometer power (r = –.86, P < .01) and VO2peak (r = –.67, P < .05) correlated with the sprint-time decrement. All off-ice variables except VO2peak correlated with technique-test time (r = –.58 to .73, all P < .05).

Conclusion:

Maximal strength and power are associated with the ability to sprint fast and rapid execution of a technically complex test, whereas mode-specific endurance capacity is particularly important for maintenance of sprint ability in ice sledge hockey.

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Brian T. McCormick, James C. Hannon, Maria Newton, Barry Shultz, Nicole Detling and Warren B. Young

Plyometrics is a popular training modality for basketball players to improve power and change-of-direction speed. Most plyometric training has used sagittal-plane exercises, but improvements in change-of-direction speed have been greater in multidirection programs.

Purpose:

To determine the benefits of a 6-wk frontal-plane plyometric (FPP) training program compared with a 6-wk sagittal-plane plyometric (SPP) training program with regard to power and change-of-direction speed.

Methods:

Fourteen female varsity high school basketball players participated in the study. Multiple 2 × 2 repeated-measures ANOVAs were used to determine differences for the FPP and SPP groups from preintervention to postintervention on 4 tests of power and 2 tests of change-of-direction speed.

Results:

There was a group main effect for time in all 6 tests. There was a significant group × time interaction effect in 3 of the 6 tests. The SPP improved performance of the countermovement vertical jump more than the FPP, whereas the FPP improved performance of the lateral hop (left) and lateral-shuffle test (left) more than the SPP. The standing long jump, lateral hop (right), and lateral-shuffle test (right) did not show a significant interaction effect.

Conclusions:

These results suggest that basketball players should incorporate plyometric training in all planes to improve power and change-of-direction speed.

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Jorge Carlos-Vivas, Jorge Perez-Gomez, Ola Eriksrud, Tomás T. Freitas, Elena Marín-Cascales and Pedro E. Alcaraz

Purpose: To analyze and compare the effects of 4 different resisted sprint training (RST) modalities on youth soccer players’ performance after 8 weeks of training. Methods: Forty-eight youth soccer players were first randomly assigned to 4 groups and only then completed 8 weeks of RST: horizontal resisted sprint, vertical resisted sprint (VRS), combined resisted sprint, and unresisted sprint. Performance in horizontal and vertical jumps, sprint, and change of direction (COD) ability were assessed 1 week before and after the training intervention. Magnitude-based inference analysis was performed for calculating within-group pre–post differences. In addition, an analysis of covariance test was performed for between-group comparison, using the pretest values as covariates. After that, the analysis of covariance P values and the effect statistic were transformed to magnitude-based inference. Results: Within-group outcomes showed that all resisted training modalities experienced improvements in sprint (small to moderate) and COD (small to large) performance. Moreover, all groups, except unresisted sprint, enhanced the horizontal jump performance. However, only VRS improved on vertical jump. Between-group comparison outcomes revealed that only VRS improved the sprint time compared with horizontal resisted sprint (moderate) and COD performance compared with all groups (moderate to large). In addition, VRS enhanced the countermovement jump performance (small to large) compared with the other groups. Conclusions: Independent of the orientation of the resistance applied, RST is an effective training method for improving sprinting and COD performance. Nevertheless, VRS may promote greater improvements on sprint and COD ability and have a positive additional effect on countermovement jump performance and the reduction of COD deficit.

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Blake D. McLean, Cloe Cummins, Greta Conlan, Grant Duthie and Aaron J. Coutts

suggesting that accumulated accelerometer load may be an alternate measure of overall external work in team sports. However, to date, no studies have specifically examined accelerometer loads during different collision sport training modalities (eg, running/agility vs match simulation and tackling drills

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Michael E. Hales and John D. Johnson II

determine their familiarity level with a variety of agility and running drills. The participants were provided with nutritional instruction 48 hours prior to testing to ensure hydration and glycogen levels were at optimal levels. Each athlete was instructed to fast 2 hours prior to testing and not to engage

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Jorge López-Fernández, Javier Sánchez-Sánchez, Jorge García-Unanue, José Luis Felipe, Enrique Colino and Leonor Gallardo

such as Stone et al 8 recommend the SSP because it includes a repeated sprint test halfway through each of the 6 bouts and nonlinear sprint actions at maximum speed (agility tests). The latest comparative studies, suggest that players’ performance is similar on AT and NG, 6 – 8 although it has been