Search Results

You are looking at 21 - 30 of 1,471 items for :

  • "direction" x
Clear All
Restricted access

Brian J. McMorrow, Massimiliano Ditroilo and Brendan Egan

RSS training (80% BM) is an effective method of improving sprint performance over 5 and 20 m. 20 Given the potential effects of RSS training on initial acceleration and the role of acceleration in change-of-direction (COD) speed, 22 , 23 RSS training may also have positive impacts on COD and agility

Restricted access

Giancarlo Condello, Kevin Schultz and Antonio Tessitore

The aim of the current study was to investigate the relationship between straight-sprint and change-of-direction performance. Total sprinting time and split time at 5 m were collected from 44 college football players during a 15-m straight sprint (SS15m) and a 15-m zigzag sprint with two 60° changes of direction (COD15m). Differences in sprinting time between COD15m and SS15m and between COD5m and SS5m were expressed as percentage of decrement at 5 m and 15 m (Δ%5m and Δ%15m). Significant and high correlations emerged between SS15m and COD15m (r = .86, P < .0001), SS5m and SS15m (r = .92, P < .0001), SS5m and COD5m (r = .92, P < .0001), and COD5m and COD15m (r = .71, P < .0001). Δ%5m and Δ%15m showed a range of 1.2–30.0% and 34.9–59.4%, respectively. These results suggested how straight-sprint and change-of-direction performance are similar abilities in college football players, in particular when a smaller angle of the change of direction is considered. Moreover, it seems necessary to have athletes undergo tests that mimic the demands of football game, which is characterized by sprint on short distances and with changes of direction.

Restricted access

Bruce D. Hale and Adam Whitehouse

This study attempted to manipulate an athlete’s facilitative or debilitative appraisal (direction; Jones, 1995) of competitive anxiety through imagery-based interventions in order to study the effects on subsequent anxiety intensity (heart rate and CSAI-2) and direction (CSAI-2D; Jones & Swain, 1992). In a within-subjects’ design, 24 experienced soccer players were relaxed via progressive relaxation audiotape and then randomly underwent an imagery-based video- and audiotaped manipulation of their appraisal of taking a hypothetical gamewinning penalty kick under either a “pressure” or “challenge” appraisal emphasis. There was no significant effect for heart rate. A repeated measures MANOVA for CSAI-2 and CSAI-2D scores revealed that for both intensity and direction scores the challenge condition produced less cognitive anxiety, less somatic anxiety, and more self-confidence (all p < .001) than the pressure situation. This finding suggests that a challenge appraisal manipulation taught by applied sport psychologists might benefit athletes’ performance.

Restricted access

Tyler R. Keith, Tara A. Condon, Ayana Phillips, Patrick O. McKeon and Deborah L. King

The Star Excursion Balance Test (SEBT) is a valid and reliable measure of dynamic postural control. Center of pressure (COP) behavior during the SEBT could provide additional information about direction-dependent SEBT balance strategies. The purpose of this study was to quantify spatiotemporal COP differences using COP area and velocity among three different SEBT reach directions (anterior, posteromedial, posterolateral). The anterior direction COP velocity was significantly lower than both posterior directions. However, the anterior COP area was significantly greater than posterior. Based on COP behavior, the anterior and posterior reach directions appear to use different postural control strategies on the SEBT.

Restricted access

Giancarlo Condello, Thomas W. Kernozek, Antonio Tessitore and Carl Foster

This study aimed to investigate biomechanical parameters during a change-of-direction task in college soccer players. Fourteen male and 12 female players performed a 10-m sprint with a 60° change of direction at 5 m. Vertical and mediolateral groundreaction force (GRF) and contact time were measured by having the subjects run in both directions while contacting a force plate with either their preferred (kicking) or nonpreferred leg. Using the midpoint between 2 pelvic markers, further parameters were evaluated: performance cutting angle and horizontal distance. Relationships between parameters, sex, and leg preference were analyzed. Significant correlations emerged between vertical and mediolateral GRF (r = .660–.909) and between contact time and performance cutting angle (r = –.598 to –.793). Sex differences were found for mediolateral GRF (P = .005), performance cutting angle (P = .043), and horizontal distance (P = .020). Leg differences were observed for vertical GRF (P = .029), performance cutting angle (P = .011), and horizontal distance (P = .012). This study showed that a sharper change of direction corresponded to a longer contact time, while no relationships were found with GRF. Moreover, measuring the angle revealed that the real path traveled was different from the theoretical one, highlighting the performance of sharper or more rounded execution. In conclusion, this study showed that specific biomechanical measurements can provide details about the execution of a change of direction, highlighting the ability of the nonpreferred leg to perform better directional changes.

Restricted access

Håvard Lorås, Gertjan Ettema and Stig Leirdal

Changes in pedaling rate during cycling have been found to alter the pedal forces. Especially, the force effectiveness is reduced when pedaling rate is elevated. However, previous findings related to the muscular force component indicate strong preferences for certain force directions. Furthermore, inertial forces (due to limb inertia) generated at the pedal increase with elevated pedaling rate. It is not known how pedaling rate alters the inertia component and subsequently force effectiveness. With this in mind, we studied the effect of pedal rate on the direction of the muscle component, quantified with force effectiveness. Cycle kinetics were recorded for ten male competitive cyclists at five cadences (60–100 rpm) during unloaded cycling (to measure inertia) and at a submaximal load (~260 W). The force effectiveness decreased as a response to increased pedaling rate, but subtracting inertia eliminated this effect. This indicates consistent direction of the muscle component of the foot force.

Restricted access

Peter Düking, Dennis-Peter Born and Billy Sperlich

Purpose:

To determine the reliability, usefulness, and validity of 3 different change-of-direction tests on a SpeedCourt (SCCODT) in team-sport players.

Methods:

For reliability and usefulness, 30 players (16 female and 14 male; age 19 ± 3 y, height 169 ± 30 cm, body mass 70 ± 11 kg) performed 3 SCCODTs differing in duration (7–45 s) on 3 occasions 1 wk apart. The total sprint times (TT) and time to change direction (TCD) were analyzed for each SCCODT. For validity, 14 players performed the Illinois Agility Test (IAT) and 505 test on a separate occasion.

Results:

TT for all SCCODTs is reliable (ICC > .79, CV < 5%), useful (TE < SWC0.5), and valid (IAT r > .71, P < .05; 505 test r > .54, P < .05). SCCODT variable TCD may be useful (TE = SWC0.5) but shows limited reliability with ICC >.65 and a CV >5%.

Conclusions:

All SCCODTs are reliable, useful, and valid to detect moderate performance changes regarding TT, with limited reliability for TCD. The quality of assessment improves when players are well familiarized with the SCCODT.

Restricted access

Michael Wilkinson, Damon Leedale-Brown and Edward M. Winter

Purpose:

We examined the validity and reproducibility of a squash-specifc test designed to assess change-of-direction speed.

Methods:

10 male squash and 10 male association-football and rugby-union players completed the Illinois agility run (IAR) and a squash change-of-direction-speed test (SCODS) on separate days. Tests were repeated after 24 h to assess reproducibility. The best time from three attempts was recorded in each trial.

Results:

Performance times on the IAR (TE 0.27 s, 1.8%, 90% CI 0.21 to 0.37 s; LOA -0.12 s ± 0.74; LPR slope 1, intercept -2.8) and SCODS (TE 0.18 s, 1.5%, 90% CI 0.14 to 0.24 s; LOA 0.05 s ± 0.49; LPR slope 0.95, intercept 0.5) were reproducible. There were no statistically significant differences in performance time between squash (14.75 ± 0.66 s) and nonsquash players (14.79 ± 0.41 s) on the IAR. Squash players (10.90 ± 0.44 s) outperformed nonsquash players (12.20 ± 0.34 s) on the SCODS (P < .01). Squash player rank significantly correlated with SCODS performance time (Spearman’s ρ = 0.77, P < .01), but not IAR performance time (Spearman’s ρ = 0.43, P = .21).

Conclusions:

The results suggest that the SCODS test is a better measure of sport-specific capability than an equivalent nonspecific field test and that it is a valid and reliable tool for talent identification and athlete tracking.

Restricted access

Nikos Ntoumanis and Stuart J.H. Biddle

The purpose of the present study was to examine how coping strategies in sport relate to differences in levels of anxiety intensity and to the interpretation of these levels as being facilitative or debilitative to performance. British university athletes were asked to recall a recent stressful situation in their sport, the coping strategies they used, and the intensity and direction of their anxiety symptoms. Results showed that perceptions of facilitative cognitive anxiety were related to the use of problem-focused coping. High levels of cognitive anxiety intensity were related to emotion-focused coping and avoidance coping. With regard to somatic anxiety, there was a significant interaction between the intensity and direction dimensions in that similar high levels of anxiety intensity were related to different coping strategies, depending on whether somatic anxiety was perceived to be facilitative or debilitative. From a practical point of view, the results show that athletes with positive perceptions of their anxiety level are able to use effective coping strategies. Lastly, suggestions are offered for further exploration of the nature of the interrelationship between coping strategies and anxiety.

Restricted access

Andrew R. Kemper, Joel D. Stitzel, Craig McNally, H. Clay Gabler and Stefan M. Duma

The purpose of this study was to determine the influence of loading direction on the structural response of the human clavicle subjected to three-point bending. A total of 20 clavicles were obtained from 10 unembalmed fresh-frozen postmortem human subjects ranging from 45 to 92 years of age. The right and left clavicles from each subject were randomly divided into two test groups. One group was impacted at 0° from the transverse plane, and the second group was impacted at 45° angle from the transverse plane. There was no statistically significant difference in peak force (p = .22), peak moment (p = .30), or peak displacement (p = .44) between specimens impacted at 0° versus 45° from the transverse plane. However, there was a significant difference in the structural stiffness (p = .01) and peak strain (p < .01) between specimens impacted at 0° versus 45° from the transverse plane. The peak strain, however, must be evaluated with caution because of the variation in fracture location relative to the strain gauge. Due to the controlled matched data set, the differences in the structural stiffness with respect to loading direction can be attributed to the complex geometry of the clavicle and not material differences.