The effects of imagery direction on self-efficacy and performance in a dart throwing task were examined. Two imagery types were investigated: skill-based cognitive specific (CS) and confidence-based motivational general-mastery (MG-M). Seventy-five novice dart throwers were randomly allocated to one of three conditions: (a) facilitative imagery, (b) debilitative imagery, or (c) control. After 2 imagery interventions, the debilitative imagery group rated their self-efficacy significantly lower than the facilitative group and performed significantly worse than either the facilitative group or the control group. Efficacy ratings remained constant across trials for the facilitative group, but decreased significantly for both the control group and the debilitative group. Performance remained constant for the facilitative and the control groups but decreased significantly for the debilitative group. Similar to Short et al. (2002), our results indicate that both CS and MG-M imagery can affect self-efficacy and performance.
Sanna M. Nordin and Jennifer Cumming
Paola Zamparo, Ivan Zadro, Stefano Lazzer, Marco Beato and Luigino Sepulcri
Shuttle runs can be used to study the physiological responses in sports (such as basketball) characterized by sprints (accelerations/decelerations) and changes of direction.
To determine the energy cost (C) of shuttle runs with different turning angles and over different distances (with different acceleration/deceleration patterns).
Nine basketball players were asked to complete 6 intermittent tests over different distances (5, 10, 25 m) and with different changes of direction (180° at 5 and 25 m; 0°, 45°, 90°, and 180° at 10 m) at maximal speed (v ≍ 4.5 m/s), each composed by 10 shuttle runs of 10-s duration and 30-s recovery; during these runs oxygen uptake (VO2), blood lactate (Lab), and C were determined.
For a given shuttle distance (10 m) no major differences where observed in VO2 (~33 mL · min−1 · kg−1), Lab (~3.75 mM), and C (~21.2 J · m−1 · kg−1) when the shuttle runs were performed with different turning angles. For a given turning angle (180°), VO2 and Lab were found to increase with the distance covered (VO2 from 26 to 35 mL · min−1 · kg−1; Lab from 0.7 to 7.6 mM) while C was found to decrease with it (from 29.9 to 10.6 J · m−1 · kg−1); the relationship between C and d (m) is well described by C = 92.99 × d 0.656, R 2 = .971.
The metabolic demands of shuttle tests run at maximal speeds can be estimated based on the running distance, while the turning angle plays a minor role in determining C.
Pamela J. Hoyes Beehler
Hand laterality research efforts have shown a performance advantage in terms of pointing accuracy and limb speed (movement time—MVT) for the preferred hand (right-hand), and a slight reaction time (RT) performance advantage for the non-preferred hand (left-hand) for rapid manual aiming movements (Flowers, 1975; Roy, 1983; Roy & Elliott, 1986). These performance advantages for the right and left-hands, respectively, are considered an enigma in the motor behavior literature (Magill, 1993) and were investigated. The purpose of this study was to determine the effects of skill level, hand laterality, and movement direction during visuomotor processing of female athletes performing manual aiming tasks. Results showed that skill level and hand laterality did not influence the initiation of manual aiming movements; but, left direction movements were initiated faster than right direction movements. Right-hand MVT was faster than left-hand MVT; but, main effects skill level and movement direction were not significant for MVT. Skill level did interact with hand laterality and movement direction for MVT. Also, right-hand right direction movements were the easiest manual aiming tasks to complete while left-hand right direction movements were the most difficult manual aiming tasks to complete. Differences in hemispheric visuomotor processing when performing manual aiming movements based on skill level and hand laterality were discussed. Training implications for manual aiming movements were also discussed.
Eadric Bressel and Gary D. Heise
The purpose of this study was to compare muscle activity, kinematic, and oxygen consumption characteristics between forward and reverse arm cranking. Twenty able-bodied men performed 5-min exercise bouts of forward and reverse arm cranking while electromyographic (EMG), kinematic, and oxygen consumption data were collected. EMG activity of biceps brachii, triceps brachii, deltoid, and infraspinatus muscles were recorded and analyzed to reflect on-time durations and amplitudes for each half-cycle (first 180° and second 180° of crank cycle). Kinematic data were quantified from digitization of video images, and oxygen consumption was calculated from expired gases. Dependent measures were analyzed with a MANOVA and follow-up univariate procedures; alpha was set at .01. The biceps brachii, deltoid, and infraspinatus muscles displayed greater on-time durations and amplitudes for select half-cycles of reverse arm cranking compared to forward arm cranking (p < 0.01). Peak wrist flexion was 9% less in reverse arm cranking (p < 0.01), and oxygen consumption values did not differ between conditions (p = 0.25). Although there were no differences in oxygen consumption and only minor differences kinematically, reverse arm cranking requires greater muscle activity from the biceps brachii, deltoid, and infraspinatus muscles. These results may allow clinicians to more effectively choose an arm cranking direction that either minimizes or maximizes upper extremity muscle activity depending on the treatment objectives.
Norikazu Hirose and Chikako Nakahori
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.
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.
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.
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.
Olivia R. Barber, Christopher Thomas, Paul A. Jones, John J. McMahon and Paul Comfort
To determine the reliability of the 505 change-of-direction (COD) test performed with both a stationary and a flying start.
Fifty-two female netball players (age 23.9 ± 5.4 y, height 169.9 ± 3.3 cm, body mass 65.2 ± 4.6 kg) performed 6 trials of the 505 COD test, 3 with a flying start and 3 with a stationary start, once per week over a 4-wk period to determine within- and between-sessions reliability.
Testing revealed high within-session reliability for the stationary start (ICC = .96–.97) and for the flying start (ICC = .90–.97). Similarly, both the stationary start (ICC = .965) and the flying start (ICC = .951) demonstrated high reliability between sessions, although repeated-measures analysis of variance (P < .001) revealed learning effects between sessions for both tests. Performances stabilized on day 2 for the static start and on day 3 for the flying start.
The 505 COD test is a reliable test in female netball players, with either a stationary or flying start. Smallest detectable differences of 3.91% and 3.97% for the stationary start and the flying start, respectively, allow practitioners to interpret whether changes in time taken to complete the 505 COD test reflect genuine improvements in performance or are measurement errors. It is suggested that 1 d of familiarization testing be performed for the stationary start and 2 d of familiarization for the flying start, to minimize learning effects.
Abbas Asadi, Hamid Arazi, Warren B. Young and Eduardo Sáez de Villarreal
To show a clear picture about the possible variables of enhancements of change-of-direction (COD) ability using longitudinal plyometric-training (PT) studies and determine specific factors that influence the training effects.
A computerized search was performed, and 24 articles with a total of 46 effect sizes (ESs) in an experimental group and 25 ESs in a control group were reviewed to analyze the role of various factors on the impact of PT on COD performance.
The results showed that participants with good fitness levels obtained greater improvements in COD performance (P < .05), and basketball players gained more benefits of PT than other athletes. Also, men obtained COD results similar to those of women after PT. In relation to the variables of PT design, it appears that 7 wk (with 2 sessions/wk) using moderate intensity and 100 jumps per training session with a 72-h rest interval tends to improve COD ability. Performing PT with a combination of different types of plyometric exercises such as drop jumps + vertical jumps + standing long jumps is better than 1 form of exercise.
It is apparent that PT can be effective at improving COD ability. The loading parameters are essential for exercise professionals, coaches, and strength and conditioning professionals with regard to the most appropriate dose-response trends to optimize plyometric-induced COD-ability gains.
Martin Buchheit, Bachar Haydar, Karim Hader, Pierre Ufland and Said Ahmaidi
To examine physiological responses to submaximal feld running with changes of direction (COD), and to compare two approaches to assess running economy (RE) with COD, ie, during square-wave (SW) and incremental (INC) exercises.
Ten male team-sport athletes performed, in straight-line or over 20 m shuttles, one maximal INC and four submaximal SW (45, 60, 75 and 90% of the velocity associated with maximal pulmonary O2 uptake [vVO2pmax]). Pulmonary (VO2p) and gastrocnemius (VO2m) O2 uptake were computed for all tests. For both running mode, RE was estimated as the O2 cost per kilogram of bodyweight, per meter of running during all SW and INC.
Compared with straight-line runs, shuttle runs were associated with higher VO2p (eg, 33 ± 6 vs 37 ± 5 mL O2·min–1·kg–1 at 60%, P < .01) and VO2m (eg, 1.1 ± 0.5 vs 1.3 ± 0.8 mL O2·min–1·100 g–1 at 60%, P = .18, Cohen’s d = 0.32). With COD, RE was impaired during SW (0.26 ± 0.02 vs 0.24 ± 0.03 mL O2·kg–1·m–1, P < .01) and INC (0.23 ± 0.04 vs 0.16 ± 0.03 mL O2·kg–1·m–1, P < .001). For both SW and INC tests, the changes in RE with COD were related to height (eg, r = .56 [90%CL, 0.01;0.85] for SW) and weekly training/competitive volume (eg, r = –0.58 [–0.86;–0.04] for SW). For both running modes, RE calculated from INC was better than that from SW (both P < .001).
Although RE is impaired during feld running with COD, team-sport players of shorter stature and/or presenting greater training/competitive volumes may present a lower RE deterioration with COD. Present results do not support the use of INC to assess RE in the feld, irrespective of running mode.
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.
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.
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.
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.
These results suggest that basketball players should incorporate plyometric training in all planes to improve power and change-of-direction speed.
Sandra E. Short, Jared M. Bruggeman, Scott G. Engel, Tracy L. Marback, Lori J. Wang, Anders Willadsen and Martin W. Short
This experiment examined the interaction between two imagery functions (Cognitive Specific, CS; and Motivation - General Mastery, MG-M) and two imagery directions (facilitative, debilitative) on self-efficacy and performance in golf putting. Eighty-three participants were randomly assigned to one of 7 conditions: (a) CS + facilitative imagery, (b) CS + debilitative imagery, (c) MG-M + facilitative imagery, (d) MG-M + debilitative imagery, (e) CS imagery only, (f) MG-M imagery only, (g) no imagery (stretching) control group. A 3 (imagery direction) X 3 (imagery function) X 2 (gender) ANCOVA with pretest scores used as the covariate was used. Results showed a main effect for performance; means were higher for the facilitative group compared to the debilitative group. For self-efficacy, there was a significant imagery direction by imagery function by gender interaction. These findings suggest imagery direction and imagery function can affect self-efficacy and performance and that males and females respond differently to imagery interventions.