The aim of this study was to investigate the effectiveness of a caffeinated energy drink to enhance physical performance in elite junior tennis players. In 2 different sessions separated by 1 wk, 14 young (16 ± 1 y) elite-level tennis players ingested 3 mg caffeine per kg body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed a handgrip-strength test, a maximal-velocity serving test, and an 8 × 15-m sprint test and then played a simulated singles match (best of 3 sets). Instantaneous running speed during the matches was assessed using global positioning (GPS) devices. Furthermore, the matches were videotaped and notated afterward. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased handgrip force by ~4.2% ± 7.2% (P = .03) in both hands, the running pace at high intensity (46.7 ± 28.5 vs 63.3 ± 27.7 m/h, P = .02), and the number of sprints (12.1 ± 1.7 vs 13.2 ± 1.7, P = .05) during the simulated match. There was a tendency for increased maximal running velocity during the sprint test (22.3 ± 2.0 vs 22.9 ± 2.1 km/h, P = .07) and higher percentage of points won on service with the caffeinated energy drink (49.7% ± 9.8% vs 56.4% ± 10.0%, P = .07) in comparison with the placebo drink. The energy drink did not improve ball velocity during the serving test (42.6 ± 4.8 vs 42.7 ± 5.0 m/s, P = .49). The preexercise ingestion of caffeinated energy drinks was effective to enhance some aspects of physical performance of elite junior tennis players.
César Gallo-Salazar, Francisco Areces, Javier Abián-Vicén, Beatriz Lara, Juan José Salinero, Cristina Gonzalez-Millán, Javier Portillo, Victor Muñoz, Daniel Juarez and Juan Del Coso
Markus Tilp, Simon Steib, Gudrun Schappacher-Tilp and Walter Herzog
Force enhancement following muscle stretching and force depression following muscle shortening are well-accepted properties of skeletal muscle contraction. However, the factors contributing to force enhancement/depression remain a matter of debate. In addition to factors on the fiber or sarcomere level, fiber length and angle of pennation affect the force during voluntary isometric contractions in whole muscles. Therefore, we hypothesized that differences in fiber lengths and angles of pennation between force-enhanced/depressed and reference states may contribute to force enhancement/depression during voluntary contractions. The purpose of this study was to test this hypothesis. Twelve subjects participated in this study, and force enhancement/depression was measured in human tibialis anterior. Fiber lengths and angles of pennation were quantified using ultrasound imaging. Neither fiber lengths nor angles of pennation were found to differ between the isometric reference contractions and any of the force-enhanced or force-depressed conditions. Therefore, we rejected our hypothesis and concluded that differences in fiber lengths or angles of pennation do not contribute to the observed force enhancement/depression in human tibialis anterior, and speculate that this result is likely true for other muscles too.
Josh Trout and Eddie Vela
In 2009, California State University-Chico implemented a unique system of course redesign with the aim of improving student learning, increasing instructional efficiency, and reducing university costs. Inspired by and modeled after the National Center for Academic Transformation, the “Academy e-Learning” program involves a 3-week training covering models of course design, learning theories, assessment methods, and a host of instructional technologies. This paper summarizes data from 40 courses, across five separate cohort groups from 2009–2013, with respect to the efficacy of Academy e-Learning (re)design training. Data show improvements in student learning outcomes in over half of the course redesigns. Benefits of course redesign included increased instructional efficiency, enhanced student learning, and a reduction in university costs by offering some instruction online and increasing enrollment caps. Barriers to a successful course redesign included lack of time, technology malfunction, and workload concerns. This paper outlines the redesign process at California State University-Chico, discusses similar redesign initiatives at other institutions, and offers solutions for measuring effectiveness of a redesigned course.
Jim Wilcox, Rich Larson, Kevin M. Brochu and Avery D. Faigenbaum
The purpose of this investigation was to determine whether the performance of explosive-force movements before bench-press exercise would improve 1-repetition-maximum (1RM) strength.
Twelve male college athletes participated in 3 testing sessions separated by at least 5 days of rest. During each testing session, the 1RM was assessed on the bench-press exercise. After a general warm-up, subjects performed a specific warm-up that consisted of submaximal sets with increasing loads on the bench-press exercise before attempting a 1RM lift. During the first testing trial, subjects performed a series of 1RM attempts with increasing loads until their 1RM was determined. During the second and third testing trials, subjects performed in a counterbalanced randomized order either 2 plyometric push-ups or 2 medicine-ball (3 to 5 kg) chest passes 30 seconds before each 1RM attempt.
Analysis of the data revealed that 1RM bench-press strength was significantly greater after plyometric push-ups (P = .004) or chest passes (P = .025) in comparison with the first trial (123.8 ± 23.5 kg and 124.0 ± 24.1 kg vs 120.9 ± 23.2 kg, respectively).
These data suggest that an acute bout of low-volume, explosive-force upper body movements performed 30 seconds before a 1RM attempt might enhance bench-press performance in athletic men.
Roy J. Shephard and Hughes Lavallée
The influence of 1 hour per day of required physical education upon aerobic fitness was tested in 546 prepubescent children recruited from an urban and a rural school in Québec. Two cohorts of experimental students began the enhanced program in Grade 1, with immediately preceding and succeeding classes as controls. V̇O2 peak (treadmill) and PWC170 were measured each year within 2 weeks of each child’s birthday. The data showed significant effects of sex (M>F) and environment (urban>rural). Experimental students showed a significant advantage of V̇O2 peak from 8 to 11 years (M>F; urban>rural). Many students reached less than a centrally limited V̇O2max, although the quality of peak effort was somewhat better in experimental than in control students. PWC170 values confirmed a training response in the boys but not in the girls. The data illustrate some of the problems of repeated testing of young children, but nevertheless support the value of training in the prepubescent years.
E. Dean Ryan and Jeff Simons
To investigate the mental imagery aspect of mental rehearsal, 80 male traffic officers from the California Highway Patrol learned a novel balancing task during a single session. Based on a pretest questionnaire, subjects were categorized as imagers, nonimagers, or occasional imagers and assigned to one of six groups accordingly: imagers asked to use imagery in mental rehearsal, imagers asked to try not to use imagery, nonimagers asked not to use imagery, nonimagers asked to try to use imagery, physical practice, or no practice. It was hypothesized that a person's preferred cognitive style would prove most effective for use in mental rehearsal and that using another style would cause a decrement in learning. Improvement scores indicated no differences between subjects who initially reported typically using imagery and those reported typically not using it, but groups asked to use imagery in mental rehearsal were superior to those asked not to (p<.001). Overall, physical practice was better than the grouped mental rehearsal conditions, and both were better than no practice. Subjects reporting strong visual imagery were superior to those with weak visual images (p<.03), and those reporting strong kinesthetic imagery were superior to those with weak kinesthetic images (p<.03). Regardless of one's typical cognitive style, the use of vivid imagery appears quite important for enhancement of motor performance through mental rehearsal.
Daniel Gould, Ken Hedge, Kirsten Peterson and John Giannini
Two studies were conducted to assess strategies elite coaches use to enhance self-efficacy in athletes, in particular the degree to which coaches use 13 strategies to influence self-efficacy and their evaluation of the effectiveness of those strategies. Self-efficacy rating differences between categories of coaches were also examined. Intercollegiate wrestling coaches (iV=101) surveyed in Study 1 indicated they most often used instruction-drilling, modeling confidence oneself, encouraging positive talk, and employing hard physical conditioning drills. Techniques or strategies judged most effective by these coaches included instraction-drilling, modeling confidence oneself, liberal use of reward statements, and positive talk. In Study 2, 124 national team coaches representing 30 Olympic-family sports served as subjects. The strategies they most often used were instruction-drilling, modeling confidence oneself, encouraging positive talk, and emphasizing technique improvements while downplaying outcome. The techniques judged most effective were instruction-drilling, encouraging positive talk, modeling confidence onself, and liberal use of reward statements. Few between-coach differences were found in efficacy use and effectiveness ratings. Findings are discussed in light of Bandura's (1977) theory of self-efficacy.
Rachel W. Thompson, Keith A. Kaufman, Lilian A. De Petrillo, Carol R. Glass and Diane B. Arnkoff
The purpose of the present investigation was to evaluate the long-term effects of mindful sport performance enhancement (MSPE), a program designed to improve athletic performance and psychological aspects of sport. One-year follow-up assessments were conducted on archers, golfers, and long-distance runners (N = 25) who attended Kaufman, Glass, and Arnkoff’s (2009) and De Petrillo, Kaufman, Glass, and Arnkoff’s (2009) MSPE workshops. Across the athlete groups, participants reported significant increases in the ability to act with awareness (an aspect of trait mindfulness) and overall trait mindfulness from pretest to follow-up, along with significant decreases in task-related worries and task-irrelevant thoughts (both aspects of cognitive interference during sport). The long-distance runners exhibited significant improvement in their mile times from pretest to follow-up, with significant correlations between change in runners’ performance and trait variables. Results suggest that MSPE is a promising intervention associated with long-term changes in trait variables that may contribute to optimal athletic performance.
Mark A. Tarnopolsky and Dan P. MacLennan
Creatine monohydrate supplementation has been shown to enhance high-intensity exercise performance in some but not all studies. Part of the controversy surrounding the ergogenic effect(s) of creatine monohydrate supplementation may relate to design issues that result in low statistical power. A further question that remains unresolved in the creatine literature is whether or not males and females respond in a similar manner to supplementation. We studied the effect of creatine supplementation upon high intensity exercise performance in 24 subjects (n = 12 males, n = 12 females). Creatine monohydrate (Cr; 5g, 4x/d × 4d) and placebo (PI; glucose polymer × 4d) were provided using a randomized. double-blind crossover design (7 week washout). Outcome measures included: 2 × 30-S anaerobic cycle lest, with plasma lactate pre- and post-test; dorsi-flexor: maximal voluntary contraction (MVC), 2-min fatigue test, and electrically stimulated peak and tetanic torque; isokinetic knee extension torque and I -min ischeniic handgrip strength. Significant main effects of Cr treatment included: increased peak and relative peak anaerobic cycling power (↑3.7%; p < .05), dorsi-flexion MVC torque (↑6.6% p < .05), and increased lactate (↑20.8%; p < .05) with no gender specific responses. We concluded that short-term Cr supplementation can increase indices of high-intensity exercise performance for both males and females.
Ronald E. Smith, Frank L. Smoll and Bill Curtis
Little League Baseball coaches were exposed to a preseason training program designed to assist them in relating more effectively to children. Empirically derived behavioral guidelines were presented and modeled, and behavioral feedback and self-monitoring were used to enhance self-awareness and to encourage compliance with the guidelines. Trained coaches differed from controls in both overt and player-perceived behaviors in a manner consistent with the behavioral guidelines. They were also evaluated more positively by their players, and a higher level of intrateam attraction was found on their teams despite the fact that they did not differ from controls in won-lost records. Children who played for the trained coaches exhibited a significant increase in general self-esteem compared with scores obtained a year earlier; control group children did not. The greatest differences in attitudes toward trained and control coaches were found among children low in self-esteem, and such children appeared most sensitive to variations in coaches' use of encouragement, punishment, and technical instruction.