Purpose: Endothelial progenitor cells (EPCs) appear to interact with physical training. This study aimed to provide a comprehensive assessment of the relationship of moderate to vigorous physical activity (MVPA) with both angiogenic factors and EPC function in healthy children. Methods: Forty children (22 boys and 18 girls) aged 7 to 11 years participated in a 10-week MVPA program (duration: 45 min; intensity: 75%–85% of heart rate reserve; frequency: 4 sessions/wk). The anthropometric data, biochemical profile, EPCs number, EPCs colony-forming units, and vascular endothelial growth factor-A (VEGF-A) and nitric oxide (NO) plasma levels were evaluated before and after the MVPA program. Results: After a 10-week MVPA program, a significant increase was detected in circulating/functional capacity of EPCs, NO, and VEGF-A levels, associated with improvement of waist circumference and estimated maximum rate of oxygen consumption (VO2max). A strong positive correlation was found between delta of EPCs number and variation of both NO level (r = .677, P < .001) and VEGF-A level (r = .588, P < .001). Furthermore, a significant correlation between NO level variation and delta of VEGF-A level was observed (r = .708, P < .001). Conclusion: Our findings suggest that lifestyle intervention implemented by MVPA program can contribute meaningfully to improve circulating/functional capacity of EPCs in healthy children, possibly due to the increase of plasma NO and VEGF-A levels.
Livia Victorino Souza, Franciele De Meneck, Vanessa Oliveira, Elisa Mieko Higa, Eliana Hiromi Akamine and Maria do Carmo Franco
Chad Van Ramshorst and Woochol Joseph Choi
This study investigated the contact forces and muscle activation during 2 choreographed fall techniques in contemporary dancers and how these were affected by the fall technique. Ten collegiate-level dancers were instructed in 2 choreographed falls: (1) an anteriorly focused fall involving ankle plantar flexion, knee flexion, and hip flexion with dispersion of forces up the anterior surface of the shank (technique 1) and (2) a laterally focused fall involving inversion at the ankle with dispersion of forces up the lateral aspect of the shank (technique 2). The knee and hip contact forces were 26.3% smaller (technique 1: 1743 N vs technique 2: 1284 N) and 24.1% greater (technique 1: 1334 N vs technique 2: 1656 N), respectively, in technique 2 (P < .03). At the time of knee contact, percentage of maximal voluntary isometric contraction (%MVIC) was 45.8% greater for rectus femoris muscle (technique 1: 7.2% vs technique 2: 10.5%) and 96.9% greater for gluteus medius muscle (technique 1: 3.2% vs technique 2: 6.3%) (P < .01) in technique 2. The results provide insight into determining safer landing strategies to avoid knee injuries in individuals who experience a fall (ie, dancers, athletes, and older adults).
Dalia Mickeviciene, Renata Rutkauskaite, Dovile Valanciene, Diana Karanauskiene, Marius Brazaitis and Albertas Skurvydas
The aim of the study was to establish whether there were differences in speed–accuracy movement learning strategies between children, young adults, and older adults. A total of 30 boys, 30 young adult men, and 30 older men were seated in a special chair at a table with a Dynamic Parameter Analyzer 1. Participants had to perform a speed–accuracy task with the right-dominant hand. It may be assumed that the motor variables of children are more prone to change during the fast learning process than those of young adults and older adults and that the development of internal models is more changeable in children than in young adults and the older adults during the fast adaptation-based learning process.
Laura St. Germain, Amanda M. Rymal and David J. Hancock
Sport participants continually seek methods to hone their skills and achieve expert performance. One means to achieve this is through the use of observational learning (OL). The Functions of Observational Learning Questionnaire (FOLQ) was created to measure the types of OL athletes used. The data presented herein builds from prior research in which the use of the FOLQ was extended to coaches and officials. The researchers included the following open-ended question: “Do you observe others/self for anything not addressed above?” Responses to this question, however, have yet to be reported. As such, the purpose of this study was to analyze participants’ responses to understand how coaches and officials use observational learning. Many identified codes encompassed ideas already included within the FOLQ; however, new coding categories emerged. Specifically, coaches reported using observational learning for Self-Reflection, officials reported using observational learning for Self-Presentation, and both groups reported using observational learning to improve Communication. These results demonstrate the importance of OL to coaches’ and officials’ development. Further, the results highlight that the FOLQ might overlook coaches’ and officials’ uses of OL. Regardless, the various uses of OL ought to be included in coaching and officiating education programs to foster elite performance.
Giovani dos Santos Cunha and Gabriela Tomedi Leites
Blaine E. Arney, Reese Glover, Andrea Fusco, Cristina Cortis, Jos J. de Koning, Teun van Erp, Salvador Jaime, Richard P. Mikat, John P. Porcari and Carl Foster
Purpose: The session rating of perceived exertion (sRPE) is a well-accepted method of monitoring training load in athletes in many different sports. It is based on the category-ratio (0–10) RPE scale (BORG-CR10) developed by Borg. There is no evidence how substitution of the Borg 6–20 RPE scale (BORG-RPE) might influence the sRPE in athletes. Methods: Systematically training, recreational-level athletes from a number of sport disciplines performed 6 randomly ordered, 30-min interval-training sessions, at intensities based on peak power output (PPO) and designed to be easy (50% PPO), moderate (75% PPO), or hard (85% PPO). Ratings of sRPE were obtained 30 min postexercise using either the BORG-CR10 or BORG-RPE and compared for matched exercise conditions. Results: The average percentage of heart-rate reserve was well correlated with sRPE from both BORG-CR10 (r = .76) and BORG-RPE (r = .69). The sRPE ratings from BORG-CR10 and BORG-RPE were very strongly correlated (r = .90) at matched times. Conclusions: Although producing different absolute numbers, sRPE derived from either the BORG-CR10 or BORG-RPE provides essentially interchangeable estimates of perceived exercise training intensity.
Yan Shi, Wendy Yajun Huang, Jane Jie Yu, Sinead Sheridan, Cindy Hui-Ping Sit and Stephen Heung-Sang Wong
Purpose: The aim of this study was to examine the factors that influence compliance and practical utility of a continuous wear protocols for activPAL™ among adolescents. Methods: Seven hundred and fifty-five (11–18 y; 50.6% girls) students wore the waterproof activPAL™ for 7 consecutive days. The effects of factors such as weather and practical strategies on compliance were assessed. Students were asked to note reasons for removing it in a log. After the 7-day period, students anonymously completed a practical utility questionnaire. Results: The final sample used to analyze compliance contained 588 available data points; 72.4% met the validity criteria, which were ≥4 valid days. Rainfall was inversely associated with total wear time, whereas using alcohol pads and cartoon stickers during the application were positively associated with total wear time. Sweating (25.2%) and skin irritation (39.0%) were the most reasons for 290 removal episodes by 235 students. The 131 questionnaires showed that 80.1% regarded the continuous wear period as too long and encountered problems, and 55% would rather not wear it again. Conclusion: Rainy weather affected girls’ compliance with the continuous wear protocol for activPAL™. Skin irritation and sweat-induced inadvertent drops caused removal. Future studies should investigate more user-friendly protocols.
Kevin A. Becker, Ayana F. Georges and Christopher A. Aiken
Empirical findings consistently suggest that an external focus of attention leads to superior performance when compared to an internal focus by encouraging more automatic processing. However, for certain skills (e.g., gymnastics routines) it can be challenging to identify a meaningful external focus cue. A related line of research suggests that focusing on the general feeling of a movement (i.e., holistic focus) may also be useful in avoiding conscious control of movements. The purpose of this study was to determine how an internal focus (INT), external focus (EXT), and holistic focus (HOL) impact the performance of a standing long jump. Participants (N = 27) completed two baseline jumps followed by two jumps in each focus condition. Jump distance was analyzed in a 6 (Order) × 4 (Focus) mixed ANOVA. Results indicated a significant main effect of focus (p < .001), with EXT and HOL resulting in farther jumps than INT and baseline conditions (p-values < .05). EXT and HOL did not differ significantly from each other, and INT did not differ significantly from baseline. The findings suggest that a holistic focus can be another effective means of avoiding conscious control of movement when an external focus is not practical or desired.
Seihati A. Shiroma, Ursula F. Julio and Emerson Franchini
Purpose: To evaluate criterion validity, reliability, and usefulness of a test to measure maximal aerobic power using judo-specific movements (uchi-komi test [UKtest]). Methods: A total of 12 judokas performed 5 graded exercise tests (GETs) in 4 sessions. In sessions 1 and 2, upper-body (UBtest), lower-body (LBtest), and familiarization UKtest were performed. GETs were randomly performed and separated by at least 48 h. In sessions 3 and 4, test and retest UKtest were performed (7 d apart). For all GETs, peak oxygen consumption (
David Giles, Joel B. Chidley, Nicola Taylor, Ollie Torr, Josh Hadley, Tom Randall and Simon Fryer
Purpose: To determine if the mathematical model used for the estimation of critical force (CF) and the energy store component W′ are applicable to intermittent isometric muscle actions of the finger flexors of rock climbers, using a multisession test. As a secondary aim, the agreement of estimates of CF and W′ from a single-session test was also determined. The CF was defined as the slope coefficient, and W′ was the intercept of the linear relationship between total “isometric work” (W lim) and time to exhaustion (T lim). Methods: Subjects performed 3 (separated by either 20 min or >24 h) tests to failure using intermittent isometric finger-flexor contractions at 45%, 60%, and 80% of their maximum voluntary contraction. Results: Force plotted against T lim displayed a hyperbolic relationship; correlation coefficients of the parameter estimates from the work–time CF model were consistently very high (R 2 > .94). Climbers’ mean CF was 425.7 (82.8) N (41.0% [6.2%] maximum voluntary contraction) and W′ was 30,882 (11,820) N·s. Good agreement was found between the single-session and multisession protocol for CF (intraclass correlation coefficient [ICC3,1] = .900; 95% confidence interval, .616–.979), but not for W′ (ICC3,1 = .768; 95% confidence interval, .190–.949). Conclusions: The results demonstrated the sensitivity of a simple test for the determination of CF and W′, using equipment readily available in most climbing gyms. Although further work is still necessary, the test of CF described is of value for understanding exercise tolerance and to determine optimal training prescription to monitor improvements in the performance of the finger flexors.