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Boris Dugonjić, Saša Krstulović and Goran Kuvačić

The aim of this observational cross-sectional survey was to determine the prevalence of rapid weight loss (RWL) in elite kickboxers. Kickboxers (61 males; age = 24.2 ± 4.6 years, weight = 73.9 ± 12.8 kg, and height = 179.2 ± 7.9 cm) from eight European countries completed a Rapid Weight Loss Questionnaire regarding prevalence, magnitude, and methods of RWL. All athletes (100%) were practicing RWL before the competition with a Rapid Weight Loss Questionnaire score of 52.4 ±12.9. Most kickboxers ‘usually lose between 2% and 5% of their body mass, whereas ∼30% lose between 6% and 8%. However, it is alarming that almost 30% reported cutting 10% of body weight or more sometime during their kickboxing career. Almost half of the athletes always practice gradual dieting (45.9%) and increased exercising (44.3%) to reduce body mass. Kickboxers usually reduce weight three to four times during a year, usually 7–15 days before a competition. More than a third (34.4%) started with RWL practice under the age of 17. There was no significant difference between weight divisions in weight management behaviors (p = .5, F = 0.6; η2 = .0) and no relation between the main characteristics of elite kickboxing athletes and the total RWL score. In conclusion, RWL practices in kickboxing athletes are somewhat specific and different when compared with other combat sports, which can be explained by greater number of weight classes and specific weigh-in protocol.

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Mhairi J. MacDonald, Samantha G. Fawkner, Ailsa G. Niven and David Rowe

Background: Currently, it is not known how much walking should be advocated for good health in an adolescent population. Step count recommendations for minimum time in moderate-intensity activity have been translated predominantly from treadmill walking. Purpose: To compare the energy cost of walking on a treadmill with overground walking in adolescent girls. Methods: A total of 26 adolescent girls undertook resting metabolic measurements for individual determination of 1 metabolic equivalent using indirect calorimetry. Energy expenditure was subsequently assessed during treadmill and overground walking at slow, moderate, and fast walking speeds for 4 to 6 minutes. Treadmill step rates were matched overground using a metronome. Results: The energy cost of treadmill walking was found to be significantly greater than and not equivalent to overground walking at 133 steps per minute; (equivalent to the fast walking pace): V˙O2 3.90 (2.78–5.01), P < .001, mean absolute percentage error (MAPE) = 18.18%, and metabolic equivalent 0.77 (0.54–1.00), P < .001, MAPE = 18.16%. The oxygen cost per step (V˙O2 mL·step−1) was significantly greater and not equivalent on the treadmill at 120 and 133 steps per minute: 0.43 (0.12–0.56), P < .05, MAPE = 10.12% versus 1.40 (1.01–1.76), P < .001, MAPE = 17.64%, respectively. Conclusion: The results suggest that there is a difference in energy cost per step of walking on a treadmill and overground at the same step rate. This should be considered when utilizing the treadmill in energy expenditure studies. Studies which aim to provide step recommendations should focus on overground walking where most walking activity is adopted.

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Nili Steinberg, Roger Adams, Moshe Ayalon, Nadav Dotan, Shiri Bretter and Gordon Waddington

Objective: Assessing the effects of ankle injury and sport participation level on ankle proprioceptive sensitivity using a joint position reproduction (JPR) test and an inversion movement extent discrimination test. Design: Cross-sectional. Setting: Biomechanics lab. Participants: Forty-five student athletes ages 21–30 (mean = 24.8 y). Main Outcome Measures: Participants were tested for ankle inversion sensitivity using 2 devices; movement reproduction error was obtained from JPR in a non-weight-bearing (N-WB) state at 10° and 15° of inversion, and an ankle proprioceptive sensitivity score was obtained from the active movement extent discrimination apparatus (AMEDA), representing the ability to differentiate 5 inversion movement extents between 10.5° and 14.5°, with testing in both N-WB and weight-bearing (WB) states. Results: For the 34 athletes with no ankle injury in the previous 12 months, the sensitivity scores achieved on the AMEDA were significantly higher (P < .01) than those for the 11 athletes with ankle injury, and the injury effect was significantly greater in WB (P = .01). In JPR testing, the 2.96° error of reproduction for athletes with no recent ankle injury was not significantly different from the 3.36° error for those with ankle injury (P = .46). Correlation of current sport participation level with JPR showed less error for higher-level performers (r = .49, P = .001) but no significant relationship to WB or N-WB AMEDA scores (both P > .61). WB AMEDA scores were significantly higher for athletes who had competed at a higher level of sport competition when <18 years old (r = −.57, P < .001). Conclusions: Previous ankle sprains affected proprioceptive scores on the WB AMEDA and N-WB AMEDA tests, indicating the sensitivity of the AMEDA movement discrimination test to the effects of ankle injury. The correlation between JPR scores and current level of sport participation suggests the sensitivity of the JPR test to current ankle use.

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Damien Moore, Tania Pizzari, Jodie McClelland and Adam I. Semciw

Context: Many different rehabilitation exercises have been recommended in the literature to target the gluteus medius (GMed) muscle based mainly on single-electrode, surface electromyography (EMG) measures. With the GMed consisting of 3 structurally and functionally independent segments, there is uncertainty on whether these exercises will target the individual segments effectively. Objective: To measure individual GMed segmental activity during 6 common, lower-limb rehabilitation exercises in healthy young adults, and determine if there are significant differences between the exercises for each segment. Method: With fine-wire EMG electrodes inserted into the anterior, middle, and posterior segments of the GMed muscle, 10 healthy young adults performed 6 common, lower-limb rehabilitation exercises. Main Outcome Measures: Recorded EMG activity was normalized, then reported and compared with median activity for each of the GMed segments across the 6 exercises. Results: For the anterior GMed segment, high activity was recorded for the single-leg squat (48% maximum voluntary isometric contraction [MVIC]), the single-leg bridge (44% MVIC), and the resisted hip abduction–extension exercise (41% MVIC). No exercises recorded high activity for the middle GMed segment, but for the posterior GMed segment very high activity was recorded by the resisted hip abduction–extension exercise (69% MVIC), and high activity was generated by the single-leg squat (48% MVIC) and side-lie hip abduction (43% MVIC). For each of the GMed segments, there were significant differences (P < .05) in the median EMG activity levels between some of the exercises and the side-lie clam with large effect sizes favoring these exercises over the side-lie clam. Conclusions: Open-chain hip abduction and single-limb support exercises appear to be effective options for recruiting the individual GMed segments with selection dependent on individual requirements. However, the side-lie clam does not appear to be effective at recruiting the GMed segments, particularly the anterior and middle segments.

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Esra Uzelpasaci, Türkan Akbayrak, Serap Özgül, Ceren Orhan, Emine Baran, Gülbala Nakip, Sinan Beksac and Semra Topuz

Background: Evaluation of physical activity by condition-specific surveys provides more accurate results than generic physical activity questionnaires. The aim of this study was to investigate the reliability and validity of the Kaiser Physical Activity Survey (KPAS) in Turkish pregnant women. Methods: In the translation and cultural adaptation of the KPAS, the 6-phase guidelines recommended in the literature were followed. The study included a total of 151 pregnant women who were assessed using the Turkish version of KPAS, the Pregnancy Physical Activity Questionnaire, and the SenseWear Pro3 Armband. To determine the test–retest reliability, the KPAS was reapplied after 7 days. The psychometric properties of KPAS were analyzed with respect to internal consistency, test–retest reliability, and concurrent validity. Results: Cronbach α coefficient indicating the internal consistency of the Turkish KPAS was found to be .60 to .80, showing moderate reliability. The intraclass correlation coefficient for test–retest reliability was very strong (intraclass correlation coefficient: .96–.98). The total KPAS scores were found to be moderately correlated with the total Pregnancy Physical Activity Questionnaire score and the total energy expenditure value on the SenseWear Pro3 Armband. Conclusions: This study showed that KPAS is a valid and reliable instrument for evaluating physical activity in Turkish pregnant women in different aspects.

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Diogo V. Leal, Lee Taylor and John Hough

Purpose: Progressively overloading the body to improve physical performance may lead to detrimental states of overreaching/overtraining syndrome. Blunted cycling-induced cortisol and testosterone concentrations have been suggested to indicate overreaching after intensified training periods. However, a running-based protocol is yet to be developed or demonstrated as reproducible. This study developed two 30-min running protocols, (1) 50/70 (based on individualized physical capacity) and (2) RPETP (self-paced), and measured the reproducibility of plasma cortisol and testosterone responses. Methods: Thirteen recreationally active, healthy men completed each protocol (50/70 and RPETP) on 3 occasions. Venous blood was drawn preexercise, postexercise, and 30 min postexercise. Results: Cortisol was unaffected (both P > .05; 50/70, ηp2 = .090; RPETP, ηp2 = .252), while testosterone was elevated (both P < .05; 50/70, 35%, ηp2 = .714; RPETP, 42%, ηp2 = .892) with low intraindividual coefficients of variation (CVi) as mean (SD) (50/70, 7% [5%]; RPETP, 12% [9%]). Heart rate (50/70, effect size [ES] = 0.39; RPETP, ES = −0.03), speed (RPETP, ES = −0.09), and rating of perceived exertion (50/70 ES = −0.06) were unchanged across trials (all CVi < 5%, P < .05). RPETP showed greater physiological strain (P < .01). Conclusions: Both tests elicited reproducible physiological and testosterone responses, but RPETP induced greater testosterone changes (likely due to increased physiological strain) and could therefore be considered a more sensitive tool to potentially detect overtraining syndrome. Advantageously for the practitioner, RPETP does not require a priori exercise-intensity determination, unlike the 50/70, enhancing its integration into practice.

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Nicholas D. Gilson, Caitlin Hall, Andreas Holtermann, Allard J. van der Beek, Maaike A. Huysmans, Svend Erik Mathiassen and Leon Straker

Background: This systematic review assessed evidence on the accelerometer-measured sedentary and physical activity (PA) behavior of nonoffice workers in “blue-collar” industries. Methods: The databases CINAHL, Embase, MEDLINE, PubMed, and Scopus were searched up to April 6, 2018. Eligibility criteria were accelerometer-measured sedentary, sitting, and/or PA behaviors in “blue-collar” workers (≥10 participants; agricultural, construction, cleaning, manufacturing, mining, postal, or transport industries). Data on participants’ characteristics, study protocols, and measured behaviors during work and/or nonwork time were extracted. Methodologic quality was assessed using a 12-item checklist. Results: Twenty studies (representing 11 data sets), all from developed world economies, met inclusion criteria. The mean quality score for selected studies was 9.5 (SD 0.8) out of a maximum of 12. Data were analyzed using a range of analytical techniques (eg, accelerometer counts or pattern recognition algorithms). “Blue-collar” workers were more sedentary and less active during nonwork compared with work time (eg, sitting 5.7 vs 3.2 h/d; moderate to vigorous PA 0.5 vs 0.7 h/d). Drivers were the most sedentary (work time 5.1 h/d; nonwork time 8.2 h/d). Conclusions: High levels of sedentary time and insufficient PA to offset risk are health issues for “blue-collar” workers. To better inform interventions, research groups need to adopt common measurement and reporting methodologies.

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Landy Di Lu and Kathryn L. Heinze

Multilevel examinations of sport policy institutionalization are scarce in sport management scholarship. As sport policies diffuse across geographic boundaries, there is often variation in the timing of adoption. In this study, the authors used event history analysis to examine the effect of institutional factors, within and between states, on the speed of youth sport concussion legislation adoption. Our quantitative analyses show that a series of intrastate factors—state norms, disruptive events, and local advocacy—had a significant influence on the timing of state policy adoption, but interstate social networks did not. Supporting qualitative data provide additional insight about the relationship between disruptive events and local advocacy in the adoption of concussion legislation. This study contributes to a better understanding of institutional factors in the diffusion of sport policy across geographic boundaries and offers an approach for future research examining variation in sport policy or practice adoption.

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Thomas A. Haugen, Felix Breitschädel and Stephen Seiler

Purpose: To quantify possible differences in sprint mechanical outputs in handball and basketball players according to playing standard and position. Methods: Sprint tests of 298 male players were analyzed. Theoretical maximal velocity (v 0), horizontal force (F 0), horizontal power (P max), force–velocity slope (S FV), ratio of force (RFmax), and index of force application technique (D RF) were calculated from anthropometric and spatiotemporal data using an inverse dynamic approach applied to the center-of-mass movement. Results: National-team handball players displayed clearly superior 10-m times (0.03, ±0.02 s), 40-m times (0.12, ±0.07 s), F 0 (0.1, ±0.2 N·kg−1), v 0 (0.3, ±0.2 m·s−1), and P max (0.9, ±0.5 W·kg−1) than corresponding top-division players. Wings differed from the other positions in terms of superior 10-m times (0.02, ±0.01 to 0.07, ±0.02 s), 40-m times (0.07, ±0.05 to 0.27, ±0.07 s), F 0 (0.2, ±0.1 to 0.4, ±0.2 N·kg−1), v 0 (0.1, ±0.1 to 0.5, ±0.1 m·s−1), P max (0.7, ±0.4 to 2.0, ±0.5 W·kg−1), and RFmax (0.6, ±0.4 to 1.3, ±0.4%). In basketball, guards differed from forwards in terms of superior 10-m times (0.03, ±0.02 s), 40-m times (0.10, ±0.08 s), v 0 (0.2, ±0.1 m·s−1), P max (0.6, ±0.6 W·kg−1), and RFmax (0.4, ±0.3%). The effect magnitudes of the substantial differences observed ranged from small to large. Conclusions: The present results provide an overall picture of the force–velocity profile continuum in sprinting handball and basketball players and serve as useful background information for practitioners when diagnosing individual players and prescribing training programs.

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Thiago S. Duarte, Danilo L. Alves, Danilo R. Coimbra, Bernardo Miloski, João C. Bouzas Marins and Maurício G. Bara Filho

Purpose: To analyze the technical and tactical training load in professional volleyball players, using subjective internal training load (session rating of perceived exertion  [SRPE]) and objective internal training load (training impulse of the heart rate [HR]) and the relationship between them. Methods: The sample was composed of 15 male professional volleyball players. They were monitored during 37 training sessions that included both technical (n = 23) and tactical (n = 14) training. Technical and training load was calculated using SRPE and training impulse of the HR. Results: Significant correlations were found between the methods in tactical (r = .616) and technical training (r = −.414). Furthermore, it was noted that technical training occurs up to 80% of HRmax (zone 3) and tactical training between 70% and 90% of HRmax (zones 3–4). Conclusions: The training impulse of the HR method has proved to be effective for training-load control during tactical training. However, it was limited compared with technical training. Thus, the use of SRPE is presented as a more reliable method in the different types of technical training in volleyball.