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Anis Rostami, Amir Letafatkar, Alli Gokeler and Mehdi Khaleghi Tazji

Context: Female volleyball players are more predisposed to anterior cruciate ligament injury in comparison with their male counterparts. Recent research on anterior cruciate ligament injury prevention strategies has shown the positive results of adopting the external focus (EF) of attention in sports. Objective: To determine the effect of 6-week EF instruction exercises on performance and kinetic factors associated with lower-extremity injury in landing after the volleyball blocks of female athletes. Design: Pretest and posttest control study. Setting: University research laboratory. Participants: Thirty-two female volleyball players (18–24 y old) from the same team randomly divided into experimental (n = 16) and control (n = 16) groups. Intervention: The experimental group performed a 6-week exercise program with EF instructions. The control group continued its regular volleyball team schedule. Main Outcome Measures: To assess function, single-leg triple hop test for distance was used. A force plate was used to evaluate kinetic variables including vertical ground reaction forces, the rate of loading, and dynamic postural stability index. All data were assessed at baseline and after the intervention. Results: There was a significant increase in single-leg triple hop test (P < .05) and in the first and second peak ground reaction force, rate of loadings, dynamic postural stability index (P < .05). Conclusion: According to the results of this study, anterior cruciate ligament injury prevention programs should incorporate EF instruction exercises to enhance the kinetics and to increase athletes’ functional performance.

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Peter A. van de Hoef, Jur J. Brauers, Maarten van Smeden, Frank J.G. Backx and Michel S. Brink

Background: Plyometric training is a specific form of strength training that is used to improve the physical performance of athletes. An overview of the effects of plyometric training on soccer-specific outcomes in adult male soccer players is not available yet. Purpose: To systematically review and meta-analyze the effects of plyometric training on soccer-specific outcome measures in adult male soccer players and to identify which programs are most effective. Methods: PubMed, Embase/Medline, Cochrane, PEDro, and Scopus were searched. Extensive quality and risk of bias assessments were performed using the Cochrane ROBINS 2.0 for randomized trials. A random effects meta-analysis was performed using Cochrane Review Manager 5.3. Results: Seventeen randomized trials were included in the meta-analysis. The impact of plyometric training on strength, jump height, sprint speed, agility, and endurance was assessed. Only jump height, 20-m sprint speed, and endurance were significantly improved by plyometric training in soccer players. Results of the risk of bias assessment of the included studies resulted in overall scores of some concerns for risk of bias and high risk of bias. Conclusion: This review and meta-analysis showed that plyometric training improved jump height, 20-m sprint speed, and endurance, but not strength, sprint speed over other distances, or agility in male adult soccer players. However, the low quality of the included studies and substantial heterogeneity means that results need to be interpreted with caution. Future high-quality research should indicate whether or not plyometric training can be used to improve soccer-specific outcomes and thereby enhance performance.

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Rumit S. Kakar, Hilary B. Greenberger and Patrick O. McKeon

Context: Anterior knee pain also known as patellofemoral pain syndrome is a frequently encountered musculoskeletal disorder that worsens with activity. The multifactorial etiology of patellofemoral pain syndrome alters lower-extremity mechanics, increasing patellofemoral joint stresses during weight-bearing tasks. Kinesio and McConnell tapings are often incorporated into the treatment, but their efficacy is still unclear. Objective: To test the efficacy of Kinesio taping, McConnell taping, and sham taping in improving knee mechanics and reducing pain during activity. Design: Cross-sectional design. Setting: Clinical biomechanics laboratory. Participants: Ten participants (age: 20.3 [1.5] y, height: 169.9 [10.4] cm, and mass: 70.17 [13.1] kg) with anterior knee pain and no history of trauma. Intervention: Three trials each of squat, drop jump, and step-down tasks with 3 taping conditions in a counterbalanced order. Main Outcome Measures: Two-dimensional motion capture data of lower-extremities in frontal and sagittal planes were recorded and analyzed using 3 iPads and Spark Motion® application. Pooled effect sizes (Hedges’ g), 95% confidence intervals, and repeated-measures analysis of variance (P < .05) compared baseline and taping conditions during exercises for pain Visual Analog Scale and knee flexion in all exercises, hip abduction during step-down and drop jump, frontal plane projection during step-downs, and knee translation in sagittal plane during squats. Results: Significant reductions in Visual Analog Scale were recorded during squats between tapes (F 2.505,12.867 = 3.407, P = .04, Hedges’ g = −0.70). Pairwise comparison showed a decrease in Visual Analog Scale for sham taping (mean difference = 1.14 cm, P = .01) and Kinesio taping (mean difference = 1.54 cm, P = .02) compared with baseline during squats. Conclusions: A variety of taping methods can potentially reduce perceived pain in individuals with patellofemoral pain syndrome, allowing clinicians to perform rehabilitation exercises. Sensory effects associated with short-term taping may be sufficient enough to modify knee pain acutely by afferent input blocking nocioceptive pain before the participants could adapt. Most interestingly, the sham taping technique demonstrated promise for enhancing functional outcomes, depending on the length of the tape and area covered.

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Jennifer E. McGarry

In her 2019 Earle F. Zeigler address, Jennifer McGarry drew on the 2017 Academy of Management Report “Measuring and Achieving Scholarly Impact” to examine how the field of sport management and the North American Society for Sport Management operationalize impact. She pointed to a broader, more inclusive, and critical examination of impact. McGarry highlighted impact on practice and impact through being explicit, particularly about the ways gender and race affect what we deem to have impact. Finally, she spoke to impact through individual and collective action, such as educating students, scholarship, and policy and advocacy. She provided examples of where we could disrupt the structures that work to maintain the status quo in terms of impact—the in-groups and the out-groups, the metrics and evaluations. She also gave examples of impact that have happened, that are happening, and that can happen even more.

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Nathan Philip Hilton, Nicholas Keith Leach, Melissa May Craig, S. Andy Sparks and Lars Robert McNaughton

Enteric-formulated capsules can mitigate gastrointestinal (GI) side effects following sodium bicarbonate (NaHCO3) ingestion; however, it remains unclear how encapsulation alters postingestion symptoms and acid–base balance. The current study aimed to identify the optimal ingestion form to mitigate GI distress following NaHCO3 ingestion. Trained males (n = 14) ingested 300 mg/kg body mass of NaHCO3 in gelatin (GEL), delayed-release (DEL), and enteric-coated (ENT) capsules or a placebo in a randomized cross-over design. Blood bicarbonate anion concentration, potential hydrogen, and GI symptoms were measured pre- and postingestion for 3 hr. Fewer GI symptoms were reported with ENT NaHCO3 than with GEL (p = .012), but not with DEL (p = .106) in the postingestion phase. Symptom severity decreased with DEL (4.6 ± 2.8 arbitrary units) compared with GEL (7.0 ± 2.6 arbitrary units; p = .001) and was lower with ENT (2.8 ± 1.9 arbitrary units) compared with both GEL (p < .0005) and DEL (p = .044) NaHCO3. Blood bicarbonate anion concentration increased in all NaHCO3 conditions compared with the placebo (p < .0005), although this was lower with ENT than with GEL (p = .001) and DEL (p < .0005) NaHCO3. Changes in blood potential hydrogen were reduced with ENT compared with GEL (p = .047) and DEL (p = .047) NaHCO3, with no other differences between the conditions. Ingestion of ENT NaHCO3 attenuates GI disturbances for up to 3 hr postingestion. Therefore, ENT ingestion forms may be favorable for those who report GI disturbances with NaHCO3 supplementation or for those who have previously been deterred from its use altogether.

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Stephanie G. Kerrigan, Evan M. Forman, Mitesh Patel, Dave Williams, Fengqing Zhang, Ross D. Crosby and Meghan L. Butryn

Background: Despite interest in financial incentive programs, evidence regarding the feasibility, acceptability, and effectiveness of deposit contracts (ie, use of participants’ own money as a financial reward) for increasing physical activity (PA) is limited. Furthermore, evidence regarding the use of feedback within incentive programs is limited. Purpose: To evaluate: (1) the feasibility and acceptability of deposit contracts for increasing objectively measured PA and (2) the effects of deposit contracts with or without ongoing feedback on PA. Methods: Participants (n = 24) were exposed to 3 conditions (1) self-monitoring, (2) incentive, and (3) incentive with feedback in an ABACABAC design, with the order of incentive conditions counterbalanced across participants. Results: Effect sizes suggest that individuals had a modest increase in PA during the incentive conditions compared with self-monitoring. Presentation order moderated results, such that individuals exposed to incentives with feedback first performed more poorly across both incentive conditions. In addition, individuals often cited the deposit contract as a reason for not enrolling, and those who did participate reported inadequate acceptability of the incentives and feedback. Conclusions: Results suggest that while deposit contracts may engender modest increases in PA, this type of incentive may not be feasible or acceptable for promoting PA.

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Catrine Tudor-Locke, John M. Schuna Jr, Damon L. Swift, Amber T. Dragg, Allison B. Davis, Corby K. Martin, William D. Johnson and Timothy S. Church

Background: Step-counting interventions with discrepant intensity emphases may elicit different effects. Methods: A total of 120 sedentary/low-active, postmenopausal women were randomly assigned to one of the following 3 groups: (1) 10,000 steps per day (with no emphasis on walking intensity/speed/cadence; basic intervention, 49 completers), (2) 10,000 steps per day and at least 30 minutes in moderate intensity (ie, at a cadence of at least 100 steps per minute; enhanced intervention, 47 completers), or (3) a control group (19 completers). NL-1000-determined steps and active minutes (a device-specific indicator of time at moderate+ intensity) were collected as process variables during the 12-week intervention. Outcome variables included systolic and diastolic blood pressure, anthropometric measurements, fasting blood glucose and insulin, flow-mediated dilation, gait speed, and ActiGraph GT3X+-determined physical activity and sedentary behavior. Results: The “basic group” increased 5173 to 9602 steps per day and 9.2 to 30.2 active minutes per day. The “enhanced group” similarly increased 5061 to 10,508 steps per day and 8.7 to 38.8 active minutes per day. The only significant change over time for clinical variables was body mass index. Conclusions: Interventions that use simple step-counters can achieve elevated volume and intensity of daily physical activity, regardless of emphasis on intensity. Despite this, few clinical outcomes were apparent in this sample of postmenopausal women with generally normal or controlled hypertension.

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Sean H. Kerr, Tiffanye M. Vargas, Mimi Nakajima and Jim Becker

The purpose of this exploratory study was to examine youth American football coaches and their knowledge of, and attitudes toward, sport concussions. Coaches (n = 103) were recruited from a randomized sample of Pop Warner leagues within a large Western state to complete the Rosenbaum Concussion Knowledge and Attitudes Survey. Coaches ranged from 25–75 years of age and were coaching youth athletes ranging from 6–14 years of age. Coaches scored in the 80th percentile on concussion knowledge, and in the 85th percentile on concussion attitudes. However, coaches were lacking in some areas of concussion knowledge such as concussion symptomology. There was also a statistically significant positive correlation between coaches’ scores on the Concussion Knowledge Index and the Concussion Attitudes Index, r = .43, p < .01. The results of this research indicate that while youth sport coaches report basic knowledge of concussions, there remain gaps in their education. This highlights the need for research to review current coaching curriculum, observe actual coaching behaviors, and to determine best practices for teaching coaches.