Search

There is a lack of reporting effect sizes and confidence intervals in the current biomedical literature. The objective of this article is to present a discussion of the recent paradigm shift encouraging the use of reporting effect sizes and confidence intervals. Although P values help to inform us about whether an effect exists due to chance, effect sizes inform us about the magnitude of the effect (clinical significance), and confidence intervals inform us about the range of plausible estimates for the general population mean (precision). Reporting effect sizes and confidence intervals is a necessary addition to the biomedical literature, and these concepts are reviewed in this article.

Objectives: Studies comparing multiple groups (i.e., experimental and control) often examine the efficacy of an intervention by calculating within group effect sizes using Cohen's d. This method is inappropriate and largely impacted by the pre-test variability as opposed to the variability in the intervention itself. Furthermore, the percentage change is often analyzed, but this is highly impacted by the baseline values and can be potentially misleading. Thus, the objective of this study was to illustrate the common misuse of the effect size and percent change measures., Design: Here we provide a realistic sample data set comparing two resistance training groups with the same pre-test to post-test change., Methods: Statistical tests that are commonly performed within the literature were computed., Results: Analyzing the within group effect size favors the control group, while the percent change favors the experimental group. The most appropriate way to present the data would be to plot the individual responses or, for larger samples, provide the mean change and 95% confidence intervals of the mean change. This details the magnitude and variability within the response to the intervention itself in units that are easily interpretable., Conclusions: This manuscript demonstrates the common misuse of the effect size and details the importance for investigators to always report raw values, even when alternative statistics are performed., (Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Objective: To describe confidence intervals (CIs) and effect sizes and provide practical examples to assist clinicians in assessing clinical meaningfulness., Background: As discussed in our first article in 2015, which addressed the difference between statistical significance and clinical meaningfulness, evaluating the clinical meaningfulness of a research study remains a challenge to many readers. In this paper, we will build on this topic by examining CIs and effect sizes., Description: A CI is a range estimated from sample data (the data we collect) that is likely to include the population parameter (value) of interest. Conceptually, this constitutes the lower and upper limits of the sample data, which would likely include, for example, the mean from the unknown population. An effect size is the magnitude of difference between 2 means. When a statistically significant difference exists between 2 means, effect size is used to describe how large or small that difference actually is. Confidence intervals and effect sizes enhance the practical interpretation of research results., Recommendations: Along with statistical significance, the CI and effect size can assist practitioners in better understanding the clinical meaningfulness of a research study.

Miller and Ulrich (2015) critique our claim (Hoekstra et al., Psychonomic Bulletin & Review, 21(5), 1157-1164, 2014), based on a survey given to researchers and students, of widespread misunderstanding of confidence intervals (CIs). They suggest that survey respondents may have interpreted the statements in the survey that we deemed incorrect in an idiosyncratic, but correct, way, thus calling into question the conclusion that the results indicate that respondents could not properly interpret CIs. Their alternative interpretations, while correct, cannot be deemed acceptable renderings of the questions in the survey due to the well-known reference class problem. Moreover, there is no support in the data for their contention that participants may have had their alternative interpretations in mind. Finally, their alternative interpretations are merely trivial restatements of the definition of a confidence interval, and have no implications for the location of a parameter.

Interval estimates - estimates of parameters that include an allowance for sampling uncertainty - have long been touted as a key component of statistical analyses. There are several kinds of interval estimates, but the most popular are confidence intervals (CIs): intervals that contain the true parameter value in some known proportion of repeated samples, on average. The width of confidence intervals is thought to index the precision of an estimate; CIs are thought to be a guide to which parameter values are plausible or reasonable; and the confidence coefficient of the interval (e.g., 95 %) is thought to index the plausibility that the true parameter is included in the interval. We show in a number of examples that CIs do not necessarily have any of these properties, and can lead to unjustified or arbitrary inferences. For this reason, we caution against relying upon confidence interval theory to justify interval estimates, and suggest that other theories of interval estimation should be used instead.

This commentary is the second of a series outlining one specific concept in interpreting biomarkers data. In the first, an observational method was presented for assessing the distribution of measurements before making parametric calculations. Here, the discussion revolves around the next step, the choice of using standard error of the mean or the calculated standard deviation to compare or predict measurement results.

Researchers often want to place a confidence interval around estimated parameter values calculated from a sample. This is commonly implemented by bootstrapping. There are several different frequently used bootstrapping methods for this purpose. Here we demonstrate that authors of recent papers frequently do not specify the method they have used and that different methods can produce markedly different confidence intervals for the same sample and parameter estimate. We encourage authors to be more explicit about the method they use (and number of bootstrap resamples used). We recommend the bias corrected and accelerated method as giving generally good performance; although researchers should be warned that coverage of bootstrap confidence intervals is characteristically less than the specified nominal level, and confidence interval evaluation by any method can be unreliable for small samples in some situations., (© 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.)

Background: An understanding of p-values and confidence intervals is necessary for the evaluation of scientific articles. This article will inform the reader of the meaning and interpretation of these two statistical concepts., Methods: The uses of these two statistical concepts and the differences between them are discussed on the basis of a selective literature search concerning the methods employed in scientific articles., Results/conclusions: P-values in scientific studies are used to determine whether a null hypothesis formulated before the performance of the study is to be accepted or rejected. In exploratory studies, p-values enable the recognition of any statistically noteworthy findings. Confidence intervals provide information about a range in which the true value lies with a certain degree of probability, as well as about the direction and strength of the demonstrated effect. This enables conclusions to be drawn about the statistical plausibility and clinical relevance of the study findings. It is often useful for both statistical measures to be reported in scientific articles, because they provide complementary types of information.

Context: Analyzing flick movement kinematics biomechanically is important to prevent sport-related injuries in underwater hockey players since the aquatic-based flick movement is completely different from land-based flick movements. The study aimed to describe the flick movement kinematic biomechanically in underwater hockey players. Moreover, this study further aimed to investigate the effect of the Thrower's Ten exercises on flick movement kinematics in underwater hockey players. Design: Descriptive laboratory study. Methods: Seventeen underwater hockey players (age: 26.2 [4.3] y; sports age: 6.2 [4.5] y) were included. First, 2 underwater cameras using motion capture video analysis MATLAB were used to biomechanically analyze the angular changes on the shoulder, elbow, wrist, and body while players were performing the flick movements. Players were then recruited to the Thrower's Ten exercise program for 6 weeks. Flick movement kinematics and flick-throwing distance were recorded at baseline and 6 weeks. Results: The flick movement kinematic patterns demonstrated increased shoulder flexion (from 102.5° to 144.9°), wrist extension (from 9.5° to 10.8°), and upper-extremity rotation (from 5.7° to 56.8°) while decreased elbow extension (from 107.7° to 159.2°) from the stick met the puck until the competition of the movement. The Thrower's Ten exercises improved the elbow extension (P =.04), wrist extension (P =.01), body rotation (P <.001), and flick-throwing distance (P <.001) from baseline to 6 weeks. Conclusion: This study describes the underwater flick kinematic technique biomechanically and interprets preliminary findings for the first time. Thus, 6 weeks of Thrower's Ten exercise program provides more body muscle movements than the smaller ones during the flick movements and higher flick-throwing distance in underwater hockey players. [ABSTRACT FROM AUTHOR]

Research interest in thriving at work has burgeoned over the past decades, but little is known about how human resource (HR) practices affect employees' thriving at work. Drawing upon self‐determination theory and person‐organization fit theory, we developed and tested a moderated mediation model to explain how fun HR practices influence employees' thriving at work. The results of two studies, a scenario experiment (N = 164) and a time‐lagged survey (N = 253), supported our hypotheses. Specifically, the findings revealed that fun HR practices relates positively to employees' thriving at work. Autonomous motivation partially mediates the abovementioned relationship. Furthermore, fun HR practices translate into higher autonomous motivation and subsequent thriving at work for employees with higher preference for workplace fun. Our research contributes to the existing literature by identifying fun HR practices as an antecedent of thriving at work and revealing the psychological mechanisms through which fun HR practices affect employees' thriving at work. The practical implications, limitations, and future research avenues are also discussed. [ABSTRACT FROM AUTHOR]

Recent methodological recommendations suggest the use of the "3-step method," consisting of calendar-based counting, urinary ovulation testing, and serum blood sampling, for the identification of subtle menstrual disturbances (SMDs). However, the use of the 3-step method is not always feasible, so a less demanding combination of calendar-based counting and urinary ovulation testing, that is, the 2-step method, may be a viable alternative. Purpose: To investigate the agreement between the 2- and 3-step methods for the detection of SMDs. Methods: Menstrual cycles (MCs, 98) of 59 athletes were assessed using the 2- and 3-step methods. Regular-length MCs (ie, ≥21 and ≤35 d) were classified as either having no SMD (luteal phase length ≥10 d, midluteal progesterone concentration ≥16 nmol·L−1, and being ovulatory) or having an SMD (eg, short luteal phase [<10 d], inadequate luteal phase [midluteal progesterone concentration <16 nmol·L−1], or being anovulatory). Method agreement was assessed using the McNemar test and Cohen kappa (κ). Results: Substantial agreement was observed between methods (κ =.72; 95% CI,.53–.91), but the 2-step method did not detect all MCs with an SMD, resulting in evidence of systematic bias (χ2 = 5.14; P =.023). The 2-step method detected 61.1% of MCs that had an SMD ([51.4, 70.8]), as verified using the 3-step method, and correctly identified 100% of MCs without an SMD. Conclusions: MCs classified as being disturbed using the 2-step method could be considered valid evidence of SMDs. However, MCs classified without SMDs do not definitively confirm their absence, due to the proven underdetection via the 2-step method. [ABSTRACT FROM AUTHOR]

Context: Poor knee biomechanics contribute to knee joint injuries. Neuromuscular control over knee position is partially derived from the hip. It is unknown whether isolated activation training of the gluteal muscles improves lower-extremity frontal plane mechanics. This study examined if a home-based hip muscle activation program improves performance on the Forward Step-Down Test as well as increases surface electromyography (sEMG) activation of the gluteal muscles. Design: The study utilized a single-group repeated-measures design. Methods: Thirty-five participants (24 females, mean age = 23.17 [SD 1.36] years) completed an 8-week hip muscle activation program. The Forward Step-Down Test score and sEMG of gluteus maximus and medius were assessed preintervention and postintervention. Results: Forward Step-Down Test scores improved significantly from preintervention (Mdn = 3.5) to postintervention (Mdn = 3.0, T = 109, P =.010, r =.31.), but this result did not meet clinical significance. sEMG analysis revealed a significant increase in mean gluteus maximus activation (P =.028, d = 1.19). No significant dose–response relationship existed between compliance and the Forward Step-Down Test scores or sEMG results. Conclusions: A home-based hip activation program increases gluteus maximus activation without clinically significant changes in frontal plane movement quality. Future studies may find clinical relevance by adding motor learning to the activation training program to improve functional muscle use. [ABSTRACT FROM AUTHOR]

Purpose: To investigate how cycling time-trial (TT) performance changes over a cycling season, both in a "fresh" state and in a "fatigued" state (durability). Additionally, the aim was to explore whether these changes are related to changes in underlying physiological factors such as gross efficiency, energy expenditure (EE), and substrate oxidation (fat oxidation [FatOx] and carbohydrate oxidation [CarbOx]). Methods: Sixteen male semiprofessional cyclists visited the laboratory on 3 occasions during a cycling season (PRE, START, and IN) and underwent a performance test in both fresh and fatigued states (after 38.1 [4.9] kJ/kg), containing a submaximal warm-up for the measurement of gross efficiency, EE, FatOx, and CarbOx and a maximal TT of 1 (TT1min) and 10 minutes (TT10min). Results were compared across states (fresh vs fatigued) and periods (PRE, START, and IN). Results: The average power output (PO) in TT1min decreased (P <.05) from fresh to fatigued state across all observed periods, whereas there was no change in the PO in TT10min. Over the course of the season, the PO in TT1min in the fatigued state improved more compared with the PO in TT1min in the fresh state. Furthermore, while EE did not significantly change, there was an increase in FatOx and a decrease in CarbOx toward the fatigued state. These changes diminished during the cycling season (IN), indicating a greater contribution of CarbOx in the fatigued state. Conclusions: TT1min performance is more sensitive to fatigue compared with TT10min. Also, during a cycling season, durability improves more when compared with fresh maximal POs, which is also observed in the changes in substrate oxidation. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this review was to evaluate the effects of physical activity on children's free recall, cued recall, and recognition episodic memory and to explore potential moderating factors. Methods: The following databases were searched: PubMed, ERIC, APA Psych Info, CINHAL, SPORTDiscus, and Google Scholar. Studies were included if: (1) participants were aged 4–18 years, (2) participants were typically developed, (3) participants were randomized to groups, (4) interventions employed gross movements, (5) sedentary group was used for control, (6) memory tests were quantitative, and (7) employed acute or chronic intervention. Results: 14 studies met inclusion criteria resulting in the analysis of data from 7 free recall, 7 cued recall, and 8 recognition memory tests. Physical activity was found to have a positive influence on tests free (g = 0.56), cued recall (g = 0.67), and no influence on tests of recognition (g = 0.06). While some moderator analyses were significant, the authors do not consider these results to be meaningful in application. Conclusions: The effects of acute and chronic physical activity enhance specific aspects of long-term episodic memory. These findings suggest physical activity interventions developed for children may be expected to benefit some, but not all, types of memory processing. [ABSTRACT FROM AUTHOR]

Individuals with intellectual disabilities often face unique challenges in physical capabilities, making traditional training methods less effective for their specific needs. This study aimed to investigate the effect of combining balance, plyometric, and strength (CBPS) training with sprint training on physical performance in male athletes with intellectual disabilities. Twenty-seven participants were randomly assigned to either a CBPS group or a control group that only maintained their regular sprint training. Participants underwent pre- and posttraining tests, including measures of balance, jumping, agility, and sprinting ability. The results showed that the CBPS group demonstrated significant improvements (p <.05) in one-leg stance, crossover-hop jump, squat jump, countermovement jump, and 10- and 30-m sprint at posttraining compared with pretraining. CBPS training combined with sprinting significantly improves physical performance in male athletes with intellectual disabilities, suggesting implications for tailored training programs to enhance their physical fitness and overall health. [ABSTRACT FROM AUTHOR]

Context: Dual-task (simultaneous cognitive–motor activities) assessments have been adapted into reliable and valid clinical concussion measures. However, abundant motor and cognitive variations leave researchers and clinicians uncertain about which combinations elicit the intended dual-task effect. Our objective was to examine differences between commonly employed dual-task motor and cognitive combinations among healthy, college-aged individuals. Design: Cross-sectional laboratory study. Methods: Twenty participants (age: 21.3 [2.4] y; height: 176.0 [9.1] cm; mass: 76.0 [16.4] kg; 20% with concussion history) completed 4 motor tasks (gait, tandem gait, single-leg balance, and tandem balance) under 5 cognitive conditions (single task, subtraction, month reversal, spelling backward, and visual Stroop) in a research laboratory. The motor performance outcomes were spatiotemporal variables for gait and tandem gait and center of pressure path length (in centimeters) for single-leg and tandem balance. Cognitive outcomes were response rate (responses/second) and cognitive accuracy. We used separate repeated-measures analyses of variance for each motor and cognitive outcome with post hoc Tukey t tests. Results: Gait velocity, gait stride length, and tandem gait velocity demonstrated significant cognitive–motor interactions (P's <.001) such that all dual-task conditions resulted in varyingly slower or shorter movement than single task. Conversely, single-leg balance (P =.627) and tandem balance (P =.434) center of pressure path length did not significantly differ among the dual-task cognitive conditions or relative to single task. Statistically significant cognitive–motor interactions were observed only for spelling backward accuracy (P =.004) and response rates for spelling backward, month reversal, and visual Stroop (P's <.001) such that worse accuracy, but faster response rates, occurred during motor tasks. Conclusions: Gait and tandem gait motor tasks accompanied with spelling backward or subtraction cognitive tasks demonstrated consistently strong dual-task effects and, therefore, may be the best suited for clinical and research use following concussion. [ABSTRACT FROM AUTHOR]

Purpose: To complete a reanalysis study of two similarly designed prospective controlled studies exploring prognostic factors associated with the surgical outcomes of reconstructive treatment of peri-implantitis. Materials and Methods: Individual patient data of both studies were gathered. The initial study employed a submerged healing approach via primary wound closure with implant suprastructure removal and complete coverage of grafted sites. The second study employed a nonsubmerged healing protocol in which healing abutments were kept in place and the implants were not fully submerged. Both studies measured all prognostic factors at similar time points throughout 1 year and included clinical defect fill (DF) and radiographic defect fill (RDF), reduction of pocket depth (PDR), and bleeding on probing (BoP). Multilevel regression was used for statistical assessment of outcomes relative to the impact of site, local, surgical, and patient-related variables. Results: Overall, 59 implants (30 submerged and 29 nonsubmerged) were treated. Statistically significant higher DF (on average 0.9 mm higher), RDF (1.7 mm), and PDR (1.3 mm) were observed when a submerged reconstructive approach was performed, whereas BoP reduction was similar. After controlling for treatment (submerged/nonsubmerged), there were no other significant associations with patient-related (age, sex, smoking, prior periodontitis etc), or implant-related (previous prosthesis type, arch, keratinized tissue width [KTW], etc) factors. Conclusions: Within the study's limitations, we conclude that a submerged reconstructive approach for surgical management of peri-implantitis leads to significantly enhanced clinical and radiographic outcomes when compared to a nonsubmerged approach. [ABSTRACT FROM AUTHOR]

Purpose: To assess the complications, satisfaction, and quality of life of patients rehabilitated with delayed and immediate loading of single crowns. Materials and Methods: An electronic search was conducted in PubMed/MEDLINE, Scopus, Web of Science, Cochrane Library, and Embase databases up to February 2023. Only prospective studies and randomized and nonrandomized clinical trials comparing immediate and delayed loading were included. For the quantitative analysis, dichotomous and consistent variables were evaluated with a 95% confidence interval. Results: A total of 20 studies were evaluated. No statistically significant difference was observed between protocols: satisfaction (I²: 0%; P = .42), quality of life (I²: 0 %; P = .05), biologic complications (I²: 9%; P = .17), mechanical complications (I²: 58%; P = .84), and survival rate (I²: 0%; P = .38). The subgroup analysis showed significant differences only for marginal bone loss (MBL) when immediate implants were placed in the mandible (I²: 15%; P = .01) and posterior zone (I²: 0%; P = .001). Conclusions: Complications and patient-centered outcomes for immediate single-implant crowns were comparable to delayed loading. Scientific evidence showed no significant difference between loading protocols for survival rates. Note that several factors could interfere with the complication events, implant failures, and MBL. The subgroup analysis showed that only immediate implants placed in the posterior mandible had a higher and statistically significant mean MBL. [ABSTRACT FROM AUTHOR]

We integrate the job characteristics and dual work passion models to explore the indirect (via work meaningfulness) effects of job characteristics (i.e., job autonomy, task identity, skill variety, task significance, feedback from the job and feedback from others) on two types of work passion, harmonious passion (HP) and obsessive passion (OP). We first advance occupation‐specific predictions for job characteristics‐to‐work passion relationships and then explore differences in those relationships between HP and OP across four occupational sectors: knowledge work (n = 201), blue‐collar work (n = 148), nonprofit work (n = 141), and managerial work (n = 133). Our findings demonstrate that job characteristics are important drivers of work passion. However, our key discovery is that the motivational impact of the job characteristics is not universally applicable but rather depends on the specific occupational context and whether passion is harmonious or obsessive. We therefore conclude that when it comes to translating job characteristics into work passion, the one‐size‐fits‐all approach is not appropriate. [ABSTRACT FROM AUTHOR]

Purpose: Precooling (PreC) may only benefit performance when thermal strain experienced by an individual is sufficiently high. We explored the effect of mixed-method PreC on 20-km cycling time-trial (CTT) performance under 3 different apparent temperatures (AT). Methods: On separate days, 12 trained or highly trained male cyclists/triathletes completed six 20-km CTTs in 3 different ATs: hot-dry (35 °C AT), moderately hot-humid (40 °C AT), and hot-humid (46 °C AT). All trials were preceded by 30 minutes of mixed-method PreC or no PreC (control [CON]). Results: Faster 2.5-km-split completion times occurred in PreC compared with CON in 46 °C AT (P =.02), but not in 40 °C AT (P =.62) or 35 °C AT (P =.57). PreC did not affect rectal and body temperature during the 20-km CTT. Skin temperature was lower throughout the CTT in PreC compared with CON in 46 °C AT (P =.01), but not in 40 °C AT (P = 1.00) and 35 °C AT (P = 1.00). Heart rate had a greater rate of increase during the CTT for PreC compared with CON in 46 °C AT (P =.01), but not in 40 °C AT (P =.57) and 35 °C AT (P = 1.00). Ratings of perceived exertion (P <.001) and thermal comfort (P =.04) were lower for PreC compared with CON in 46 °C AT only, while thermal sensation was not different between PreC and CON. Conclusion: Mixed-method PreC should be applied prior to 20-km CTTs conducted in hot-humid conditions (≥46 °C AT). Alternatively, mixed-method PreC may be a priority in moderately hot-humid (∼40 °C AT) conditions but should not be in hot-dry (∼35 °C AT) conditions for 20-km CTT. [ABSTRACT FROM AUTHOR]

Context: Decreased trunk neuromuscular control is a risk factor for both upper- and lower-extremity injuries, yet there are few reliable and valid clinical tests to identify deficits. Objective: The purpose of this study was to determine the reliability and known-groups validity of a novel clinical test, the seated trunk control test (STCT). Design: Cross-sectional reliability and known-groups validity study. Setting: Laboratory. Participants: 89 unique participants: 34 were 3 months postoperative anterior cruciate ligament reconstruction (ACLR) and 55 healthy controls. Methods: For the STCT, participants sat on a balance board with their eyes closed for three 30-second trials while investigators counted balance errors. Intraclass correlations (ICCs) were used to assess interrater reliability (N = 20) and test–retest reliability (N = 40). To assess known-groups validity, independent t tests were used to compare STCT errors at 3 months post-ACLR with healthy matched controls (N = 34/group). Area under a receiver operating characteristic curve identified an optimal cutoff for distinguishing between groups. Results: The STCT had perfect interrater reliability (ICC2,3 = 1.00) and good test–retest reliability (ICC3,3 =.79; 95% confidence interval =.61–.89). The ACLR group made significantly more errors on the STCT (mean [SD] = 15.5 [5.4]) than controls (mean [SD] = 8.2 [4.1]; P <.001, Cohen d = 1.52). The STCT's ability to distinguish between groups was excellent (area under a ROC curve = 0.86). A cutoff of 12 errors maximized sensitivity (76%) and specificity (85%). Conclusions: The STCT is reliable between raters and across days. It also has excellent ability to distinguish between individuals with a recent ACLR and healthy matched controls, which provides initial evidence to suggest that the STCT may be clinically useful for identifying deficits in trunk neuromuscular control. [ABSTRACT FROM AUTHOR]

Context: Blood flow restriction (BFR) is a rehabilitation tool which may introduce a constraint, similar to muscle fatigue, that challenge patients' sensorimotor system during balance exercises. The purpose of our study was to examine whether adding BFR to dynamic balance exercises produced a decrease in balance performance and an increase in ratings of perceived exertion and instability in individuals with chronic ankle instability (CAI) compared with dynamic balance exercises without BFR. Designs: Crossover design. Methods: Our sample included N = 25 young adults with a history of CAI. Participants completed 2 laboratory visits. At each visit, participants completed 4 sets (30×-15×-15×-15×) of dynamic balance exercises, performed similar to the modified star excursion balance test (SEBT), once with BFR and once with control (no BFR) conditions. We measured composite SEBT scores at baseline and during the final repetitions of each set of balance exercise (sets 1–4). We also measured ratings of perceived exertion and instability following each balance exercise set. Results: We observed no difference in composite SEBT scores between conditions at baseline; however, composite SEBT scores were significantly lower during all balance exercises sets 1 to 4 with the BFR condition compared with control. During the BFR condition, composite SEBT scores were significantly lower during all balance exercise sets compared with baseline. During the control condition, composite SEBT scores did not significantly change between baseline and each balance exercise set. Ratings of perceived exertion and instability scores were significantly greater in the BFR group compared with the control group during all balance exercise sets. Conclusions: Individuals with CAI demonstrated lower composite SEBT scores and greater perceived instability and exertion during dynamic balance exercise with BFR compared to without BFR. BFR introduced a novel muscle fatigue constraint during dynamic balance exercises in individuals with CAI. Additional research is needed to determine if adding BFR to balance training could improve clinical outcomes in CAI patients. [ABSTRACT FROM AUTHOR]

Context: Plantar intrinsic foot muscle strength training is difficult to master to a degree sufficient to elicit muscle hypertrophy in most individuals. It is possible that combining neuromuscular electrostimulation (NMES) and blood flow restriction (BFR) can elicit plantar intrinsic foot muscle hypertrophy regardless of the individual's technique. This study aimed to determine the effects of NMES training with BFR on acute muscle swelling in the abductor hallucis. Design: Randomized, controlled, single-blind trial design. Methods: Forty-eight participants were randomly allocated to the NMES + BFR, NMES, or Sham NMES + BFR groups. All participants received abductor hallucis NMES for 15 minutes. Participants in the NMES + BFR and Sham NMES + BFR groups received NMES with BFR. The intensity of NMES was the sensory threshold in the Sham NMES + BFR group. The cross-sectional area of the abductor hallucis was measured pretraining and posttraining using ultrasonography by a single investigator blinded to the participants' allocations. Results: After 15 minutes of training, the cross-sectional area of the abductor hallucis was significantly increased in the NMES + BFR (P<.001) and the Sham NMES + BFR (P = .004) groups. Moreover, the rate of increase was significantly higher in the NMES + BFR group than in the NMES or the Sham NMES + BFR groups (P<.001 and P = . 001, respectively). Conclusions: Since it is possible that the amount of muscle swelling immediately after training correlates with muscle hypertrophy when training is continued, the results of this study suggest that NMES training with BFR is a training method that can be expected to produce plantar intrinsic foot muscle hypertrophy. Further studies are needed to confirm the long-term effects of NMES training with BFR. [ABSTRACT FROM AUTHOR]

Purpose: To report the prevalence of early implant failure and evaluate factors that contribute to the early failure of dental implants placed at a teaching clinic. The study also aims to identify risk indicators for early implant loss to better predict and prevent early implant loss in the future. Materials and Methods: This retrospective study included all patients with a dental implant placed by the Section of Oral Surgery and Oral Medicine, Department of Clinical Dentistry, University of Bergen, between January 2011 and December 2018. All information was collected from operation logbooks and from patient records. A failed implant in this study was defined as an implant lost before functional loading. Results: A total of 1,005 dental implants were placed in the studied time period, of which 54 failed early, giving an early failure rate (EFR) of 5.4%, with functional loading obtained for the remaining 94.6%. Analysis showed an increased hazard for early implant failure among smokers, men, and younger patients. With an age increase of 10 years, the risk of implant failure was reduced by 14% (hazard ratio [HRR] = 0.86, P = .037). A higher failure rate was found in anterior maxillary implants than in posterior maxillary implants (7.79% vs 3.29%, respectively; HRR = 0.47; P = .041). The probability for early failure in the posterior mandible was significantly increased compared to the posterior maxilla (HRR = 3.68, P = .005). If the first implant failed, it was more likely that the consecutive implant would also fail (HRR = 1.82). In the study, 53.4% of the placed implants were Straumann (EFR = 5.2%), 30.3% were Nobel Biocare (EFR = 7.2%), and 16.3% were Astra Tech (EFR = 2.5%). Conclusions: This study found that younger, male, and smoker patients were associated with an increase in early failure of dental implants. Significantly increased failure rates were also seen for implants placed in the mandible, and there were differences with respect to implant system. Although differences were found in early failure both for patient- and implant-related factors, the overall early failure rate (5.4%) in this study was low. [ABSTRACT FROM AUTHOR]

Purpose: To assess the core temperature fluctuations during 10-km open-water swimming (OWS) in cool water and the relationship between thermal sensation (TS) after 10-km OWS, core temperature, and local skin thermal sensitivity. Methods: Nine highly trained OWS swimmers (4 female; age 22 [3] y) completed a single 10-km trial in cool water (22.3 °C) wearing swimsuits for OWS. During the trial, core temperature was continuously recorded via ingestible temperature sensors, and TS after trial was also measured. Then, local skin warm/cool sensitivity was measured in the forearm. Results: All swimmers completed the 10-km OWS. Mean swimming speed for males and females were 1.39 (1.37–1.42 m/s) and 1.33 m/s (1.29–1.38 m/s), respectively. Core temperature increased in 8 out of 9 swimmers during 10-km OWS (P =.047), with an average increase of 0.8 °C. TS after 10-km OWS varied among swimmers. There were no correlations between post-OWS TS and post-OWS core temperature (P =.9333), whereas there was a negative correlation between post-OWS TS and local skin cool sensitivity (P =.0056). Conclusion: These results suggest that core temperature in elite swimmers might not decrease during 10-km OWS in the cool water temperature of official OWS. In addition, individual differences in TS after 10-km OWS may be related to skin cool sensitivity rather than core temperature. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of a Nordic hamstring exercise intervention on biceps femoris long head, semitendinosus, and semimembranosus muscle's activity and relative contributions through multichannel electromyography. Twenty-four injury-free male basketball players (mean age 20 [3] y) were randomly assigned to a 12-week intervention (n = 13) or control group (n = 11). The primary outcome measures were normalized muscle activity (percentage of maximal voluntary isometric contraction, %MVIC) and relative contribution of hamstring muscles over 12 weeks. No effects were found on any of the primary outcome measures. Between-group differences over 12 weeks were 2.7%MVIC (95% confidence interval 95% CI, −0.7 to 6.1) for the biceps femoris long head, 3.4%MVIC (95% CI, −1.4 to 8.2) for the semitendinosus, and 0.8%MVIC (95% CI, −3.0 to 4.6) for the semimembranosus, P =.366. Between-group differences over 12 weeks were 1.0% relative contribution (%con; 95% CI, −3.0 to 5.1) for the biceps femoris long head, 2.2% relative contribution (95% CI, −2.8 to 7.2) for the semitendinosus, and −3.3% relative contribution (95% CI, −6.4 to −0.1) for the semimembranosus P =.258. A positive value implies a higher value for the Nordic group. A Nordic hamstring exercise intervention did not affect the level of muscle activity and relative contribution of hamstring muscles in performance of the Nordic hamstring exercise. [ABSTRACT FROM AUTHOR]

We aimed to examine exercise intensity among older adults participating from home in remotely delivered EnhanceFitness (Tele-EF). Exercise intensity was assessed through Fitbit-measured heart rate and the Borg 10-point rating of perceived exertion over 1 week of a 16-week exercise program. Outcomes included mean minutes spent at or above the heart rate reserve calculated threshold for moderate intensity and mean rating of perceived exertion. Pearson and Spearman rank correlations were used to examine associations between baseline characteristics with exercise intensity. During the 60-min classes, the 55 participants achieved moderate intensity for a mean of 21.0 min (SD = 13.5) and had a mean rating of perceived exertion of 4.9 (SD = 1.2). There were no significant associations between baseline characteristics and exercise intensity. Older adults can achieve sustained moderate-intensity exercise during Tele-EF supervised classes. Baseline physical function, physical activity, and other health characteristics did not limit ability to exercise at a moderate intensity, though further investigation is warranted. [ABSTRACT FROM AUTHOR]

Purpose: To determine the minimum number of events (training or matches) for producing valid acceleration–speed (AS) profiles from global navigation satellite system (GNSS) data. Methods: Nine elite female soccer players participated in a 4-week training camp consisting of 19 events. AS profile metrics calculated from different combinations of athlete events were compared to force–velocity (FV) profile metrics from 2 × 40-m stand-alone sprint effort trials, using the same GNSS 10-Hz technology. Force–velocity profiles were calculated, from which AS profiles were obtained. AS profiles from training and matches were generated by plotting acceleration and speed points and performing a regression through the maximal points to obtain the AS metrics (theoretical maximal speed, x-intercept [in meters per second], theoretical maximal acceleration, y-intercept [in meters per second squared], and the slope per second). A linear mixed model was performed with the AS metrics as the outcome variables, the number of events as a fixed effect, and the participant identifier as a mixed effect. Dunnett post hoc multiple comparisons were used to compare the means of each number of event grouping (1–19 events) to those estimated from the dedicated sprint test. Results: Theoretical maximal speed and theoretical maximal acceleration means were no longer significantly different from the isolated sprint reference with 9 to 19 (small to trivial differences = −0.31 to −0.04 m·s−1, P =.12–.99) and 6 to 19 (small differences = −0.4 to −0.28 m·s−2, P =.06–.79) events, and the slopes were no longer different with 1 to 19 events (trivial differences = 0.06–0.03 s−1, P =.35–.99). Conclusions: AS profiles can be estimated from a minimum of 9 days of tracking data. Future research should investigate methodology resulting in AS profiles estimated from fewer events. [ABSTRACT FROM AUTHOR]

Context: Single- and dual-task walking gait assessments have been used to identify persistent movement and cognitive dysfunction among athletes with concussions. However, it is unclear whether previous ankle sprain injuries confound these outcomes during baseline testing. The purpose of this study was to determine the effects of (1) ankle sprain history and (2) time since prior ankle sprain injury on single- and dual-task spatiotemporal gait outcomes and cognitive measures. Design: Cross- sectional study. Methods: We assessed 60 college Division-I athletes (31 with ankle sprain history; 13 females and 18 males, 19.3 [0.8] y; 29 with no ankle sprain history, 14 females and 15 males, 19.7 [0.9] y) who completed injury history forms and underwent concussion baseline testing. Athletes completed single- and dual-task gait assessments by walking back and forth along an 8-m walkway for 40 seconds. Athletes wore a smartphone with an associated mobile application on their lumbar spine to record spatiotemporal gait parameters and dual-task cognitive performance. Separate multivariate analyses of variance were used to assess the effects of ankle sprain injury history on spatiotemporal measures, gait variability, and cognitive performance. We performed a multivariate regression subanalysis on athletes who reported time since injury (n = 23) to assess temporal effects on gait and cognitive performance. Results: Athletes with and without a histoiy of ankle sprains had comparable spatiotemporal and gait variability outcomes during single- (P = .42; P = .13) and dual-task (P = .75; P = .55) conditions. Additionally, ankle sprain injury history did not significantly influence cognitive performance (P = .35). Finally, time since ankle sprain did not significantly affect single- (P = .75) and dual-task gait (P = .69), nor cognitive performance (P = 19). Conclusions: Ankle sprain injury history did not significantly alter spatiotemporal gait outcomes nor cognitive performance during this common clinical assessment. Future studies may consider including athletes with ankle sprain injury history during concussion assessments. [ABSTRACT FROM AUTHOR]

Context: An easy-to-administer, function-based questionnaire to assess patients with various foot problems was required for a Greek-speaking population. This study aimed to translate and cross-culturally adapt the Quick Foot and Ankle Ability Measure (Quick-FAAM) into Greek and evaluate its reliability and validity. Design: Cross-sectional study. Methods: Established international guidelines for the cross-cultural adaptation of questionnaires were followed. The face and content validity of the Greek version of the Quick-FAAM (Quick-FAAM-GR), as well as the internal consistency and test-retest reliability upon repeated administration after 5 days, were examined. In addition, the construct validity of the scale was examined via exploratory factor analysis as well as by testing for associations with the Manchester Foot Pain and Disability Index, the 12-item Short-Form Survey (version 2), and a functional balance assessment test--the Y-Balance Test. Results: Sixty participants (18 women) with self-reported chronic ankle instability symptoms, with a median (interquartile range) age of 27 (7.7) years, participated in the study. Half of the participants were included in the test-retest reliability study. The Quick-FAAM-GR demonstrated face and content validity. Excellent internal consistency (Cronbach a =.961) and intrarater test-retest reliability (intraclass correlation coefficient ICC[2,1] = .93) were demonstrated, with a comparable error margin to the original version (standard error of the measurement = 2.1, 95% minimum detectable change = 5.9). Associations of the Quick-FAAM-GR scores to other questionnaires ranged from weak to strong (Spearman rho), all being statistically significant (Manchester Foot Pain and Disability Index from -.26, P = .04, to -.67, P< .001, and 12-item Short-Form Survey, version 2, between .41 and .72, P<.001), and to the Y-Balance Test between lower-limb differences (-.35 to -.58, P< .001). The exploratory factor analysis confirmed the single- factor structure of this scale. No floor/ceiling effects were observed. Conclusions: The Greek Quick-FAAM has proven to be a valid and reliable tool for evaluating chronic ankle instability and can be used for clinical and research purposes in Greek- speaking individuals. [ABSTRACT FROM AUTHOR]

Purpose: To investigate differences in time to exhaustion (TTE), O2 uptake ( V ˙ O 2 ), and accumulated O2 deficit ( O 2 def ) between competitive and recreational cross-country (XC) skiers during an intermittent-interval protocol standardized for maximal aerobic power (MAP). Methods: Twelve competitive (maximal V ˙ O 2 [ V ˙ O 2 max ] = 76.5 ± 3.8 mL · kg − 1 · min − 1 ) and 10 recreational ( V ˙ O 2 max = 63.5 ± 6.3 mL · kg − 1 · min − 1 ) male XC skiers participated. All tests were performed on a rollerski treadmill in the V2 ski-skating technique. To quantify MAP and maximal accumulated oxygen deficit (MAOD), the skiers performed a steady-state submaximal test followed by a 1000-m time trial. After a 60-minute break, TTE, V ˙ O 2 , and accumulated O 2 def were measured during an intermittent-interval protocol (40-s work and 20-s recovery), which was individually tailored to 120% and 60% of each subject's MAP. Results: During the 1000-m time trial, the competitive skiers had 21% (95% CI, 12%–30%) shorter finish time and 24% (95% CI, 14%–34%) higher MAP (all P <.01) than the recreational skiers. No difference was observed in relative exercise intensity (average power/MAP; P =.28), MAOD (P =.18), or fractional utilization of V ˙ O 2 max. During the intermittent-interval protocol, the competitive skiers had 34% (95% CI, 3%–65%) longer TTE (P =.03) and accumulated 61% (95% CI, 27%–95%) more O 2 def (P =.001) than the recreational skiers during work phases. Conclusions: Competitive XC skiers have longer TTE and accumulate more O 2 def than recreational XC skiers during an intermittent-interval protocol at similar intensity relative to MAP. This implies that performance in intermittent endurance sports is related to the ability to repeatedly recharge fractions of MAOD. [ABSTRACT FROM AUTHOR]

Purpose: This study assessed physical activity (PA) and body composition of ambulatory children and adolescents with cerebral palsy (CP) and their typically developing peers. Methods: Participants included youth with CP (ages 8–18 y and Gross Motor Function Classification System [GMFCS] levels I–III) and their typically developing peers. Outcomes included PA (actigraphy) and fat/lean mass index (FMI/LMI; dual-energy X-ray absorptiometry). Statistical analyses included linear mixed effects models with Bonferroni adjustment. Fixed effects were study group (CP and typically developing); random effects were participant clusters (sex and age). Exploratory analyses included association of body composition and PA, GMFCS level, and CP involvement (unilateral and bilateral). Results: Seventy-eight participants (CP: n = 40, girls: n = 29; GMFCS I: n = 20; GMFCS II: n = 14; GMFCS III: n = 6) met inclusion criteria. Individuals with CP had lower moderate to vigorous PA (MVPA; β = −12.5; 98.3% confidence interval, −22.6 to −2.5 min; P =.004) and lower LMI (β = −1.1; 97.5% confidence interval, −2.1 to −0.0 kg/m2; P =.020). Exploratory analyses indicated increased LMI with greater MVPA (P =.001), reduced MVPA for GMFCS II (P =.005) and III (P =.001), increased sedentary time for GMFCS III (P =.006), and greater fat mass index with unilateral motor impairment (P =.026). Conclusions: The findings contribute to the knowledge base of increasing MVPA and LMI deficits with the greater functional impact of CP. Associations of increasing LMI with greater MVPA support efforts targeting enhanced PA participation to promote independent mobility. [ABSTRACT FROM AUTHOR]

This study explored the acute effects of different running intensities on cognitive and motor performances in individuals with intellectual disability (ID). An ID group (age, M = 15.25 years, SD = 2.76) and a control group without ID (age, M = 15.11 years, SD = 1.54) performed visual simple and choice reaction times, auditory simple reaction time, and finger tapping tests before and after running at low or moderate intensity (30% and 60% of heart rate reserve [HRR], respectively). Visual simple reaction time values decreased (p <.001) after both intensities at all time points with higher (p =.007) extend after the 60% HRR intensity for both groups. After both intensities, the VCRT decreased (p <.001) in the ID group at all time points compared with preexercise (Pre-EX) while, in the control group, these values decreased (p <.001) only immediately (IM-EX) and after 10 min (Post-10) of exercise cessation. Compared withs Pre-EX, in the ID group, the auditory simple reaction time values decreased (p <.001) at all time points after the 30% HHR intensity whereas, after the 60% HRR, these values decreased only at IM-EX (p <.001), Post-10 (p =.001) and Post-20 (p <.001). In the control group, auditory simple reaction time values decreased (p =.002) only after the 30% HRR intensity at IM-EX. The finger tapping test increased at IM-EX (p <.001) and at Post-20 (p =.001) compared to Pre-EX in both groups only after the 30% HHR intensity and for the dominant hand. The effect of physical exercise on cognitive performances in individuals with ID seems to depend on the cognitive test type as well as the exercise intensity. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to examine the effect of a 6-day basketball tournament on the physical demands, perceptual–physiological responses, well-being, and game statistics of elite under-18 (years of age) players. Methods: Physical demands (player load [PL], steps, impacts, and jumps, all normalized by playing time), perceptual–physiological responses (heart rate and rating of perceived exertion), well-being (Hooper index), and game statistics of 12 basketball players were monitored during 6 consecutive games. Linear mixed models and Cohen d effect sizes were used to assess differences among games. Results: Significant changes were found for PL per minute, steps per minute, impacts per minute, peak heart rate, and Hooper index over the tournament. Pairwise comparisons showed that PL per minute was higher in game #1 than in games #4 (P =.011, large), #5 (P <.001, very large), and #6 (P <.001, very large). PL per minute recorded during game #5 was also lower than in games #2 (P =.041, large) and #3 (P =.035, large). The number of steps per minute was higher in game #1 than in all other games (all P <.05, large to very large). Impacts per minute were significantly higher in game #3 than in games #1 (P =.035, large) and #2 (P =.004, large). The only physiological variable that varied significantly was peak heart rate (higher in game #3 than in game #6; P =.025, large). The Hooper index gradually increased throughout the tournament, indicating poorer player well-being as the tournament advanced. Game statistics did not significantly change among games. Conclusions: The average intensities of each game and the players' well-being gradually decreased throughout the tournament. Conversely, physiological responses were mostly unaffected, and game statistics were unaffected. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the survival rate (primary outcome) and the marginal bone loss (secondary outcome) of the OsseoSpeed EV Implants (Astra Tech Implant System, Dentsply Sirona Implants; hereinafter EV implants) used in a wide range of clinical scenarios and followed up to 8 years in a nonuniversity setting. Materials and Methods: All EV implants consecutively placed from 2013 to 2021 in a private dental clinic were included, and medical and radiologic records were retrospectively investigated. Independent reviewers collected 11 data types as potential influencing variables and measured the mesial and distal marginal bone levels to the nearest 0.5 mm on available radiographs, either panoramic or periapical. Tables of descriptive statistics were made at implant and patient levels. Univariate and multiple Cox regression models were adjusted for clustering effects and determined the hazard ratio (HR) and odds ratio (OR) for each independent variable collected. Results: The study sample consisted of 597 EV implants and 235 patients. During a mean follow-up of 42.1 ± 23 months (range: 10 to 94 months), 44 implants were lost (7.4%)--34 early (5.7%) and 10 late (1.7%)--in 38 patients (16.1%). The overall survival rate (SR) was 92.6% (CI: 90.5% to 94.7%), and the proportion of patients with all their implants surviving was 83.8% (CI: 79.1% to 88.5%). At the end of the study, the probability of survival of an implant that did not fail early was 98.2% (CI: 97.1% to 99.3%). Implant-level analysis identified two significant variables: implant diameter (HR 0.37, P = .009**) and immediate postextraction placement (HR 2.35, P = .025*). At the patient level, bruxism (OR = 3.29; P = .009**), history of periodontitis (OR = 2.18, P = .030*), and the number of implants placed (OR = 1.43; P = .001**) were found to be statistically significant. After removing dropouts and early failures from a sample of 528 implants, 412 (78%) had a marginal bone loss (MBL) = 0 mm at the end of the observation time, and 106 surviving implants (22%) showed a mean MBL of 1.42 ± 1.08 mm (range: 0.25 to 6.75 mm). Conclusions: An overall medium-term SR of the EV implants was 92.6%. Four of five EV implants showed a mid-term MBL = 0 mm, and 91.86% of implants completed the observation period with an MBL < 2 mm. Thus, the EV implant system was shown to be a valid alternative for routine use in a nonuniversity setting. Clinicians should remember that there is no 100% implant survival in everyday practice and that bruxism, periodontitis, narrow-diameter implants, and immediate placement are risk factors for a higher failure rate. [ABSTRACT FROM AUTHOR]

Purpose: To examine whether patient-level disease diagnoses, drug treatments, and dental clinical factors are correlates of early implant failure. Materials and Methods: This historical, nested case-control study used electronic medical records to retrieve patient-level data on individuals with implant failure occurring up to 6 months after implantation, including demographics, clinical information (number, location, and complicated status of implants), underlying diseases (osteoporosis, diabetes, hypertension, inflammatory bowel disease [IBD], myocardial infarction [MI]), and drug purchases (chemotherapy, bisphosphonates, selective serotonin inhibitors, antihypertensive medications, proton pump inhibitors [PPIs], disease-modifying antirheumatic drugs, corticosteroids, and nonsteroidal anti-inflammatory drugs) among adult members of a large, state-mandated health provider in Israel between 2015 and 2020. Individuals with implant extraction occurring up to 6 months after implantation were matched 1:1 to controls. Univariate and adjusted multivariate conditional logistic regression models were used to examine the odds ratios (ORs) of all dental implant risk factors among the patients. Results: A total of 585 individuals with implant failure (mean age, 53 years [42,62], 51.3% females and 49.7% males) were identified among 29,378 eligible patients. Compared to controls, patients who experienced implant failure (ie, cases) were more likely to have smoked in their lifetime (18% vs 11.5%, P = .009), experienced IBD (1.5% vs 0.02%, P = .059), and consumed PPIs within 6 months of the implant surgery (40.0% vs 32.5%, P = .028). Clinical factors, including the number of implants per person (individuals with two implants, OR = 1.53; individuals with at least four implants, OR = 3.33; P < .01), location of implant (maxilla; OR = 1.59; 95% CI: 1.2-2.04), and smoking (OR = 1.57; 95% CI: 1.09-2.26) were significant correlates of early implant failure among the included cases. Crohn's disease, MI, and osteoporosis were found to be borderline significant correlates of early dental implant failure. Conclusions: Among the factors examined, the number of implants, the location of implants, and smoking history were significant correlates of early implant failure, while Crohn's disease, MI, and osteoporosis were found to not be significant. Larger patient-level studies are needed to examine the individual and combined effects of diseases, medications, and clinical factors on early implant failure. [ABSTRACT FROM AUTHOR]

Purpose: The efficacy of isolated and relative performance indicators (PIs) has been compared in rugby union; the latter more effective at discerning match outcomes. However, this methodology has not been applied in women's rugby. The aim of this study was to identify PIs that maximize prediction accuracy of match outcome, from isolated and relative data sets, in women's rugby union. Methods: Twenty-six PIs were selected from 110 women's international rugby matches between 2017 and 2022 to form an isolated data set, with relative data sets determined by subtracting corresponding opposition PIs. Random forest classification was completed on both data sets, and feature selection and importance were used to simplify models and interpret key PIs. Models were used in prediction on the 2021 World Cup to evaluate performance on unseen data. Results: The isolated full model correctly classified 75% of outcomes (CI, 65%–82%), whereas the relative full model correctly classified 78% (CI, 69%–86%). Reduced respective models correctly classified 74% (CI, 65%–82%) and 76% (CI, 67%–84%). Reduced models correctly predicted 100% and 96% of outcomes for isolated and relative test data sets, respectively. No significant difference in accuracy was found between data sets. In the relative reduced model, meters made, clean breaks, missed tackles, lineouts lost, carries, and kicks from hand were significant. Conclusions: Increased relative meters made, clean breaks, carries, and kicks from hand and decreased relative missed tackles and lineouts lost were associated with success. This information can be utilized to inform physical and tactical preparation and direct physiological studies in women's rugby. [ABSTRACT FROM AUTHOR]

Purpose: This study sought to quantify the within-individual relationships between spatiotemporal variables and initial acceleration sprint performance in elite rugby backs and to establish a normative data set of relevant strength-based measures. Methods: First, the spatiotemporal variables, ratios of step length to step rate and of contact time to flight time, and initial acceleration performance were obtained from 35 elite male rugby backs (mean [SD] age 25 [3] y) over the first 4 steps of 3 sprints. Angular and linear kinematic aspects of technique and strength-based qualities were collected from 25 of these participants. Second, the same spatiotemporal variables were collected from 19 of the participants on 3 further occasions (12 trials in total) to determine the within-individual associations of these variables and initial acceleration performance. Results: Moderate to very large meaningful within-individual relationships (|r| =.43–.88) were found between spatiotemporal variables and initial acceleration performance in 17 of the 19 participants. From these relationships, a theoretically "desirable" change in whole-body kinematic strategy was individually determined for each participant, and normative strength-based measures to contextualize these were established. Conclusions: Meaningful within-individual relationships are evident between sprint spatiotemporal variables and initial acceleration performance in elite rugby backs. Individualized approaches are therefore necessary to understand how aspects of technique relate to initial acceleration performance. This study provides an objective, evidence-based approach for applied practitioners to identify the initial acceleration technical needs of individual rugby backs. [ABSTRACT FROM AUTHOR]

Context: Slideboards are commonly used in exercise programs, but there is limited information about how they affect muscle activities during exercise. We aim to compare the activation levels of quadriceps and hamstring muscles and hip- and knee-flexion angles during lunge and single-leg squat exercises between normal ground and slideboard in physically active individuals. Design: Cross-sectional study. Methods: Thirty healthy individuals (age: 23.83 [2.84] y, body mass index: 21.75 [1.72] kg/m2) were included in the study. Surface electromyography was used to measure vastus medialis, vastus lateralis, biceps femoris, and semitendinosus activation levels during reaching and returning phases of the forward, lateral, and back lunges and squats that were performed on the normal ground and slideboard. Exercises were performed at a slow pace (60 beats/min). Hip- and knee-flexion angles during the exercises were evaluated by using 2-dimensional motion analysis. Repeated measures of analysis of variance were used for statistical analysis. Results: Vastus medialis and vastus lateralis activation levels were greater during reaching and returning phases of the exercises on slideboard compared with normal ground (P <.05). However, semitendinosus and biceps femoris activity were greater only during the returning phase of the forward lunge (P <.001) and the returning phase of the back squat (P =.002, P =.009, respectively). Hip-to-knee flexion ratios were closer to 1 when the forward lunge (P <.001), back lunge (P =.004), and forward squat (P =.001) exercises were performed on a slideboard. Conclusion: In exercise programs that target the quadriceps and hamstring muscles, slideboards can be effectively used in exercise progressions as they can increase muscle activity. Moreover, squat and lunge exercises on slideboard with a slow pace may also be helpful for improving the balance between hip- and knee-flexion angles. [ABSTRACT FROM AUTHOR]

Purpose: Mental fatigue causes decreases in aspects of athletes' performance. Elite coaches commonly undertake cognitively demanding tasks and are seemingly at similar risk of subsequent performance impairment. However, elite sport coaches' experiences of mental fatigue, alongside other markers of psychobiological stress, have yet to be quantified. Methods: Three elite coaching and performance staff (2 women and 1 man) provided 100-mm visual analog scale ratings of mental fatigue, physical fatigue, readiness to perform, and salivary samples for later cortisol (sCort) and alpha-amylase (sAA) analysis. Data were obtained on the same morning each week across a 16-week preseason. Data were subset by individual coach for descriptive and repeated-measures correlational analyses. Results: Fluctuating mental fatigue was observed over the 16 weeks (min–max; coach 1 = 25–86 AU; coach 2 = 0–51 AU; and coach 3 = 15 − 76 AU). Elevated levels of mental fatigue were reported at multiple time points, with individual variability observed. sCort (in nanomoles per liter), sAA (in micromoles per liter), and sAA:sCort indicated that coaches experienced psychophysiological stress (min–max; coach 1 sCort = 8.42–17.31, sAA = 52.40–113.06, sAA:sCort = 3.20–12.80; coach 2 sCort = 4.20–9.70, sAA = 158.80–307.20, sAA:sCort = 21.10–61.70; and coach 3 sCort = 6.81−19.66, sAA = 86.55–495.85, sAA:sCort = 4.90–35.50). A significant inverse relationship between mental fatigue and readiness to perform (r = −.44 [−.64 to −.17], P =.002) was identified. Conclusions: Elite sport coaches report elevated instances of mental fatigue during a preseason training period. Those involved in elite sports should act to understand the presence and potential subsequent impacts of staff mental fatigue and consider management or mitigation strategies. Optimization of the cognitive performance of coaches and performance staff presents as a potential source of competitive advantage. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated the effects of 4 weeks of repeated sprint training (RST) versus repeated high-intensity technique training (RTT) on the physiological responses (ie, blood lactate), mean and peak heart rate, rating of perceived exertion, technical–tactical performance, and time–motion variables during simulated taekwondo combats. Methods: Twenty-four taekwondo athletes (18 male and 6 female; age: 16 [1] y) were randomly and equally assigned to RST (10 × 35-m running sprints interspersed by 10-s rest) or RTT (10 × 6-s bandal-tchagui kicking executions interspersed by 10-s rest) groups in addition to their regular training. Both groups performed simulated combats before and after training. Results: Delta lactate and peak heart rate were attenuated following training (P <.001 and P =.03, respectively), with no differences identified between RTT and RST conditions. Rating of perceived exertion decreased after training only in the RTT (P =.002). Time fighting and preparatory activities increased following training (P <.001), with higher values observed following RTT than RST (P <.001). Nonpreparatory time decreased after training (P <.001), with more pronounced reductions observed following RTT when compared to RST (P <.001). The number of single attacks decreased only following RST (P <.001), whereas combined attacks increased only after RTT training (P <.001). Conclusions: Similar adjustments in the physiological responses to combat were observed following 4 weeks of either RST or RTT, but RTT elicited more favorable perceptual responses and combat-related performance. This highlights the importance of specificity of training and its effective transfer to combat. [ABSTRACT FROM AUTHOR]

Context: Aberrant movement patterns among individuals with concussion history have been reported during sport-related movement. However, the acute postconcussion kinematic and kinetic biomechanical movement patterns during a rapid acceleration–deceleration task have not been profiled and leaves their progressive trajectory unknown. Our study aimed to examine single-leg hop stabilization kinematics and kinetics between concussed and healthy-matched controls acutely (≤7 d) and when asymptomatic (≤72 h of symptom resolution). Design: Prospective, cohort laboratory study. Methods: Ten concussed (60% male; 19.2 [0.9] y; 178.7 [14.0] cm; 71.3 [18.0] kg) and 10 matched controls (60% male; 19.5 [1.2] y; 176.1 [12.6] cm; 71.0 [17.0] kg) completed the single-leg hop stabilization task under single and dual task (subtracting by 6's or 7's) at both time points. Participants stood on a 30-cm tall box set 50% of their height behind force plates while in an athletic stance. A synchronized light was illuminated randomly, queuing participants to initiate the movement as rapidly as possible. Participants then jumped forward, landed on their nondominant leg, and were instructed to reach and maintain stabilization as fast as possible upon ground contact. We used 2 (group) × 2 (time) mixed-model analyses of variance to compare single-leg hop stabilization outcomes separately during single and dual task. Results: We observed a significant main group effect for single-task ankle plantarflexion moment, with greater normalized torque (mean difference = 0.03 N·m/body weight; P =.048, g = 1.18) for concussed individuals across time points. A significant interaction effect for single-task reaction time indicated that concussed individuals had slower performance acutely relative to asymptomatic (mean difference = 0.09 s; P =.015, g = 0.64), while control group performance was stable. No other main or interaction effects for single-leg hop stabilization task metrics were present during single and dual task (P ≥.051). Conclusions: Greater ankle plantarflexion torque coupled with slower reaction time may indicate stiff, conservative single-leg hop stabilization performance acutely following concussion. Our findings shed preliminary light on the recovery trajectories of biomechanical alterations following concussion and provide specific kinematic and kinetic focal points for future research. [ABSTRACT FROM AUTHOR]