Carbon Fiber Insoles Enhance Perception of Performance Despite Variable Objective Outcomes: Specific to the Moderately Active Individual.

Carbon fiber insoles (CFIs) may benefit performance in elite athletes, however, their use in moderately active individuals has been adopted without evidence supporting such enhancements in this population. Fifteen male subjects performed vertical jump (VJ) and repeat treadmill sprint tests before and after a VO2peak while wearing 1) CFIs and 2) control insoles (CON). Subjects completed a subjective survey regarding their perceived performance abilities for both conditions. There were no significant differences between CFIs and CON in VJ height, sprint distance, heart rate following sprints; and rate of oxygen consumption, perceived fatigue, and perceived exertion at 85% of maximal speed (p > 0.05) during the VO2peak. At maximal speed, although there was no difference between conditions in peak rate of oxygen consumption (95%CI [-4.85, 0.21]) and respiratory exchange ratio (95%CI [-0.01, 0.03]), CFIs resulted in a reduced level of perceived fatigue (95%CI [-1, 0]) and perceived exertion (95%CI [-2, 0]) compared to CON. Subjects subjectively reported increased feelings of "propulsion or explosiveness" (p = 0.026) and being able to "perform better while jumping" (p = 0.029) while wearing CFIs. Heightened perceptions of performance enhancements when wearing CFIs indicate, in the moderately active, perceptual benefits could be more influential for determining CFI use.

Association of Dynamic Knee Valgus and Bone Stress Injury in US Military Academy Cadets.

CONTEXT: Early identification of incoming military personnel at elevated odds for bone stress injury (BSI) is important for the health and readiness of the US military. DESIGN: Prospective cohort study. METHODS: Knee kinematic data of the incoming US Military Academy cadets were collected while performing a jump-landing task (The Landing Error Scoring System) using a markerless motion capture system and depth camera. Data on incidence of lower-extremity injury, including BSI, were collected throughout the study period. RESULTS: A total of 1905 participants (452 females, 23.7%) were examined for knee valgus and BSI status. A total of 50 BSI occurred during the study period (incidence proportion = 2.6%). The unadjusted odds ratio for BSI at initial contact was 1.03 (95% confidence interval [CI], 0.94-1.14; P = .49). Adjusted for sex, the odds ratio for BSI at initial contact was 0.97 (95% CI, 0.87-1.06; P = .47). At the instant of maximum knee-flexion angle, the unadjusted odds ratio was 1.06 (95% CI, 1.02-1.10; P = .01), and the odds ratio was 1.02 (95% CI, 0.98-1.07; P = .29) after adjusting for sex. This suggests that there was not a significant enough association for an increase in the odds of BSI based on either degree of knee valgus. CONCLUSIONS: Our results did not demonstrate an association between knee valgus angle data during a jump-landing task and future increased odds of BSI in a military training population. Further analysis is warranted, but the results suggests the association between kinematics and BSI cannot be effectively screened by knee valgus angle data in isolation.

Strength Training Rehabilitation Incorporating Power Exercises (STRIPE) for individuals with patellofemoral pain: a randomised controlled trial protocol.

Patellofemoral pain (PFP) is a chronic condition that presents with patellar pain during various daily and recreational activities. Individuals with PFP have a wide range of impairments that result in long-term disability and reduced quality of life. Current interventions target hip muscle weakness with strength-based exercises, but recurrence rates are as high as 90%. A single feasibility study demonstrated success with power-based exercises; however, there is limited evidence evaluating pain or self-reported function in larger cohorts, and no study has assessed recurrence rates. This protocol details a study evaluating a strength-based rehabilitation programme compared with a strength-based programme incorporating power-based exercises in individuals with PFP. This single-blinded randomised controlled trial will evaluate 88 participants with PFP, aged 18-40 years old. Participants will be recruited from three universities, the surrounding community and sports medicine clinics. Participants will receive three telemedicine rehabilitation sessions a week for 6 weeks. The rehabilitation programme will consist of either strength-based exercises or a combination of power and strength-based exercises. Pain, subjective function and recurrence rates will be assessed at baseline, immediately after the intervention and at four follow-up time points: 6-month, 12-month, 18-month and 24-month postintervention. We will also assess neuromuscular function of the hips and global rating of change at each postintervention time point. Trial registration number NCT05403944.

Hybrid effectiveness-implementation study designs in sports injury prevention research.

Despite vast evidence supporting the effectiveness of lower extremity injury prevention programs in a variety of sport settings, age groups, and levels of competition, there is limited evidence on implementation strategies that positively impact the feasibility, scale-up and sustainability of such programs. Sport-related injury prevention is affected by the research-to-practice gap, a pervasive issue in healthcare, where high-quality experimental research is not used in routine clinical practice. An intervention shown to be efficacious in a controlled environment, such as a lab or in a field-study conducted by scientists, will demonstrate a decline in benefit when implemented in the intended clinical setting. Real-world considerations, such as foundational knowledge and training, time constraints, or end user motivation, influence the quality and consistency of implementation. Acknowledging and addressing implementation barriers in a systematic way is essential to promote effective program dissemination. Study design methods that measure both clinical effectiveness and implementation strategies need to be identified. Hybrid effectiveness-implementation designs simultaneously measure both an intervention's effect on clinical outcomes as well as critical information related to implementation strategy; however these study designs are not frequently utilized. The purpose of this mini-review is to describe: the basics of hybrid designs, rationale for using hybrid designs, and examples of how these designs could be used in athletic healthcare injury prevention research.

Using Predictive Modeling Technique to Assess Core Temperature Adaptations from Heart Rate, Sweat Rate, and Thermal Sensation in Heat Acclimatization and Heat Acclimation.

Assessing the adaptation of rectal temperature (Trec) is critical following heat acclimatization (HAz) and heat acclimation (HA) because it is associated with exercise performance and safety; however, more feasible and valid methods need to be identified. The purpose of this study was to predict adaptations in Trec from heart rate (HR), sweat rate (SR), and thermal sensation (TS) using predictive modeling techniques. Twenty-five male endurance athletes (age, 36 ± 12 y; VO2max, 57.5 ± 7.0 mL⋅kg-1⋅min-1) completed three trials consisting of 60 min running at 59.3 ± 1.7% vVO2max in a hot environment. During trials, the highest HR and TS, SR, and Trec at the end of trials were recorded. Following a baseline trial, participants performed HAz followed by a post-HAz trial and then completed five days HA, followed by a post-HA trial. A decision tree indicated cut-points of HR (<-13 bpm), SR (>0.3 L·h-1), and TS (≤-0.5) to predict lower Trec. When two or three variables met cut-points, the probability of accuracy of showing lower Trec was 95.7%. Greater adaptations in Trec were observed when two or three variables met cut-points (-0.71 ± 0.50 °C) compared to one (-0.13 ± 0.36 °C, p < 0.001) or zero (0.0 3 ± 0.38 °C, p < 0.001). Specificity was 0.96 when two or three variables met cut-points to predict lower Trec. These results suggest using heart rate, sweat rate, and thermal sensation adaptations to indicate that the adaptations in Trec is beneficial following heat adaptations, especially in field settings, as a practical and noninvasive method.

Barriers and facilitators to the adoption and implementation of evidence-based injury prevention training programmes: a narrative review.

While there is a multitude of evidence supporting the efficacy of injury prevention training programmes, the literature investigating the implementation of these programmes is, in contrast, rather limited. This narrative review sought to describe the commonly reported barriers and facilitators of the implementation of injury prevention training programmes among athletes in organised sport. We also aimed to identify necessary steps to promote the uptake and sustainable use of these programmes in non-elite athletic communities. We identified 24 publications that discussed implementing evidence-based injury prevention training programmes. Frequently reported barriers to implementation include the perceived time and financial cost of the programme, coaches lacking confidence in their ability to implement it, and the programme including exercises that were difficult or confusing to follow. Frequently reported facilitators to implementation include the coach being aware of programme efficacy, shared motivation to complete the programme from both coaches and athletes, and the ability to easily integrate the programme into practice schedules. The current literature is focused on high-income, high-resource settings. We recommend that future studies focus on understanding the best practices of programme dissemination in culturally and economically diverse regions. Programmes ought to be of no financial burden to the user, be simply adaptable to different sports and individual athletes and be available for use in easily accessible forms, such as in a mobile smartphone application.

Association Between Landing Error Scoring System (LESS) Items and the Incidence Rate of Lower Extremity Stress Fracture.

Background: Lower extremity stress fracture injuries are a major cause of morbidity in physically active populations. The ability to screen for modifiable risk factors associated with injury is critical in developing injury-prevention programs. Purpose: To determine if baseline Landing Error Scoring System (LESS) scores are associated with the incidence rate of lower extremity stress fracture. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 1772 participants with no history of lower extremity stress fracture were included. At preinjury baseline, the authors conducted a lower extremity movement assessment during a jump-landing task using the LESS. Incident lower extremity stress fractures were identified during a 4-year follow-up period. Potential incident cases were reviewed by 2 sports medicine fellowship-trained orthopaedic surgeons blinded to baseline LESS data. Univariate and multivariable Poisson regression models were used to estimate the association between baseline total LESS scores, individual LESS items, and the incidence rate ratio (IRR) of lower extremity stress fracture. Results: A total of 94 incident lower extremity stress fractures were documented, for a 5.3% (95% CI, 4.3%-6.5%) cumulative incidence. The overall LESS score was associated with the incidence rate of lower extremity stress fracture. For every additional movement error documented at baseline, there was a 15% increase in the incidence rate of lower extremity stress fracture (IRR, 1.15 [95% CI, 1.02-1.31]; P = .025). In univariate analyses, ankle flexion, stance width, asymmetrical landing, and trunk flexion at initial contact, in addition to overall impression, were associated with the incidence rate of stress fracture. After controlling for sex and year of entry into the study cohort, participants who consistently landed flat-footed or heel-to-toe were 2.33 times (95% CI, 1.36-3.97; P = .002) more likely to sustain a lower extremity stress fracture. Similarly, participants who consistently demonstrated asymmetric landing at initial contact were 2.53 times (95% CI, 1.34-4.74; P = .004) more likely to sustain a stress fracture. Conclusion: Components of the LESS may be associated with increased lower extremity stress fracture risk and may be helpful in efficiently assessing high-risk lower extremity biomechanics in large groups.

The relationship between single-limb squat and jump-cut kinematics.

No objective criteria exist for progressing athletes into cutting manoeuvres following ACL reconstruction (ACLR). The purpose of this study was to evaluate the relationship between a jump-cut task (JC) and the single-limb squat (SLS) in both ACLR and healthy controls. Case-control, laboratory based. Twenty-three participants with a history of ACLR (Age = 21 ± 3 years; Height = 174.5 ± 7.2 cm; Mass = 76.2 ± 9.9 kg) and 23 healthy controls participants (Age = 21 ± 3 years; Height = 173.8 ± 9.2 cm; Mass = 75.0 ± 10.5 kg) were included. Kinematics were collected bilaterally. Correlations between tasks were evaluated for kinematics. Independent sample t-tests were used to evaluate differences between groups for each dependent variable. Peak trunk rotation and medial knee displacement were strongly correlated (p < 0.001, r2 = 0.63), between tasks. ACLR group performed SLS and JC tasks with less sagittal plane motion compared to healthy controls (p < 0.05). Lack of frontal and transverse plane control during SLS resulted in positions of increased lateral trunk flexion, hip adduction, and medial knee displacement during JC. The SLS may be considered for use as a clinical predictor of JC during rehabilitation following ACLR.

Effects of Heat Acclimatization, Heat Acclimation, and Intermittent Exercise Heat Training on Time-Trial Performance.

BACKGROUND: The purpose of this study was to investigate effects of heat acclimatization (HAz) followed by heat acclimation (HA), and intermittent heat training (IHT) on time-trial performance. HYPOTHESIS: Time-trial performance will improve after HA and will further improve with twice a week of IHT. STUDY DESIGN: Interventional study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 26 male athletes (mean ± SD; age, 35 ± 12 years; body mass, 72.8 ± 8.9 kg; peak oxygen consumption [VO2peak], 57.3 ± 6.7 mL·kg-1·min-1) completed five 4-km time trials (baseline, post-HAz, post-HA, post-IHT4, post-IHT8) in the heat (ambient temperature, 35.4°C ± 0.3°C; relative humidity, 46.7% ± 1.2%) on a motorized treadmill. After baseline time trial, participants performed HAz (109 ± 10 days) followed by post-HAz time trial. Then, participants completed 5 days of HA, which involved exercising to induce hyperthermia (38.50°C-39.75°C) for 60 minutes. Participants were then divided into 3 groups and completed IHT either twice per week (IHTMAX), once per week (IHTMIN), or not at all (IHTCON) over an 8-week period. The exercise used for the IHT matched the HA. Four-kilometer time trials were performed after 4 weeks (post-IHT4) and 8 weeks of IHT (post-IHT8). RESULTS: Time trial was faster in post-HA (17.98 ± 2.51 minutes) compared with baseline (18.61 ± 3.06 minutes; P = 0.037) and post-HAz (18.66 ± 3.12 minutes; P = 0.023). Percentage change in time trial was faster in IHTMAX (-3.9% ± 5.2%) compared with IHTCON (11.5% ± 16.9%) (P = 0.020) and approached statistical significance with large effect (effect size = 0.96) compared with IHTMIN (1.6% ± 6.2%; P = 0.059) at post-IHT8. Additionally, IHTMAX (-2.2% ± 4.2%) was faster than IHTCON (3.6% ± 6.9%) (P = 0.05) at post-IHT4. CONCLUSION: These results indicate that HA after HAz induces additional improvement in time-trial performance. IHT twice per week shows improvement after 8 weeks, while once per week maintains performance for 8 weeks. No IHT results in a loss of adaptations after 4 weeks and even greater losses after 8 weeks. CLINICAL RELEVANCE: HA after HAz improves time-trial performance, twice a week of IHT improves performance further, and once a week of IHT maintains performance for at least 8 weeks.

Automated Landing Error Scoring System Performance and the Risk of Bone Stress Injury in Military Trainees.

CONTEXT: Lower extremity bone stress injuries (BSIs) place a significant burden on the health and readiness of the US Armed Forces. OBJECTIVE: To determine if preinjury baseline performance on an expanded and automated 22-item version of the Landing Error Scoring System (LESS-22) was associated with the incidence of BSIs in a military training population. DESIGN: Prospective cohort study. SETTING: US Military Academy at West Point, NY. PATIENTS OR OTHER PARTICIPANTS: A total of 2235 incoming cadets (510 females [22.8%]). MAIN OUTCOME MEASURE(S): Multivariable Poisson regression models were used to produce adjusted incidence rate ratios (IRRs) to quantify the association between preinjury LESS scores and BSI incidence rate during follow-up and were adjusted for pertinent risk factors. Risk factors were included as covariates in the final model if the 95% CI for the crude IRR did not contain 1.00. RESULTS: A total of 54 BSIs occurred during the study period, resulting in an overall incidence rate of 0.07 BSI per 1000 person-days (95% CI = 0.05, 0.09). The mean number of exposure days was 345.4 ± 61.12 (range = 3-368 days). The final model was adjusted for sex and body mass index and yielded an adjusted IRR for a LESS-22 score of 1.06 (95% CI = 1.002, 1.13; P = .04), indicating that each additional LESS error documented at baseline was associated with a 6.0% increase in the incidence rate of BSI during the follow-up period. In addition, 6 individual LESS-22 items, including 2 newly added items, were significantly associated with the BSI incidence. CONCLUSIONS: We provided evidence that performance on the expanded and automated version of the LESS was associated with the BSI incidence in a military training population. The automated LESS-22 may be a scalable solution for screening military training populations for BSI risk.

Preventive Training Program Feedback Complexity, Movement Control, and Performance in Youth Athletes.

CONTEXT: Preventive training programs (PTPs) reduce injury risk by improving movement control. Corrective feedback is important; however, many cues at once may be too complicated for athletes. OBJECTIVE: To compare movement control and long-jump (LJ) changes in youth athletes participating in a season-long PTP, with simplified feedback, traditional feedback, or a warmup of the coaches' choosing. DESIGN: Cluster-randomized controlled trial. SETTING: Soccer fields. PATIENTS OR OTHER PARTICIPANTS: A total of 420 athletes (simplified feedback = 173, traditional feedback = 118, and control = 129; age = 11 ± 3 years). INTERVENTION(S): Teams were randomized into the simplified PTP, traditional PTP, or control group. Simplified and traditional PTPs lasted 10 to 12 minutes and used the same exercises. The simplified PTP provided only sagittal-plane feedback (eg, "get low"), and the traditional PTP provided feedback targeting all motion planes (eg, "don't let your knees cave inward"). Research assistants administered the PTP warmups 2 to 3 times/week for the season. Control team coaches chose and ran their own warmup strategies. MAIN OUTCOME MEASURE(S): Participants completed 4 sessions (preseason [PRE], postseason [POST] at approximately 8 weeks after PRE, retention 1 [R1] at 6 weeks postseason, and retention 2 [R2] at 12 weeks postseason). They performed 3 trials of a jump-landing task, which was evaluated using the Landing Error Scoring System (LESS) and 2 recorded standing LJ trials at each test session. A time series panel was used to evaluate group differences across time points for the LESS and LJ. RESULTS: Change score analyses revealed improvements in the LESS score from PRE to POST for all groups. Improvements from PRE were retained at R1 and R2 for the intervention groups (simplified and traditional). The traditional group demonstrated better LJ performance at POST (P < .001) and R1 (P = .049) than the simplified or control group. CONCLUSIONS: Simplified cues were as effective as traditional cues in improving LESS scores from PRE to POST season. Participating in PTPs, regardless of their complexity, likely provides movement benefits.

Suppressed quadriceps fascicle behavior is present in the surgical limbs of those with a history of ACL reconstruction.

The balance of published data have largely focused on adaptations in muscle and fiber size after anterior cruciate ligament reconstruction (ACLR), failing to account for the dynamic changes in the behavior of the muscles' contractile elements that strongly contribute to force production. To better understand the sources of quadriceps dysfunction, the purpose of our research was to determine if alterations in fascicle behavior are present after ACLR. Unilateral ACLR individuals (9 m/9f; 21 ± 3 yrs; 1.74 ± 0.12 m;71.58 ± 13.31 kg; months from surgery:38 ± 36) and healthy controls (3 m/6f; 23 ± 2 yrs; 1.67 ± 0.10 m; 63.51 ± 10.11 kg) participated. In-vivo vastus lateralis fascicle behavior was recorded using ultrasonography during three maximal isokinetic knee extensions (60°·s-1). Fascicle length, angle, and shortening velocity were calculated and analyzed from rest to peak torque. Peak knee extension torque was averaged between isokinetic trials (Nm·kg-1). Group by limb interactions were assessed using separate two-way analyses of variance and were further evaluated by comparing 95% confidence intervals where appropriate. Significant interactions were present for fascicle angle at peak torque (P = 0.01), fascicle length excursion (P = 0.05), fascicle angle excursion (P < 0.01), fascicle shortening velocity (P = 0.05) and strength (P = 0.03). Upon post-hoc evaluation, the surgical limb displayed altered in-vivo fascicle behavior compared to all limbs (P < 0.05) and reduced strength compared to the contralateral and right control limbs (P < 0.05). No other significant interactions were present (P > 0.05). Our data show that those with a history of ACLR have fascicles that are slower, lengthen less and operate with lower angles relative to the axis of force production. Altered fascicle behavior after ACLR may be an important underlying factor to explaining the protracted quadriceps dysfunction.

Youth Perceptions of Sport-Confidence.

ABSTRACT: Zuk, EF, Maksymiw, K, Evanovich, J, McGarry, JE, Root, HJ, and Distefano, LJ. Youth perceptions in sport-confidence. J Strength Cond Res 35(11): 3232-3235, 2021-Sport-confidence is an important construct that is often missed during physical activity interventions in youth. Male and female children might display differences in sport-confidence that influences their activity levels. The purpose of this study is to assess any association between sport-confidence and gender in elementary school and middle-school children. All 286 children {(boys [ES: n = 71, age = 8±1 years; MS: n = 63, 11±1 years]; girls [ES: n = 67, 7±1 years; MS: n = 85, 11±1 years])} completed the Physical Literacy Assessment for Youth-Self Questionnaire. Separate chi-square tests of the association were used to evaluate the association between gender and sport-confidence among elementary (grades K-4) and middle-school (grades 5-8) children because of varying injury and participation rates for these groups, for each relevant question with a significance set at p ≤ 0.05. For elementary school children, there were no significant associations between genders and sport-confidence (p > 0.05). In middle-school children, there were significant associations detected for learning new skills (ϕ = 0.12; p = 0.031), perception of skill (ϕ = 0.12; p = 0.054), confidence in activity (ϕ = 0.17; p = 0.035), and being the best in the class (ϕ = 0.15; p = 0.048) between genders and sport-confidence. For all results, boys displayed more sport-confidence than girls. Education for key stakeholders about the importance of including sport-confidence in physical activity interventions is integral in promoting life-long activity, specifically in middle-school girls.

The Utilization of Core Exercises in Patients With Patellofemoral Pain: A Critically Appraised Topic.

Clinical Scenario: Patellofemoral pain (PFP) is characterized by general anterior knee pain around the patella and is one of the most prevalent knee conditions. PFP is challenging to treat due to a wide range of contributing factors and often has chronic, reoccurring symptoms. Traditional treatment focuses on quadriceps and gluteal strengthening with minimal emphasis on deep trunk musculature. Recently, there has been a growing body of literature supporting the beneficial effects of core stability exercises as a treatment option for PFP. Clinical Question: Are core stability exercises coupled with traditional rehabilitation more effective than only traditional rehabilitation techniques for decreasing pain in patients with PFP? Summary of Key Findings: Three articles met the inclusion criteria and investigated core strengthening exercises as a treatment for PFP. Two studies investigated a 4-week exercise protocol and demonstrated a greater decrease in pain when compared to the control group. The third study examined the effects of a 6-week program where both the intervention and control groups resulted in similar reduction of pain. All articles included received a minimum of 6 on the PEDro scale. Clinical Bottom Line: There is evidence that supports core stability exercise protocols coupled with traditional rehabilitation as being more effective in reducing pain in patients with PFP when compared to traditional rehabilitation alone. Strength of Recommendation: The grade of A is recommended based on the Strength of Recommendation Taxonomy.

Differences in Lower Extremity Movement Quality by Level of Sport Specialization in Cadets Entering a United States Service Academy.

BACKGROUND: Sport specialization in youth athletes is associated with increased risk for musculoskeletal injury; however, little is known about whether sport specialization is associated with lower extremity movement quality. The purpose of this study was to examine differences in lower extremity movement quality by level of sport specialization in US Service Academy cadets. HYPOTHESIS: Cadets who report an increased level of sport specialization would have a lower level of movement quality than those who are less specialized. STUDY DESIGN: Cross-sectional analysis from an ongoing prospective cohort study. LEVEL OF EVIDENCE: Level 3. METHODS: Cadets completed the Landing Error Scoring System (LESS) and a baseline questionnaire evaluating level of sport specialization during high school. Data were analyzed using separate 1-way analysis of variance models. RESULTS: Among all participants (n = 1950), 1045 (53.6%) reported low sport specialization, 600 (30.8%) reported moderate sport specialization, and 305 (15.6%) reported high sport specialization at the time of data collection during the first week. Ages ranged from 17 to 23 years. Men (1491) and women (459) reported comparable specialization levels (P = 0.45). There were no statistically significant differences in lower extremity movement quality by level of specialization for all subjects combined (P = 0.15) or when only men were included in the analyses (P = 0.69). However, there were statistically significant differences in movement quality by level of specialization in women (P = 0.02). Moderately specialized women had the best movement quality (mean, 4.63; SD, 2.21) followed by those with high specialization (mean, 4.90; SD, 2.08) and those with low levels of specialization (mean, 5.23; SD, 2.07). CONCLUSION: Women reporting moderate sport specialization had improved movement quality and significantly better LESS scores compared to those with high/low specialization. CLINICAL RELEVANCE: Athletes, especially women, should be encouraged to avoid early sport specialization to optimize movement quality, which may affect injury risk.

Movement Technique and Standing Balance After Graded Exercise-Induced Dehydration.

CONTEXT: Hypohydration has been shown to alter neuromuscular function. However, the longevity of these impairments remains unclear. OBJECTIVE: To examine the effects of graded exercise-induced dehydration on neuromuscular control 24 hours after exercise-induced hypohydration. DESIGN: Crossover study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 23 men (age = 21 ± 2 years, height = 179.8 ± 6.4 cm, mass = 75.24 ± 7.93 kg, maximal oxygen uptake [VO2max] = 51.7 ± 5.5 mL·kg-1·min-1, body fat = 14.2% ± 4.6%). INTERVENTION(S): Participants completed 3 randomized exercise trials: euhydrated arrival plus fluid replacement (EUR), euhydrated arrival plus no fluid (EUD), and hypohydrated arrival plus no fluid (HYD) in hot conditions (ambient temperature = 35.2°C ± 0.6°C, relative humidity = 31.3% ± 2.5%). Each trial consisted of 180 minutes of exercise (six 30-minute cycles: 8 minutes at 40% VO2max; 8 minutes, 60% VO2max; 8 minutes, 40% VO2max; 6 minutes, passive rest) followed by 60 minutes of passive recovery. MAIN OUTCOME MEASURE(S): We used the Landing Error Scoring System and Balance Error Scoring System (BESS) to measure movement technique and postural control at pre-exercise, postexercise and passive rest (POSTEX), and 24 hours postexercise (POST24). Differences were assessed using separate mixed-design (trial × time) repeated-measures analyses of variance. RESULTS: The magnitude of hypohydration at POSTEX was different among EUR, EUD, and HYD trials (0.2% ± 1%, 3.5% ± 1%, and 5% ± 0.9%, respectively; P < .05). We observed no differences in Landing Error Scoring System scores at pre-exercise (2.9 ± 1.6, 3.0 ± 2.1, 3.0 ± 2.0), POSTEX (3.3 ± 1.5, 3.0 ± 2.0, 3.1 ± 1.9), or POST24 (3.3 ± 1.9, 3.2 ± 1.4, 3.3 ± 1.6) among the EUD, EUR, and HYD trials, respectively (P = .90). Hydration status did not affect BESS scores (P = .11), but BESS scores at POSTEX (10.4 ± 1.1) were greater than at POST24 (7.7 ± 0.9; P = .03). CONCLUSIONS: Whereas exercise-induced dehydration up to 5% body mass did not impair movement technique or postural control 24 hours after a prolonged bout of exercise in a hot environment, postural control was impaired at 60 minutes after prolonged exercise in the heat. Consideration of the length of recovery time between bouts of exercise in hot environments is warranted.

Trends in movement quality in US Military Academy cadets 2005-17: A JUMP-ACL study.

OBJECTIVES: This study sought to determine if there were significant trends in lower extremity movement quality, as assessed by the Landing Error Scoring System (LESS) scores and plane-specific LESS subscales, across in 12 recent cohorts of incoming USMA cadets. DESIGN: prospective cohort study. SETTING: United States Military Academy. PARTICIPANTS: 7,591. MAIN OUTCOME MEASURES: Landing Error Scoring System (LESS) scores, adjusted for sex and ACL injury history. RESULTS: Statistically significant inverse trends were found between total LESS score and year (p < 0.01) and sagittal plane subscale and year (p < 0.01). A statistically significant direct trend was found for the frontal/transverse plane subscale and year (p < 0.01). However, each of these trends had a small associated effect size, and none were considered clinically meaningful. CONCLUSIONS: There were no meaningful changes in lower extremity movement quality in incoming US Military Academy cadets between 2005 and 2017.

Adoption of Lightning Safety Best-Practices Policies in the Secondary School Setting.

CONTEXT: Lightning-related injuries are among the top 10 causes of sport-related death at all levels of sport, including the nearly 8 million athletes participating in US secondary school sports. OBJECTIVE: To investigate the adoption of lightning safety policies and the factors that influence the development of comprehensive lightning safety policies in United States secondary schools. DESIGN: Cross-sectional study. SETTING: Secondary school. PATIENTS OR OTHER PARTICIPANTS: Athletic trainers (ATs). MAIN OUTCOME MEASURE(S): An online questionnaire was developed based on the "National Athletic Trainers' Association Position Statement: Lightning Safety for Athletics and Recreation" using a health behavior model, the precaution adoption process model, along with facilitators of and barriers to the current adoption of lightning-related policies and factors that influence the adoption of lightning policies. Precaution adoption process model stage (unaware for need, unaware if have, unengaged, undecided, decided not to act, decided to act, acting, maintaining) responses are presented as frequencies. Chi-square tests of associations and prevalence ratios with 95% CIs were calculated to compare respondents in higher and lower vulnerability states, based on data regarding lightning-related deaths. RESULTS: The response rate for this questionnaire was 13.43% (n = 365), with additional questionnaires completed via social media (n = 56). A majority of ATs reported maintaining (69%, n = 287) and acting (6.5%, n = 27) a comprehensive lightning safety policy. Approximately 1 in 4 ATs (25.1%, n = 106) described using flash to bang as an evacuation criterion. Athletic trainers practicing in more vulnerable states were more likely to adopt a lightning policy than those in less vulnerable states (57.4% versus 42.6%, prevalence ratio [95% CI] = 1.16 [1.03, 1.30]; P = .009). The most commonly cited facilitator and barrier were a requirement from a state high school athletics association and financial limitations, respectively. CONCLUSIONS: A majority of ATs related adopting (eg, maintaining and acting) the best practices for lightning safety. However, many ATs also indicated continued use of outdated methods (eg, flash to bang).

What Are Our Patients Really Telling Us? Psychological Constructs Associated With Patient-Reported Outcomes After Anterior Cruciate Ligament Reconstruction.

CONTEXT: Depressed patient-reported outcomes (PROs) are directly related to suboptimal recovery after anterior cruciate ligament reconstruction (ACLR). Various PROs commonly used after ACLR can provide a gross estimation of function but do not fully elucidate the causes of self-perceived disability. OBJECTIVE: To more fully characterize the factors driving responses on PROs. DESIGN: Cross-sectional study. A mixed-methods approach was used, in which qualitative interviews were conducted alongside administration of PROs to uncover the themes behind a participant's PRO responses. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-one individuals with unilateral ACLR (age = 20.90 ± 2.86 years, height = 172.0 ± 11.03 cm; mass = 71.52 ± 13.59 kg, postsurgery = 3.66 ± 3.03 years). MAIN OUTCOME MEASURE(S): Patient-reported outcome measures were administered and qualitative interviews were conducted. The PROs consisted of the International Knee Documentation Committee form, Knee Injury and Osteoarthritis Outcomes Score (KOOS), ACL-Return to Sport after Injury (ACL-RSI) scale, and Tampa Scale of Kinesiophobia (TSK). A hierarchical cluster analysis was used to identify subgroups based on PRO responses. Qualitative interviews provided supplemental insight into perceived disability. Independent t tests examined cluster differences for themes. Spearman ρ correlations indicated associations between PRO responses and themes. RESULTS: Two clusters (perceived high or low disability) emerged. Individuals with low perceived disability scored better on all PROs (P < .05) except for the KOOS-Activities of Daily Living. Internal and external facilitators or barrier subthemes emerged from the interviews. A significant difference was present between clusters and themes. Lower TSK andgreater ACL-RSI and KOOS-Quality of Life scores were associated with more perceived facilitators. CONCLUSIONS: Participants with greater internal motivation and confidence and a support network had improved PROs. Those with avoidance tendencies, fear, lack of clear expectations, and less social support scored worse on PROs. The TSK, ACL-RSI, and KOOS-Quality of Life scales were best able to capture the constructs associated with perceived wellness, which reinforces their utility in recovery.