Refinement of saliva microRNA biomarkers for sports-related concussion

Background:Recognizing sport-related concussion(SRC)is challenging and relies heavily on subjective symptom reports.An objective,biological marker could improve recognition and understanding of SRC.There is emerging evidence that salivary micro-ribonucleic acids(miRNAs)may serve as biomarkers of concussion;however,it remains unclear whether concussion-related miRNAs are impacted by exercise.We sought to determine whether40 miRNAs previously implicated in concussion pathophysiology were affected by participation in a variety of contact and non-contact sports.Our goal was to refine a miRNA-based tool capable of identifying athletes with SRC without the confounding effects of exercise.Methods:This case-control study harmonized data from concussed and non-concussed athletes recruited across 10 sites.Levels of salivary miRNAs within 455 samples from 314 individuals were measured with RNA sequencing.Within-subjects testing was used to identify and exclude miRNAs that changed with either(a)a single episode of exercise(166 samples from 83 individuals)or(b)season-long participation in contact sports(212 samples from 106 individuals).The miRNAs that were not impacted by exercise were interrogated for SRC diagnostic utility using logistic regression(172 samples from 75 concussed and 97 non-concussed individuals).Results:Two miRNAs(miR-532-5p and miR-182-5p)decreased(adjusted p<0.05)after a single episode of exercise,and 1 miRNA(miR-4510)increased only after contact sports participation.Twenty-three miRNAs changed at the end of a contact sports season.Two of these miRNAs(miR-26b-3p and miR-29c-3p)were associated(R>0.50;adjusted p<0.05)with the number of head impacts sustained in a single football practice.Among the 15 miRNAs not confounded by exercise or season-long contact sports participation,11 demonstrated a significant difference(adjusted p<0.05)between concussed and non-concussed participants,and 6 displayed moderate ability(area under curve>0.70)to identify concussion.A single ratio(miR-27a-5p/miR-30a-3p)displayed the highest accuracy(AUC=0.810,sensitivity=82.4%,specificity=73.3%)for differentiating concussed and non-concussed participants.Accuracy did not differ between participants with SRC and non-SRC(z=0.5,p=0.60).Conclusion:Salivary miRNA levels may accurately identify SRC when not confounded by exercise.Refinement of this approach in a large cohort of athletes could eventually lead to a non-invasive,sideline adjunct for SRC assessment.

Biomechanics of ankle giving way:A case report of accidental ankle giving way during the drop landing test

Background:Several case studies observed that the lateral ankle sprain resulted from a sudden increase in ankle inversion accompanied by internal rotation.However,without sufficient ankle kinetics and muscle activity information in the literature,the detailed mechanism of ankle sprain is still unrevealed.The purpose of our case report is to present 2 accidental ankle giving way incidents for participants with chronic ankle instability(CAI)and compare to their normal trials with data of kinematics,kinetics,and electromyography(EMG).Case description:Two young female participants accidentally experienced the ankle giving way when landing on a 25°lateral-tilted force plate.3 D kinematics,kinetics,and muscle activity were recorded for the lower extremity.Qualitative comparisons were made between the giving way trials and normal trials for joint angles,angular velocities,moments,centers of pressure and EMG linear envelopes.Results:One participant’s giving way trial displayed increased ankle inversion and internal rotation angles in the pre-landing phase and at initial contact compared to her normal trials.Another participant’s giving way trial exhibited greater hip abduction angles and delayed activation of the peroneus longus muscle in the pre-landing phase versus her normal trials.Conclusion:A vulnerable ankle position(i.e.,more inverted and internally rotated),and a late activation of peroneus activity in the pre-landing phase could result in the ankle giving way or even sprains.A neutral ankle position and early activation of ankle evertors before landing may be helpful in preventing ankle sprains.

Various performance-enhancing effects from the same intensity of whole-body vibration training

Purpose:The purpose of this study was to compare the effects of an 8-week whole-body vibration training program in various frequency and amplitude settings under the same acceleration on the strength and power of the knee extensors.Methods:Sixty-four young participants were randomly assigned to 1 of 4 groups with the same acceleration(4 g):high frequency and low amplitude(n = 16,32 Hz,1 mm) group,medium frequency and medium amplitude(n = 16,18 Hz,3 mm) group,low frequency and high amplitude(n = 16,3 Hz,114 mm) group,and control(n = 16,no vibration) group.All participants underwent 8 weeks of training with body mass dynamic squats,3 sessions a week.Results:The results showed that the high frequency and low amplitude group increased significantly in isometric contraction strength and 120°/s isokinetic concentric contraction strength;the medium frequency and medium amplitude group increased significantly in 60°/s and 120°/s isokinetic strength of both concentric and eccentric contraction;and the low frequency and high amplitude group increased significantly in 60°/s and 120°/s isokinetic eccentric contraction strength.Conclusion:All frequency and amplitude settings in the 8-week whole-body vibration training increased muscle strength,but different settings resulted in various neuromuscular adaptations despite the same intensity.

Assessment of scapulohumeral rhythm for scapular plane shoulder elevation using a modified digital inclinometer

AIM: To develop a better understanding of scapulohumeral rhythm during scapular plane shoulder elevation.METHODS: Thirteen healthy, college-aged subjects participated in this study. Subjects were free from any upper extremity, neck or back pathology. A modified digital inclinometer was utilized to measure scapular upward rotation of the subject's dominant shoulder. Upward rotation was measured statically as subjects performed clinically relevant amounts of shoulder elevation in the scapular plane. Testing order was randomized by arm position. Scapular upward rotation was assessed over the entire arc of motion and over a series of increments. The percent contributions to shoulder elevation for the scapula and glenohumeral joint were calculated. Scapulohumeral rhythm was assessed and represented the ratio of glenohumeral motion to scapulothoracic motion(glenohumeral elevation: scapular upward rotation). A one-way ANOVA wasused to compare scapular upward rotation between elevation increments.RESULTS: Scapulohumeral rhythm for the entire arc of shoulder elevation was equal to a ratio of 2.34 :1 and ranged from 40.01:1 to 0.90:1 when assessed across the different increments of humeral elevation. Total scapular motion increased over the arc of shoulder elevation. The scapula contributed 2.53% of total motion for the first 30 degrees of shoulder elevation, between 20.87% and 37.53% for 30o-90 o of shoulder elevation, and 52.73% for 90o-120 o of shoulder elevation. Statistically significant differences in scapular upward rotation were identified across the shoulder elevation increments [F(3,48) = 12.63, P = 0.0001].CONCLUSION: Clinically, we must recognize the usefulness of the inclinometer in documenting the variable nature of scapulohumeral rhythm in healthy and injured shoulders.

Use of clinical movement screening tests to predict injury in sport

Clinical movement screening tests are gaining popularity as a means to determine injury risk and to implement training programs to prevent sport injury. While these screens are being used readily in the clinical field, it is only recently that some of these have started to gain attention from a research perspective. This limits applicability and poses questions to the validity, and in some cases the reliability, of the clinical movement tests as they relate to injury prediction, intervention, and prevention. This editorial will review the following clinical movement screening tests: Functional Movement Screen?, Star Excursion Balance Test, Y Balance Test, Drop Jump Screening Test, Landing Error Scoring System, and the Tuck Jump Analysis in regards to test administration, reliability, validity, factors that affect test performance, intervention programs, and usefulness for injury prediction. It is important to review the aforementioned factors for each of these clinical screening tests as this may help clinicians interpret the current body of literature. While each of these screening tests were developed by clinicians based on what appears to be clinical practice, this paper brings to light that this is a need for collaboration between clinicians and researchers to ensure validity of clinically meaningful tests so that they are used appropriately in future clinical practice. Further, this editorial may help to identify where the research is lacking and, thus, drive future research questions in regards to applicability and appropriateness of clinical movement screening tools.

Dual-frequency whole body vibration enhances vertical jumping and change-of-direction ability in rugby players

Background:Traditional vertical and side-alternating whole body vibrations(WBV) can effectively improve muscle power performance but have a limited efficacy for enhancing change-of-direction(COD) ability.Novel dual-plate WBV uniquely providing various directions of movements with higher and distinctive frequencies for each leg may cause better acute effect on muscle power and stretch-shortening cycle efficacy contributing to COD ability.Therefore,the purpose of this study was to investigate the acute effect of dual-or single-frequency WBV on squat jumps(SJs),countermovement jumps(CMJs),eccentric utilization ratios(EURs),and COD ability in rugby players.Methods:Fourteen male rugby players were recruited and performed a 4 min partial squat with 3 types of WBV protocols on a dual-plate WBV machine,including 1 dual-frequency WBV protocol(DFW) with the dominant leg receiving 35 Hz and the non-dominant leg receiving 45 Hz,and2 single-frequency WBV protocols(SFWs) with 35 Hz or 45 Hz provided to both legs(SFW35Hz and SFW45Hz) on 3 different days.Results:The results showed that all the vibration protocols significantly improved SJ and CMJ performances(SJ:p = 0.008;CMJ:p < 0.001),but did not significantly change EURs(p > 0.05).In addition,only the DFW significantly improved COD ability(p = 0.001 for the pre–post comparison).Conclusion:A 4 min dual-frequency WBV session improved both vertical jumping and COD ability in rugby players,suggesting that this could be a potential warm-up protocol for athletes.

Cross-cultural adaptation and validation of an ankle instability questionnaire for use in Chinese-speaking population

Background:The Identification of Functional Ankle Instability(IdFAI)is a valid and reliable tool to identify chronic ankle instability;however,it was developed in English,thus limiting its usage only to those who can read and write in English.The objectives of our study were to(1)cross-culturally adapt a Chinese(Mandarin)version of the IdFAI and(2)determine the psychometric properties of the Chinese version IdFAI.Methods:The cross-cultural adaptation procedures used by the investigators and translators followed previously published guidelines and included 6 stages:(1)initial translation,(2)synthesis of the translations,(3)back translation,(4)developing the pre-final version for field testing,(5)testing the pre-final version,and(6)finalizing the Chinese version of IdFAI(IdFAI-C).Five psychometric properties of the IdFAI-C were assessed from results of 2 participant groups:bilingual(n=20)and Chinese(n=625).Results:A high degree of agreement was found between the English version of IdFAI and IdFAI-C(intra-class correlation_(2,1)=0.995).An excellent internal consistency(Cronbach'sα=0.89),test—retest reliability(intra-class correlation_(2,1)=0.970),and construct validity(r(625)=0.67)was also found for the IdFAI-C.In addition,the results of exploratory and confirmatory factor analysis indicated that ankle instability was the only construct measured from the IdFAI.Conclusion:The IdFAI-C is a highly reliable and valid self-report questionnaire that can be used to assess ankle instability.Therefore,we suggest that it can be used to effectively and accurately assess chronic ankle instability in clinical settings for Chinese-speaking individuals.

Critical assessment of a wide-spread method for estimating energy expenditure during accelerated running based on positioning tracking systems

1.Introduction An innovative method for estimating energy cost is to consider accelerated/decelerated running on flat terrain metabolically equivalent to uphill/downhill running at constant speed. In this method,the authors estimated an acceleration-dependent body slope.That slope corresponded to a given terrain slope during constant speed running,for which energy costs were known. Then they used accelerations(transformed into equivalent slopes)in a previously reported regression equation for energy cost estimation during uphill and downhill running at constant speed. This method allows researchers to estimate energy cost via player accelerations,thus making energy estimations feasible in team sports matches.

Observations regarding open access publishing in hybrid journals in sport sciences

Hybrid journals are journals that provide both of 2 common publication options:(a)the traditional approach,where either institutions pay for a subscription or readers purchase individual articles(free of charge for the submitting author);and(b)open access,where articles are accessible without a subscription and free of charge for the reader(the submitting author typically pays an article processing charge).Hybrid journals earn a fixed amount of money from subscriptions,and they earn additional income from the article processing charges associated with their open access option.A hybrid journal can increase its income by publishing a greater number of open access articles.

Corticospinal activity during a single-leg stance in people with chronic ankle instability

Purpose:The aim of the study was to determine whether corticospinal excitability and inhibition of the tibialis anterior during single-leg standing differs among individuals with chronic ankle instability(CAI),lateral ankle sprain copers,and healthy controls.Methods:Twenty-three participants with CAI,23 lateral ankle sprain copers,and 24 healthy control participants volunteered.Active motor threshold(AMT),normalized motor-evoked potential(MEP),and cortical silent period(CSP)were evaluated by transcranial magnetic stimulation while participants performed a single-leg standing task.Results:Participants with CAI had significantly longer CSP at 100%of AMT and lower normalized MEP at 120%of AMT compared to lateral ankle sprain copers(CSP100%:p=0.003;MEP120%:p=0.044)and controls(CSP100%:p=0.041;MEP120%:p=0.006).Conclusion:This investigation demonstrate altered corticospinal excitability and inhibition of the tibialis anterior during single-leg standing in participants with CAI.Further research is needed to examine the effects of corticospinal maladaptations to motor control of the tibial anterior on postural control performance in those with CAI.

Collecting shoulder kinematics with electromagnetic tracking systems and digital inclinometers: A review

The shoulder complex presents unique challenges for measuring motion as the scapula,unlike any other bony segment in the body,glides and rotates underneath layers of soft tissue and skin.The ability for clinicians and researchers to collect meaningful kinematic data is dependent on the reliability and validity of the instrumentation utilized.The aim of this study was to review the relevant literature pertaining to the reliability and validity of electromagnetic tracking systems(ETS) and digital inclinometers for assessing shoulder complex motion.Advances in technology have led to the development of biomechanical instrumentation,like ETS,that allow for the collection of threedimensional kinematic data.The existing evidence has demonstrated that ETS are reliable and valid instruments for collecting static and dynamic kinematic data of the shoulder complex.Similarly,digital inclinometers have become increasingly popular among clinicians due to their cost effectiveness and practical use in the clinical setting.The existing evidence supports the use of digital inclinometers for the collection of shoulder complex kinematics as these instruments have been demonstrated to yield acceptable reliability and validity.While digital inclinometers pose a disadvantage to ETS regarding accuracy,precision,and are limited to twodimensional and static measurements,this instrument provides clinically meaningful data that allow clinicians and researchers the ability to measure,monitor,and compare shoulder complex kinematics.