KNOWLEDGE OF VESTIBULAR OCULAR DYSFUNCTION AND UTILIZATION OF VESTIBULAR OCULAR MOTOR SCREENING (VOMS) TOOL COMPONENTS AMONG PROFESSIONAL SPORTS LEAGUE ATHLETIC TRAINERS

Background:The Vestibular Ocular Motor Screen (VOMS) is a relatively new measurement tool intended for the non-vestibular practitioner to identify vestibular ocular dysfunction (VOD) following sport related concussion (SRC). Specific knowledge of VOD and usage of the VOMS among athletic trainers in professional sports leagues is currently unknown.Hypothesis/Purpose:The purpose of this study was to examine knowledge of VOD following SRC and utilization of the VOMS tool and other vestibular ocular tests and measures among athletic trainers in professional sports.Study Design:Cross Sectional StudyMethods:A total of 117 athletic trainers from Major League Baseball, the National Basketball Association, the National Football League and Major League Soccer, with a mean of 17 ± 9 years in the athletic training profession were surveyed via Qualtrics™ with a response rate of 33%. The survey contained three primary sub-sections; demographics, knowledge of vestibular ocular deficits following SRC, and VOMS component utilization at baseline, acute and return-to-play phases of management. Total knowledge scores as well as percentage of utilization based on concussion management stages were calculated.Results:The average percentage correct on the knowledge items was 56% (range of 30% to 65%). There was no difference in knowledge score among athletic trainers with formal post-professional concussion training (p = 0.29) compared to those with no formal training. There was no relationship found between total years practicing and total knowledge score, r = -.128, (p = 0.17). Smooth pursuit testing was the most commonly utilized (70%) in clinical practice and Visual Motion Sensitivity (VMS) was the least utilized (17%). Balance assessment measures to examine vestibular functioning remained the highest utilized examination technique at all-time points in management of SRC.Conclusion:The range of correct responses from 30% to 65% indicates that at the time of survey the participants had decreased knowledge of VOD following SRC. There was low overall utilization of all VOMS components despite recent evidence showing good sensitivity and low false positive rates in SRC. The results of this study identify an opportunity for future training specific to vestibular-ocular impairments and assessment following concussion injury.Level of Evidence:2c     

Effect of Concussion on Reaction Time and Neurocognitive Factors: Implications for Subsequent Lower Extremity Injury

BackgroundRecent evidence has demonstrated that athletes are at greater risk for a lower extremity injury following a return-to-sport (RTS) after sport-related concussion (SRC). The reason for this is not completely clear, but it has been hypothesized that persistent deficits in neurocognitive factors may be a contributing factor.Hypothesis/PurposeThis study assessed simple reaction time, processing speed, attention, and concentration in a group of athletes, post-concussion upon clearance for RTS for potential deficits that may result in slower reaction time, processing speed, attention, and concentration. The researchers hypothesized that the concussion group would demonstrate worse scores on both assessments compared to a sex-, age-, and sport-matched cohort.Study DesignCase-controlled studyMethodsTwelve participants who had suffered a SRC and eight healthy individuals who were matched to the concussed group by age, sex, and sport were evaluated. Those with a concussion had been cleared for RTS by a licensed healthcare provider. Each participant underwent neurocognitive tests that included a simple reaction time test (SRT) and the King-Devick Test (K-D). Independent t-tests were performed to compare the groups with significance set a priori at p<0.05.ResultsThere was a significant difference (p =0.024) between groups for SRT with the concussed group demonstrating a better SRT than the control group. There were no significant differences (p =0.939) between the groups for the K-D.ConclusionWith no significant differences between groups in the K-D assessment and, surprisingly, the concussed group having a better SRT compared to the healthy group, our hypothesis was not supported.Clinical RelevanceThese specific measures, compounded with extensive post-concussion time lapse until RTS clearance, may have limited capacity in revealing potential persistent deficits in relevant neurocognitive characteristics.Level of EvidenceLevel of Evidence 3     

Normative Data for the NeuroCom Sensory Organization Test in United States Military Academy Boxers

BackgroundBalance function is a key indicator in the identification of and recovery from concussion. The NeuroCom Sensory Organization Test (SOT) is used to objectively quantify balance using input from the visual, vestibular, and somatosensory systems. Baseline tests are necessary for comparison post-concussion.PurposeThe primary purpose of this study was to establish baseline SOT measures for the population that will be useful in the concussion assessment, diagnosis, and return to duty decisions following a concussion. Secondary aims were to compare females and males as well as concussed versus non-concussed. To the knowledge of the authors these are the only published normative data for a highly-active military population ages 17-23.Study DesignCross-sectional studyMethodsTwo hundred fifty-three (70 female and 183 male) cadets in a boxing course at a service academy were enrolled. The participants were evaluated on the SOT using the NeuroCom Balance Manager (Natus Medical Inc., Seattle, WA) and each condition, composite (COMP) score, and ratio score were recorded.ResultsNo significant differences were observed in SOT COMP scores between females (COMP = 76.67 ± 7.25) and males (COMP = 76.57 ± 7.77), nor between participants with history of concussion (COMP = 75.83 ± 7.90) versus those never concussed (COMP = 76.75 ± 7.57).ConclusionThis study provides SOT reference values for young, healthy, active individuals, which will assist in the interpretation of individual scores for concussion diagnosis and recovery, as well as serve as baseline data for future studies. These data on 17-23-year-olds will add to the currently available normative values of 14-15-year-olds and 20-59-year-olds.Level of Evidence4     

Injuries in Quidditch: A Prospective Study from a Complete UK Season

BackgroundQuidditch is a mixed-gender, full-contact sport founded in the USA in 2005, played worldwide by an estimated 25,000 players. It is one of the few mixed-gender full-contact sports, yet there remain few published studies regarding injury rates and patterns. A previous study suggested that the overall rate of injury in quidditch is in line with other contact sports, however raised concerns that female players were sustaining a higher rate of concussion when compared to male players.PurposeTo examine injury rates and injury patterns in UK quidditch athletes over the course of a single season.Study designProspective epidemiological studyMethodsData were prospectively collected by professional first aid staff for the 2017-18 season spanning all major UK tournaments, involving 699 athletes. Anonymized player demographics were collected by an online survey. Time loss injury rates were measured per 1000 athletic exposures (AEs) and hours of play.ResultsThe overall time loss injury rate was 20.5 per 1000 hours or 8.0 per 1000 AEs. The combined rate of concussion was 7.3 per 1000 hours or 2.8 per 1000 AEs. There was no statistical difference between time loss injuries in males (20.9/1000 hours and 8.1/1000 AEs) and females (13.9/1000 hours and 5.4/1000 AEs) (p=0.30) and no statistical difference between concussion rates in males (n=7) and females (n=4) (p=0.60).ConclusionsTotal time loss injury rates in quidditch appear to be comparable with other full-contact sports such as football. The rate of concussions for both males and females appear higher when compared to other contact sports.Level of evidence3     

Comparison of Rest to Aerobic Exercise and Placebo-like Treatment of Acute Sport-Related Concussion in Male and Female Adolescents

ObjectiveTo compare a sample of adolescents with sport-related concussion (SRC) who were prescribed rest with 2 arms of a randomized controlled trial comparing aerobic exercise with placebo-like stretching. We also compared sex differences across the 3 approaches to treatment.DesignQuasi-experimental trial.SettingUniversity concussion management clinics.ParticipantsAdolescent athletes (aged 13-18 years) presenting within 10 days of SRC (mean, 5 days after injury) received a recommendation for rest (rest group [RG], n=48, 15.4±1y, 25% female). Their outcomes were compared with matched samples of adolescents assigned to aerobic exercise (exercise group [EG], n=52, 15.3±2y, 46% female) or placebo-like stretching (placebo group [PG], n=51, 15.4±2y, 47% female) (N=151).Main Outcome MeasuresThe primary outcome was median days from injury to recovery. The secondary outcome was proportion classified as normal recovery (<30d) or delayed recovery (≥30d).ResultsThe RG recovered in 16 days (interquartile range, 9.25-23.25d), which was significantly delayed (P=.020) compared with EG (13d; interquartile range, 10-18.5d). The PG recovered in 17 days (interquartile range, 13-23d). Four percent of the EG, 14% of the PG, and 13% of the RG had delayed recovery (P=.190). There was no difference in recovery time or delayed recovery between male participants and female participants across groups. Female participants prescribed rest experienced an increase in symptoms vs the other groups (P=.013).ConclusionRelative rest and a placebo-like stretching program were very similar in days to recovery and symptom improvement pattern after SRC. Both conditions were less effective than subsymptom threshold aerobic exercise. Female adolescents appear to be susceptible to symptom increase when prescribed rest.     

Balance control in youth hockey players with and without a history of concussions during a lower limb reaching task

BackgroundSport-related concussion (SRC) is a functional injury that affects several clinical domains, including balance and cognition. The purpose of this study was, 1) to determine whether a lower limb visuomotor task could identify balance control differences between youth athletes with and without previous SRC; and 2) if balance is affected by training over time.MethodsYouth hockey players (n = 34) who reported previous SRC (CONCUSSED; n = 12; mean age = 14.4 yrs., SD = 1.6, mean time from injury = 1.9 yrs., median = 1.7 yrs. [0.6–4.6]) and no history of SRC (CONTROL; n = 22; mean age = 14.7, SD = 1.5) were tested twice over 70 days. Participants stood in single support on a Nintendo Wii Balance board sampled at 100 Hz and performed Go/No-Go tasks with each foot. Five FitLight Trainer™ (Aurora, ON) lights were arranged on the floor at 60°, 30°, and 0° and illuminated in random GREEN (Go) or RED (No-Go). Balance was assessed using root mean square displacement and velocity of CoP in anterior-posterior and medial-lateral directions.FindingsCONCUSSED had significantly lower velocity of CoP in the anterior-posterior (F_{(1, 32)} = 13.81, p < .001) and medial-lateral (F_{(1, 32)} = 13.80, p < .001) directions than CONTROL, with no learning effects over time (anterior-posterior: F_{(1, 32)} = 0.30, p = .137: F_{(1, 32)} = 0.91, p = .346; medial-lateral: F_{(1, 32)} = 0.91, p = .346). These findings suggest that CONCUSSED consistently performed the task more conservatively.InterpretationA lower limb Go/No-Go task may objectively identify differences between youth athletes with and without previous SRC. These visuomotor and balance control deficits may persist beyond clinical recovery.     

Depression and neurocognitive performance after concussion among male and female high school and collegiate athletes

Kontos AP, Covassin T, Elbin RJ, Parker T. Depression and neurocognitive performance after concussion among male and female high school and collegiate athletes.ObjectivesTo prospectively examine the relationship of sport-related concussion with depression and neurocognitive performance and symptoms among male and female high school and college athletes. A secondary objective was to explore age and sex differences.DesignPretest, multiple posttest, repeated-measures design.SettingLaboratory.ParticipantsHigh school and collegiate athletes (N=75) with a diagnosed concussion.InterventionsNot applicable.Main Outcome MeasuresBeck Depression Inventory-II and computerized neurocognitive test battery (Immediate Post-concussion Assessment and Cognitive Test), which includes concussion symptoms (Post-concussion Symptom Scale) at baseline and at 2, 7, and 14 days postinjury.ResultsConcussed athletes exhibited significantly higher levels of depression from baseline at 2 days (P≤.001), 7 days (P=.006), and 14 days postconcussion (P=.04). Collegiate athletes demonstrated a significant increase in depression at 14 days postconcussion than did high school athletes (P=.03). There were no sex differences in depression levels. Neurocognitive decrements at 14 days were supported for reaction time (P=.001) and visual memory (P=.001). Somatic depression at 7 days postconcussion was related to slower reaction time at 7 days postconcussion. Somatic depression at 14 days postinjury was related to lower visual memory scores at 14 days postinjury.ConclusionsAlthough not clinically significant, athletes experienced increased depression scores up to 14 days after concussion that coincided with neurocognitive decrements in reaction time and visual memory. Somatic depression appears to be most salient with regard to lower neurocognitive performance. Mood assessments after concussion are warranted to help monitor and enhance recovery.     

The Functional Assessment of Balance in Concussion (FAB-C) Battery

BackgroundThere is no clinical tool that assesses multiple components of postural control potentially impacted by sport-related concussion (SRC).ObjectiveTo develop and assess the feasibility and construct validity of the Functional Assessment of Balance in Concussion (FAB-C) battery.Study DesignCross-sectional study.MethodsTests for inclusion in the FAB-C battery were identified through a search of the literature. The feasibility and construct validity of the battery was assessed with a convenience sample of active individuals (13–24 years) with and without a SRC. Feasibility outcomes included battery completion (yes/no), number of adverse events, time to administer (minutes) and cost of the battery (Canadian Dollars). Construct validity was assessed by examining correlations between tests included in the battery, and describing differences [mean (standard deviation), median (range) or proportion] in outcomes between uninjured participants and participants with SRC.ResultsSeven tests were included in the FAB-C battery. All 40 uninjured participants [12 female; median age 17 years] completed the FAB-C assessment compared to 86% of seven participants with SRC [1 female; median age 17]. No participants demonstrated adverse effects. The median administration time of the battery was 49 minutes (range 44-60). The cost of the battery was low (~$100 Canadian Dollars). Limited correlations (r<0.7) between tests in the battery were observed. A greater percentage of uninjured participants (52% to 82%) passed individual tests in the battery compared to participants with SRC (17% to 66%).ConclusionAlthough promising, the FAB-C battery requires further evaluation before adoption for widespread clinical use.Level of EvidenceLevel 3b     

The Test Re-Test Reliability of A Novel Single Leg Hop Test (T-Drill Hop Test)

BackgroundFunctional training and testing are an important part of a comprehensive rehabilitation program stressing the neuromuscular system in ways that simulate athletic performance to help determine criteria for return to sport. There are numerous single leg hop tests that have been used for these purposes, however, the validity and clinical relevance has been questioned. Many of the functional performance tests assess only the sagittal plane or forward direction and may only partially assess a person’s athletic abilities. There is a need for reliable and valid functional tests to assess in a multi-directional manner.Purpose/HypothesisThe purpose of this study is to determine the test re-test reliability of a novel multi-directional timed single leg hop test (T-Drill Hop Test) for use in rehabilitation and performance assessments.Study DesignCross-sectional reliability study.MethodsFifty healthy recreationally active college age subjects, (23 males and 27 females) between the ages of 18 and 35, (mean age 23.48 with SD 3.82) consented to perform the test. The subjects hopped along a 10ft. x 10ft. “T” shaped course. Subjects performed two timed maximum effort trials of the T-Drill Hop Test on each leg with an interval of 3-7 days between the two testing days. Intraclass Correlation Coefficients (ICC) were calculated to determine intersession reliability.ResultsThe inter-rater reliability (ICC’s) for the entire group of 50 subjects ranged between .98 and 1.00 suggesting excellent reliability. The bilateral comparison, utilizing paired t-tests, of the T-Drill Hop Test demonstrated no significant differences between the time scores for the dominant and non-dominant legs for either males or females (p>.05).ConclusionThis study demonstrates the T-Drill Hop Test has excellent test re-test reliability. These results are important prior to validation and utilization as a clinical functional performance test.Levels of EvidenceLevel 2     

RELIABILITY OF CENTER OF PRESSURE-BASED MEASURES DURING DUAL-TASK POSTURAL CONTROL TESTING IN A YOUTH POPULATION

Background:Dual-task assessments can identify changes in postural control during recovery from a concussion. However, developing postural control in children presents a challenge when using adult balance assessments to examine children.Purpose:The purpose of this study was to investigate the reliability of a cognitive dual-task postural control testing protocol among a youth sample with no history of concussion or exposure to head impacts.Study Design:Reliability pilot study.Methods:Testing comprised nine 120 second trials of standing on a force plate collecting data at 250 Hz. Test conditions included no dual-task, counting backwards by 2, counting backwards by 3, listening, and the Stroop test. Subjects completed each test with open and closed eyes, except for the Stroop test. The force plate was used to measure the subjects’ center of pressure (COP) trajectory.Results:Nine healthy, youth subjects (average age: 11.6 ± 0.5 years) with no history of concussion or exposure to head impacts participated. Reliability was good (>0.6) or excellent (>0.75) for COP speed, sway, and sample entropy measures for several test conditions. The eyes open, no task condition produced the lowest COP measures. No differences were observed between the other dual-task conditions.Conclusion:Given its high measures of reliability, this dual-task protocol might be able to detect postural control changes in concussed youth athletes.Evidence Level:2     

Second time around: Corticospinal responses following repeated sports-related concussions within the same season. A transcranial magnetic stimulation study

ObjectiveTo investigate the degree of neurophysiological and cognitive performance changes resulting from repeat concussions sustained in a single season of Australian Rules football.MethodsThree amateur football players were recruited after sustainingtwo concussions during a single season of playing. Each player was assessed at multiple time points by transcranial magnetic stimulation (TMS) and electromyography, as well as tested for fine motor and cognitive performance after each concussion.ResultsIn all three cases, concussions resulted in reduction in fine dexterity and visuomotor reaction time, cognitive attention performance and increase in intracortical inhibition from TMS. No changes in performance or TMS outcomes were found as a result of the order of the concussions. However, changes observed were dependent on the severity of the concussion.ConclusionsThis multiple-case study has demonstrated that concussion result in increased intracortical inhibition and reduction in cognitive and motor performance. Further, TMS, in conjunction with tests of cognitive and motor performance, can be useful as a prognostic technique in assessing recovery from acute concussion injury.     

Neurocognitive measures predict voluntary stepping performance in older adults post-hip fracture

BackgroundHip fracture is a debilitating injury, especially in older adults. The purpose of this study was to determine the relationships between Trail-Making test performance and parameters of the choice stepping reaction time test in community-dwelling older adults after hip fracture.MethodsTwenty-four older adults post-hip fracture repair participated in an ancillary study for physical therapy interventions. Measures included Trail-Making test (Parts A & B) scores, movement time (time from foot liftoff to touchdown), step speed, reaction time (time from cue to foot liftoff), and total response time (time from step cue to touchdown) in the forward and lateral directions. Paired t-tests and multiple linear regressions were used for analysis.FindingsSignificant differences were found in movement time, speed and reaction time between limbs in the lateral direction, and in movement and reaction time in the forward direction. Trails A predicted step speed, reaction time and total response time for the fractured limb in the lateral direction, as well as reaction time and total response time in the forward direction. However, Trails A could not predict performance for the non-fractured limb. Trails B predicted stepping performance for both limbs in the forward and lateral directions.InterpretationTrails A correlated with the fractured limb's ability to perform the choice stepping test, but not in the non-fractured limb. Meanwhile, Trails B correlated with stepping performance in both limbs, suggesting those with poorer executive function have a lower protective stepping capability and may be at a higher risk for future falls and injury.     

External validation of prognostic models for recovery in patients with neck pain

BackgroundNeck pain is one of the leading causes of disability in most countries and it is likely to increase further. Numerous prognostic models for people with neck pain have been developed, few have been validated. In a recent systematic review, external validation of three promising models was advised before they can be used in clinical practice.ObjectiveThe purpose of this study was to externally validate three promising models that predict neck pain recovery in primary care.MethodsThis validation cohort consisted of 1311 patients with neck pain of any duration who were prospectively recruited and treated by 345 manual therapists in the Netherlands. Outcome measures were disability (Neck Disability Index) and recovery (Global Perceived Effect Scale) post-treatment and at 1-year follow-up. The assessed models were an Australian Whiplash-Associated Disorders (WAD) model (Amodel), a multicenter WAD model (Mmodel), and a Dutch non-specific neck pain model (Dmodel). Models’ discrimination and calibration were evaluated.ResultsThe Dmodel and Amodel discriminative performance (AUC < 0.70) and calibration measures (slope largely different from 1) were poor. The Mmodel could not be evaluated since several variables nor their proxies were available.ConclusionsExternal validation of promising prognostic models for neck pain recovery was not successful and their clinical use cannot be recommended. We advise clinicians to underpin their current clinical reasoning process with evidence-based individual prognostic factors for recovery. Further research on finding new prognostic factors and developing and validating models with up-to-date methodology is needed for recovery in patients with neck pain in primary care.     

Post-concussion symptoms in mild traumatic brain injury: findings from a paediatric outpatient clinic

Purpose Mild traumatic brain injury (mTBI) is common among children and is associated with a range of symptomatology and clinical presentations. This study uses data from a paediatric outpatient TBI clinic to (1) investigate characteristics associated with more severe post-concussive symptoms and (2) examine differences in the proportion of individuals endorsing specific post-concussion symptoms based on group (e.g., sex, type of injury, and psychiatric history). Methods Data from the Children’s Hospital of Richmond’s TBI outpatient programme were analysed (N?=?157). Results Gender and sports injury were associated with severity of symptoms. In addition, females endorsed a greater number of overall symptoms than males. A number of specific symptoms were found to be endorsed to a greater extent based on psychiatric history and type of injury; however, overall total number of symptoms endorsed did not differ based on these characteristics. Conclusions Findings from this study provide further evidence that mTBI affects a wide range of youth and that associated symptomatology can indeed be varied. Moreover, results revealed differences in endorsement of specific symptoms and symptom severity based on patient and injury characteristics which have implications for concussion assessment and treatment.

• Implications for Rehabilitation

• Symptoms following mild traumatic brain injury (mTBI) in children and adolescents can have varied presentation, ranging from minimal to severe.

• Females and those with non-sports-related injuries are more likely to endorse greater symptoms following concussion.

• Symptom evaluation is an essential component of the concussion assessment and treatment of paediatric patients following mTBI, and clinicians should be aware of patient characteristics associated with increased symptoms, especially when baseline symptom data are not available.

     

Sex-Related Discrepancies in the Access to Optimal Care and Outcomes After Traumatic Spinal Cord Injury: A Retrospective Cohort Study Using Data From a Canadian Registry

ObjectiveTo compare males and females who were stratified into subgroups corresponding to premenopausal, perimenopausal, and postmenopausal ages, regarding access to optimal care and their outcomes after traumatic spinal cord injury (tSCI).Study DesignRetrospective cohort study.SettingEighteen acute care centers and 13 rehabilitation facilities across Canada.ParticipantsThis study included 5571 individuals with tSCI at C1-L2 who were enrolled in the Rick Hansen Spinal Cord Injury Registry from July 2004 to September 2019 (N=5571). Females were compared with males in the younger (aged ≤40 years), middle-aged (ages 41-50), and older (aged >50 years) subgroups.InterventionNot applicable.Main Outcome MeasuresFemales were compared with males in each subgroup with regard to their demographic data, pre-existing comorbidities, injury characteristics, management choices, access to optimal care, and clinical, neurologic, and functional outcomes after tSCI.ResultsIn the younger subgroups, females (n=408) were significantly younger, had a greater proportion of aboriginals and transportation-related tSCIs, underwent surgical treatment more often, and had a greater sensory score change than males (n=1613). In the middle-aged subgroups, females (n=174) had a greater proportion of high-thoracic tSCIs than males (n=666). In the older subgroups, females (n=660) were significantly older, had more fall-related and less severe tSCIs, had a shorter stay at the rehabilitation center, had less spasticity, and were discharged home less often than males (n=2050).ConclusionsThe results of this study suggest some sex-related differences in individuals’ demographics and injury characteristics, but fewer discrepancies between females and males regarding their access to optimal care and outcomes after tSCI. Overall, future clinical trials could consider inclusion of males and females of all age groups to enhance recruitment and augment generalizability.     

Assessment of Sleep Quantity and Sleep Disturbances During Recovery From Sports-Related Concussion in Youth Athletes

Objective

To determine the relation between sleep quantity and sleep disturbances on symptoms and neurocognitive ability during the acute phase (<7d) and after sports-related concussion (SRC; >21d).

The lateral neck flexor endurance test: Normative values in the young adult population

BackgroundUnilateral muscular deficits have been identified in individuals with neck pain, although no unilateral clinical tests have been described in the literature. Assessment of lateral neck flexor endurance may allow identification of abnormal unilateral muscle function. The lateral neck flexor (LNF) endurance test, where an individual holds their head parallel to the ground while side-lying, may be a clinical option. We sought to (1) determine inter-rater reliability of the LNF endurance test and (2) establish normative LNF values in healthy individuals.MethodsInter-rater reliability was assessed for four raters, working in pairs to assess a pilot sample of 20 individuals. Normative data was subsequently collected for 60 healthy adults, age 20–40. All participants completed the International Physical Activity Questionnaire to assess physical activity and the LNF endurance test was assessed once per side.ResultsThe LNF endurance test demonstrated excellent inter-rater reliability: ICC_(2,1) = 0.972 [0.941–0.987]. Left and right median LNF hold times were 122.0, 133.94 s for males and 97.42, 93.73 s for females, respectively. Individual median hold time ratios were 72.1% for males and 68.7% for females. There were no meaningful correlations between reported physical activity and LNF endurance.ConclusionThe LNF endurance test is a reliable measure. Males generally displayed greater LNF endurance than females, although variability within groups was high. Based on the observed values in this healthy population, 120 s for males and 90 s for females with a 70% side:side ratio appear to be useful normative benchmarks although further research is required including clinical populations.