The efficacy of injury screening for lower back pain in elite golfers.

Background: Injury prevention is a growing focus for golfers in general and for elite golfers in particular. Movement screening has been proposed as a possible cost-effective means of identifying underlying risk factors and is widely utilised by therapists, trainers and coaches. Objectives: Our study aimed to establish whether results from movement screening were associated with subsequent lower back injury in elite golfers. Methods: Our prospective longitudinal cohort study with one baseline time point included 41 injury-free young elite male golfers who underwent movement screening. After this, the golfers were monitored for 6 months for lower back pain. Results: Seventeen golfers developed lower back pain (41%). Screening tests that were able to differentiate golfers who developed and those who did not develop lower back pain, included: rotational stability test on the non-dominant side (p = 0.01, effect size = 0.27), rotational stability test on the dominant side (p = 0.03; effect size = 0.29) and plank score (p = 0.03; effect size = 0.24). There were no differences observed in any other screening tests. Conclusion: Out of 30 screening tests, only three tests were able to identify golfers not at risk of developing lower back pain. All three of these tests had weak effect sizes. Clinical implications: Movement screening was not effective in identifying elite golfers at risk of lower back pain in our study.

Lower Quadrant Swing Biomechanics Identifies Golfers With Increased Risk of Low Back Pain: A Prospective Longitudinal Cohort Study.

CONTEXT: Elite golfers have a high incidence of low back pain. Recent reviews have emphasized the need for investigation into how to prevent low back pain in golfers, prompting the current study. DESIGN: Prospective longitudinal cohort study. METHODS: Forty-one injury-free golfers were included in this study. At baseline, lower quadrant joint angles and club and ball performance were measured while each golfer performed 10 drives. The golfers were then monitored for 6 months and were allocated into 2 groups depending on whether or not they developed low back pain. The initial, baseline kinematic variables of the low back pain group and the uninjured group were then compared. RESULTS: Over the 6-month monitoring period, 17 (41%) of the golfers developed low back pain. At baseline assessment, the low back pain group had 4° less lead ankle dorsiflexion at setup (P = .01; effect size = 0.82), 6° less lead knee flexion at the top of the backswing (P = .05; effect size = 0.64), 6° less lead ankle dorsiflexion at the top of the backswing (P = .01; effect size = 0.82), 6° more trail hip adduction at the top of the backswing (P = .02; effect size = 0.79), 9° more trail knee flexion at impact (P = .05; effect size = -0.64), and 6° more trail hip adduction at the end of follow through (P < .00; effect size = 1.00). CONCLUSION: Golfers who developed low back pain during the 6-month monitoring period displayed distinct differences in biomechanics at baseline when all golfers were injury free. These biomechanical differences may be considered a precursor to injury. Three-dimensional motion analysis may indicate whether elite golfers are at risk of developing low back pain. Research is needed to assess whether targeted exercise and sports drills aimed at addressing the biomechanical risk factors identified may prevent low back pain in elite golfers.

Increased trunk muscle recruitment during the golf swing is linked to developing lower back pain: A prospective longitudinal cohort study.

BACKGROUND: This is the first study that presents electromyographic measurements prior to the development of lower back pain in young elite golfers. STUDY DESIGN: Prospective longitudinal cohort study. METHODS: Thirty-three injury free elite golfers were included. Muscle activity from latissimus dorsi, rectus abdominis, external oblique and erector spinae muscles were recorded during 10 drive golf swings. Lower back pain, training and performance were monitored over a six-month period. Muscle activation comparisons were made between the baseline results of those who went on to develop lower back pain versus those who did not go on to develop lower back pain. RESULTS: After the six-month monitoring period 17 participants developed lower back pain. The group that developed lower back pain had increased dominant rectus abdominis and dominant latissimus dorsi activation at various time points throughout the swing. DISCUSSION: The increased dominant rectus abdominis and dominant latissimus dorsi during the golf swing is linked with developing lower back pain. Training strategies aimed at reducing these muscles activation during the swing may reduce the incidence of lower back pain in young elite male golfers.

Restless legs syndrome: Clinical changes in nervous system excitability at the spinal cord level.

Restless legs syndrome (RLS) is a complex multifactorial disorder whose aetiology has yet to be fully elucidated. Some of the features of RLS, such as processing of sensations and activation of movement, may result from a dysfunction in spinal processing giving rise to a state of spinal hyperexcitability. In the current article we review studies investigating spinal excitability in RLS patients looking specifically at electrophysiological studies of spinal activity, sensory evaluations, and spinal reflex studies. Increased spinal excitability has been shown in RLS patients based on the combined data from electrophysiological studies. Results from studies assessing sensory evaluations in RLS patients show enhanced spinal processing of nociceptive inputs possibly due to central sensitisation. However, not all sensory modalities demonstrate an increase in sensitivity. An increase in nervous system excitability would result in an increase in reflex responses in RLS patients however the data from reflex analyses in RLS patients has failed to consistently show this expected result. Overall changes to RLS spinal excitability have been demonstrated though these changes might be heterogeneous as not all afferent input appears to be affected in the same manner. There may be phase-dependent and modality-dependent alterations in spinal excitability suggesting that the theory of absolute spinal hyperexcitability in RLS patients' needs to be reconsidered.

Characterization of painful Restless Legs Syndrome sensations in an English-speaking South African population.

Background and aims Restless Legs Syndrome (RLS) is characterised by unusual sensations in the legs which can be described as painful in up to 60% of RLS patients. The purpose of this study was to characterise and examine whether the presence of pain influenced the words used to describe the sensations of RLS in an English speaking population. Methods RLS participants (n=55) were divided according to whether or not painful RLS sensations were reported upon questioning. They completed the McGill Pain Questionnaire (MPQ), the International Restless Legs Syndrome Severity Scale (IRLS) and selected descriptors from a list of previously published RLS terms. Results Thirty-five percent of the RLS patients had painful sensations. The participants with painful RLS had higher Pain Rating Index (PRI) scores [median (interquartile range) 21 (17-28) vs. 14 (7.5-21) p=0.0008] and IRLS scores [23 (17-28) vs. 18 (11.5-22.5) p=0.0175] than the participants with non-painful RLS. Patients with painful RLS symptoms selected more pain-related literature terms, chose significantly different words in eight of the MPQ subclasses (both sensory and affective) and selected more intense descriptors from certain MPQ subclasses than the non-painful RLS group. The terms that characterised painful RLS were "aching", "painful", "cramping" and "unbearable". Conclusions Descriptors of RLS sensations are changed by the presence of pain, which may indicate an aetiological difference in the patients who have painful RLS. Clinically, patients complaining of cramping and painful sensations may be diagnosed with a condition that mimics RLS. Thus, it is important that the most accurate set of descriptors for RLS are used to enable recognition of RLS and optimised treatment according to the RLS phenotype. Implications The diagnosis of RLS may be improved by overcoming language and cultural barriers and obtaining differential diagnostic terms for painful conditions mimicking RLS.

Distal muscle activity alterations during the stance phase of gait in restless leg syndrome (RLS) patients.

OBJECTIVE: To assess if there is a circadian variation in electromyographical (EMG) muscle activity during gait in restless legs syndrome (RLS) patients and healthy control participants. METHODS: Gait assessment was done in 14 RLS patients and 13 healthy control participants in the evening (PM) and the morning (AM). Muscle activity was recorded bilaterally from the tibialis anterior (TA), lateral gastrocnemius (GL), rectus femoris (RF) and biceps femoris (BF) muscles. RESULTS: A circadian variation during the stance phase in only TA (PM > AM, p < 0.005) and BF (PM < AM, p = 0.008) activity was observed in control participants. Conversely no circadian variation was seen in any muscles in the RLS patients. RLS patients had an increased TA and GL activity (RLS > Controls, p < 0.05) during early stance and decreased GL activity (RLS < Controls, p < 0.01) during terminal stance in comparison to control participants in the evening. No other significant differences were noted between RLS patients and control participants. Activation of GL during the swing phase was noted in 79% of RLS patients and in 23% of control participants in the morning compared to 71% and 38% in the evening, respectively. CONCLUSION: EMG muscle activity shows no circadian variation in RLS patients. Evening differences in gait muscle activation patterns between RLS patients and control participants are evident. These results extend our knowledge about alterations in spinal processing during gait in RLS. A possible explanation for these findings is central pattern generator sensitization caused by increased sensitivity in cutaneous afferents in RLS patients.

Circadian variation of flexor withdrawal and crossed extensor reflexes in patients with restless legs syndrome.

An evening state of spinal hyperexcitability has been proposed to be a possible cause of evening increases in restless legs syndrome symptoms. Thus, the objective of the current study was to assess the circadian variation in spinal excitability in patients with restless legs syndrome based on flexor withdrawal reflex and crossed extensor reflex responses. The reflexes were elicited on 12 participants with restless legs syndrome and 12 healthy control participants in the evening (PM) and the morning (AM). Reflex response magnitudes were measured electromyographically and kinematically. Both the reflexes showed a circadian rhythm in participants with restless legs syndrome but not in control participants. Changes in ankle (median flexor withdrawal reflex PM: 16.0 ° versus AM: 2.8 °, P = 0.042; crossed extensor reflex PM: 0.8 ° versus AM: 0.2 °, P = 0.001) angle were significantly larger, and ankle angular velocity (median flexor withdrawal reflex PM: 38.8 ° s-1 versus AM: 13.9 ° s-1 , P = 0.049; crossed extensor reflex PM: 2.4 ° s-1 versus AM: 0.5 ° s-1 , P = 0.002) was significantly faster in the evening compared with the morning in participants with restless legs syndrome, for both reflexes. For participants with restless legs syndrome, evening change in hallux angle was significantly larger than morning responses (median PM: 5.0 ° versus AM: 1.3 °, P = 0.012). No significant differences for any of the electromyographic or kinematic variables were observed between participants with restless legs syndrome and controls. The flexor withdrawal reflex and the crossed extensor reflex show a circadian rhythm in participants with restless legs syndrome suggesting an evening increase in spinal excitability. We hypothesize the circadian variation in spinal excitability may be due to a possible nocturnal form of afferent circuitry central sensitization in the dorsal horn of the spinal cord in patients with restless legs syndrome.

Plantar reflex excitability is increased in the evening in restless legs syndrome patients.

OBJECTIVE: To investigate if diurnal changes in spinal excitability (plantar reflex) occur in restless legs syndrome (RLS) participants compared to healthy matched controls. METHODS: Thirteen RLS participants and 13 healthy control participants' plantar reflex responses were evaluated in the evening (PM) and the morning (AM). Plantar reflex responses were assessed electromyographically, using motion analysis (kinematically) and by subjective nociception (Visual Analogue Scale). RESULTS: RLS participants showed a circadian variation in plantar reflex responses whilst control participants did not. Evening ankle angle changes were larger and faster in RLS participants compared to morning responses. In addition RLS participants displayed significantly smaller change in ankle angle and significantly slower ankle movements in the evening and the morning as well as significantly lower lateral gastrocnemius maximum amplitude in the compared to control participants. CONCLUSION: The findings of the current study support the theory of RLS circadian fluctuations in spinal excitability. An unexpected finding was decreased plantar reflex responses in RLS participants compared to healthy control participants. However this finding supports the theory of mechanical hypoesthesia in RLS. The results of this study provide further insight into the pathophysiology of RLS, highlighting that not all sensory processing is affected in the same manner.

Combined individual scrummaging kinetics and muscular power predict competitive team scrum success.

Scrummaging is a major component of Rugby Union gameplay. Successful scrummaging is dependent on the coordination of the forward players and the strength of the eight individuals. The study aim was to determine whether individual scrummaging kinetics and other candidate factors associated with scrummaging performance discriminate team scrum performances. Sixteen club-level forwards (stature: 1.80 ± 0.1 m; mass: 99.0 ± 18.2 kg) were initially divided into two scrummaging packs. A total of 10 various scrum permutations were tested, where players were randomly swapped between the two packs. Winning scrums were determined by two observers on opposite sides of the scrum. Fatigue (100 mm visual analogue scale (VAS)) and scrummaging effort (6-20 rating of perceived exertion (RPE)) were assessed following each scrum contest. Individual scrummaging kinetics were acquired through an instrumented scrum ergometer and muscular power indicated through vertical jump heights. Student's t-tests were used to differentiate between winning and losing scrum packs. VAS and RPE were assessed using repeated measures ANOVAs. Winning scrum packs had significantly larger combined force magnitudes (p < .002), regardless of the player contribution calculations. Additionally, winning packs had less individual movement (p = .033) and higher combined vertical jump heights (p < .001) but were not significantly heavier (p = .759) than losing scrum packs. While perceived VAS and RPE values progressively increased (p < .001), no differences in the individual scrum magnitudes were observed between the 1st and 10th scrum (p = .418). The results indicated that the combination of individual forces, variation in movement and factors related to scrummaging performance, such as vertical jump height, were associated with team scrummaging success.

Which Extrinsic and Intrinsic Factors are Associated with Non-Contact Injuries in Adult Cricket Fast Bowlers?

BACKGROUND: The high prevalence of injury amongst cricket fast bowlers exposes a great need for research into the risk factors associated with injury. Both extrinsic (environment-related) and intrinsic (person-related) risk factors are likely to be implicated within the high prevalence of non-contact injury amongst fast bowlers in cricket. Identifying and defining the relative importance of these risk factors is necessary in order to optimize injury prevention efforts. OBJECTIVE: The objective of this review was to assess and summarize the scientific literature related to the extrinsic and intrinsic factors associated with non-contact injury inherent to adult cricket fast bowlers. METHOD: A systematic review was performed in compliance with the PRISMA guidelines. This review considered both experimental and epidemiological study designs. Studies that included male cricket fast bowlers aged 18 years or above, from all levels of play, evaluating the association between extrinsic/intrinsic factors and injury in fast bowlers were considered for inclusion. The three-step search strategy aimed at finding both published and unpublished studies from all languages. The searched databases included MEDLINE via PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Cochrane Controlled Trials Register in the Cochrane Library, Physiotherapy Evidence Database (PEDro), ProQuest 5000 International, ProQuest Health and Medical Complete, EBSCO MegaFile Premier, Science Direct, SPORTDiscus with Full Text and SCOPUS (prior to 28 April 2015). Initial keywords used were 'cricket', 'pace', 'fast', 'bowler', and 'injury'. Papers which fitted the inclusion criteria were assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI). RESULTS: A total of 16 studies were determined to be suitable for inclusion in this systematic review. The mean critical appraisal score of the papers included in this study was 6.88 (SD 1.15) out of a maximum of 9. The following factors were found to be associated with injury: bowling shoulder internal rotation strength deficit, compromised dynamic balance and lumbar proprioception (joint position sense), the appearance of lumbar posterior element bone stress, degeneration of the lumbar disc on magnetic resonance imaging (MRI), and previous injury. Conflicting results were found for the association of quadratus lumborum (QL) muscle asymmetry with injury. Technique-related factors associated with injury included shoulder-pelvis flexion-extension angle, shoulder counter-rotation, knee angle, and the proportion of side-flexion during bowling. Bowling workload was the only extrinsic factor associated with injury in adult cricket fast bowlers. A high bowling workload (particularly if it represented a sudden upgrade from a lower workload) increased the subsequent risk to sustaining an injury 1, 3 or 4 weeks later. CONCLUSION: Identifying the factors associated with injury is a crucial step which should precede the development of, and research into, the effectiveness of injury prevention programs. Once identified, risk factors may be included in pre-participation screening tools and injury prevention programs, and may also be incorporated in future research projects. Overall, the current review highlights the clear lack of research on factors associated with non-contact injury, specifically in adult cricket fast bowlers. SYSTEMATIC REVIEW REGISTRATION NUMBER: Johanna Briggs Institute Database of Systematic Reviews and Implementation Reports 1387 (Olivier et al., JBI Database Syst Rev Implement Rep 13(1):3-13. doi: 10.11124/jbisrir-2015-1387 , 2015).

The Interrater Reliability of Subjective Assessments of the Babinski Reflex.

The Babinski reflex is a clinical diagnostic tool; however, the interrater reliability of this tool is currently greatly contested. A comparison between rater groups with objective measurements of the Babinski reflex was therefore conducted. Fifteen recorded Babinski reflexes were assessed by 12 neurologists and 12 medical students as being either pathological or nonpathological. Kinematic and electromyographic variables were collected and used to assess which aspects of the Babinski reflex predict classification. Substantial interrater agreement within the neurologist and student groups (κ = .72 and .67, respectively) was shown; however, there were some differing aspects between what neurologists and students used to assess the reflex as determined by objective kinematic measurements.

Extrinsic and intrinsic factors associated with non-contact injury in adult pace bowlers: a systematic review protocol.

REVIEW QUESTION/OBJECTIVE: Review question: which extrinsic and intrinsic factors are associated with non-contact injury in adult cricket pace bowlers?Review objective: the objective of this review is to determine the extrinsic and intrinsic factors associated with non-contact injury in adult pace bowlers. BACKGROUND: Cricket is generally considered to be a sport of low injury risk compared to other sports. In cricket, the pace bowler strives towards the adoption of a bowling technique with a relatively low injury threat that will, at the same time, allow for a fast (>120km/hr) and accurate delivery to the opposing batsman. However, of all the various roles of the cricket player, the pace bowler has the highest risk of injury, especially for low back and lower limb (lower quarter) injury. The reason for this high risk of injury is due to the inherent, high-load biomechanical nature of the pace bowling action. The high prevalence of injury amongst pace bowlers highlights the great need for research into factors associated with injury.Both extrinsic and intrinsic factors work in combination to predispose the bowler to injury. Extrinsic or environment-related factors include bowling workload (the numbers of overs a bowler bowls), player position (first, second or third change) and time of play (morning or afternoon). A high bowling workload has been linked with a higher risk of injury in pace bowlers. Foster et al. found in an observational study that bowling too many overs in a single spell or bowling too many spells may increase the pace bowler's risk of sustaining a low back injury. In another observational study, Dennis et al. found that an exceptionally high bowling workload as well as an uncommonly low bowling workload is associated with injury risk. The major extrinsic factors for bowling injury identified by Orchard et al. are a high number of match overs bowled in the previous week, number of days of play and bowling second (batting first) in a match. Extrinsic factors are known to make the bowler more susceptible to injury, especially in the presence of intrinsic factors.Intrinsic, or person-related, factors include muscle strength, flexibility, balance and biomechanics. Intrinsic, strength-related factors, such as shoulder depression, horizontal flexion strength for the preferred limb and quadriceps power in the non-preferred limb are also significantly related to back injuries in fast bowlers. Both upper limb and lower limb-related intrinsic factors are known to be associated with injury. A prospective study by Dennis et al. aimed to identify the risk factors for injury in adolescent cricket fast bowlers. Their findings concluded that bowlers with a hip internal rotation range of motion of ≤30° on the leg ipsilateral to the bowling arm were at a significantly reduced risk of injury compared with bowlers with >40° of rotation. Moreover, bowlers with ankle dorsiflexion lunge of 12.1-14.0 cm on the leg contralateral to the bowling arm were at a significantly increased risk of injury compared to bowlers with a lunge of >14 cm. Reduced hamstring flexibility was also associated with lumbar disc abnormalities. Bowling-related biomechanical risk factors for injury have been established such as trunk rotation of the shoulders by to a more side-on position during the delivery stride. Portus et al. also reported that shoulder counter-rotation was significantly higher in bowlers who reported lumbar spine stress fractures, while the non-trunk injured group displayed a more flexed knee at front foot contact and ball release. In addition to the above kinematic risk factors, there are high ground reaction forces associated with the power phase - between the front foot placement and ball release components of the pace bowling action. A combination of kinematic bowling related issues as described above and high ground reaction forces may predispose the bowler to injury.Morton et al. conducted a systematic review on pace bowlers between the ages of 13.7 and 22.5 years on risk factors and successful interventions for cricket-related low back pain. Young cricketers between the ages of 13 and 18 years are different to adults in terms of their physiology which impacts on their predisposition to injury and phases of healing. Young cricketers may differ from an adult population in that young pace bowlers who sustain injuries during their bowling career may have given up on the sport by the time they approach adulthood, and the composition of the adult pace bowler population group is therefore affected by natural selection which may cause this group to differ from the original population. Caution is thus advised when generalizing findings from this young population group to adult pace bowlers which emphasizes the need for studies amongst adult pace bowlers. Furthermore, the review by Morton et al. included articles that specifically investigated factors associated with low back pain. However, due to the interconnectedness between the spine and the lower limbs, kinematic variables affecting the spine will also affect the load placed on the lower limbs with subsequent risk of injury. The interdependent mechanical interactions in a linked segment system such as the system of motion of the low back can be caused by movement coordination patterns in other body segments. The systematic review by Morton et al. only included intrinsic factors while the proposed review will also look at extrinsic factors. Therefore, the primary objective of this review is to determine extrinsic and intrinsic factors associated with non-contact injury in adult pace bowlers.

Injury and lumbar reposition sense in cricket pace bowlers in neutral and pace bowling specific body positions.

BACKGROUND AND CONTEXT: The cricket pace bowling action consists of a complex sequence of forceful actions, involving practiced, particular movements of the lumbar spine. The nature and repetition of the pace bowling action is known to be associated with a high incidence of low back injuries. PURPOSE: This study aimed to establish whether lumbar proprioception (as measured by joint position sense) in the neutral lumbar spine position as well as lumbar positions corresponding to those at front foot placement and ball release positions of the cricket pace bowling action were related to previous injury and injury sustained during the cricket season under review. Injuries specifically sustained during the bowling action and those specific to the low back were explicitly investigated. STUDY SETTING: Longitudinal study with participants tested at the start and monitored over the duration of a cricket season. PARTICIPANT SAMPLE: Seventeen male cricket pace bowlers between the ages of 18 and 26 years participated in this study. OUTCOME MEASURES: Physiological outcome measures were used. Lumbar position sense was established using electrogoniometry. METHODS: Lumbar reposition error was measured in three positions (neutral lumbar spine, front foot placement, and ball release bowling positions). In each position, lumbar orientation was determined in the sagittal (flexion-extension) and coronal (left-right lateral flexion) planes. Wilcoxon matched-pairs ranks and Kruskal-Wallis tests were used to establish the relationship between variables. RESULTS: Reposition error was associated with general injuries sustained in the past and during the cricket season under review, low back injuries, as well as injuries sustained during the bowling action (p<.05). CONCLUSION: Lumbar position sense, as a measure of proprioception, was related to injury in general, injuries sustained during the bowling action, and, especially, low back injury sustained in the past. Low back injury prevention methods are particularly needed because of the high load nature of the pace bowling action. If the proprioception of the lumbar spine is improved in pace bowlers, their risk of lumbar injury can potentially be reduced.

The accuracy of subjective clinical assessments of the patellar reflex.

INTRODUCTION: Measurement precision and accuracy of spinal reflexes plays an essential role in the clinical neurological examination. Reflexes are conventionally assessed either electromyographically or with rating scales. In this study we compared objective kinematic T-reflex and subjective assessments of patellar reflexes in 15 normal healthy subjects. METHODS: Randomized recordings of objectively quantified reflexes were rated by 24 medical students, 16 general practitioners, and 12 neurologists, using a visual analog scale and the NINDS and Mayo clinical reflex scales. RESULTS: For all groups of raters, Spearman rank correlations showed that subjective ratings significantly correlated with change of knee angle (R2 = 0.72-0.79, P < 0.001) and maximum T-reflex amplitude (R2 = 0.84-0.94, P < 0.001). Stepwise multiple regression analysis showed that all subjective rater groups relied most on the change of knee angle to assess the reflex. CONCLUSIONS: These findings show that subjective assessments of reflexes using reflex rating scales correlate strongly with biomechanical and electromyographic measures.

Descriptors of restless legs syndrome sensations.

BACKGROUND: Restless legs syndrome (RLS) is characterised by an urge to move in response to unusual sensations in the legs. Patients experience difficulty describing their RLS sensations, resulting in a diverse range of descriptors which have not been fully categorised. The purpose of this study was to describe RLS sensations and to evaluate the accuracy of current diagnostic descriptors. METHODS: Forty-one RLS participants completed an interview which involved: providing spontaneous descriptions of RLS sensations, completing the McGill Pain Questionnaire (MPQ), and selecting descriptors from a list of previously published RLS terms (prompted descriptors). RESULTS: The most frequent spontaneous descriptors were: "irritating" (17%), "painful" (17%), and "urge to move" (24%); prompted descriptors were: "restless" (88%), "uncomfortable" (78%), and "need to stretch" (76%); and MPQ words were: "tingling" (56%) and "jumping" (54%). DISCUSSION: The most frequently cited descriptors in this study differ from the terminology used in the RLS diagnostic criteria. Inclusion of these frequently used descriptors may improve the diagnostic accuracy of RLS. Our data emphasise the need for an international, large scale, multicultural study to determine the most accurate diagnostic descriptors to define RLS more clearly.

The patellar reflex: does activity of quadriceps femoris muscles reflect leg movement?

OBJECTIVES: The assessment of spinal reflexes has traditionally been performed by clinicians with minimal need for recording equipment, where doctors rely on their training and may use established subjective reflex rating scales. With advances in technology, it is now possible to assess reflexes objectively. This study compared two objective methods of assessing patellar reflex magnitude, duration, and latency, namely electromyography (EMG) of the quadriceps muscles and kinematic assessment of the leg movement around the knee joint. METHODS: Reflexes of 24 healthy participants were assessed and seven variables were found to describe each reflex. These were the change in knee angle, the velocity of the reflex, the time to maximum knee angle, the biomechanical movement latency, the EMG maximum amplitude, the negative peak duration, and the EMG latency. Spearman's rank correlation tests were run in order to compare all of the variables. RESULTS: The results showed that there were positive correlations between EMG maximum amplitude and the change in knee angle (R(2) = 0.75; P < 0.0001) as well as the EMG maximum amplitude and the velocity of the reflex (R(2) = 0.30; P = 0.0058). There was also a negative correlation between EMG maximum amplitude and the biomechanical movement latency (R(2) = 0.35; P = 0.0024). DISCUSSION: The results show that there is a relationship between muscle activity and the actual visual movement of the leg assessed using kinematics. This relationship is closest between kinematic measurements and EMG measures of reflex amplitude.

Anthropometric, biomechanical, and isokinetic strength predictors of ball release speed in high-performance cricket fast bowlers.

Fast bowling is fundamental to all forms of cricket. The purpose of this study was to identify parameters that contribute to high ball release speeds in cricket fast bowlers. We assessed anthropometric dimensions, concentric and eccentric isokinetic strength of selected knee and shoulder muscle groups, and specific aspects of technique from a single delivery in 28 high-performance fast bowlers (age 22.0 +/- 3.0 years, ball release speed 34.0 +/- 1.3 m s(-1)). Six 50-Hz cameras and the Ariel Performance Analysis System software were used to analyse the fast and accurate deliveries. Using Pearson's correlation, parameters that showed significant associations with ball release speed were identified. The findings suggest that greater front leg knee extension at ball release (r=0.52), shoulder alignment in the transverse plane rotated further away from the batsman at front foot strike (r=0.47), greater ankle height during the delivery stride (r=0.44), and greater shoulder extension strength (r=0.39) contribute significantly to higher ball release speeds. Predictor variables failed to allow their incorporation into a multivariate model, which is known to exist in less accomplished bowlers, suggesting that factors that determine ball release speed found in other groups may not apply to high-performance fast bowlers.

The agreement between reaction-board measurements and kinematic estimation of adult male human whole body centre of mass location during running.

The segmental method for estimating the centre of mass (COM) location of the human body has been widely used since 1889. How closely this method agrees with direct measurements of the location and movement of COM during activity however, remains unclear. To test this, a novel reaction-board utilizing life sized projections of human subjects is designed for measuring COM location. Agreement between the segmental method and the more direct reaction-board measurement method is then assessed. Our data demonstrate that the reaction-board system has a physical maximum error of 1.28 cm and 1.95 cm for locating COM along the vertical (board length) and horizontal (board width) axes respectively, and show that the reaction-board and segmental methods agree to within limits of 6.0 cm for the location of COM and to within 5.6 cm for the movement of COM between two points, in recumbent individuals. Applied to running, the segmental method agrees to within limits of 4.8 cm for oscillation of COM and 5.3 cm for stride median COM height. The segmental method agrees with a more direct technique of known accuracy, the reaction-board method, most closely when measuring averaged oscillation over repeated strides, where it displays a measurement error range of 5.1 cm to 0.1 cm in runners.