Metabolic Differences Between Shod and Barefoot Walking in Children.

Footwear affects the biomechanics of children's gait; however, there has been less research addressing the energetics of walking with and without shoes. This study investigated the effects of barefoot and shod walking on metabolic parameters in children. 25 children (9.7±1.4 years) walked at a self-selected pace for 5 min on an instrumented treadmill under 2 footwear conditions (barefoot, running shoe). Vertical oscillations of centre of mass were calculated from ground reaction forces. Expired gases were collected in the last minute of each trial. Paired t-tests revealed significantly higher oxygen consumption (17.6±2.5 ml.kg(-1).min(-1) vs. 16.3±3.1 ml.kg(-1).min(-1)), energy expenditure (3.25±0.86 kcal.min(-1) vs. 2.97±0.68 kcal.min(-1)), and economy (298.2±47.5 ml.kg(-1).km(-1) vs. 275.9±56.9 ml.kg(-1).km(-1)) during the shod condition. There was no difference in substrate utilization between conditions. The barefoot condition elicited a smaller centre of mass vertical displacement (1.24±0.14 cm vs. 1.34±0.17 cm). At a natural walking speed, barefoot walking is more economical than shod walking at the same velocity in children. The higher energy cost of shod walking should be considered when evaluating the use of footwear by children.

A retrospective review over 1999 to 2007 of head, shoulder and knee soft tissue and fracture dislocation injuries and associated costs for rugby league in New Zealand.

King et al. reported that of 5 941 moderate to serious claims resulting in medical treatment for rugby league injuries, the knee, shoulder, and head and neck body sites and soft tissue and fracture-dislocation injuries were most frequent and costly in the New Zealand national no-fault injury compensation corporation database during 1999 to 2007. However, additional analyses of knee, shoulder and head and neck body sites by soft tissue and fracture-dislocation injury types was required to enable a greater understanding of the nature of injuries most likely to be seen by sports medical personnel dealing with rugby league players. From 1999 to 2007 the injury claims and costs for head and neck soft tissue, fracture-dislocations, shoulders soft tissue significantly increased. Knee soft tissue injury claims and costs significantly decreased from 1999 to 2007. There was no significant difference in knee fracture-dislocation injury claims but there was a significant increase in knee fracture-dislocation injury costs from 1999 to 2007. Changes in the nature of injuries may be related to changes in defensive techniques employed in rugby league during this time. Sports medical personnel dealing with rugby league players should focus their injury prevention strategies on reducing musculoskeletal injuries to the head and shoulder. There should be a focus on increasing awareness of correct tackling technique, head injury awareness and management of suspected cervical spine injuries.

The effect of player positional groups on the nature of tackles that result in tackle-related injuries in professional rugby league matches.

AIM: The aim of this study was to describe the effect of player positional groups on the nature of tackles that result in tackle-related injuries in professional rugby league matches. METHODS: Prospective observational epidemiology analyses for tackle-related injuries and video analyses for the nature of tackles were conducted for a single team in the National Rugby League (NRL) throughout the 2007 and 2008 competitions for a total of 48 games. Risk ratios (RR) were calculated for comparisons between positional groups (adjustable, hit-up forwards or outside backs). RESULTS: The total missed match tackle-related injury rate was 57.8 per 1 000 player hours. Hit-up forwards recorded significantly more total tackle-related injuries than outside backs (RR: 1.3; P=0.049), but not more than adjustables (RR: 1.0; P=0.922). Hit-up forwards recorded significantly more chest-back tackle-related injuries than adjustables (RR: 6.0; P=0.008). Outside backs recorded significantly more tackle injuries as the ball carrier than the tackler (RR: 2.4; P=0.015) while adjustables recorded significantly more tackle injuries as the tackler than the ball carrier (RR: 1.8; P<0.001). Hit-up forwards had a higher incidence of contusions, and sprains while adjustables had a higher incidence of fracture/dislocations. There were no differences in injury severity between the positional groups. CONCLUSION: Player positional group had an effect on tackle-related injury type and injury site. Hit-up forwards and outside backs recorded more tackle-related injuries as a ball carrier than as a tackler, while in contrast, adjustables recorded more tackle-related injuries as the tackler than the ball carrier.

Training injury incidence in an amateur women's rugby union team in New Zealand over two consecutive seasons.

OBJECTIVES: To describe the training injury incidence in amateur women's rugby union in New Zealand over two consecutive seasons. DESIGN: A prospective cohort observational study METHODS: A total of 69 amateur women's rugby 15s team playerswere observed. Training exposure and training injury incidence were calculated. RESULTS: The 38 training injuries resulted in a total injury incidence of 11.4 (8.3-15.6) per 1,000 training-hours. There were 12 injuries that resulted in a time-loss injury incidence of 3.6 (95% CI: 2.0-6.3) per 1,000 training-hours. Forwards recorded more total (RR: 1.8 [95% CI: 0.9-3.5]; p=0.0516) and time-loss (RR: 2.0 [95% CI: 0.6-6.6]; p=0.2482) injuries than Backs. The tackle was the most common injury cause for total (3.0 [95% CI: 1.6-5.6] per 1,000 training-hours.) injuries, but collisions (1.5 [95% CI: 0.6-3.6] per 1,000 training-hours.) with the ground or another person were the most common cause for time-loss injuries.The training injuries occurred most often to the lower limb and during the latter part of training sessions. These injuries were mostly minor in nature resulting in minimal time-loss away from training. DISCUSSION: The time-loss injury incidence (3.6 per 1,000 training-hours.) for the amateur women's rugby 15s team players was higher than that reported for National (1.2 per 1,000 training-hours.) and Rugby World Cup for women (0.2 to 3.0 per 1,000 training-hours.) competitions. CONCLUSION: The training injury incidence in amateur women's rugby union in New Zealand was higher than that reported for national and international rugby union injury incidences.

Women's rugby league injury claims and costs in New Zealand.

AIM: There is scarce information on rugby league injuries in female players. This paper provides an overview of the epidemiology of women's rugby league injuries requiring medical treatment and associated costs in New Zealand. METHOD: New Zealand Accident Compensation Corporation injury data for the period 1999-2007 were searched for rugby league injury cases occurring in females. Data were analysed by demographics, body region, nature/severity of injury, and medical procedure and costs. RESULTS: There were 320 moderate to serious injury claims recorded for females participating in rugby league activities over the study period. There was a mean (SD) of 37.9 (9.5) injury claims per year. The mean cost per year for the study period was $196 514 ($99,133) (£76,066 (£38,374)) with half of the injury claims occurring in New Zealand Maori. Concussion/brain injuries accounted for 3.8% of total female moderate to serious injury claims but accounted for 5.4% of female injury costs ($84,399 (£32,688)) with the highest mean cost per claim ($7033 (£2724)). The lower limb accounted for 65% of the total female injury claims and 58.7% of total injury costs ($922,296 (£356,968)). The mean cost per claim was higher for the lower limb ($4434 (£1714)) than the upper ($3331 (£1288)) limb. Clerks recorded 16.3% of the total injury claims, 20.3% of total injury costs ($319,474 (£123,211)) and had the highest mean cost per claim ($6144 (£2370)). The 25-29 age group recorded 31.9% of injury claims and 33.8% of injury costs. The 35-39 age group recorded the highest mean cost per claim ($6200 (£2392)) but only 10.9% of total claims and 13.8% of total costs. DISCUSSION: When compared with other studies in rugby league injuries, it appears that females incur substantially fewer injuries (5.7%) than males (94.3%). Although no participation data by sex are available, it is likely that participation percentages are reflected in the injury percentages. The high frequency (65%) and cost proportion (58.7%) for lower limb injuries was higher in females than in male rugby league players (previously reported as 42.4% of the injury claims and 31.5% of the total injury claim costs for the lower limb). CONCLUSIONS: Injury prevention programmes for women's rugby league should focus on the 25-29 age group and address ways to prevent concussion and lower limb injuries.

Use of the King-Devick test for the identification of concussion in an amateur domestic women's rugby union team over two competition seasons in New Zealand.

OBJECTIVE: To investigate the use of the King-Devick (K-D) test for sideline assessment of concussive injuries in a New Zealand amateur women's rugby union team. DESIGN: Prospective cohort observational. METHODS: All players were K-D tested during pre-season using a tablet (iPad; Apple Inc., Cupertino, CA). Differences in K-D scores and test-retest reliability were calculated for baseline test scores, baseline, and post-injury (concussion) sideline assessment and baseline and post-season testing scores for tests by year and as a combined score. RESULTS: One training-related (0.3 per 1000 training-hrs) and nine match-related (16.1 per 1000 match-hrs) concussions were recorded. The K-D post-injury (concussion) sideline test score were significantly slower than established baseline (-4.4 [-5.8 to -3.4] s; χ2(1) = 42.2; p < 0.0001; t(9) = -4.0; p = 0.0029; d = -0.8). There was good-to-excellent reliability of the K-D test for baseline (ICC: 0.84 to 0.89), post-injury (concussion) sideline assessment (ICC: 0.82 to 0.97) and post-season evaluation (ICC: 0.79 to 0.83). DISCUSSION: By utilising the baseline to post-injury (concussion) assessment comparisons, any player with a post-injury (concussion) assessment slowing of their K-D test time, regardless of whether the player has, or has not had a witnessed insult, should be withheld from any further participation until they are evaluated by a medical professional trained in the management of concussion. CONCLUSION: This study has provided additional evidence to support the use of the K-D test as a frontline method of assessing concussion with good to excellent reliability of the test for baseline, side-line assessment and post-season evaluation.

Rugby league injuries in New Zealand: a review of 8 years of Accident Compensation Corporation injury entitlement claims and costs.

AIM: This paper provides an overview of the epidemiology of rugby league injuries and associated costs in New Zealand requiring medical treatment. METHOD: New Zealand national Accident Compensation Corporation injury data for the period 1999 to 2007 were searched for rugby league injury cases. Data were analysed by demographics, body region, nature/severity of injury, and medical procedure and costs. RESULTS: A total of 5941 injury entitlement claims were recorded over the study period with a significant decrease observed in the injury rate between the 1999-2000 and 2002-2003 reporting years. The total cost of the injuries for the study period was $42,822,048 (equivalent to pound15,916,072). The mean (SD) number of injury entitlement claims per year was 743 (271) and yearly cost was $5,352,760 (pound1,989,880) ($2,485,535 (pound923,994)). The knee was the most commonly reported injury site (225 per 1000 entitlement claims; $8,750,147 (pound3,252,020)) and soft tissue injuries were the most common injury types (474 per 1000 entitlement claims; $17,324,214 (pound6,438,599)). Accounting for only 1.8% of total injury entitlement claims, concussion/brain injuries accounted for 6.3% of injury entitlement costs and had the highest mean cost per claim ($25 347 (pound9420)). The upper and lower arm recorded the highest mean injury site claim cost of $43,096 (pound16,016) per claim. The 25-29 age group recorded 27.7% of total injury entitlement claims and 29.6% of total injury entitlement costs, which was slightly more than the 20-24 age group (27.3% claims; 24.7% costs). Nearly 15% of total moderate to serious injury entitlement claims and 20% of total costs were recorded from participants 35 years or older. DISCUSSION: This study identified that the knee was the most common injury site and soft tissue injuries were the most common injury type requiring medical treatment, which is consistent with other international studies on rugby league epidemiology. This study also highlights that the rate of injury and the average age of injured rugby league players increased over time. The high cost of concussion/brain injuries is a cause for concern as it reflects the severity of the injuries. CONCLUSION: Injury prevention programmes for rugby league should focus on reducing the risk of concussion/brain injury and knee and soft tissue injury, and should target participants in the 20-30 years old age range. More longitudinal epidemiological studies with specific details on injury mechanisms and participation data are warranted to further identify the injury circumstances surrounding participation in rugby league activities.

Female rugby union injuries in New Zealand: A review of five years (2013-2017) of Accident Compensation Corporation moderate to severe claims and costs.

OBJECTIVES: To provide epidemiological data and related costs for moderate-to-serious and serious injury claims for women's rugby union in New Zealand. DESIGN: A retrospective analytical review of injury entitlement claims for women's rugby from 2013 to 2017. METHODS: Data were analysed by year of competition, age, body site and injury type for total and moderate-to-severe (MSC) Accident Compensation Corporation (ACC) claims and costs. RESULTS: Over 2013 to 2017 there were 26,070 total claims for female rugby union costing $18,440,812 [AD$16,956,998]. The 15-19-year age group recorded 40% (n=1,009) of the total female rugby union Moderate-to-serious and serious (MSC) claims and 41% ($5,419,157 [AD$4,983,112]) of the total female rugby union MSC costs. The knee was the most commonly recorded injury site accounting for 40.3% (n=1,007) of MSC claims and 46.9% ($6,229,714 [AD$5,728732]) of MSC costs with an average cost of $1,245,943 ±$217,796 [AD$595,351 ±AD$104,070] per-year for female rugby union. CONCLUSIONS: This is the first study to report the nature and related costs for moderate-to-serious and serious injury claims for women's rugby union in New Zealand. A total of 26,070 injury claims were lodged over the duration of the study but only 9.6% (n=2,501) of these were classified as MSC injury entitlement claims. Participants 25 years and older accounted for 31% of the female rugby union player claims. Females in the over 35-year age groups compete against younger participants which may account for the higher mean cost per-claim seen as the age groups increase in years until they retire from the game.

Interim evaluation of the effect of a new scrum law on neck and back injuries in rugby union.

BACKGROUND: In January 2007 the International Rugby Board implemented a new law for scrum engagement aimed at improving player welfare by reducing impact force and scrum collapses. In New Zealand the new law was included in RugbySmart, an annual compulsory workshop for coaches and referees. OBJECTIVE: To determine the effect of the new law on scrum-related moderate to serious neck and back injury claims in 2007. METHODS: Claims filed with the Accident Compensation Corporation (the provider of no-fault injury compensation and rehabilitation in New Zealand) were combined with numbers of registered players to estimate moderate to serious scrum-related claims for players who take part in scrums (forwards). Poisson linear regression was used to compare the observed claims per 100 000 forwards for 2007 with the rate predicted from data for 2002-6. RESULTS: The observed and predicted claims per 100 000 forwards were 52 and 76, respectively (rate ratio 0.69; 90% CI 0.42 to 1.12). The likelihoods of substantial benefit (rate ratio <0.90) and harm (rate ratio >1.1) attributable to the scrum law were 82% and 5%, respectively. CONCLUSION: The decline in scrum-related injury claims is consistent with a beneficial effect of the new scrum law in the first year of its implementation. Another year of monitoring should provide more evidence for the efficacy of the new law.

The Influence of Head Impact Threshold for Reporting Data in Contact and Collision Sports: Systematic Review and Original Data Analysis.

BACKGROUND: Head impacts and resulting head accelerations cause concussive injuries. There is no standard for reporting head impact data in sports to enable comparison between studies. OBJECTIVE: The aim was to outline methods for reporting head impact acceleration data in sport and the effect of the acceleration thresholds on the number of impacts reported. METHODS: A systematic review of accelerometer systems utilised to report head impact data in sport was conducted. The effect of using different thresholds on a set of impact data from 38 amateur senior rugby players in New Zealand over a competition season was calculated. RESULTS: Of the 52 studies identified, 42% reported impacts using a >10-g threshold, where g is the acceleration of gravity. Studies reported descriptive statistics as mean ± standard deviation, median, 25th to 75th interquartile range, and 95th percentile. Application of the varied impact thresholds to the New Zealand data set resulted in 20,687 impacts of >10 g, 11,459 (45% less) impacts of >15 g, and 4024 (81% less) impacts of >30 g. DISCUSSION: Linear and angular raw data were most frequently reported. Metrics combining raw data may be more useful; however, validity of the metrics has not been adequately addressed for sport. Differing data collection methods and descriptive statistics for reporting head impacts in sports limit inter-study comparisons. Consensus on data analysis methods for sports impact assessment is needed, including thresholds. Based on the available data, the 10-g threshold is the most commonly reported impact threshold and should be reported as the median with 25th and 75th interquartile ranges as the data are non-normally distributed. Validation studies are required to determine the best threshold and metrics for impact acceleration data collection in sport. CONCLUSION: Until in-field validation studies are completed, it is recommended that head impact data should be reported as median and interquartile ranges using the 10-g impact threshold.

Equipment set-up among Olympic sprint and slalom kayak paddlers.

The anthropometry and equipment set-up for sprint (31 male; 11 female) and slalom (12 male; 12 female) kayak paddlers who competed at the 2000 Olympic Games in Sydney were measured in the 15 day period before competition. This paper provides normative data for equipment set-up in these sports, as well as information about differences in rigging and paddle dimensions between sprint and slalom kayak paddlers. These differences were consistent for both male and female athletes, with sprint paddlers seated higher and using longer paddles with longer, though narrower, blades (p < 0.0001). Among male sprint paddlers, only minor differences in equipment set-up were found between competitors ranked in the top 10 places compared to the rest of the field. Considering all male paddlers initially, then sprint paddlers alone, significant (p < 0.01) regression equations were developed for the prediction of foot bar distance (r2 = 0.482 and 0.589 respectively) and hand grip distance (r2 = 0.400 and 0.541 respectively). The process of fine tuning equipment set-up often requires hours of practice with subjective feedback from the athlete. The normative data presented in this paper should assist coaches with this process as their athletes evolve toward their individual optimum set-up.

Relationship between pedal force asymmetry and performance in cycling time trial.

AIM: It remains unclear if cyclists with better performance have less asymmetry. Therefore, this study aimed at assessing the relationship between cycling time trial performance and bilateral asymmetries in pedal forces. METHODS: Ten cyclists/triathletes performed an incremental cycling test to exhaustion to measure maximal oxygen uptake and power output. In a second session, bilateral pedal forces were acquired during a 4-km cycling time trial on the stationary cycle ergometer. Resultant and effective forces were computed along with the index of effectiveness at 500 m sections of the time trial using instrumented pedals. Intra-limb variability and the asymmetry index were calculated for each force variable. RESULTS: Multivariate analysis assessed bilateral differences in pedal forces accounting for power output, pedalling cadence and oxygen uptake of each cyclist. Force variables did not change throughout the test (effective - P=0.98, resultant - P=0.90 and index of effectiveness - P=0.99) with larger force applied by the dominant limb (11-21%). The relationship between asymmetries and performances was strong for the effective force (r=-0.72) but weak for the resultant force (r = 0.01) and for the index of effectiveness (r=-0.29). Substantial asymmetries were observed for the effective force (36-54%), resultant force (11-21%) and for the index of effectiveness (21-32%) at greater range than intra-limb variability (effective force =8-22%, resultant force =5-10% and index of effectiveness =1-3%). CONCLUSION: Larger asymmetries in effective force were related to better performances during the 4-km time trial with low intra-limb variability for force measures suggesting consistence in asymmetries for individual cyclists.

Use of the King-Devick test for sideline concussion screening in junior rugby league.

AIM: To determine whether the King-Devick (K-D) test used as a sideline test in junior rugby league players over 12 matches in a domestic competition season could identify witnessed and incidentally identified episodes of concussion. METHODS: A prospective observational cohort study of a club level junior rugby league team (n=19) during the 2014 New Zealand competition season involved every player completing two pre-competition season baseline trials of the K-D test. Players removed from match participation, or who reported any signs or symptoms of concussion were assessed on the sideline with the K-D test and referred for further medical assessment. Players with a pre- to post-match K-D test difference >3s were referred for physician evaluation. RESULTS: The baseline test-retest reliability of the K-D test was high (rs=0.86; p<0.0001). Seven concussions were medically identified in six players who recorded pre- to post-match K-D test times greater than 3s (mean change of 7.4s). Post-season testing of players demonstrated improvement of K-D time scores consistent with learning effects of using the K-D test (67.7s vs. 62.2s). DISCUSSION: Although no witnessed concussions occurred during rugby play, six players recorded pre- to post-match changes with a mean delay of 4s resulting in seven concussions being subsequently confirmed post-match by health practitioners. All players were medically managed for a return to sports participation. CONCLUSION: The K-D test was quickly and easily administered making it a practical sideline tool as part of the continuum of concussion assessment tools for junior rugby league players.

The King-Devick test was useful in management of concussion in amateur rugby union and rugby league in New Zealand.

AIM: To use the King-Devick (K-D) test in senior amateur rugby union and rugby league players over a domestic competition season to see if it could identify witnessed and unwitnessed episodes of concussion that occurred from participation in competition matches over three years. METHODS: A prospective observational cohort study was conducted on a club level senior amateur rugby union team (n=36 players in 2012 and 35 players in 2013) and a rugby league team (n=33 players in 2014) during competition seasons in New Zealand. All 104 players completed two trials 10min apart of the K-D at the beginning of their competition season. Concussions (witnessed or unwitnessed) were only recorded if they were formally diagnosed by a health practitioner. RESULTS: A total of 52 (8 witnessed; 44 unwitnessed) concussive events were identified over the duration of the study resulting in a concussion injury incidence of 44 (95% CI: 32 to 56) per 1000 match participation hours. There was a six-fold difference between witnessed and unwitnessed concussions recorded. There were observable learning effects observed between the first and the second K-D test baseline testing (50 vs. 45s; z=-8.81; p<0.001). For every 1 point reduction in each of the post-injury SAC components there was a corresponding increase (worsening) of K-D test times post-match for changes in orientation (2.9s), immediate memory (1.8s) concentration (2.8s), delayed recall (2.0s) and SAC total score (1.7s). DISCUSSION: The rate of undetected concussion was higher than detected concussions by using the K-D test routinely following matches. Worsening of the K-D test post-match was associated with reduction in components of the SAC. The appeal of the K-D test is in the rapid, easy manner of its administration and the reliable, objective results it provides to the administrator. The K-D test helped identify cognitive impairment in players without clinically observable symptoms.

A non-invasive test for the pre-cancerous breast.

This paper describes a non-invasive, self-measured procedure by which the precancerous breast can be distinguished from the normal breast. The method involves wearing a specially designed thermometric brassiere for 90 min each evening at home through one menstrual cycle. Profiles of progesterone through the cycle, obtained from daily saliva sampling, and determination of the steroid content by radioimmunoassay, are made to allow the status and calendar date timing of the luteal phase to be established. Thus, cycles can be synchronised across subjects. In this study, two types of breast were compared: 50 normal breasts and 41 age-matched precancerous breasts. Differences between the groups were striking in terms of amplitude, phasing and average temperature during the luteal heat cycle. When these parameters and others were used as predictors in a linear discrimination and/or neural net analysis, a sensitivity and specificity of > 90% was achieved.

Effectiveness of external ankle support. Bracing and taping in rugby union.

Ankle inversion sprain is common in rugby. This review outlines research evidence relating to the effects of external ankle support by means of bracing and taping, on the incidence of ankle injuries, how performance is affected by support, how support may act at the joint (with respect to end range of motion, strength, resistive torque, muscle activation patterns and proprioception) to prevent injury, and how exercise changes the effectiveness of support. In addition, the implications of the laws of rugby for the use of external support are discussed. Prospective epidemiological studies have shown a decrease in the incidence of ankle injury with external ankle support use. The effectiveness of external ankle support was dependent upon the material properties and application method of the tape or brace, and on the athlete's status of ankle stability or previous injury. Experimental studies have indicated that the degree of ankle inversion restriction provided, and the degree of loss of restriction after exercise, were dependent upon the external support tested. External ankle support has been reported to have no effect on performance, or to have an adverse effect on performance in a variety of movement tasks. No prophylactic external ankle support has been shown to improve performance. If an external support is to provide mechanical support to a ligament it should exceed the strength of the ligament, which for the anterior fibular ligament is a force limit of between 6 and 56 kg. Tape can provide only limited mechanical support of the ankle joint complex, but it may have proprioceptive effects. Taping may work as a psychological reminder, so that the athlete consciously moderates lower limb-loading behaviour. There is equivocal evidence of the effect of brace use on ground reaction force excursions, balance ability and ankle strength. It is concluded that while there have been many investigations of the effects of tape and some forms of brace on ankle range of motion with and without exercise, there is equivocal evidence regarding the mechanism by which an external support acts. It is recommended that future research address the effects of external ankle support during dynamic exercise and that brace manufacturers utilise the information in the development of future brace designs to help reduce the risk of ankle inversion sprain injury. As external support can decrease the incidence of ankle inversion sprain the International Rugby Board should consider the use of ankle braces in rugby, allowing for stiff lateral components of the brace.

Evaluation of lower extremity overuse injury potential in runners.

INTRODUCTION: The purpose of this study was to identify biomechanical and anthropometric variables that contribute to overuse injuries in runners. METHODS: Comparisons were made between a group of runners who had sustained at least one overuse running injury and a group of runners who had been injury free throughout their running careers. Groups were well matched in important training variables. Synchronized kinetic and rearfoot kinematic variables of both feet were collected by filming subjects running over a force platform at a speed of 4 m x s(-1). RESULTS: The injury-free group demonstrated significantly greater posterior thigh (hamstring) flexibility, as measured by a standard sit and reach test. This was the only anthropometric variable in which the groups differed. Within each group, there were no significant differences between left and right foot landing for any biomechanical variable. Biomechanical variables that demonstrated significantly lower values for the injury free group were the vertical force impact peak and the maximal vertical loading rate, with the maximal rate of rearfoot pronation and the touchdown supination angle showing a trend toward being greater in the injury free group. CONCLUSION: These results suggest that runners who have developed stride patterns that incorporate relatively low levels of impact forces, and a moderately rapid rate of pronation are at a reduced risk of incurring overuse running injuries.

Training intensity of elite male distance runners.

To quantify training intensity in 13 nationally ranked male distance runners, training heart rates, environmental factors, and motivational factors were recorded throughout a 6-8 wk period of normal training. Variation in motivational and environmental factors such as intended effort, terrain, and running with companions altered training session mean heart rates by up to 4.min-1 (standard deviation). Heart rates and blood lactate concentrations, recorded in a series of steady-state treadmill runs, were used to convert training session mean heart rates to mean training speeds (TS) and to derive a measure of the anaerobic threshold (AT, the treadmill speed at a blood lactate concentration of 4 mmol.l-1). TS (15.6 +/- 1.4 km.h-1, mean +/- SD) was considerably lower than AT (20.2 +/- 1.1 km.h-1) in all subjects (P less than 0.001). Relative TS (TS expressed as a fraction of AT) differed significantly (P less than 0.001) between subjects and correlated significantly with the distance of the event for which the subject was training (r = 0.59, P less than 0.05). Relative TS may therefore be determined by the subject's or coach's perception of the appropriate intensity for the event. If the AT is the optimum training intensity, these subjects have considerable scope for improvement.

A preliminary investigation of injury prevention strategies in Netball: are players heeding the advice?

All netball players who sought treatment for injury during the three-day 1995 New South Wales State Netball Championships were surveyed. Of 940 participants, 131 incurred injuries (139.4 injuries per 1,000 players; 23.8 injuries per 1,000 playing hours). Ankle and knee injuries were most frequent, with ligament sprains, bruising/contusions, and muscle strains presenting as the most common injury types. The most frequent causes of injury were incorrect landings, collisions with players, being struck by the ball, or repetitive movements. Although most players heeded advice pertaining to warm-up, occurrence of injuries during warm-up and cool-down suggested that activities performed during these periods may be inappropriate. To reduce risk of ankle ligament sprain in netball, high-cut netball shoes have been advocated. However, only 5.1% of players surveyed wore high-cut shoes. Furthermore, although players have been advised to seek immediate treatment when injured, 54.7% of players finished the game before seeking treatment. Relative to previous netball injury investigations, the frequency and nature of injuries, and the injury prevention behaviours of players have not changed. Therefore, wider promotion of injury prevention resources, combined with research into the effectiveness of these resources and how players can be encouraged to adopt appropriate injury prevention strategies in netball, is recommended.

Predictors of attainment in rhythmic sportive gymnastics.

Correlates of attainment in rhythmic sportive gymnastics (RSG) were investigated in a cross-sectional study of 106 female gymnasts aged 7-27 years. Physical attributes were obtained by anthropometry and from tests of flexibility, leg power, maximum oxygen uptake and visuo-motor proficiency. Training and psychological measures were derived from self-administered questionnaires that included the Leadership Scale for Sport, Psychological Skills Inventory for Sport, General Health Questionnaire, Sport Competition Anxiety Test, and several questions on sport motivation and enjoyment. Attainment was expressed as competition grade level and mean performance score in 4 competitions. The best correlates of attainment were cumulative and current training time (r = 0.84-0.53). Age, lean body mass and composite measures of flexibility, leg power and visuo-motor proficiency were also significant correlates of attainment (r = 0.69-0.29), as were coach democratic and coach social behaviours (r = 0.41-0.28). The significant positive psychometric correlates of attainment were mental preparation, motivation by creativity, and several dimensions of enjoyment (r = 0.35-0.26); significant negative correlates were recent anxiety-depression and enjoyment of training (r = -0.34-(-)0.32). No previous study has identified the relative contributions of such a comprehensive range of physical, psychological and training measures to performance of a sport.