Kinetic analysis of push-up exercises: a systematic review with practical recommendations.

Push-ups represent one of the simplest and most popular strengthening exercise. The aim of this study was to systematically review and critically appraise the literature on the kinetics-related characteristics of different types of push-ups, with the objective of optimising training prescription and exercise-related load. A systematic search was conducted in the electronic databases PubMed, Google Scholar and Science Direct up to April 2018. Studies that reported kinetic data (e.g. initial and peak-force supported by the upper-limbs, impact-force, peak-flexion-moment of the elbow-joint, rate of propulsive- and impact-, and vertebral-joint compressive-forces) related to push-ups and included trained, recreational and untrained participants, were considered. The risk of bias in the included studies was assessed using the Critical Appraisal Skills Programme scale. From 5290 articles retrieved in the initial search, only 26 studies were included in this review. Kinetic data for 46 push-up variants were assessed. A limitation of the current review is that the relationship between our findings and actual clinical or practical consequences is not statistically proven but can only be inferred from our critical descriptive approach. Overall, this review provides detailed data on specific characteristics and intensities of push-up variations, in order to optimise exercise prescription for training and rehabilitation purposes.

Leg asymmetry and muscle function recovery after anterior cruciate ligament reconstruction in elite athletes: a pilot study on slower recovery of the dominant leg.

The aim of this study was to examine performance in hopping tests in male athletes after anterior cruciate ligament reconstruction (ACLR) in the 4-to-6 months post-surgery period. A total of 36 athletes (24 ACLR and 12 controls) participated in this study. The ACLR group consisted of athletes who had undergone an ACLR on their dominant side (ACL DG n=16) or non-dominant side (ACL NDG n=8). Participants completed the following functional tests: a single-leg hop (SLH), single-leg triple hop (SL3H) and single-leg counter movement jump (SLCMJ), then the limb symmetry index (LSI) was calculated. There were no significant differences between the dominant and the non-dominant legs for all functional tests when comparing the ACL DG and the ACL NDG at 6 months after surgery. At 6 months after ACLR, the LSI of the two legs was within acceptable values, whether the athlete had the operation on their dominant or non-dominant leg (except the mean LSI for the ACL DG in the SLCMJ test). Furthermore, the control group showed higher performances as compared to the ACL group for all variables at 6 months after surgery, despite acceptable LSI. We concluded that an early return to "full participation to training" is not recommended in participants who have undergone an ACLR with patellar tendon grafts.

Reliability and validity of the Zebris FDM-THQ instrumented treadmill during running trials.

Little is known about the reliability, validity and smallest detectable differences of selected kinetic and temporal variables recorded by the Zebris FDM-THQ instrumented treadmill especially during running. Twenty male participants (age = 31.9 years (±5.6), height = 1.81 m (±0.08), mass = 80.2 kg (±9.5), body mass index = 24.53 kg/m2 (±2.53)) walked (5 km/h) and ran (10 and 15 km/h) on an instrumented treadmill, wearing running shoes fitted with Pedar-X insoles. A test-double retest protocol was conducted over two consecutive days. Maximal vertical force (Fmax), contact time (CT) and flight time (FT) data from 10 consecutive steps were collected. Within- and between-day reliability, smallest detectable differences (SDD) and validity (95% limits of agreement (LOA)) were calculated. ICC values for the Zebris for Fmax were acceptable (ICC ≥ 0.7) while CT and FT reliability indices were predominantly good (ICC ≥ 0.8) to excellent (ICC ≥ 0.9). The Zebris significantly underestimated Fmax when compared with the Pedar-X. The 95% LOA increased with speed. SDD ranged between 96 N and 169 N for Fmax, 0.017s and 0.055s for CT and 0.021s and 0.026s for FT. In conclusion, Zebris reliability was acceptable to excellent for the variables examined, but inferior in comparison with Pedar-X. With increased running speeds, a bias effect (underestimation) existed for the Zebris compared with Pedar-X.

Motor Skill Interventions in Children With Developmental Coordination Disorder: A Systematic Review and Meta-Analysis.

OBJECTIVES: To determine the characteristics and effectiveness of motor skill interventions in children with developmental coordination disorder (DCD) and to identify potential moderators of training effects using meta-analysis. DATA SOURCES: A search was conducted in 6 databases (CINAHL Plus, Cochrane Library, Embase, ERIC, PsycINFO, and PubMed) for articles published between 1995 and August 2017 using search items which were grouped into 3 components (motor skill interventions, DCD, and age group of interest). STUDY SELECTION: Studies were included if they recruited children 3 to 17 years of age with DCD, reported performance of motor-related skills as outcomes, were published in peer-reviewed journals, and were written in English. Qualitative synthesis was conducted for all included studies. Quantitative synthesis (meta-analysis) was only conducted for studies using a (quasi) randomized controlled trial design. DATA EXTRACTION: Methodology, participant characteristics, intervention components, outcomes, and statistically significant training effects of each included study were extracted. DATA SYNTHESIS: Sixty-six studies met the inclusion criteria with 18 of the studies eligible for meta-analysis. Motor performance and cognitive, emotional, and other psychological factors were the most common outcomes. Other 3 outcome categories included perceptions and/or satisfaction regarding the children's improvement from significant others, physical fitness, and physical activity and participation. Immediate and moderate training effects were found for motor performance (Hedges g=.63; 95% confidence interval [CI], .31-.94; P<.001) and cognitive, emotional, and other psychological factors (Hedges g=0.65; 95% CI, 0.25-1.04; P=.001). Additionally, dose (minutes in total) and frequency of the intervention were significant moderators of training effect on motor performance. CONCLUSIONS: Motor skill interventions are effective in improving motor competence and performance on cognitive, emotional, and other psychological aspects in children with DCD in the short term. These effects are more robust in interventions using a large training dose and a practicing schedule of high frequency.

A comprehensive strength testing protocol offers no clinical value in predicting risk of hamstring injury: a prospective cohort study of 413 professional football players.

BACKGROUND: Hamstring injuries remain prevalent across a number of professional sports. In football, the incidence has even increased by 4% per year at the Champions League level over the last decade. The role of muscle strength or strength ratios and their association with risk of hamstring injury remain restricted by small sample sizes and inconclusive results. PURPOSE: The purpose of this study is to identify risk factors for hamstring injury in professional football players in an adequately powered, prospective cohort study. Using both established (isokinetic) and novel (eccentric hamstring test device) measures of muscle strength, we aimed to investigate the relationship between these strength characteristics over the entire range of motion with risk of hamstring injury. METHODS: All teams (n=18) eligible to compete in the premier football league in Qatar underwent a comprehensive strength assessment during their annual periodic health evaluation at Aspetar Orthopaedic and Sports Medicine Hospital in Doha, Qatar. Variables included isokinetic strength, Nordic hamstring exercise strength and dynamic hamstring: quadriceps ratios. RESULTS: Of the 413 players included (68.2% of all league players), 66 suffered a hamstring injury over the two seasons. Only isokinetic quadriceps concentric at 300°/s (adjusted for bodyweight) was associated with risk of hamstring injury when considered categorically. Age, body mass and playing position were also associated with risk of hamstring injury. None of the other 23 strength variables examined were found to be associated with hamstring injury. CONCLUSION: The clinical value of isolated strength testing is limited, and its use in musculoskeletal screening to predict future hamstring injury is unfounded.

Change of direction ability in young elite soccer players: determining factors vary with angle variation.

BACKGROUND: The ability to change direction is considered of paramount importance in team sports. Currently there is a lack of consensus regarding the most important physical factors that determine change of direction (COD) ability. Therefore, the aim of this study was to examine the relationship between COD ability and targeted selected physical attributes of sprinting, isometric strength and explosive power. METHODS: Thirty-one young elite soccer players (mean±SD, age =17.4±0.6 years, height =177±0.5 cm; leg length =96.9±3.3 cm, body-mass =69.0±6.2 kg) were recruited. A total of eight COD tasks consisting of; a 5-m sprint then a COD of 45°, 90°, 135° or 180° followed by another 5m sprint were performed using dominant (DL) and non-dominant legs (NDL). Physical tests including a 10-m Straight-Line Sprint Test, 12 lower limb isometric strength tests, and jumping tests including: 1) five alternate Leg Jump Test; 2) triple hop distance (DL and NDL); and 3) Standing Broad Jump Test were performed. RESULTS: Stepwise multiple regression analysis showed that the physical attributes explained between 30% and 74% of the variance of the COD performance. Furthermore, these physical attributes were dependent upon COD angle and direction. CONCLUSIONS: The affecting variables of the COD performance differ according to the angle of COD and the leg used to turn. Moreover, isometric strength of the lower-limb muscles represented a major determinant factor of the COD-ability. Consequently, physical fitness coaches should include isometric muscle strengthening exercises in addition to traditional dynamic muscle strength exercises. Moreover, they should implement specific lower limb strength exercises depending on players' deficit in each COD's angles.

The Effect of Variation of Plyometric Push-Ups on Force-Application Kinetics and Perception of Intensity.

PURPOSE: To examine differences between ground-reaction-force (GRF)-based parameters collected from 5 types of plyometric push-ups. Between-trials reliability and the relationships between parameters were also assessed. METHODS: Thirty-seven highly active commando soldiers performed 3 trials of 5 variations of the plyometric push-up in a counterbalanced order: standard countermovement push-up (SCPu), standard squat push-up (SSPu), kneeling countermovement push-up (KCPu), kneeling squat push-up (KSPu), and drop-fall push-up (DFPu). Vertical GRF was measured during these exercises using a portable Kistler force plate. The GRF applied by the hands in the starting position (initial force supported), peak GRF and rate of force development during takeoff, flight time, impact force, and rate of force development impact on landing were determined. RESULTS: During standard-position exercises (SCPu and SSPu) the initial force supported and impact force were higher (P < .001) than with kneeling exercises (KCPu, KSPu, and DFPu). The peak GRF and rate of force development during takeoff were higher (P < .001) in the countermovement push-up exercises ([CMP] SCPu, KCPu, and DFPu) than squat push-up exercises ([SP] SSPu and KSPu). Furthermore, the flight time was greater (P < .001) during kneeling exercises than during standard-position exercises. A significant relationship (P < .01) between impact force and the rate of force development impact was observed for CMP and SP exercises (r = .83 and r = .62, respectively). The initial force supported was also negatively related (P < .01) to the flight time for both CMP and SP (r = -.74 and r = -.80, respectively). It was revealed that the initial force supported and the peak GRF during takeoff had excellent reliability; however, other parameters had poor absolute reliability. CONCLUSIONS: It is possible to adjust the intensity of plyometric push-up exercises and train athletes' muscle power by correctly interpreting GRF-based parameters. However, caution is required as some parameters had marginal absolute reliability.

Impact of Climatic Conditions on Physical Activity: A 2-Year Cohort Study in the Arabian Gulf Region.

BACKGROUND: Little is known about the effects that climatic conditions, especially extreme heat, have on physical activity (PA) levels. The aim of this 2-year cohort analysis undertaken in the Arabian Gulf region was to assess changes in objectively-assessed PA as a result of changes in climatic conditions. METHODS: A total of 2088 adults (1390 men and 698 women) from many regions of the world were enrolled in a community health program in Qatar, were included in this study. For 2 years participants recorded daily step count using an Omron HJ-720 ITC pedometer. Daily climate parameters included temperature, relative humidity and other conditions. RESULTS: From linear mixed model analysis it was evident that higher average temperature and humidity, and the Wet bulb Globe Temperature (WbGT), resulted in a reduction of the number of steps taken per day. Analysis of interaction effects also revealed that the effects of heat stress were equivalent across gender, age, and the region participants came from according to a World Health Organization classification scheme. CONCLUSIONS: Increased temperature and humidity are associated with a reduction in the number of steps taken per day. Community-based PA programs in hot hot/humid climates should consider novel approaches to increase PA levels.

Effects of Fundamental Movement Skills Training on Children With Developmental Coordination Disorder.

The purpose of this study was to examine the effects of fundamental movement skills (FMS) training on FMS proficiency, self-perceived physical competence (SPC), physical activity (PA), and sleep disturbance in children with developmental coordination disorder (DCD) compared with children with typical development (TD). A total of 84 children were allocated into either experimental group (DCD[exp], TD[exp]) who received 6 weeks of FMS training or control groups (DCD[con], TD[con]). FMS were assessed using the Test of Gross Motor Development-2, whereas PA was monitored using accelerometers. SPC and sleep disturbance were evaluated using questionnaires. Results showed that the DCD[exp] group had significantly higher scores in FMS and SPC compared with the DCD[con] group at posttest. The DCD[exp] group scored lower in sleep disturbance at follow-up when compared with posttest. It is suggested that short-term FMS training is effective in improving FMS and SPC and reducing sleep disturbances for children with DCD.

A preliminary investigation of trunk and wrist kinematics when using drivers with different shaft properties.

It is unknown whether skilled golfers will modify their kinematics when using drivers of different shaft properties. This study aimed to firstly determine if golf swing kinematics and swing parameters and related launch conditions differed when using modified drivers, then secondly, determine which kinematics were associated with clubhead speed. Twenty high level amateur male golfers (M ± SD: handicap = 1.9 ± 1.9 score) had their three-dimensional (3D) trunk and wrist kinematics collected for two driver trials. Swing parameters and related launch conditions were collected using a launch monitor. A one-way repeated measures ANOVA revealed significant (p ≤ 0.003) between driver differences; specifically, faster trunk axial rotation velocity and an early wrist release for the low kick point driver. Launch angle was shown to be 2° lower for the high kick point driver. Regression models for both drivers explained a significant amount of variance (60-67%) in clubhead speed. Wrist kinematics were most associated with clubhead speed, indicating the importance of the wrists in producing clubhead speed regardless of driver shaft properties.

Multi-segment trunk models used to investigate the crunch factor in golf and their relationship with selected swing and launch parameters.

The use of multi-segment trunk models to investigate the crunch factor in golf may be warranted. The first aim of the study was to investigate the relationship between the trunk and lower trunk for crunch factor-related variables (trunk lateral bending and trunk axial rotation velocity). The second aim was to determine the level of association between crunch factor-related variables with swing (clubhead velocity) and launch (launch angle). Thirty-five high-level amateur male golfers (Mean ± SD: age = 23.8 ± 2.1 years, registered golfing handicap = 5 ± 1.9) without low back pain had kinematic data collected from their golf swing using a 10-camera motion analysis system operating at 500 Hz. Clubhead velocity and launch angle were collected using a validated real-time launch monitor. A positive relationship was found between the trunk and lower trunk for axial rotation velocity (r(35) = .47, P < .01). Cross-correlation analysis revealed a strong coupling relationship for the crunch factor (R(2) = 0.98) between the trunk and lower trunk. Using generalised linear model analysis, it was evident that faster clubhead velocities and lower launch angles of the golf ball were related to reduced lateral bending of the lower trunk.

Back pain beliefs in adolescents and adults in Australasia: A cross-sectional pilot study of selected psychometric properties of paper-based and web-based questionnaires in two diverse countries.

BACKGROUND: It is unknown whether questionnaires measuring psychosocial constructs related to low back pain (LBP) that were originally designed for adults are suitable for adolescents, and if paper and web-versions have similar measurement properties. OBJECTIVES: To examine selected psychometric properties for the paper- and web-based Back-Beliefs Questionnaire (BBQ) and the Fear Avoidance Beliefs Questionnaire (FABQ-phys) among adults and adolescents in two diverse countries and to determine whether differences existed between countries and pain groups. METHODS: A sample of 156 adults (Hong Kong, n= 75; Australia, n= 81) and 96 adolescents (Hong Kong, n= 61; Australia, n= 35) participated in this cross-sectional study. RESULTS: Main effects for country and administration mode were observed in adult BBQ scores, where Australian adults reported significantly higher BBQ scores than Hong Kong adults (mean difference (MD); 95% CI: 2.85; 0.96-4.74) and significantly higher scores were recorded on the web mode compared to the paper mode (MD 0.74; 0.10-1.38). Similarly, Hong Kong adults and adolescents reported higher FABQ-phys scores than Australian adults and adolescents (MD; 95% CI: 3.40; 1.37-5.43 and 4.88; 0.53-9.23, respectively). Internal consistency values were mostly acceptable (α ≥ 0.7). CONCLUSION: Differences exist between cultures for LBP-related beliefs. The BBQ and FABQ-phys have acceptable measurement properties in both administration modes.

An exploration of familial associations of two movement pattern-derived subgroups of chronic disabling low back pain; a cross-sectional cohort study.

BACKGROUND: Altered movement patterns with pain have been demonstrated in children, adolescents and adults with chronic disabling low back pain (CDLBP). A previously developed classification system has identified different subgroups including active extension and multidirectional patterns in patients with CDLBP. While familial associations have been identified for certain spinal postures in standing, it is unknown whether a familial relationship might exist between movement pattern-derived subgroups in families with CDLBP. OBJECTIVES: This study explored whether familial associations in movement pattern-derived subgroups within and between members of families with CDLBP existed. DESIGN: Cross-sectional cohort study. METHOD: 33 parents and 28 children with CDLBP were classified into two subgroups based on clinical analysis of video footage of postures and functional movements, combined with aggravating factors obtained from Oswestry Disability Questionnaire. Prevalence of subgroups within family members was determined, associations between parent and child's subgroup membership was evaluated using Fisher's exact test, and spearman's correlation coefficient was used to determine the strength of association between familial dyads. RESULTS: The majority of parents were classified as active extenders, sons predominately multidirectional and daughters were evenly distributed between the two subgroups. No significant association was found when comparing subgroups in nine parent-child relationships. CONCLUSIONS: The exploration of a small cohort of family dyads in this study demonstrated that children's movement pattern-derived subgroups could not be explained by their parents' subgroup membership. These results cannot be generalised to the CLBP population due to this study's small sample. Larger sample studies are needed to further elucidate this issue.

Fundamental movement skills proficiency in children with developmental coordination disorder: does physical self-concept matter?

PURPOSE: The purpose of this study was to (1) examine differences in fundamental movement skills (FMS) proficiency, physical self-concept, and physical activity in children with and without developmental coordination disorder (DCD), and (2) determine the association of FMS proficiency with physical self-concept while considering key confounding factors. METHOD: Participants included 43 children with DCD and 87 age-matched typically developing (TD) children. FMS proficiency was assessed using the Test of Gross Motor Development - second edition. Physical self-concept and physical activity were assessed using self-report questionnaires. A two-way (group by gender) ANCOVA was used to determine whether between-group differences existed in FMS proficiency, physical self-concept, and physical activity after controlling for age and BMI. Partial correlations and hierarchical multiple regression models were used to examine the relationship between FMS proficiency and physical self-concept. RESULTS: Compared with their TD peers, children with DCD displayed less proficiency in various components of FMS and viewed themselves as being less competent in physical coordination, sporting ability, and physical health. Physical coordination was a significant predictor of ability in object control skills. DCD status and gender were significant predictors of FMS proficiency. CONCLUSIONS: Future FMS interventions should target children with DCD and girls, and should emphasize improving object control skills proficiency and physical coordination. IMPLICATIONS FOR REHABILITATION: Children with DCD tend to have not only lower FMS proficiency than age-matched typically developing children but also lower physical self-concept. Self-perceptions of physical coordination by children with DCD are likely to be valuable contributors to development of object control skills. This may then help to develop their confidence in performing motor skills. Children with DCD need supportive programs that facilitate the development of object control skills. Efficacy of training programs may be improved if children experience a greater sense of control and success when performing object control skills.

Low BACK PAIN BELIEFS AND THEIR RELATIONSHIPS WITH Low BACK PAIN-RELATED DISABILITY IN NURSES WORKING IN MAINLAND CHINA AND IN AUSTRALIA.

Beliefs held about low back pain (LBP) can influence treatment outcomes and the development of LBP-related disability. Beliefs are shaped by cultural norms but few cross-cultural studies have been done. This cross-sectional study investigated the back pain beliefs and their associations with disability in 109 Chinese nurses and 165 Australian Caucasian nurses. Chinese nurses held more pessimistic views about the consequences of LBP than the Australian and those with LBP held higher level of fear avoidance beliefs and had higher disability than the Australian nurses with LBP. In both groups, more negativeback pain beliefs were significantly associated with higher disability.

Spinal Kinematics of Adolescent Male Rowers with Back Pain in Comparison with Matched Controls During Ergometer Rowing.

There is a high prevalence of low back pain (LBP) in adolescent male rowers. In this study, regional lumbar spinal kinematics and self-reported LBP intensity were compared between 10 adolescent rowers with moderate levels of LBP relating to rowing with 10 reporting no history of LBP during a 15-minute ergometer trial using an electromagnetic tracking system. Adolescent male rowers with LBP reported increasing pain intensity during ergometer rowing. No significant differences were detected in mean upper or lower lumbar angles between rowers with and without LBP. However, compared with rowers without pain, rowers with pain: (1) had relatively less excursion of the upper lumbar spine into extension over the drive phase, (2) had relatively less excursion of the lower lumbar spine into extension over time, (3) had greater variability in upper and lower lumbar angles over the 15-minute ergometer trial, (4) positioned their upper lumbar spine closer to end range flexion for a greater proportion of the drive phase, and (5) showed increased time in sustained flexion loading in the upper lumbar spine. Differences in regional lumbar kinematics exist between adolescent male rowers with and without LBP, which may have injury implication and intervention strategies.

Outcomes of the Rope Skipping 'STAR' Programme for Schoolchildren.

Physical activity in children and adolescents is on a decline trend. To this end, we conducted a matched-pair randomized controlled trial to examine the effects of a 4-week STAR (School-based; Train-the-trainer; Accessibility of resources; Recreational) skipping programme. 1,386 schoolchildren from 20 primary and secondary schools were recruited. Schools were randomized into the experimental or wait-list control group. Participants self-reported their health-related quality of life using the KIDSCREEN-27. Accelerometers were used to measure the time a subgroup of participants (n = 480) spent in moderate-to-vigorous physical activity during school hours on five consecutive days. Measures were taken at pre- and post-test. At post-test, students in the experimental group, compared to those in the control group, engaged in less moderate-to-vigorous physical activity during school hours. Health-related quality of life from two groups of students was similar, but the experimental group reported higher levels of autonomy and parent relationships. Results suggested that although the intervention did not increase students' physical activity levels, it slightly improved their health-related quality of life. Future studies should explore personal factors that might mediate the effect of the intervention.

Carry-Over of Force Production Symmetry in Athletes of Differing Strength Levels.

This study sought to determine the level of association between bilateral force production symmetry assessment methods (standing weight distribution [WtD], unloaded and lightly loaded jumps, and isometric strength) and to determine whether the amount of symmetry carry-over between these tasks differs for strong and weak athletes. Subjects for this study included male (n = 31) and female (n = 32) athletes from National Collegiate Athletic Association Division I sports. Athletes performed WtD, unloaded and lightly loaded (20 kg) static and countermovement jumps, and isometric midthigh pull (IMTP) assessments on 2 adjacent force plates. Ground reaction force data were used to calculate symmetry variables and performance-related variables. Using Pearson zero order correlations, evaluations of the amount of symmetry carry-over were made. Weight distribution correlated strongly with jump peak force (PF) (r = 0.628-0.664). Strong relationships were also observed between loading conditions for jump variables (r = 0.568-0.957) as were the relationships between jump types for PF, peak power, and net impulse (r = 0.506-0.834). Based on the pooled sample, there was a lack of association between IMTP and WtD for jump symmetry variables. However, when examining strong and weak groups, rate of force development showed moderate to strong symmetry carry-over in the strongest athletes (r = 0.416-0.589). Stronger athletes appear to display similar explosive strength symmetry characteristics in dynamic and isometric assessments, unlike weaker athletes. Strength seems to influence the amount of force production symmetry carry-over between bilateral assessments. There may be optimal loads and variables for symmetry assessment, but these may differ based on population characteristics.

Psychometric properties of the Chinese (Cantonese) versions of the KIDSCREEN health-related quality of life questionnaire.

PURPOSE: The KIDSCREEN questionnaire assesses health-related quality of life in children and adolescents. In this study, the questionnaire was translated into Chinese (Cantonese) and administered to two independent groups of Hong Kong Chinese students. Various aspects of reliability and validity of the KIDSCREEN-52 and KIDSCREEN-27 questionnaires were examined. METHODS: The translated KIDSCREEN-52 questionnaire (and thus the KIDSCREEN-27 as a subset of the long form) was administered to cohorts of 1379 and 555 students. Confirmatory factor analysis and partial credit Rasch analyses were used to examine the underlying structure of the instrument. Test-retest reliability, convergent, and divergent validity were also examined. RESULTS: The 10-factor structure of the Chinese KIDSCREEN-52 was supported. However, the original five-factor model of the KIDSCREEN-27 was not supported as seven distinct factors were found. Internal consistency and test-retest reliability were acceptable. Evidence supporting convergent and divergent validity was found. CONCLUSIONS: Results from the two studies supported the use of the translated Chinese version of KIDSCREEN questionnaire children and adolescents' health-related quality of life. Further research is required to examine possible cultural or language differences between the original version and the translated Chinese version of the questionnaire.

Cognitive functional approach to manage low back pain in male adolescent rowers: a randomised controlled trial.

BACKGROUND: Low back pain (LBP) is prevalent among adolescent rowers. This study evaluated the efficacy of a cognitive functional approach to reduce LBP in this population. METHODS: Thirty-six adolescent male rowers reporting LBP participated. Nineteen were randomly allocated to the intervention group to receive a cognitive functional approach targeting cognitions, movement patterns, conditioning and lifestyle factors relevant to each rower for 8 weeks. The active control group (n=17) received usual care from their coaches (rowing skills and conditioning exercises). The primary outcome of the study was pain intensity as measured by the Numeric Pain Rating Scale during a 15 min ergometer trial preintervention and postintervention. Disability (Patient Specific Functional Scale and Roland Morris Disability Questionnaire) was measured preintervention/postintervention and at 12 weeks follow-up. Isometric muscle endurance of the back extensors and lower limb muscles, usual sitting posture and regional lumbar kinematic data during a 15 min ergometer row were measured preintervention/postintervention. RESULTS: Compared with the control group, the intervention group reported significantly less pain during ergometer rowing (Numeric Pain Rating Scale -2.4, p=0.008) and reduced disability (Patient Specific Functional Scale (4.1, p=0.01); Roland Morris Disability Questionnaire (-1.7, p=0.003)) following the intervention, and at 12 weeks follow-up. They also demonstrated greater lower limb muscle endurance (20.9 s, p=0.03) and postured their lower lumbar spine in greater extension during static sitting (-9.6°, p=0.007). No significant differences were reported in back muscle endurance and regional lumbar kinematics during ergometer rowing. CONCLUSION: Cognitive functional approach was more effective than usual care in reducing pain and disability in adolescent male rowers. CLINICAL TRIAL REGISTRY NUMBER: Australian and New Zealand Clinical Trial Registry Number 12609000565246.