Validity of a low-cost laser with freely available software for improving measurement of walking and running speed.

OBJECTIVES: Accurately measuring speed and acceleration during walking, running and sprinting has important implications for rehabilitation, planning training and talent identification in sporting and clinical populations. Light detection and ranging laser technology provides a continuous stream of distance data. It has the potential to allow rapid and precise measurement and may be advantageous compared with discrete methods of assessment, such as stopwatches and timing gates, which may be inaccurate over short distances. Therefore, the aim of this study was to assess the validity of a novel, low-cost and easy to implement laser-based system during walking and running trials. DESIGN: Cross-sectional study. METHODS: Thirty-two healthy adults performed walking and running trials from flying and static starts while monitored concurrently with reference standard three-dimensional motion analysis and laser systems. Velocity was calculated over short (0.5m) and longer (3m) intervals using both systems. Validity was assessed using absolute agreement intraclass correlation coefficients (ICC2,1), mean absolute errors, Pearson's correlations and regressions and Bland-Altman plots. RESULTS: All intraclass correlation coefficients and correlations were excellent (ICC>0.88, R>0.89). For the longer interval, all mean absolute errors were <0.03m/s (0.24-1.31%). Slightly higher mean absolute error values were reported for the shorter interval (3.16-5.10%), with the highest error of 0.184m/s evident for the flying start running trial. CONCLUSIONS: These results indicate that a low-cost and accessible laser system can be used to accurately assess walking and running speed. To aid implementation and further research, freely available hardware design descriptions and downloadable software can be accessed at www.rehabtools.org/LIDAR.

Knee flexion not hip extension strength is persistently reduced following hamstring strain injury in Australian Football athletes: Implications for Periodic Health Examinations.

OBJECTIVES: Determine whether clinically feasible tests of isometric lower limb strength and range of motion (ROM) in Australian Football (AF) athletes are useful in Periodic Health Examinations to identify persistent deficits following hamstring strain injury (HSI). DESIGN: Case-control. METHODS: Thirty-seven male, semi-professional AF athletes (mean±SD; age, 20.2±2.9years; height, 1.7±0.5m; mass, 81±9.2kg) participated, ten athletes (37%) reported HSI within the previous three seasons of competition. Comparisons of pre-season isometric knee flexion and hip extension strength variables (peak force, torque and torque normalised to body mass) and hip, knee and ankle ROM measures were made between athletes with and without past-history of HSI using linear mixed-effect models. A logistic regression evaluated whether any of the outcome measures could differentiate athletes with a past-history of HSI. RESULTS: Knee flexion peak force, torque and torque normalised to body mass were significantly reduced in athletes with a past-history of HSI (coefficient, 95% CI) (-44.8N, -86.3 to -3.3), (-22.2Nm, -40.5 to -3.7) and (-0.2Nmkg-1, -0.4 to 0.0) respectively. Knee flexion peak torque normalised to body mass (Nmkg-1) approached significance as a test was able to differentiate athletes with history of HSI (p=0.068). There were no differences between groups for any hip extension strength or lower limb ROM outcome measures. CONCLUSIONS: Deficits in isometric peak knee flexion strength persist for up to three seasons following HSI in AF athletes. Isometric knee flexion strength testing may be a clinically feasible option for Periodic Health Examinations and inform tertiary injury prevention strategies.

Knee flexion strength is significantly reduced following competition in semi-professional Australian Rules football athletes: Implications for injury prevention programs.

OBJECTIVES: To evaluate strength and flexibility measures pre- and post- Australian Football (AF) competition to determine their potential utility as secondary prevention measures. DESIGN: Cohort study. SETTING: Semi-professional AF club. PARTICIPANTS: Ten male AF athletes (mean ±â€¯SD; age, 21.3 ±â€¯2.2 years; height, 186.1 ±â€¯6.3 cm; weight, 83.5 ±â€¯8.6 kg). MAIN OUTCOME MEASURES: Maximal unilateral isometric knee flexion strength performed in 45 degrees of hip flexion and 30 degrees of knee flexion, flexibility measures of hip and knee extension and ankle dorsiflexion. All outcome measures were evaluated pre-match to determine baseline measurements and repeated acutely post-match and at 26, 50 and 74 h following. Comparisons were made between baseline measures and all other time points. RESULTS: Knee flexion strength was significantly reduced at a group level acutely (-122.8N, 95%CI -156.2 to -89.4, p = 0.000) and at 26 h (-89.6N, 95%CI -122.9 to -56.2, p = 0.000) following competition. Hamstring flexibility was significantly reduced at all time periods following competition (all p < 0.05), however these values were not clinically meaningful. CONCLUSIONS: Knowledge that unilateral isometric knee flexion strength returns to pre-competition levels by 50 h following match-play in AF athletes is valuable for planning recovery time frames and may inform implementation of secondary prevention strategies.

Three-dimensional assessment of squats and drop jumps using the Microsoft Xbox One Kinect: Reliability and validity.

The Microsoft Xbox One Kinect™ (Kinect V2) contains a depth camera that can be used to manually identify anatomical landmark positions in three-dimensions independent of the standard skeletal tracking, and therefore has potential for low-cost, time-efficient three-dimensional movement analysis (3DMA). This study examined inter-session reliability and concurrent validity of the Kinect V2 for the assessment of coronal and sagittal plane kinematics for the trunk, hip and knee during single leg squats (SLS) and drop vertical jumps (DVJ). Thirty young, healthy participants (age = 23 ± 5yrs, male/female = 15/15) performed a SLS and DVJ protocol that was recorded concurrently by the Kinect V2 and 3DMA during two sessions, one week apart. The Kinect V2 demonstrated good to excellent reliability for all SLS and DVJ variables (ICC ≥ 0.73). Concurrent validity ranged from poor to excellent (ICC = 0.02 to 0.98) during the SLS task, although trunk, hip and knee flexion and two-dimensional measures of knee abduction and frontal plane projection angle all demonstrated good to excellent validity (ICC ≥ 0.80). Concurrent validity for the DVJ task was typically worse, with only two variables exceeding ICC = 0.75 (trunk and hip flexion). These findings indicate that the Kinect V2 may have potential for large-scale screening for ACL injury risk, however future prospective research is required.

Exercise Interventions for the Prevention and Treatment of Groin Pain and Injury in Athletes: A Critical and Systematic Review.

BACKGROUND: Groin injury is a common musculoskeletal complaint for athletes competing in a variety of sports. The extent to which exercise interventions incorporating external load are an appropriate option for the treatment and prevention of groin injury in athletes is not yet clear. OBJECTIVES: The aim of this review was to describe and evaluate exercise therapy interventions and outcomes for the treatment and prevention of groin injury with specific attention to application of external load. DATA SOURCES: The databases Medline, PubMed, SPORTDiscus, Web of Science, and Cochrane were searched on 18 April 2016. STUDY ELIGIBILITY CRITERIA: This review was registered as PROSPERO CRD42016037752 and a systematic search was conducted with the following inclusion criteria: any study design evaluating exercise interventions for the prevention or treatment of groin pain in athletes. DATA ANALYSIS: Two independent authors screened search results, performed data extraction, assessed risk of bias using the modified Downs and Black appraisal tool and determined strength and level of evidence. Reporting standards for exercise interventions were assessed using the Consensus for Exercise Reporting Template (CERT). RESULTS: A total of 1320 titles were identified with 14 studies satisfying the inclusion criteria, four (29%) of which demonstrated low risk of bias. Ten (71%) studies utilised external load as a component of the exercise intervention. Reporting standards for exercise intervention scores ranged from 0 to 63%. CONCLUSION: There is limited evidence from level 2 and 3 studies indicating exercise therapy may reduce the incidence and hazard risk of sustaining a groin injury in athletes. There is strong evidence from level 4 studies indicating exercise therapy is beneficial as a treatment for groin injury in athletes in terms of symptom remission, return to sport and recurrence outcomes. However, there are limited studies with low risk of bias, and exercise interventions for the treatment of groin injury are poorly described.

Injuries impair the chance of successful performance by sportspeople: a systematic review.

BACKGROUND: Cost-benefit analyses have been proposed for determining acceptable risk of injury regarding training and competition participation. Currently, there is no best evidence synthesis of the literature evaluating the relationship between injury/illness and chance of success or failure. OBJECTIVE: To evaluate the relationship between injury and/or illness and success and/or failure in athletic populations (individual and team sports). METHODS: This review was prospectively registered (PROSPERO CRD42016036729) and a systematic electronic search was conducted in May 2016. Inclusion criterion was any study design describing the association between injury and/or illness and success or failure in athletic performance. Two independent authors screened search results, performed data extraction and assessed methodological quality and strength of evidence using a modified Downs and Black appraisal tool and a modified van Tulder method, respectively. RESULTS: Of 10 546 titles identified, 14 satisfied the inclusion criteria and 7 had low risk of bias. Outcome measures associated with success and/or failure included: (1) availability of team members, (2) injury incidence, (3) injury burden, (4) squad utilisation and (5, 6) precompetition and in-competition injury. There was strong evidence that (1) increased availability of team members/athletes decreased the risk of failure and (2) precompetition and in-competition injuries were associated with increased risk of failure. CONCLUSIONS: Injuries have a detrimental impact on team and individual athletic success. Increased player availability improves chances of success. Conversely, injuries sustained both prior to and during competition may increase risk of failure. Injury prevention should therefore be a priority for maximising athletic performance.

The reliability of a maximal isometric hip strength and simultaneous surface EMG screening protocol in elite, junior rugby league athletes.

OBJECTIVES: Firstly to describe the reliability of assessing maximal isometric strength of the hip abductor and adductor musculature using a hand held dynamometry (HHD) protocol with simultaneous wireless surface electromyographic (sEMG) evaluation of the gluteus medius (GM) and adductor longus (AL). Secondly, to describe the correlation between isometric strength recorded with the HHD protocol and a laboratory standard isokinetic device. DESIGN: Reliability and correlational study. METHODS: A sample of 24 elite, male, junior, rugby league athletes, age 16-20 years participated in repeated HHD and isometric Kin-Com (KC) strength testing with simultaneous sEMG assessment, on average (range) 6 (5-7) days apart by a single assessor. Strength tests included; unilateral hip abduction (ABD) and adduction (ADD) and bilateral ADD assessed with squeeze (SQ) tests in 0 and 45° of hip flexion. RESULTS: HHD demonstrated good to excellent inter-session reliability for all outcome measures (ICC(2,1)=0.76-0.91) and good to excellent association with the laboratory reference KC (ICC(2,1)=0.80-0.88). Whilst intra-session, inter-trial reliability of EMG activation and co-activation outcome measures ranged from moderate to excellent (ICC(2,1)=0.70-0.94), inter-session reliability was poor (all ICC(2,1)<0.50). CONCLUSIONS: Isometric strength testing of the hip ABD and ADD musculature using HHD may be measured reliably in elite, junior rugby league athletes. Due to the poor inter-session reliability of sEMG measures, it is not recommended for athlete screening purposes if using the techniques implemented in this study.

A simple method for quantifying jump loads in volleyball athletes.

OBJECTIVES: Evaluate the validity of a commercially available wearable device, the Vert, for measuring vertical displacement and jump count in volleyball athletes. Propose a potential method of quantifying external load during training and match play within this population. DESIGN: Validation study. METHODS: The ability of the Vert device to measure vertical displacement in male, junior elite volleyball athletes was assessed against reference standard laboratory motion analysis. The ability of the Vert device to count jumps during training and match-play was assessed via comparison with retrospective video analysis to determine precision and recall. A method of quantifying external load, known as the load index (LdIx) algorithm was proposed using the product of the jump count and average kinetic energy. RESULTS: Correlation between two separate Vert devices and three-dimensional trajectory data were good to excellent for all jump types performed (r=0.83-0.97), with a mean bias of between 3.57-4.28cm. When matched against jumps identified through video analysis, the Vert demonstrated excellent precision (0.995-1.000) evidenced by a low number of false positives. The number of false negatives identified with the Vert was higher resulting in lower recall values (0.814-0.930). CONCLUSIONS: The Vert is a commercially available tool that has potential for measuring vertical displacement and jump count in elite junior volleyball athletes without the need for time-consuming analysis and bespoke software. Subsequently, allowing the collected data to better quantify load using the proposed algorithm (LdIx).

Single-Leg Squat Performance is Impaired 1 to 2 Years After Hip Arthroscopy.

OBJECTIVE: To evaluate single-leg squat performance 1-2 years after arthroscopy for intra-articular hip pathology compared with control subjects and the nonsurgical limb, and to investigate whether single-leg squat performance on the operated limb was associated with hip muscle strength. DESIGN: Cross-sectional study. SETTING: Private physiotherapy clinic and university laboratory. PARTICIPANTS: Thirty-four participants (17 women, 36.7 ± 12.6 years) 1-2 years after hip arthroscopy and 34 gender-matched control subjects (17 women, 33.1 ± 11.9 years). METHODS: Participants performed single-leg squats using a standardized testing procedure. Squat performance was captured using video. Video footage was uploaded and reformatted for analyses. Hip muscle strength was measured with handheld dynamometry using reliable methods. OUTCOME MEASURES: Frontal plane pelvic obliquity, hip adduction, and knee valgus were measured. Repeated measures analysis of variance evaluated between-group differences, with limb as a within-subjects factor (surgical versus nonsurgical) and gender as a between-subjects factor (P < .05). RESULTS: The hip arthroscopy group demonstrated significantly greater apparent hip adduction (mean difference 2.7°, 95% confidence interval [CI] 0.7°-4.8°) and apparent knee valgus (4.0°, 95% CI 1.0°-7.1°) at peak squat depth compared with control subjects. The operated limb also demonstrated significantly greater pelvic obliquity during single-leg stance compared with the nonsurgical limb (1.2°, 95% CI 0.1°-2.3°). Women had significantly greater apparent hip adduction (standing 1.6°, 95% CI 0.5°-2.6°; peak squat depth 2.4°, 95% CI 0.3°-4.4°) and apparent knee valgus (standing 3.3°, 95% CI 1.8°-4.7°; peak squat depth 3.1°, 95% CI 0°-6.1°). Significant positive correlations were found between frontal plane angles and hip flexor and extensor peak torque (P > .05). CONCLUSION: One to 2 years after hip arthroscopy, deficits in single-leg squat performance exist that have the potential to increase hip joint impingement and perpetuate postoperative symptoms. Rehabilitation after hip arthroscopy should target retraining in functional single-leg positions.

Reliability and concurrent validity of a Smartphone, bubble inclinometer and motion analysis system for measurement of hip joint range of motion.

OBJECTIVES: Traditional methods of assessing joint range of motion (ROM) involve specialized tools that may not be widely available to clinicians. This study assesses the reliability and validity of a custom Smartphone application for assessing hip joint range of motion. DESIGN: Intra-tester reliability with concurrent validity. METHODS: Passive hip joint range of motion was recorded for seven different movements in 20 males on two separate occasions. Data from a Smartphone, bubble inclinometer and a three dimensional motion analysis (3DMA) system were collected simultaneously. Intraclass correlation coefficients (ICCs), coefficients of variation (CV) and standard error of measurement (SEM) were used to assess reliability. To assess validity of the Smartphone application and the bubble inclinometer against the three dimensional motion analysis system, intraclass correlation coefficients and fixed and proportional biases were used. RESULTS: The Smartphone demonstrated good to excellent reliability (ICCs>0.75) for four out of the seven movements, and moderate to good reliability for the remaining three movements (ICC=0.63-0.68). Additionally, the Smartphone application displayed comparable reliability to the bubble inclinometer. The Smartphone application displayed excellent validity when compared to the three dimensional motion analysis system for all movements (ICCs>0.88) except one, which displayed moderate to good validity (ICC=0.71). CONCLUSIONS: Smartphones are portable and widely available tools that are mostly reliable and valid for assessing passive hip range of motion, with potential for large-scale use when a bubble inclinometer is not available. However, caution must be taken in its implementation as some movement axes demonstrated only moderate reliability.