Kane Middleton

The influence of elbow joint kinematics on wrist speed in cricket fast bowling

Abstract This modelling study sought to describe the relationships between elbow joint kinematics and wrist joint linear velocity in cricket fast bowlers, and to assess the sensitivity of wrist velocity to systematic manipulations of empirical joint kinematic profiles. A 12-camera Vicon motion analysis system operating at 250 Hz recorded the bowling actions of 12 high performance fast bowlers. Empirical elbow joint kinematic data were entered into a cricket bowling specific “Forward Kinematic Model” and then subsequently underwent fixed angle, angular offset and angle amplification manipulations. A combination of 20° flexion and 20° abduction at the elbow was shown to maximise wrist velocity within the experimental limits. An increased elbow flexion offset manipulation elicited an increase in wrist velocity. Amplification of elbow joint flexion–extension angular displacement indicated that, contrary to previous research, elbow extension range of motion and angular velocity at the time of ball release were negatively related to wrist velocity. Some relationships between manipulated joint angular waveforms and wrist velocity were non-linear, supporting the use of a model that accounts for the non-linear relationships between execution and outcome variables in assessing the relationships between elbow joint kinematics and wrist joint velocity in cricket fast bowlers.

The association between lower limb biomechanics and ball release speed in cricket fast bowlers: a comparison of high-performance and amateur competitors.

Abstract The aim of this study was to compare the associations between lower limb biomechanics and ball release speed in 15 high-performance (HP) and 15 amateur fast bowlers. Kinematic and kinetic variables of the lower limbs collected in the laboratory environment with a 3D Vicon motion analysis system were compared between groups, as well as their associations with ball release speed. HP bowlers had a significantly higher run-up velocity at back foot impact but this difference became non-significant at ball release. Front knee kinematics were not statistically different, however effect sizes revealed medium-large differences with the HP group displaying a more extended knee joint at maximum flexion (d = 0.72) and ball release (d = 0.76). Only front hip positive power was significantly higher in the HP group and it was suggested that the probable cause was the HP bowlers having less knee flexion after front foot impact. From a joint power analysis, the extensor muscle groups of the hip and knee were shown to be important in developing ball release speed. This highlights the need for lower limb/core strength programmes to be multifaceted and focus on the muscles associated with both power and stability.

Lift performance and lumbar loading in standing and seated lifts

Abstract This study investigated the effect of posture on lifting performance. Twenty-three male soldiers lifted a loaded box onto a platform in standing and seated postures to determine their maximum lift capacity and maximum acceptable lift. Lift performance, trunk kinematics, lumbar loads, anthropometric and strength data were recorded. There was a significant main effect for lift effort but not for posture or the interaction. Effect sizes showed that lumbar compression forces did not differ between postures at lift initiation (Standing 5566.2 ± 627.8 N; Seated 5584.0 ± 16.0) but were higher in the standing posture (4045.7 ± 408.3 N) when compared with the seated posture (3655.8 ± 225.7 N) at lift completion. Anterior shear forces were higher in the standing posture at both lift initiation (Standing 519.4 ± 104.4 N; Seated 224.2 ± 9.4 N) and completion (Standing 183.3 ± 62.5 N; Seated 71.0 ± 24.2 N) and may have been a result of increased trunk flexion and a larger horizontal distance of the mass from the L5-S1 joint. Practitioner Summary: Differences between lift performance and lumbar forces in standing and seated lifts are unclear. Using a with-in subjects repeated measures design, we found no difference in lifted mass or lumbar compression force at lift initiation between standing and seated lifts.

The inter-tester repeatability of a model for analysing elbow flexion-extension during overhead sporting movements

AbstractThis study investigates the inter-tester repeatability of an upper limb direct kinematic (ULDK) model specifically for the reporting of elbow flexion-extension (FE) during overhead sporting movements, such as cricket bowling. The ULDK model consists of an upper arm and a forearm connected with a 6° of freedom elbow joint. The ULDK model was assessed for inter-tester repeatability by calculating elbow FE during cricket bowling in two sessions, with unique testers applying the kinematic marker set in each session. Analysis of both elbow FE time-varying waveforms (statistical parametric mapping = 0% time different) and extracted discrete events (no statistical differences, strong correlations > 0.9) support that this model is inter-tester repeatable at assessing elbow FE within the context of cricket bowling. This model is recommended as a framework in future studies for measuring elbow kinematics during other overhead sporting tasks, with recommendations for further participant-specific considerations. Graphical abstractᅟ

Modifiable anthropometric characteristics are associated with unilateral and bilateral carry performance.

Abstract Beck, B, Carstairs, GL, Billing, DC, Caldwell, JN, and Middleton, KJ. Modifiable anthropometric characteristics are associated with unilateral and bilateral carry performance. J Strength Cond Res 31(2): 489–494, 2017—A mismatch between physical ability and task requirements can increase the risk of on-the-job injury. Therefore, understanding key anthropometric characteristics associated with job performance is important in developing targeted training programs and selecting employees in physically demanding occupations. The aims of this study were to understand which anthropometric and demographic (age/sex) characteristics were associated with performance in a unilateral stretcher carry and bilateral jerry can and kettle bell carries. Sixty-seven enlisted Australian Army soldiers (46 men and 21 women) participated in this investigation. Body composition was quantified using dual-energy X-ray absorptiometry. Univariate and multivariable regression techniques were used to quantify correlations between anthropometric characteristics and carry performance. Median carry distance was 650 m (interquartile range [IQR] = 425–1,025 m) in the stretcher carry, 300 m (IQR = 215–445 m) in the jerry can carry, and 265 m (IQR = 200–400 m) in the kettle bell carry. Univariate analyses demonstrated that whole body, trunk, upper arm, forearm, and leg lean mass, as well as stature and body mass were associated with performance across the 3 carry tasks. Of these, leg lean mass was shown to be a key characteristic associated with carry performance. Subsequently, it is suggested that training programs focus on whole-body lean mass with specific emphasis on leg lean mass. Additionally, we demonstrated that age and sex were not significantly associated with carry performance when controlling for leg lean mass, indicating that modifiable factors can be targeted in training programs to improve job performance.

Sub-Elite Football Players With Hip-Related Groin Pain and Positive Flexion Adduction Internal Rotation Test Exhibit Distinct Biomechanical Differences Compared With the Asymptomatic Side

• BACKGROUND: Hip‐related groin pain is common in sub‐elite football players and may be associated with altered hip biomechanics. • OBJECTIVES: To compare the hip biomechanics, bony hip morphology associated with femoroacetabular impingement (FAI) syndrome, and hip strength and range of motion (ROM) between the symptomatic and asymptomatic limbs of sub‐elite football players with unilateral hip‐related groin pain and a positive flexion, adduction, and internal rotation (FADIR) test. • METHODS: Fifteen sub‐elite football (soccer) players with unilateral hip‐related groin pain and a positive FADIR test were recruited for this observational cross‐sectional study. Three‐dimensional motion analysis and ground reaction force data were recorded for walking and a single‐leg drop‐jump (SLDJ) task. Participants also underwent a standard anterior‐posterior hip radiograph and hip strength and ROM assessment. Between‐limb differences were assessed using paired t tests or Wilcoxon signed‐rank tests. • RESULTS: The symptomatic limb displayed a smaller peak hip extension angle (P = .01) and a lower peak hip adduction moment (P = .03) compared with the asymptomatic limb during the stance phase of walking. Additionally, during the SLDJ, the symptomatic limb demonstrated less total sagittal plane ROM (P = .04). The symptomatic limb also demonstrated less external rotation ROM (P = .03). However, no differences were found between limbs for bony hip morphology associated with FAI syndrome or hip strength. • CONCLUSION: This study found between‐limb asymmetries in low‐ and high‐impact functional tasks, such as walking and an SLDJ, in football players with unilateral hip‐related groin pain. Despite unilateral pain, bony morphology associated with FAI syndrome did not differ between limbs.

Proximal cueing to reduce elbow extension levels in suspect spin bowlers: A case study

Cricket bowlers must be able to deliver the ball with less than 15° of elbow extension or face suspension. The aim of this case study was to report the findings of a technique remediation programme on the elbow joint kinematics of an international cricket bowler. The bowler underwent a three-dimensional bowling analysis to measure his elbow joint kinematics before and after a technique remediation programme. The bowler was required to bowl six deliveries of each of his off-break, quicker and doosra variations. The remediation programme focussed on modifying the bowler’s run-up, shoulder alignment and ball/hand position at back foot impact. Elbow joint waveform data were analysed using statistical parametric mapping tests and coefficient of multiple determination. Elbow flexion–extension angles at discrete events were compared pre- and post-remediation using paired-sample t-tests. Results showed that the remediation programme was effective in reducing the amount of elbow flexion, particularly in the first 60% of the delivery cycle. Elbow extension range was significantly lower post-remediation for the off-break and quicker deliveries. It was concluded that basic short-term technique remediation can be effective in reducing elbow extension range.

The application of subjective job task analysis techniques in physically demanding occupations: evidence for the presence of self-serving bias.

Abstract The aim of this study was to determine if perceptions of physically demanding job tasks are biased by employee demographics and employment profile characteristics including: age, sex, experience, length of tenure, rank and if they completed or supervised a task. Surveys were administered to 427 Royal Australian Navy personnel who characterised 33 tasks in terms of physical effort, importance, frequency, duration and vertical/horizontal distance travelled. Results showed no evidence of bias resulting from participant characteristics, however participants who were actively involved in both task participation and supervision rated these tasks as more important than those involved only in the supervision of that task. This may indicate self-serving bias in which participants that are more actively involved in a task had an inflated perception of that task’s importance. These results have important implications for the conduct of job task analyses, especially the use of subjective methodologies in the development of scientifically defensible physical employment standards. Practitioner Summary: To examine the presence of systematic bias in subjective job task analysis methodologies, a survey was conducted on a sample of Royal Australian Navy personnel. The relationship between job task descriptions and participant’s demographic and job profile characteristics revealed the presence of self-serving bias affecting perceptions of task importance.

The identification of combat survivability tasks associated with naval vessel damage in maritime environments

Effective Navy personnel have the physical ability to perform combat survivability tasks commensurate with their unique physical requirements due to the distinctive characteristics of naval platforms. The aim of this investigation was to identify the physically demanding whole-of-ship tasks that are performed by Navy personnel while at sea. A mixed method design was used to identify tasks, inclusive of focus groups and field observations. From a series of ten focus groups, nine tasks were deemed to be physically demanding whole-of-ship tasks. A subsequent field observation of a combat survivability training course resulted in a refined and expanded 33-item list of physically demanding whole-of-ship tasks across six categories, including; replenishment at sea, emergency response, firefighting, leak stop and repair, toxic hazard and casualty evacuation. The findings from this study provide the basis for the development of physical employment standards for whole-of-ship tasks within the Royal Australian Navy.

Pelvic and trunk mechanics and injury in cricket: A spin bowling case study

An international cricket spin bowler was experiencing asymmetrical low back pain while bowling his off-break delivery. The aim of this study was to identify technical discrepancies between the bowler’s off-break delivery and his other variations, which did not cause low back pain. The bowler underwent a three-dimensional kinematic bowling analysis based on data captured using a 14-camera Vicon system operating at 250 images per second. To increase task representativeness, the analysis was undertaken outdoors on a turf cricket pitch. The bowler was required to bowl six deliveries of his off-break delivery and three variations. A range of pelvic and trunk kinematics were measured. A one-way independent samples analysis of variance with planned comparisons and a bootstrapping procedure was used to identify technical differences between the delivery types. Results showed that the off-break delivery displayed significantly higher trunk alignment, shoulder counter-rotation, trunk contralateral flexion and ‘crunch factor’ when compared with other delivery variations. It was concluded that the bowler who participated in this study was using an off-break technique that exhibited technical characteristics that have previously been associated with an increased likelihood of sustaining a lower back injury.