Robert N. Marshall

Three-dimensional lumbar segment kinetics of fast bowling in cricket.

Cricket fast bowlers have a high incidence of serious lumbar injuries, such as lesions in the pars interarticularis. Kinematic studies have shown that bowling actions with large shoulder counter-rotation are associated with significantly higher incidences of lumbar injury. However, in bowling, there has been no calculation of the spinal loads, which are the causal mechanisms of such injuries. In this study, 21 fast bowlers (22.4+/-3.9 years) of premier grade level and above were tested using a three-dimensional (3D) motion analysis system. The mean ball release speed was 31.9+/-2.8 m s(-1) and ranged from 27.0 to 35.6 m s(-1). Kinematics and kinetics were calculated for lumbar spine lateral bending, rotation, and flexion during the delivery and power phases of bowling. Power calculations were used to define the actuation of lumbar spine motion as either active or controlled. The actuation of the lumbar spine was complex, involving multiple sequences of active and controlled motion. In addition, lumbar spine loads were largest during the power phase when the ground reaction forces were highest. In conclusion, the dynamic loads and the cyclical nature of their application when the spine is positioned near its end range of motion may be significant factors of injury to this region. In addition, the lumbar spine in bowling has to vigorously flex, laterally bend and rotate simultaneously in a complex interdependent sequence of actuation patterns. Therefore, any technical change to reduce injury susceptibility needs to consider the mechanics of whole body coordination and timing.

Distribution of modern cricket bowling actions in New Zealand

Abstract The classification of bowling actions in cricket is particularly important from an injury perspective. Research has consistently shown that bowlers with a mixed-action technique have an elevated risk of sustaining serious lumbar injury. In this study, 34 New Zealand bowlers (mean age 22.2±0.9 years) of premier competition standard and above were assessed using a three-dimensional motion analysis system (240 Hz). Data were analysed using three previous classification systems before classifying bowlers into the side-on, semi-open, front-on, and mixed-action types based on a modified set of angle threshold criteria and a more intuitive angle convention system. The majority of bowlers in the sample (64.7%) used the mixed action with high levels of shoulder counter-rotation. The strongest predictors of shoulder counter-rotation were shoulder alignment angle and pelvic–shoulder separation angle. The current results suggest that a large proportion of fast bowlers may be at a higher risk of lumbar injury from the use of the mixed-action technique. We believe it may be advisable to recommend the semi-open action as an alternative to the front-on action. In addition, the adopted angle convention is more practical than the previous convention for bowling action classification.

The effect of a flexed elbow on bowling speed in cricket.

Abstract The laws of bowling in cricket state ‘a ball is fairly delivered in respect of the arm if, once the bowlers arm has reached the level of the shoulder in the delivery swing, the elbow joint is not straightened partially or completely from that point until the ball has left the hand’. Recently two prominent bowlers, under suspicion for transgressing this law, suggested that they are not ‘throwing’ but due to an elbow deformity are forced to bowl with a bent bowling arm. This study examined whether such bowlers can produce an additional contribution to wrist/ball release speed by internal rotation of the upper arm. The kinematics of a bowling arm were calculated using a simple two‐link model (upper arm and forearm). Using reported internal rotation speeds of the upper arm from baseball and waterpolo, and bowling arm kinematics from cricket, the change in wrist speed was calculated as a function of effective arm length, and wrist distance from the internal rotation axis. A significant increase in wrist speed was noted. This suggests that bowlers who can maintain a fixed elbow flexion during delivery can produce distinctly greater wrist/ball speeds by using upper arm internal rotation.

Centre of mass kinematics of fast bowling in cricket

Kinematic studies have shown that fast bowlers have run-up velocities, based on centre of mass velocity calculations, which are comparable to elite javelin throwers. In this study, 34 fast bowlers (22.3 ± 3.7 years) of premier grade level and above were tested using a three-dimensional (3-D) motion analysis system (240 Hz). Bowlers were divided into four speed groups: slow-medium, medium, medium-fast, and fast. The mean centre of mass velocity at back foot contact (run-up speed) was 5.3 ± 0.6 m/s. Centre of mass velocity at back foot contact was significantly faster in the fastest two bowling groups compared to the slow-medium bowling group. In addition, stepwise multiple regression analysis showed that the centre of mass deceleration over the delivery stride phase was the strongest predictor of ball speed in the faster bowling groups. In conclusion, centre of mass kinematics are an important determinant of ball speed generation in fast bowlers. In particular, bowlers able to coordinate their bowling action with periods of centre of mass deceleration may be more likely to generate high ball speed.

Biomechanical risk factors and mechanisms of knee injury in golfers.

Knee injuries in golf comprise approximately 8% of all injuries, and are considered to result from overuse, technical faults or a combination of those factors. This review examines factors involved in injury, including the structure of the knee joint, kinematics and kinetics of the golf swing, forces sustained by knee joint structures and the potential for joint injury as well as injury prevention strategies. The golf swing generates forces and torques which tend to cause internal or external rotation of the tibia on the femur, and these are resisted by the knee ligaments and menisci. Research has shown that both maximum muscle forces and the forces sustained during a golf swing are less than that required to cause damage to the ligaments. However, the complex motion of the golf swing, involving both substantial forces and ranges of rotational movement, demands good technique if the player is to avoid injuring their knee joint. Most knee injury in golf is likely related to joint laxity, previous injuries or arthritis, and such damage may be exacerbated by problems in technique or overuse. In addition to appropriate coaching, strategies to remedy discomfort include specific exercise programmes, external bracing, orthotics and equipment choices.

Kinematic and kinetic energy analysis of segmental sequencing in cricket fast bowling

Although there have been many studies to quantify the segmental sequencing in other sports, there has been little such research applied to cricket bowling. In this study, 34 fast bowlers (22.3 ± 3.7 years) of premier grade level and above were tested using 3D motion analysis, their balls speed ranging from 27.0 to 35.6 m s− 1. One-way repeated measures ANOVA was used to test for within-participant differences in segmental sequencing based on the timings of maximum segmental angular velocities and kinetic energies, the data showing that bowlers exhibited a general order of proximal-to-distal sequencing. Bivariate Pearsons product-movement correlation coefficients were calculated to assess the relationships between kinematic variables and ball release speed, yielding a set of variables for entry into a stepwise multiple regression model. The multiple regression model with the sequential timing variables of thoracic linear kinetic energy (KE), upper-arm circumduction velocity and forearm rotation KE, as well as the pelvic–shoulder separation acceleration accounted for 55% of the variability in ball speed (R 2 = 0.55, adjusted R 2 = 0.49, F(4, 29) = 8.86, p < 0.001). This study showed that both the magnitude and the timing of segmental activation are important to generate ball speed in fast bowling.

Mild traumatic brain injury in New Zealand: factors influencing post-concussion symptom recovery time in a specialised concussion service

INTRODUCTION By 2020, traumatic brain injuries (TBIs) are predicted to become the third largest cause of disease burden globally; 90% of these being mild traumatic brain injury (mTBI). Some patients will develop post-concussion syndrome. AIM To determine whether the time between sustaining a mTBI and the initial assessment by a specialised concussion service, along with the post-concussion symptoms reported at the assessment, affected recovery time. METHODS A retrospective medical record review of clients who had completed the Rivermead Post-Concussion Questionnaire (RPQ) at their initial assessment and were discharged from a large metropolitan concussion service in New Zealand was undertaken over a 6-month period in 2014 (n = 107). Using correlations, General Linear Mixed-effects Models (GLMM) and linear regressions, we explored associations between factors including ethnicity, gender and accident type, along with individual RPQ symptom scores and cluster scores, with time from injury to initial assessment by the specialised concussion service and initial assessment to discharge. RESULTS Time from injury to initial assessment by a specialist concussion service was correlated with proportionally more psychological symptoms present at initial assessments (r = 0.222, P = 0.024); in particular, feeling depressed or tearful (r = 0.292, P = 0.003). Time to discharge was correlated with individual RPQ symptom proportions present at initial assessment for headaches (r = -0.238, P = 0.015), sensitivity to noise (r = 0.220, P = 0.026), feeling depressed or tearful (r = 0.193, P = 0.051) and feeling frustrated or impatient (r = 0.252, P = 0.003), along with the psychological cluster proportion (r = 0.235, P = 0.017) and the total RPQ score (r = 0.425, P < 0.001). CONCLUSION Prompt diagnosis and treatment of mTBI may minimise the severity of post-concussion symptoms, especially symptoms associated with mental health and wellbeing.

Development, implementation and evaluation of nurse-led integrated, person-centred care with long-term conditions

Purpose The purpose of this paper is to outline a conceptual plan for innovative, integrated care designed for people living with long-term conditions (LTCs). Design/methodology/approach The conceptual plan delivers a partnership between the health system, the person with LTCs (chronic), their family, and the community. The partnership aims to support people at home with access to effective treatment, consistent with the New Zealand Government Health Strategy. This concept of people-owned care is provided by nurses with advanced practice skills, who coordinate care across services, locations and multiple LTCs. Findings With the global increase in numbers of people with multiple chronic conditions, health services are challenged to deliver good outcomes and experience. This model aims to demonstrate the effective use of healthcare resources by supporting people living with a chronic condition, to increase their self-efficacy and resilience in accordance with personal, cultural and social circumstance. The aim is to have a model of care that is replicable and transferable across a range of health services. Social implications People living with chronic conditions can be empowered to manage their health and well-being, whilst having access to nurse-led care appropriate to individual needs. Originality/value Although there are examples of case management and nurse-led coordination, this model is novel in that it combines a liaison nursing role that works in partnership with patients, whilst ensuring that care across a number of primary and secondary care services is truly integrated and not simply interfaced.

A twenty-segment kinematics and kinetics model for analysing golf swing mechanics

The golf swing is a complex, multi-planar, three-dimensional (3D) motion sequence performed at very high speeds. These properties make biomechanical analysis of the golf swing difficult. Hence, the aim of this study was to develop a computer model of the golf swing capable of calculating a diverse range of 3D kinematics and kinetics values based on motion analysis data collected in the laboratory. Five golfers performed six swings in the field of view of eight Falcon High Speed Resolution cameras (240 Hz), which captured the movements of 56 markers placed on the golfers and their clubs, resulting in marker trajectories that were processed into linear xyz-coordinates using the Eva Motion Analysis system. To perform the kinematics and kinetics calculations, a 20-segment rigid body model of the human body was designed in the Mechanical Systems Pack, connecting the segments by a selection of linear and spherical constraints, resulting in a system of segments with 58 degrees of freedom, with the constraint equations of motion calculated by the Newton–Lagrangian iteration method. The model allowed for the derivation of segmental sequencing, separation angles, segmental planes of motion, segmental velocity contributions, joint torques and muscle powers. The preliminary data suggest that such an integrated kinematics and kinetics analysis is necessary to understand the mechanical complexity of golf swing. Even with the small sample size analysed in this study, some interesting trends were found, such as certain violations of the classical proximal-to-distal sequencing scheme, differing swing plane and club head trajectories in the backswing and downswing phases, minimal hip angular velocity contribution to the ball at impact, concentric and eccentric muscle powers in the downswing phase, and increased lumbar loading factors from the mid-downswing phase to ball impact.

Nurse perceptions of the use of seclusion in mental health inpatient facilities: have attitudes to Māori changed?

Purpose The purpose of this paper is to examine the results of New Zealand initiatives to reduce seclusion rates and report the attitudes of mental health nurses to seclusion, factors involved in seclusion use, and alternatives to seclusion. Design/methodology/approach A questionnaire was circulated to mental health inpatient staff. Data from the Ministry of Health for seclusion numbers and rates for Ma¯ori and non-Ma¯ori were also collected. Findings The major barriers to reducing the use of seclusion related to staffing issues, a lack of management and medical support, and physical characteristics of the facility. Data from the Office of the Director of Mental Health annual reports from 2007-2014 clearly show a reduction in the total seclusion events, the number of patients secluded, and the percentage of total patients secluded. However, the percentage of Ma¯ori secluded compared to the total number of patients secluded showed little change from 2007 to 2013. Originality/value Further analysis of the nurse’s responses showed that four of the six least-used strategies incorporated Ma¯ori cultural approaches. The authors surmise that an inability to provide culturally sensitive care, either through staffing or education factors, may be implicated in the lack of change in the seclusion rates for Ma¯ori. This may also be pertinent to seclusion rates for indigenous peoples in other countries.