Max Stuelcken

Anthropometric characteristics of elite cricket fast bowlers

Abstract The aims of this study were to describe the current anthropometric profiles of elite Australian female and male cricket fast bowlers and establish a set of reference values useful for future investigations on player selection, talent identification, and training programme development. The participants were 26 female (mean age 22.5 years, s = 4.5; height 1.71 m, s = 0.05; body mass 66.2 kg, s = 7.5) and 26 male (mean age 23.9 years, s = 3.5; height 1.88 m, s = 0.05; body mass 87.9 kg, s = 8.2) fast bowlers. The anthropometric profiles included the measurement of skinfolds, and segment lengths, breadths, and girths. A series of derived variables assessing the distribution of subcutaneous adipose tissue, the bivariate overlap zone, relative body size and proportionality, and somatotype were also calculated. The male bowlers had larger length, breadth, and girth measurements than their female counterparts. There were differences in proportionality between the sexes, with only the male bowlers exhibiting characteristics that could be considered “large” relative to height. The female bowlers had a higher sum of seven skinfolds (P < 0.001), were more endomorphic (F 1,50 = 30.18, P < 0.001), and less mesomorphic (F 1,50 = 10.85, P < 0.01) than the male bowlers. These reference data should be useful to practitioners and researchers interested in cricket. Further research is needed to clarify why only male fast bowlers had variables that were proportionally large relative to height.

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 external ankle support on knee and ankle joint movement and loading in netball players

OBJECTIVES External ankle support has been successfully used to prevent ankle sprains. However, some recent studies have indicated that reducing ankle range of motion can place larger loads on the knee. The aim of this study was to investigate the effect of external ankle support (braces and high-top shoes) on the ankle and knee joint loading during a netball specific landing task. DESIGN A repeated measure design. METHODS High performance netball players with no previously diagnosed severe ankle or knee injury (n=11) were recruited from NSW Institute of Sport netball programme. The kinematic and kinetic data were collected simultaneously using a 3-D Motion Analysis System and one Kistler force plate to measure ground reaction forces. Players performed a single leg landing whilst receiving a pass while wearing a standard netball shoe, the same shoe with a lace-up brace and a high-top shoe. RESULTS Only the brace condition significantly reduced the ankle range of motion in the frontal plane (in/eversion) by 3.95 ± 3.74 degrees compared to the standard condition. No changes were found for the knee joint loading in the brace condition. The high-top shoes acted to increase the peak knee internal rotation moment by 15%. Both the brace and high-top conditions brought about increases in the peak ankle plantar flexion moment during the landing phase. CONCLUSIONS Lace-up braces can be used by netball players to restrict ankle range of motion during a single leg landing while receiving a pass without increasing the load on the knee joint.

Mechanisms of anterior cruciate ligament injuries in elite women’s netball: a systematic video analysis

ABSTRACT This study involved a systematic video analysis of 16 anterior cruciate ligament (ACL) injuries sustained by elite-level netball players during televised games in order to describe the game situation, the movement patterns involved, the player’s behaviour, and a potential injury mechanism. Eight of the ACL injuries were classified as “indirect contact” and eight as “non-contact”. Two common scenarios were identified. In Scenario A the player was jumping to receive or intercept a pass and whilst competing for the ball experienced a perturbation in the air. As a result the player’s landing was unbalanced with loading occurring predominantly on the knee of the injured side. In Scenario B the player was generally in a good position at ground contact, but then noticeably altered the alignment of the trunk before the landing was completed. This involved rotating and laterally flexing the trunk without altering the alignment of the feet. Apparent knee valgus collapse on the knee of the injured side was observed in 3/6 Scenario A cases and 5/6 Scenario B cases. Players may benefit from landing training programmes that incorporate tasks that use a ball and include decision-making components or require players to learn to cope with being unbalanced.

A pilot study of the front foot ground reaction forces in elite female fast bowlers

This pilot study aimed to determine the magnitude of ground reaction forces experienced by female cricket fast bowlers at front foot contact in the delivery stride of the bowling action. The peak vertical force, peak horizontal braking force and vertical loading rate were assessed in 15 elite Australian female fast bowlers. A sequential averaging procedure indicated that a mean of twelve trials (+/-2.8) were required to achieve performance stability across these ground reaction force variables and this demonstrated the importance of analyzing a sufficient number of trials to obtain representative data. The mean peak vertical ground reaction force was 3.49kN (+/-0.81) and the mean peak horizontal braking force was 2.13kN (+/-0.52). Statistical analyses revealed that differences in body mass explained only 2.3% of the variance in peak vertical force and 2.0% of the variance in peak horizontal braking force so normalization using body mass a covariate is not recommended when reporting front foot ground reaction forces in elite female fast bowlers. The mean time to the peak vertical force was 0.033s (+/-0.009) and the vertical loading rate was 121.31kNs(-1) (+/-73.78). Further work is required to determine the best ways to minimise and attenuate front foot ground reaction forces.

Musculoskeletal profile of the lumbar spine and hip regions in cricket fast bowlers.

OBJECTIVES To determine the career history of low back pain (LBP) in current elite female cricket fast bowlers and then compare measures of lumbar spine and hip range of motion (ROM) and trunk extensor endurance between those bowlers with and without a history of LBP. Measures for the female bowlers were also compared to a small sample of male fast bowlers. PARTICIPANTS Twenty-six elite female fast bowlers and eight male fast bowlers of similar age and bowling experience. MAIN OUTCOME MEASURES The career history of LBP was determined by a self-administered questionnaire and by accessing medical records. Range of motion measures for the lumbar spine and hips were obtained using inclinometry or goniometry. Trunk extensor endurance was assessed using a modified Sorensen test. RESULTS Fourteen female fast bowlers had a history of LBP. There was a significant difference in lumbar lateral flexion ROM to the bowling arm side between those female fast bowlers with and without a history of LBP (p < or = 0.05). The female fast bowlers had significantly more bilateral hip extension ROM (p < or = 0.05) compared to the male fast bowlers. CONCLUSIONS This information should be useful for practitioners involved in the conditioning and rehabilitation of cricketers. Future prospective studies should investigate potential predictors of LBP in female fast bowlers.

Knee loading patterns in a simulated netball landing task

Abstract The knee is a common site of injury in netball players. In this study, 10 high-performance netball players underwent a biomechanical assessment of their single leg landing technique whilst receiving a pass. Three-dimensional video and ground reaction force data were recorded using a motion analysis system. Net internal knee joint moments were calculated using a rigid body analysis and inverse dynamics. The kinematics of the support leg and front-on video footage was used to investigate whether players adhered to guidelines on safe and effective landing strategies. Results indicated that for most players the internal valgus moment was the largest frontal plane knee moment during the landing phase. This may reflect a relatively greater need to resist varus knee excursion or may be related to the kinematics of the hip. For 6 of the 10 players the rapid change to an internal knee valgus moment coincided with hip adduction. Since an increase in the magnitude of the internal valgus moment may increase the compressive forces in the medial compartment of the knee, further work should be undertaken to determine if a neuromuscular training intervention to improve the strength of the hip musculature may be beneficial for these players. A large relative excursion of the knee compared to the hip may indicate that these players had a greater reliance on the more distal segments of the lower extremity for the attenuation of the ground reaction forces. This information may be used to better understand potential knee injury mechanisms in netball players.

A snapshot of chronic ankle instability in a cohort of netball players

OBJECTIVES Ankle injuries account for the highest percentage of injuries in netball, yet the chronic nature of ankle sprains is under reported within this population group. Chronic ankle instability is a term used to describe certain insufficiencies that persist after an acute ankle sprain. The aim of this study was to investigate recurrent sprain, perceived ankle instability and mechanical ankle instability in a cohort of netball players. DESIGN Cross-sectional study. METHODS Ninety-six female netball players (24.1±7.9 years) were recruited (42 club players and 54 inter-district players). Recurrent sprain was defined as two or more lifetime sprains to the same ankle. Perceived ankle instability was quantified with the Cumberland Ankle Instability Tool - Youth. Mechanical ankle instability was quantified via inversion-eversion rotations using an ankle arthrometer at torques of 3Nm. RESULTS Forty-seven percent of the cohort had recurrently sprained an ankle. Of the 69 players with a previously sprained ankle, 64% had a moderate-severe degree of perceived ankle instability. The total inversion-eversion angle was 31.1±8.7 degrees. Club players had more cases of moderate-severe perceived ankle instability (p=0.01) and larger inversion-eversion angles (p=0.001) compared to inter-district players. CONCLUSIONS Recurrent ankle sprain and perceived ankle instability are easily identifiable aspects of chronic ankle instability shown to be prevalent within this cohort. Additional research is required to quantify a cut-off value for mechanical instability. Club netball players were found to have more counts of moderate-severe perceived ankle instability and larger inversion-eversion angles when compared to the inter-district netball players.

The effect of external ankle support on knee and ankle joint loading in netball players

Background External ankle support has been successfully used to prevent ankle sprains [1]. However, some recent studies [2,3] have indicated that reducing ankle range of motion can place larger loads on the knee and increase the risk of knee injuries. The aim of this study is to investigate the effect of external ankle support (braces and high top shoes) on ankle kinematics and knee kinetics in high performance netball players. Materials and methods Eleven high performance netball players were recruited from NSW Institute of Sport. A 14-camera motion analysis system was used to synchronously collect threedimensional video and force plate data. Twenty-four retro-reflective markers were attached to anatomical landmarks to allow the formation of rearfoot, forefoot, shank, thigh, and pelvis segments. Each player performed a single-leg-landing whilst receiving a chest pass.

Rear leg kinematics and kinetics in cricket fast bowling

The purpose of this study was to analyse the kinematics and kinetics of the rear leg drive in fast bowling, and then investigate whether any of these variables were associated with ball release speed. Eighteen young fast bowlers (17.2 ± 1.7 years) were recruited from the Cricket New South Wales development squad, and their bowling actions were captured by a Cortex 2.0 motion analysis system (200 Hz). Bivariate Pearsons product-movement correlation coefficients were calculated in SPSS (Version 17.0) to assess the relationships between wrist speed (of the bowling hand) and the kinematics and kinetics variables corresponding with rear leg motion. A number of kinematic variables were correlated with bowling wrist speed, most of them during the delivery stride, including mean thigh extension angular velocity (r = 0.606, p = 0.008), thigh adduction angular velocity at back foot contact (r = 0.515, p = 0.029) and maximum change in knee extension angular velocity (r = 0.559, p = 0.016). This study also showed that rear leg drive was not an actively actuated process. Instead, the hip and knee motions in the flexion–extension and adduction–abduction planes were generally subjected to controlled and negligible torque motion-effects.