Rebecca M. Kerr

Kinematics of the field hockey penalty corner push‐in

Abstract The aims of the study were to determine those variables that significantly affect push‐in execution and thereby formulate coaching recommendations specific to the push‐in. Two 50 Hz video cameras recorded transverse and longitudinal views of push‐in trials performed by eight experienced and nine inexperienced male push‐in performers. Video footage was digitized for data analysis of ball speed, stance width, drag distance, drag time, drag speed, centre of massy displacement and segment and stick displacements and velocities. Experienced push‐in performers demonstrated a significantly greater (p < 0.05) stance width, a significantly greater distance between the ball and the front foot at the start of the push‐in and a significantly faster ball speed than inexperienced performers. In addition, the experienced performers showed a significant positive correlation between ball speed and playing experience and tended to adopt a combination of simultaneous and sequential segment rotation to achieve accuracy and fast ball speed. The study yielded the following coaching recommendations for enhanced push‐in performance: maximize drag distance by maximizing front foot‐ball distance at the start of the push‐in; use a combination of simultaneous and sequential segment rotations to optimise both accuracy and ball speed and maximize drag speed.

Comparison of physiological responses to graded exercise test performance in outrigger canoeing

Abstract The aim of this study was to establish a graded exercise test protocol for determining the peak physiological responses of female outrigger canoeists. Seventeen trained female outrigger canoeists completed two outrigger ergometer graded exercise test protocols in random order: (1) 25 W power output for 2 min increasing by 7.5 W every minute until exhaustion; and (2) 25 W power output for 2 min increasing by 15 W every 2 min to exhaustion. Heart rate and power output were recorded every 15 s. Expired air was collected continuously and sampled for analysis at 15-s intervals, while blood lactate concentration was measured immediately after and 3, 5, and 7 min after exercise. The peak physiological and performance variables examined included peak oxygen uptake ([Vdot]O2peak), minute ventilation, tidal volume, ventilatory thresholds 1 and 2, respiratory rate, respiratory exchange ratio, heart rate, blood lactate concentration, power output, performance time, and time to [Vdot]O2peak. There were no significant differences in peak physiological responses, ventilatory thresholds or performance variables between the two graded exercise test protocols. Despite no significant differences between protocols, due to the large limits of agreement evident between protocols for the peak physiological responses, it is recommended that the same protocol be used for all comparison testing to minimize intra-individual variability of results.

Predictors of 1000-m Outrigger Canoeing Performance

UNLABELLED This study examined the relationships between body composition, peak oxygen consumption and 1000-m time trial performance of female outrigger canoeists. PROCEDURES Female outrigger canoeists (n = 17) completed anthropometric profiling and a 1000-m outrigger ergometer time trial, during which expired air was measured continuously and analysed at 15-s intervals for determination of peak oxygen consumption. Heart rate, stroke rate and power output were also recorded at 15-s intervals. Blood lactate was measured immediately and at 3-, 5- and 7-min post-exercise. Mean power output, peak power output and progressive split times were highly correlated (r > 0.80) to 1000-m performance. Arm girths, humerus breadth, mesomorphy, peak oxygen consumption, ventilation, mean heart rate and peak lactate were moderately correlated (r > 0.50) to 1000-m performance. Stepwise multiple regression analysis verified that mean power output and to a lesser extent flexed arm girth, humerus breadth, waist girth and sitting height can predict 1000-m performance. Enhanced 1000-m performance of female outrigger canoeists appears to be achieved through a combination of greater power production and maintenance, a muscular stature and to a lesser extent, a higher aerobic capacity. These characteristics should be considered when selecting crews.

Effects of a 12-month exercise program on cardiorespiratory health indicators of Vietnam War veterans resident in the tropics.

OBJECTIVE To measure the effect of a combined aerobic and resistance exercise program on key cardiovascular disease risk factors (i.e. body composition or anthropometry and cardiorespiratory function) of Australian male, Vietnam War veterans living in the tropics. DESIGN Twelve-month exercise program with assessments at commencement, 3, 6 and 12 months. SETTING North Queensland regional centre. PARTICIPANTS Australian male, Vietnam War veterans (n = 164) resident in north Queensland. MAIN OUTCOME MEASURES Measurement of heart rate, blood pressure, skinfold and girth measurements, exercise heart rate response and estimated aerobic capacity to determine whether the implementation of a simple aerobic and resistance exercise program could positively change selected cardiovascular disease risk factors in Vietnam Veterans. RESULTS Significant improvements were reported for systolic blood pressure (131.1 (SD 15.7) reduced to 122.7 (12.4) mmHg), diastolic blood pressure (82.7 (9.1) reduced to 76.3 (10.3) mmHg), resting heart rate (73 (11) reduced to 69 (11) bpm), sum of skinfolds (127.5 (40.3) reduced to 99.5 (32.1) mm), waist girth (103.2 (12.0) reduced to 100.5 (12.1) cm), hip girth (105.3 (9.6) reduced to 103.7 (10.4) cm) and aerobic capacity (2.17 (0.39) increased to 2.36 (0.34) L min(-1)). CONCLUSION Participation in a combined aerobic and resistance training program elicited significant anthropometric and cardiorespiratory benefits that might lead to a decreased risk of developing cardiovascular disease for male Vietnam War veterans resident in rural and regional areas.

Physiological responses to 1000-m ergometer time-trial performance in outrigger canoeing

Abstract Graded exercise tests are commonly used to assess peak physiological capacities of athletes. However, unlike time trials, these tests do not provide performance information. The aim of this study was to examine the peak physiological responses of female outrigger canoeists to a 1000-m ergometer time trial and compare the time-trial performance to two graded exercise tests performed at increments of 7.5 W each minute and 15 W each two minutes respectively. 17 trained female outrigger canoeists completed the time trial on an outrigger canoe ergometer with heart rate (HR), stroke rate, power output, and oxygen consumption ([Vdot]O2) determined every 15 s. The mean (± s) time-trial time was 359 ± 33 s, with a mean power output of 65 ± 16 W and mean stroke rate of 56 ± 4 strokes · min−1. Mean values for peak [Vdot]O2, peak heart rate, and mean heart rate were 3.17 ± 0.67 litres · min−1, 177 ± 11 beats · min−1, and 164 ± 12 beats · min−1 respectively. Compared with the graded exercise tests, the time-trial elicited similar values for peak heart rate, peak power output, peak blood lactate concentration, and peak [Vdot]O2. As a time trial is sport-specific and can simultaneously quantify sprint performance and peak physiological responses in outrigger canoeing, it is suggested that a time trial be used by coaches for crew selection as it doubles as a reliable performance measure and a protocol for monitoring peak aerobic capacity of female outrigger canoeists.

Benefits of regular exercise on body composition and cardio-respiratory function in ex-servicemen residing in the tropics

Typically the health and quality of life exhibited by Australian ex-servicemen resident in the tropics is poor. The current study examined the effects of regular exercise on body composition and cardio-respiratory function of ex-servicemen who served in varying theatres of conflict. One hundred and twenty three Australian ex-servicemen (mean age 54.2, range 28-77 yrs; height 1.75 0.63 m; mass 95.80 1.67 kg) currently residing in the tropics (North Queensland region) volunteered for this study. All participants received medical clearance from their general practitioner prior to undertaking a 6-month regular exercise programme. Cardio-respiratory and anthropometry measurements were obtained prior to and following the exercise programme. The exercise programme consisted of combined aerobic and resistance training of at least 45 minutes duration, 1 to 2 days per week. Approximately 84% of the participants completed the programme with 73.2% undertaking 1-2 sessions per week while 26.8% completed more than 2 sessions per week. Paired t-test analysis indicated significant (p<0.05) changes in resting systolic and diastolic blood pressure, all skinfold measurements, waist and hip girths, exercise heart rates and VO2max. Regular exercise of at least 1-2 sessions per week for 6 months significantly improved the body composition and cardio-respiratory function of Australian ex-servicemen residing in tropical North Queensland.