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The aim of this study was to quantify the differences between groups of elite canoe slalom athletes based on the class they paddle in and the strategies they use in competition. Canoe and kayak footage was recorded using three cameras and analysed using lapsed-time time -motion analysis. Analysis was undertaken on the ten fastest competition runs for men's kayak and canoes and women's kayak for the 22-gate semi-final/final course at the 2005 canoe slalom world championships. Comparison between the categories of paddlers revealed that despite canoe paddlers taking significantly (P # 0.05) fewer strokes than kayak paddlers, they were not significantly slower than men's single kayak paddlers with respect to their run times and only significantly slower between 4 of 22 gates. Results revealed also that paddlers using different turn strategies (spin vs. pivot) had significantly (P # 0.05) different split times for the gates before and after the execution of the manoeuvre. For a paddler this means that their individual strategy could be analysed and compared with those of others to determine if alternate strategies would be beneficial to their performance.

The three-dimensional kinematics of international female footballers performing a simulated direct free kick (curve kick) were compared with those of an instep kick. Reflective markers attached to the participants were tracked by 17 Vicon cameras sampling at 250 Hz. Foot velocity at ball impact did not differ between the two types of kick, but the way in which foot velocity was generated did differ, with instep kicks using a faster approach velocity and greater linear velocities of the hip and knee, and curve kicks using a greater knee angular velocity at impact. In both types of kick, peak knee angular velocity and peak ankle linear velocity occurred at ball impact, providing biomechanical support to the common coaching recommendation of kicking through the ball. To achieve a curved ball trajectory, players should take a wide approach angle, point the support foot to the right of the intended target (for right-footed players), swing the kicking limb across the face of the goal, and impact the ball with the foot moving upwards and in an abducted position. This information will be useful to coaches and players in identifying the fundamental coaching points necessary to achieve a curved trajectory of the ball compared with the more commonly described instep kick kinematics.

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Bronson (2020) Comparing inertial measurement units and markerbased biomechanical models during dynamic rotation of the torso. European

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A better understanding of the strains experienced by the Achilles tendon during commonly prescribed exercises and locomotor tasks is needed to improve efficacy of Achilles tendon training and rehabilitation programs. The aim of this study was to estimate in vivo free Achilles tendon strain during selected rehabilitation, locomotor, jumping, and landing tasks. Sixteen trained runners with no symptoms of Achilles tendinopathy participated in this study. Personalised free Achilles tendon moment arm and force-strain curve were obtained from imaging data and used in conjunction with motion capture and surface electromyography to estimate free Achilles tendon strain using electromyogram-informed neuromusculoskeletal modelling. There was a strong correspondence between Achilles tendon force estimates from the present study and experimental data reported in the literature (R2 > 0.85). The average tendon strain was highest for maximal hop landing (8.8±1.6%), lowest for walking at 1.4 m/s (3.1±0.8%) and increased with locomotor speed during running (run 3.0 m/s: 6.5±1.6%; run 5.0 m/s: 7.9±1.7%) and during heel rise exercise with added mass (BW: 5.8±1.3%; 1.2 BW: 6.9±1.7%). The peak tendon strain was highest during running (5 m/s: 13.7±2.5%) and lowest during walking (1.4 m/s: 7±1.8%). Overall findings provide a preliminary evidence base for exercise selection to maximise anabolic tendon remodelling during training and rehabilitation of the Achilles tendon.

The aim of this study was to assess intra-observer and inter-observer reliability of data gathered from a lapsed-time time-motion analysis of canoe slalom competition. The data were collected using a definition set developed in conjunction with elite canoe slalom coaches. Competition runs from four national-standard paddlers in a national selection race were analysed in random order three times by three observers. For each run, observers identified various events specific to canoe slalom, including time taken between gates, touched and missed gates, turn times, major and minor avoidance, rolls, paddle in and out of water times, and stroke classification. The error of measurement was determined for each of these variables. For time taken between gates and turn times, the error was < or = 0.21 and < or = 0.39 s for intra-observer and inter-observer analysis, respectively. The error for stroke in and out of water times was < or = 0.08 and < or = 0.13 s for intra-observer and inter-observer analysis, respectively. Analysis of stroke classification identification for intra-observer comparisons revealed that 91% of the time identical stroke identification occurred. Inter-observer analysis revealed identical stroke identification was achieved 81% of the time. These reliability data compare favourably with previous time-motion analysis in other sports using fewer variables.