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We propose a biomechanical model to explain the pathogenesis of iliotibial band friction syndrome in distance runners. The model is based on a kinematic study of nine runners with iliotibial band friction syndrome, a cadaveric study of 11 normal knees, and a literature review. Friction (or impingement) occurs near footstrike, predominantly in the foot contact phase, between the posterior edge of the iliotibial band and the underlying lateral femoral epicondyle. The study subjects had an average knee flexion angle of 21.4 degrees +/- 4.3 degrees at footstrike, with friction occurring at, or slightly below, the 30 degrees of flexion traditionally described in the literature. In the cadavers we examined, there was substantial variation in the width of the iliotibial bands. This variation may affect individual predisposition to iliotibial band friction syndrome. Downhill running predisposes the runner to iliotibial band friction syndrome because the knee flexion angle at footstrike is reduced. Sprinting and faster running on level ground are less likely to cause or aggravate iliotibial band friction syndrome because, at footstrike, the knee is flexed beyond the angles at which friction occurs.

In this study we analysed technique, ball speed and trunk injury data collected at the Australian Institute of Sport (AIS) from 42 high performance male fast bowlers over a four year period. We found several notable technique inter-relationships, technique and ball speed relationships, and associations between technique and trunk injuries. A more front-on shoulder alignment at back foot contact was significantly related to increased shoulder counter-rotation (p < 0.001). Bowlers who released the ball at greater speeds had an extended front knee, or extended their front knee, during the front foot contact phase (p < 0.05). They also recorded higher braking and vertical impact forces during the front foot contact phase and developed those forces more rapidly (p < or =0.05). A maximum hip-shoulder separation angle occurring later in the delivery stride (p = 0.05) and a larger shoulder rotation to ball release (p = 0.05) were also characteristics of faster bowlers. Bowlers suffering lower back injuries exhibited typical characteristics of the 'mixed' technique. Specifically, the hip to shoulder separation angle at back foot contact was greater in bowlers who reported soft tissue injuries than in non trunk-injured bowlers (p = 0.03), and shoulder counter-rotation was significantly higher in bowlers who reported lumbar spine stress fractures than non trunk-injured bowlers (p = 0.01). The stress fracture group was also characterised by a larger hip angle at front foot contact and ball release, whereas a more flexed front knee at ball release characterised the non trunk-injured group.

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Excessive foot pronation has been speculated to be a cause of leg and foot problems among runners. Foot orthotic devices are often used to modify this condition. Examination of the records of 180 patients treated for various running injuries showed that 83 individuals (46%) were prescribed orthotic devices and that 65 of these runners (78%) were able to return to their previous running programs. In order to assess further the effects of this type of orthotic device, six runners were selected from this group and filmed using two cameras (200 frames/sec) under three conditions: (1) barefoot, (2) regular shoe, and (3) regular shoe plus orthotic device. Both the period of pronation and the amount of maximum pronation were significantly reduced by using the foot orthotic device. The data support the conclusion that foot orthotic devices can be successfully used to modify selected aspects of lower extremity mechanics during the support phase of running.

Hitting great golf shots requires, in coaching terms, exquisite “timing” Despite this criterion, few people have tried to quantify this phenomenon and distinguish between well-timed (WT) and mistimed (MT) shots. The purpose of this paper was to present a way of describing the timing in the golf downswing and investigate whether biomechanical variables could be used to evaluate the sequencing of movement during the swing. Three-dimensional kinematics for a five segment model of the body and shot distance and lateral error were collected as highly skilled players hit approximately 20 driver shots. Players rated each shot as being WT or MT. A method of describing sequencing was presented and average values for the body segment speeds were presented. Comparisons of the timing lags (i.e., the times between peak angular speeds of contiguous body segments) showed no significant differences between the WT and MT shots. It seems as though golfers are much more sensitive to the “centredness” of contact than they are to subtle differences in the timing of peak body segment speeds.

In this study, we used recently developed technology to determine the force-time profile of elite swimmers, which enabled coaches to make informed decisions on technique modifications. Eight elite male swimmers with a FINA (Federation Internationale de Natation) rank of 900+ completed five passive (streamline tow) and five net force (arms and leg swimming) trials. Three 50-Hz cameras were used to video each trial and were synchronized to the kinetic data output from a force-platform, upon which a motorized towing device was mounted. Passive and net force trials were completed at the participant's maximal front crawl swimming velocity. For the constant tow velocity, the net force profile was presented as a force-time graph, and the limitation of a constant velocity assumption was acknowledged. This allowed minimum and maximum net forces and arm symmetry to be identified. At a mean velocity of 1.92+0.06 m s⁻¹, the mean passive drag for the swimmers was 80.3+4.0 N, and the mean net force was 262.4+33.4 N. The mean location in the stroke cycle for minimum and maximum net force production was at 45% (insweep phase) and 75% (upsweep phase) of the stroke, respectively. This force-time profile also identified any stroke asymmetry.