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The purposes of this study were to develop a cinematographic technique to obtain selected parameters over an entire 100-m ran and to evaluate selected characteristics of the maximum speed phase (MSP) and the final phase (FP) for female high school runners. The MSP was defined as the part of the 100-m run consisting of the five consecutive strides which together have the largest average speed value, and the FP as the last 10 m of the 100-m run. Twelve sprinters with best 100-m times from 12.3 to 13.4 s served as subjects. The major findings of this study were that (a) maximum speeds of 8.0-8.4 m/s were reached 23-37 m from the start, (b) an average of 7.3% of the maximum speed was lost by the FP, (c) no significant difference was found between the average stride lengths during the MSP and the FP, (d) the average stride frequency during the FP was equal to 93% of the corresponding value during the MSP, and (e) the decrease in average speed from the MSP to the FP was associated with an increase in support time from the MSP to the FP.

The timing of glove movements used by baseball pitchers to catch fast approaching balls (i.e., line drives) was examined in two tests to determine the responses and temporal characteristics of glove movements in high school and college baseball pitchers. Balls were projected toward the head of participants at 34.8 m·s^–1 (78 mph) on average in an indoor test and at speeds approaching 58.1 m·s^–1 (130 mph) in a field test. Pitchers caught over 80% and 15% of the projected balls in the indoor and field tests, respectively. Analyses of glove responses indicated that all pitchers could track the line drives and produce coordinated glove movements, which were initiated 160 ms (± 47.8), on average, after the ball was launched. College pitchers made initial glove movements sooner than high school pitchers in the field test (p = 0.012). In contrast, average glove velocity for pitchers increased from 1.33 (± 0.61) to 3.45 (± 0.86) m·s^–1 across the tests, but did not differ between experience levels. Glove movement initiation and speed were unrelated, and pitchers utilized visual information throughout the ball's flight to catch balls that approached at speeds exceeding the estimated speeds in competitive situations.

In animal models, hundreds of repetitions of upper extremity (UE) task practice promote neural adaptation and functional gain. Recently, we demonstrated improved UE function following a similar intervention for people after stroke. In this secondary analysis, computerized measures of UE task performance were used to identify movement parameters that changed as function improved. Ten people with chronic poststroke hemiparesis participated in high-repetition UE task-specific training 3 times per week for 6 weeks. Before and after training, we assessed UE function with the Action Research Arm Test (ARAT), and evaluated motor performance using computerized motion capture during a reach-grasp-transport-release task. Movement parameters included the duration of each movement phase, trunk excursion, peak aperture, aperture path ratio, and peak grip force. Group results showed an improvement in ARAT scores (p = .003). Although each individual changed significantly on at least one movement parameter, across the group there were no changes in any movement parameter that reached or approached significance. Changes on the ARAT were not closely related to changes in movement parameters. Since aspects of motor performance that contribute to functional change vary across individuals, an individualized approach to upper extremity motion analysis appears warranted.

A theory for equinus gait in cerebral palsy (CP) is that the strong plantarflexors prevent the weak dorsiflexors from achieving dorsiflexion, thereby causing the ankle to be in a plantarflexed position. Recent work has indicated that both the ankle dorsiflexors and plantarflexors are weak. The purpose of this research was to theoretically and experimentally demonstrate that equinus deformity gait could be a compensatory strategy for plantarflexor weakness. It was hypothesized that children with CP utilize an equinus position during gait as a consequence of their weakness. A two-dimensional, sagittal plane model estimating plantarflexor forces through the Achilles tendon was developed. Five able-bodied (AB) children were tested utilizing heel-toe and progressively increasing toe walking strategies. Four children with CP were tested as they walked using their equinus gait. Results demonstrated that AB children assuming the toe walking stance progressively reduced the plantarflexor force when compared to their heel-toe walking trials. However, their toe walking strategy could not reduce the plantarflexor force level to that of the children with CP during the gait cycle. It was concluded that the equinus deformity posture complemented the CP children's plantarflexor weakness. Therefore, by implementing a concomitant strategy to maintain a reduced force state, equinus deformity could be used as a compensatory mechanism for individuals with plantarflexor weakness.

The aims of this study were to compare drag in swimming children and adults, quantify technique using the technique drag index (TDI), and use the Froude number (Fr) to study whether children or adults reach hull speed at maximal velocity (v _max). Active and passive drag was measured by the perturbation method and a velocity decay method, respectively, including 9 children aged 11.7 ± 0.8 and 13 adults aged 21.4 ± 3.7. The children had significantly lower active (k _AD) and passive drag factor (k _PD) compared with the adults. TDI (k _AD/k _PD) could not detect any differences in swimming technique between the two groups, owing to the adults swimming maximally at a higher Fr, increasing the wave drag component, and masking the effect of better technique. The children were found not to reach hull speed at v _max, and their Fr were 0.37 ± 0.01 vs. the adults 0.42 ± 0.01, indicating adults’ larger wave-making component of resistance at v _max compared with children. Fr is proposed as an evaluation tool for competitive swimmers.

This investigation determined relationships between coronal vertical alignment (CVA) and sagittal vertical alignment (SVA) variables calculated from radiographs and surface markers representing bony landmarks. Biplanar radiographs were taken on 28 subjects (standing) after 2 metallic surface markers were placed on the skin superficial to C7 and S2. The CVA-R and SVA-R were measured on the radiographs. Similar variables were calculated from the surface markers (CVA-P-R, SVA-P-R). Correlation between CVA-R and CVA-P-R was 0.894 (p < 0.000), and between SVA-R and SVA-P-R was 0.946 (p < 0.000). Results lead to three recommendations: (1) obtain surface marker data when radiographs are taken to establish relationships between the two sets of data, (2) take care in providing instructions to the subjects if measures are to be taken at different times, and (3) observe caution in interpreting results when simultaneous x-ray and surface marker data were not recorded.

The use of magnetic tracking technology has become increasingly popular in recent years for human motion studies. However, there have been few independent evaluations of how these systems perform. The purpose of this study was to develop a dynamic pendulum calibration method to test the performance of magnetic tracking sensors. A nonmetallic pendulum was constructed and instrumented with a rotary potentiometer. A cube was attached to the distal end of the pendulum so that sensors could be mounted orthogonally. In this manner, it was possible to obtain simultaneous recordings of azimuth, elevation, and roll depending on the sensor mounting orientation relative to the axis of rotation of the pendulum. Sensor data, using Flock of Birds™ sensors, and potentiometer data were collected simultaneously during dynamic pendulum motion at two transmitter distances and then were compared. The results showed excellent trial-to-trial repeatability of 2% or better for the sensors, and high correlations between the sensor and potentiometer data. RMS errors range from about 3 to 10 mm depending on the angular velocity of the pendulum. Angular errors were less than 1 degree RMS for all speeds.

The aim of this study was to develop a functional model of monofin swimming by assigning numerical forms to certain technique parameters. The precise determination of optimal foot displacement and monofin strain points toward a model aspect for increasing swimming speed. Eleven professional swimmers were filmed underwater. The kinematic data were then used as entry variable for an artificial neural network, which itself created the foundation for a model of monofin swimming technique. The resulting network response graphs indicate a division set of standard deviation values in which the examined angular parameters of foot and monofin displacement achieve optimal values in terms of gaining maximal swimming speed. During the upward movement, it is essential to limit dorsal foot flexion (–20°) from the parallel position toward the shin (180°). During the downward movement, plantar flexion should not exceed 180°. The optimal scope of the proximal part of the fin strain is 35° in the downward movement and (–)27° in the upward; the angles of attack of the distal part of the fn and its entire surface are limited to 37° in the downward movement and (–)26° in the upward. Optimization criteria allowed for movement modification to gain and maintain maximal velocity during both cycle phases and to limit cycle velocity decrease.

The objective of the current study was to compare quantitative data on the biomechanical analysis of different techniques for fixation of intercalary bone defects of the humerus, by means of consistently applied methodology on composite models. A total of 25 humeral specimens of composite models were used. An intercalary defect was created and reconstructed using plates, intramedullary nails, external fixators and segmental prosthetic implants. The specimens were loaded under axial compression, four-point bending and torsion within the linear elastic region. Modular segmental implants and intramedullary nails were able to compensate significantly greater amounts of compressive loads compared to locking plates and external fixators. However, in flexion and torsion, the modular segmental implants and the external fixators were significantly better load-bearing devices compared to the intramedullary nails and plates. Early mobilization of the upper limb in patients with diaphyseal bone defects of the humerus could probably be more safe and tolerable when reconstructed with modular segmental implants.