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John J. Miller

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John J. Miller and John T. Wendt

On October 23, 2010 in the city of Fujairah, east of Dubai, United Arab Emirates (UAE), United States medal winning swimmer Fran Crippen failed to finish the Fédération Internationale de Natation (FINA) 10 Kilometer Marathon Swimming World Cup open water race. The conditions of the water and exterior temperature were relevant factors contributing to the death of Fran Crippen. A discussion of risk communication, as an integral part of the risk management process, describes how this tragedy could have been avoided. This case study will address how the proper authorities could have employed the risk communications to prevent this tragedy.

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Ryan K. Zapalac, John J. Miller and Kelsey C. Miller

Julie Tyler was recently hired as President of the Sacramento River Cats, a Triple-A affiliate of the San Francisco Giants. With a little over one month on the job, Julie encounters a situation she has never had to deal with when an earthquake strikes her facility. The River Cats are not severely impacted by the earthquake, but a rival organization (the Fresno Grizzlies; Triple-A affiliate of the Houston Astros) experiences some fairly serious damage and injuries. Julie has to decide whether to modify the schedule to meet the needs of the Grizzlies, to appease some of her other stakeholders with varying interests, and/or pursue a competitive advantage for her organization. Julie makes the decision to review a similar situation for guidance on her decision. The situation she decides to employ is a series relocation that the Houston Astros had to make to Tampa, Florida following the devastation created by Hurricane Harvey in August 2017. Her decision has to be made expeditiously as their next series with the Grizzlies takes place in four days.

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James G. Hay and John A. Miller Jr.

The purposes of this study were (a) to describe the techniques used by elite female athletes during the transition from approach to takeoff in the long jump and (b) to determine which characteristics were significantly related to the officially recorded distance of the jump. The subjects were the 12 finalists in the Women's Long Jump at the 1984 Olympic Games. A motion-picture camera placed with its optical axis at right angles to the runway was used to record the performances of the subjects. Means and standard deviations of the variables identified in a theoretical model and correlations between these variables and the distance of the jump were computed. Significant correlations revealed that the less the downward velocity at touchdown at the end of the third-last stride, and the less this velocity is changed by the vertical forces transmitted via the supporting foot, and the shorter the duration of the next flight phase, the greater the distance of the jump.

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James G. Hay and John A. Miller Jr.

The purposes of this study were (a) to describe the techniques used by elite triple jumpers and (b) to determine which characteristics were significantly related to the officially recorded distance of the jump. The subjects were the 12 finalists in the Triple Jump at the 1984 Olympic Games. Two motion-picture cameras placed with their optical axes at right angles to the runway were used to record the performances of the subjects. Means and standard deviations of the variables identified in a theoretical model and correlations between these variables and the distance of the jump were computed. Correlation of the distances achieved in each of the phases with the official distance of the jump suggested that, although the hop and jump phases made greater percentage contributions to the official distance than did the step phase, they accounted for only small amounts of the variance in that distance. Significant correlations of other independent variables with the distance of the jump suggested that the more the athlete's resources are expended prior to the jump phase and the more vertical his effort at takeoff into the jump, the better is the final result.

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John P. Miller, Kerriann Catlaw and Robert Confessore

The purpose of this study was to examine the effect of ankle position on the electromyographic (EMG) activity, peak torque, and peak knee flexion to extension torque ratio during isokinetic testing of the knee. Twelve healthy female athletes performed six maximal knee extension and flexion repetitions with their dominant legs at 60 and 180°/s with the ankle in a plantar flexed position and again in a dorsiflexed position. Root mean square EMG (rmsEMG) activity was determined by placing bipolar surface electrodes on the quadriceps and the hamstrings. Ankle position had no effect on the rmsEMG activity of the quadriceps or the hamstrings at either 60 or 180°/s. Significant differences were noted for peak flexor torque at 607s (p < .001) and 180°/s (p <.01) and for peak torque flexor/extensor ratio (p < .01), with higher values observed with ankle dorsiflexion. This suggests that ankle position affects knee flexor torque and flexor/extensor ratio but not hamstring activity during isokinetic testing of the knee.

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John A. Miller Jr and James G. Hay

The horizontal jumps at the 1985 TAC (U.S. national) Championships in Indianapolis were filmed as part of the Elite Athlete Project of the U.S. Olympic Committee. Jumps by Willie Banks and Mike Conley were especially outstanding and, because of this as well as some excellent performances by the third and fourth place finishers, an analysis of the jumping techniques used by the top four finishers was conducted. Its purposes were (a) to determine selected kinematic data for a world record triple jump, and (b) to compare these data with corresponding data for previous performances by the same athlete and for performances by other elite triple jumpers. A comparison of the phase distances and phase ratios for the 1985 TAC jumps with those for the best analyzed jump by Banks, Conley, and Joyner at some previous meets revealed that, as they increased their effective distances, all three decreased the emphasis they placed on the step phase. The best athletes seem to use a “pawing” (or active) landing prior to takeoff into the step phase and a “blocking” landing prior to takeoff into the jump phase.

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John P. Miller and Ronald V. Croce

Context:

Researchers have postulated that coactivation of the hamstrings during active knee extension assists the anterior cruciate ligament in maintaining knee joint stability by exerting an opposing force to anterior tibial translation.

Objective:

To compare the reciprocal coactivation of the hamstrings while performing low and high velocity isokinetic movements and two closed chain movements.

Design:

Within subject’s comparison of isokinetic and closed chain exercises.

Setting:

Biomechanics laboratory utilizing a Cybex norm isokinetic dynamometer and Biopac Data Collection system.

Participants:

12 healthy women.

Main Outcome Measures:

The root mean square of the Electromyogram (rmsEMG) was used as a measure of overall muscle activity.

Results:

The rmsEMG for hamstring coactivation during knee extension showed significant differences between the isokinetic movements and the closed chain exercises with greater coactivation when performing the isokinetic movements. In addition, greater activity was seen at the higher isokinetic velocity and during the one legged squat.

Conclusions:

These results suggest isokinetic movements, particularly at high speed, can more effectively increase the coactivation activity of the hamstrings when compared to two closed chain activities.

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Diana E. Thomas, John R. Brotherhood and Janette Brand Miller

It was hypothesized that slowly digested carbohydrates, that is, low glycemic index (GI) foods, eaten before prolonged strenuous exercise would increase the blood glucose concentration toward the end of exercise. Six trained cyclists pedaled on a cycle ergometer at 65-70% VO2max 60 min after ingestion of each of four test meals: a low-GI and a high-GI powdered food and a low-GI and a high-GI breakfast cereal, all providing 1 g of available carbohydrate per kilogram of body mass. Plasma glucose levels after more that 90 min of exercise were found to correlate inversely with the observed GI of the foods (p < .01). Free fatty acid levels during the last hour of exercise also correlated inversely with the GI (p < .05). The findings suggest that the slow digestion of carbohydrate in the preevent food favors higher concentrations of fuels in the blood toward the end of exercise.