Date of Award

2024

Degree Name

Biomechanics

College

College of Health Professions

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Dr. Steven Leigh, Committee Chairperson

Second Advisor

Dr. Suzanne Konz

Third Advisor

Dr. Elizabeth Pacioles

Abstract

Goalkeepers must perceive and analyze many different types of information in a short time to effectively move their bodies to make a save. Skilled goalkeepers enhance their actions by coupling them to information present in their environment. The information in their environment constantly changes, so the goalkeepers must adjust their strategies or positions to match the environmental demands. Goalkeepers use two types of perception and attentional strategies: stimulus-driven and goal-directed. Stimulus-driven perception is fast and compulsory, while goal-directed perception is slower and more methodical. Both visual search strategies direct the goalkeeper’s attention to where it is most needed and can be trained to improve goalkeeping performance and efficiency. Therefore, this thesis aimed to investigate the effect of visual perception training strategies on improving goalkeeping actions. It was hypothesized that goalkeepers who underwent visual perceptual training and goal-directed visual perceptual strategies would show greater improvements between reaction times and movement towards the ball during a save of a penalty kick compared to those without training or goalkeepers who used stimulus-driven perceptual strategies.

This study was designed to be observational with a longitudinal, repeated-measures analysis. Nine experienced soccer goalkeepers gave consent and participated in this study, and they were separated into three groups: video-control, stimulus-driven, and goal-directed. The subjects underwent a pre-and post-test with a 10-day visual training intervention in between. Both pre-and post-tests had the subjects try and save 6 randomized penalty kicks from the same kicker, and after each kick, the subjects verbalized their thoughts to the researcher. The training had the goalkeepers watch a compilation of 20 penalty kick videos for 10 days. The data were collected using a video camera, pressure-sensing insoles, and an IMU. The data collected from these devices were processed into discrete variables. Two-way, mixed-model ANOVA was conducted in SPSS to assess differences in the variables. A type I error rate was set at α=.01. A power analysis was conducted to determine the appropriate amount of people per group for statistical significance: a power of .8 and a Type I error rate of 10%. A qualitative analysis was used to investigate the participants’ think-aloud responses to assess how they used perceptual training strategies and how they might have benefitted from the training.

The data set was checked for normality, and no significant 2-way interactions were present within the data. Reaction time increased from pre- to post-test for our training groups. The stimulus-driven group confidently accelerated in the correct direction, while the goaldirected confidently and the video-control groups nervously accelerated in the wrong direction. The stimulus-driven group also moved faster in the y-direction compared to the other two groups.

The first hypothesis was not supported because there were no positive differences from pre- to post-testing for any variable, and reaction time increased for all participants. The second hypothesis was not supported because we predicted the goal-directed group would show the most improvement when the stimulus-driven group became the most successful after training. There was human error because we employed human kickers instead of robots. Not all the shots went to the exact right place; sometimes, they were just close enough to count, or it took the kicker a few tries, which could have thrown the goalkeepers off their rhythm. We were unable to mediate subject training due to conflicting schedules, so not all subjects completed the full regime. Shifted equipment caused incomplete data in some trials. Our main finding of this study was that stimulus-driven training was better at improving goalkeeping performance.

Subject(s)

Soccer.

Visual training.

Visual perception -- Training.

Soccer goalkeepers.

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