Team sports frequently use inertial measurement units (IMU) fixed at the scapulae for the quantification of athlete performance. Similar IMU are used in clinical settings for gait analysis and jump testing but are located at the center of mass (COM). For clinical methods of jump and gait analysis to be translated to sports related IMU, an investigation of the validity of measure from the scapulae should be assessed. The objective of the current study was to translate clinical methods of gait analysis and jump assessment to commercially available trunk-mounted accelerometers. The current study created a gait program to analyze and compile the gait data. Following completion of the gait program, the IMU (STATSports APEX) was investigated for validity against ankle accelerometers. Once the validity was determined, an application study evaluated the relevance of collecting gait data during a NCAA D1 Women's Soccer season. Similarly, the trunk-mounted accelerometer was validated against force plates to assess countermovement jump height. The final study assessed how both jump height and gait variables changed due to game-related decline in performance.
This study provides evidence that trunk-mounted accelerometers are a valid tool for assessing temporal gait variables (ICCRight = 0.95 and ICCLeft = 0.96), CMJ height (ICCJH = 0.90) and flight time (ICCFT = 0.88). A longitudinal analysis of gait showed that StepL, StrideL, kleg, and postural variables changed regularly in pre-post comparisons of performance. Postural variables had more changes towards the end of the season. Root mean squares (RMS) of accelerations and angular velocities had the highest correlations to High Speed Running (HSR). Fractal step and stride length (StepLĪ± and StrideLĪ±) had the strongest correlation to Total Distance (Rstep = -0.29 and Rstride = -0.29), or Tot Dist. When comparing gait and CMJ analyses to detect game-related changes in performance, CMJ was more descriptive of fatigue. In a proof-of-concept study, pre-post changes in CMJ immediately before and after a game had a moderate negative correlation (R = -0.57) to Tot Dist. When the protocol changed to assess the differences between the days before and after the game, the correlation weakened to R = -0.27. Spatiotemporal and spring mass variables did not change, whereas postural variables appeared to improve. The current study has provided evidence that running gait could be used as an athlete monitoring technique, however more data needs to be collected to understand how running gait variables change with team-sports related fatigue. / Doctor of Philosophy / Trunk-mounted accelerometers have become widely popular in team sports such as soccer. Prior to their use in team sports, accelerometers were used in clinical settings to assess gait, and in some cases jump performance. Different from the trunk-mounted accelerometers, the clinical accelerometers were fixed on the lower back to approximate the position of the center of mass. Consequently, the methods to assess gait and jump performance using an accelerometer assume that the accelerometer is fixed on the lower back. For these methods to be translated to trunk-mounted accelerometers, the validity of the methods needs to be established. This paper investigated the validity of trunk-mounted accelerometers in evaluating gait and countermovement jump height. A season-long assessment of gait provided insight into the utility of monitoring gait in team sports athletes. Lastly, a comparison of gait to countermovement jump analyses helped to elucidate what the changes in gait indicate, and how team staff may effectively utilize that information.
The trunk-mounted accelerometer (STATSports APEX) was valid in estimating gait and jump variables. The seasonal analysis showed that gait variables changed frequently throughout the season. The main variables affected described the step and stride length of the individual, the stiffness of the leg, and variables representing the variability in trunk movements associated with running. The variability in trunk movements were more perturbed towards the end of the season when players may be beginning to tire from continuous training and competition. In the final study, the jump analysis proved to be more representative of the player's state of fatigue than gait. The gait variables appeared to improve after exhaustive exercise. The apparent improvement in gait variables could indicate that the players recovered quickly from the exhaustive exercise, or that gait variables respond in a more complex fashion than jump variables. More data needs to be collected on how gait changes due to game-related fatigue in soccer players to better understand its effect on neuromuscular performance.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/103617 |
| Date | 02 June 2021 |
| Creators | Jaskowak, Daniel Joseph |
| Contributors | Human Nutrition, Foods and Exercise, Williams, Jay H., Davy, Kevin P., Hulver, Matthew W., Tegarden, David P. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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