Rourk, Zachary2017-04-112017-04-112016-12https://hdl.handle.net/11299/185551University of Minnesota M.S. thesis. December 2016. Major: Kinesiology. Advisor: Eric Snyder. 1 computer file (PDF); ix, 73 pages.The relationship between core stability and sport performance is unclear. Proponents of core exercise theorize that improved core stability will lead to improvements in sport performance. Detractors argue that current measures of core stability have shown little relationship to sport performance. Current measures of core stability focus on core endurance and core strength, characteristics of subsystems of the greater construct of core stability. Sport performance can generally be characterized as being high in complexity. During these performances it can be reasoned that the demands placed on the core stability system will be similarly complex. However, the current measures of Core Stability are low in complexity, calling into question their validity, by virtue of the principle of dynamic correspondence. PURPOSE: To assess the validity of two common core stability tests (The Sahrmann Core Stability Test (SCST and The Sport Specific Endurance Plank Test (SSEPT)) within the context of level of sport performer (Elite vs. Non-elite). As well as to compare the neuromuscular activity of core muscles between Elite and Non-Elite athletes during a specific sport performance, an ice hockey slapshot. METHODS: Athletes were recruited into two groups, Elite (n=9, Age= 23.11 ± 1.69yrs, Weight= 190.3 ± 5.88lbs, Playing Experience= 18.33 ± 1.55yrs), and Non-Elite (n=8, Age= 28.25 ± 3.26yrs, Weight= 186.2 ± 2.91lbs, Playing Experience= 2.90 ± .83yrs). After being outfitted with an electromyogram device attached to 5 core muscles (Transversus abdominus, Rectus abdominus, Gluteus Medius, Gluteus Maximus, Multifidus), participants completed 10 slapshot trials, the SCST and the SSEPT. RESULTS: There were no significant between group differences for SCST (Elite 2.00 ± 0.47, Non-Elite 2.50 ± 0.38 p = .429) or SSEPT (Elite 228.89 ± 24.07, Non-Elite 215.38 ± 29.65 p = .726). There were significant between group differences in slapshot accuracy (Elite 5.00 ± 0.76, Non-Elite 0.75 ± .53, p = <.001). There were also significant between group differences in EMG Duration, Relative Energy and Relative Power. The Elite group had shorter EMG Duration in TVA (555.70 ± 21.97ms, 1111.29 ± 59.67ms), RA (367.33 ± 25.85ms, 803.63 ± 65.03ms), GMed (584.05 ± 35.69ms, 1486.89 ± 134.35ms), GMax (786.21 ± 54.94ms, 1522.92 ± 81.28ms) and Multi (961.11 ± 46.81ms, 1973.34 ± 115.7ms) , lower Relative Energy in TVA (56.94 ± 2.81mV•ms, 209.76 ± 29.16mV•ms), RA (27.65 ± 3.06mV•ms, 94.77 ± 10.09mV•ms), GMax (62.04 ± 4.72mV•ms, 128.30 ± 5.64mV•ms) and Multi (93.57 ± 3.67mV•ms, 218.18 ± 16.03mV•ms), as well as lower Relative Power in TVA (.1053 ± .0050, .1589 ± .0117mV) and RA (.0746 ± .0054, .1119 ± .0071 mV) and higher Relative Power in GMed (.0592 ± .0026, .0447 ± .0028 mV). CONCLUSION: The SCST and the SSEPT are not valid measures of core stability within the context of level of sport performance. Neither measure was able to distinguish between Elite and Non-Elite groups. It is important to stress the difference in playing experience between the two groups (Playing Experience, Elite= 18.33 ± 1.55yrs, Non-Elite= 2.90 ± .83yrs). The Elite group was comprised of professional and D-I NCAA hockey players, whereas the Non-Elite group was comprised of bottom level recreational players described as working on skills such as learning to skate with the puck. The differences in sport specific skill level were further reinforced by the significant between group differences observed in the slapshot accuracy test. The inability of the two studied measures to differentiate between such different levels of athlete bring into question their validity within the broader context of sport performance in general. Further research is necessary to justify such extrapolations of findings. The neuromuscular activity of the core musculature of Elite and Non-Elite hockey athletes during a slapshot differs in terms of muscle activation duration, relative energy and relative power. These differences imply that neuromuscular coordination may play a role in the core stability of an athlete during a specific sport performance. Based on these results, a valid measure of Core Stability should be similar in complexity to the targeted sport performance and related to meaningful outcomes specific to the nature of that sport, in accordance with the principle of dynamic correspondence. An approach in which exercises are chosen based on their similarity to desired sport performance in terms of neuromuscular coordination, as opposed to training general athletic qualities such as, in this case, core endurance or core strength.enCorePlankSahrmannStabilityThesis or Dissertation