Date of Graduation

5-2013

Document Type

Thesis

Degree Name

Bachelor of Science Education

Degree Level

Undergraduate

Department

Health, Human Performance and Recreation

Advisor/Mentor

McDermott, Brendon P

Committee Member/Reader

Oliver, Gretchen D

Committee Member/Second Reader

Ganio, Matthew S.

Committee Member/Third Reader

Hammig, Bart

Abstract

Human movement is based on proximal to distal sequencing of the kinetic chain. Efficiency of the shoulder is dependent upon the stability and function of the pelvis and scapula. PURPOSE: To determine if pelvic and scapular muscle activations are altered in overhead throwing following fatigue. METHODS: Eleven [19.2 ± 1.0 years; 168.9 ± 6.6 cm; 68.9 + 8.7 kg] softball players volunteered. Surface electromyographic [sEMG] electrodes were placed on bilateral gluteus medius, throwing arm latissimus dorsi, lower trapezius [LT], middle trapezius [MT], and serratus anterior [SA]. Participants had to catch a simulated hit ball and perform their positional throw. Infielders caught and threw to second base and outfielders crow hopped and threw to second, simulating a game setting where a runner was trying to steal. After 5 throws, participants threw a 2 kg ball into a rebounder until maximum perceived fatigue on 0-3 scale [3 = fatigue]. Following fatigue, 5 more throws were performed. The fastest throw pre and post fatigue were selected for sEMG analysis using a paired T-test. RESULTS: There were no significant differences in muscle activation pre and post fatigue during the acceleration phase of throwing. It was revealed that all muscles activation was increased post-fatigue excluding LT. CONCLUSION: The SA and LT provide a force couple to stabilize the scapula in arm elevation. Thus, while no statistical differences were observed, the increase in SA and decrease in LT could be an indicator of possible scapular instability following fatigue. Further research is needed to understand the effects of fatigue on pelvic and scapula stabilization during overhead throwing.

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