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Effect of an Acute Bout of High Intensity Game Simulation Exercise on Direct and Indirect measures of Neuromuscular Fatigue in Canadian Football Players: 134 May 28, 1100 AM - 1115 AM

Clarke, Nicky1; Farthing, Jonathan P.2; Norris, Stephen R.3; Lanovaz, Joel L.2; Krentz, Joel2

Medicine & Science in Sports & Exercise: May 2014 - Volume 46 - Issue 5S - p 18
doi: 10.1249/01.mss.0000493219.49809.d6
A-31 Free Communication/Slide - The Science of Concussions Wednesday, May 28, 2014, 9:30 AM - 11:30 AM Room: 305
Free

1University of Saskatchewan, Victoria, BC, Canada. 2University of Saskatchewan, Saskatoon, SK, Canada. 3University of Calgary and the Mount Royal College, Calgary, AB, Canada.

(No relationships reported)

PURPOSE: By assessing the effects of a fatiguing game simulation (G-Sim) exercise bout on the balance of collegiate Canadian football players, the primary purpose of this study was to evaluate postural control as a potential alternative or supplementary tool for monitoring neuromuscular fatigue (NMF) in collision-based team sports.

METHODS: Fifteen male participants (mean ± SD: age 21.8 ± 1.6 years, weight 97.6 ± 14.7 kg, height 187.2 ± 5.2 cm) from the competitive roster of the University of Saskatchewan Canadian Football team were recruited. Indirect NMF measures, postural sway and countermovement jump (CMJ), were performed 24 hours before (TBase), immediately before (TPre), as well as immediately (TPost), 24 hours (T24) and 48 hours after (T48) a high intensity Canadian football G-Sim. Peak isometric knee extensor torque of a maximal voluntary contraction (MVC) and electrically evoked tetani at 20Hz (P20) and 80Hz (P80) were collected as direct NMF measures at TBase, TPre, TPost, and T48.

RESULTS: Significant declines in MVC (from 373.4 ±82.9 to 303.9 ± 67.0 Nm; p<0.016), P20 (from 243.1 ±78.9 to 188.5 ± 54.4 Nm; p<0.016). and MVC/P80 (from 0.95 ±0.33 to 0.85 ± 0.31; p<0.016) at TPost were accompanied by significant reductions in CMJ takeoff velocity (p<0.016;-6.3%) and peak power (p<0.016; -5.9%) as well as a significantly larger area covered by the center of pressure trajectory (p<0.016; -95.2%) during a 70s postural sway task.

CONCLUSION: Impairment of neuromuscular function in Canadian football players after a G-Sim is attributed to alterations in excitation-contraction coupling due to structural damage and central activation failure. Congruency between the direct and indirect measures of NMF suggests postural sway monitoring, in combination with CMJ, may present a more comprehensive assessment of both the neuromuscular and somatosensory alterations induced by acute G-Sim or game-induced fatigue in collision-based team sport players.

© 2014 American College of Sports Medicine