1. TEMPLATE DESIGN © 2008 www.PosterPresentations.com ABSTRACTRESULTSRESULTS (CONT.) METHODS INTRODUCTION PURPOSE RESULTS CONT. SUMMARY & CONCLUSIONS Muscle pennation angle and thickness have been shown to influence force production. To our knowledge, there is limited data on muscle architecture and power production. BACKGROUND: Muscle pennation angle and thickness have been shown to influence force production. However, to our knowledge, there is limited data on muscle architecture and power production. PURPOSE: The purpose of this study was to examine the relationship between Vastus Lateralis muscle thickness (VLMT) and pennation angle (PA) on measures of peak power and peak velocity in both the dominant (D)and non-dominant leg (ND). METHODS: Twenty competitive female NCAA Division 1 soccer players (mean ± SD; age: 19.5 ± 0.9 yrs; height: 167.7 ± 8.2cm; weight: 63.3 ± 7.9kg) participated in performance assessment in the UCF Human Performance Lab (HPL). VLMT and PA were assessed in both dominant and non-dominant legs using ultrasonography. Measures of power and velocity during unilateral and bilateral countermovement vertical jump tests were assessed using an accelerometer. Muscle morphology and measures of peak power and velocity were interpreted using Pearson product moment correlation coefficients. RESULTS: VLMT of the dominant leg (1.66cm ± 0.30) was shown to be significantly correlated to peak power in both the bilateral vertical jump (1658W ± 261; r = 0.502, P = 0.024) and unilateral vertical jump using the dominant leg (1272 ± 172; r = 0.701, P = 0.001). However, VLMT of the non-dominant leg (1.42cm ± 0.28) was shown to be significantly correlated to peak power in the bilateral vertical jump only (r = 0.459, P = 0.042) and not the unilateral jump using the non-dominant leg (1271 ± 204; r = 0.320, P = 0.170). VLMT was not significantly correlated with measures of peak velocity in either bilateral or unilateral jumps. PA of the non-dominant leg (10.64 ± 2.44) was shown to be significantly correlated to peak velocity in the bilateral vertical jump only (r = 0.488, P = 0.029). However, PA of the dominant leg was not significantly correlated to peak velocity in either the bilateral or unilateral jump. Additionally, PA was not significantly correlated with peak power in either bilateral or unilateral vertical jumps. CONCLUSIONS: Correlation statistics indicate that the dominant leg plays a more predominant role in bilateral jump power than does the non-dominant leg in female collegiate soccer players. The lack of correlation between VLMT and peak power in the non-dominant unilateral jump, could in part be explained by a deficit in jump coordination, for which the dominant leg compensates during the bilateral jump. The correlation between PA in the non-dominant leg and bilateral jump velocity could in part be explained by the invoked stretch reflex of the plant leg when striking the ball. PRACTICAL APPLICATION: Female soccer players are particularly prone to ACL injuries. A contralateral deficit in strength between the dominant and non-dominant leg may increase the risk of injury. Therefore, unilateral training may be warranted by soccer coaches to achieve more balanced power production and reduce ACL injuries. The purpose of this study was to examine the relationship between Vastus Lateralis muscle thickness (VLMT) and pennation angle (PA) on measures of peak power and peak velocity in both the dominant and non-dominant leg. SUBJECTS: Twenty competitive female NCAA Division 1 soccer players (mean ± SD; age: 19.5 ± 0.9 yrs; height: 167.7 ± 8.2cm; weight: 63.3 ± 7.9kg) participated in performance assessment in the UCF Human Performance Lab (HPL). MUSCLE MORPHOLOGY: VLMT and PA were assessed in both dominant and non-dominant legs using B-mode ultrasonography with a 12MHz linear transducer. POWER & VELOCITY: Measures of peak power and peak velocity during unilateral and bilateral countermovement vertical jump tests were assessed using an accelerometer. STATISTICS: Muscle morphology and measures of peak power and velocity were interpreted using Pearson product moment correlation coefficients. The dominant leg plays a more predominant role in bilateral jump power than does the non-dominant leg in female collegiate soccer players. A deficit in jump coordination may exist in the non-dominant leg, for which the dominant leg compensates during the bilateral jump. The correlation between PA (ND) and bilateral jump velocity could be explained in part by a training effect with regards to the stretch reflex of the plant leg when striking the ball in the game of soccer. Figure 1: Ultrasound image of the dominant leg Vastus Lateralis from a representative participant, showing muscle thickness and pennation angle. Muscle thickness was measured as the distance between the deep aponeurosis & superficial aponeurosis of the Vastus Lateralis. Pennation Angle was measured as the crossing between the superficial aponeurosis & fascicle. PRACTICAL APPLICATIONS Reducing the deficit between the dominant and non-dominant leg may serve to reduce the risk of injury and increase power performance [1]. Unilateral training may be warranted by soccer coaches to achieve more balanced power production and reduce ACL injuries [2]. Representative image of the countermovement jump. Peak power and peak velocity were measured using an accelerometer. Subjects were instructed to jump as they would during a game utilizing the arms for momentum. significance (p ≤.05) Relationship Between Vastus Lateralis Muscle Morphology and Measures of Power and Velocity in Female Collegiate Soccer Players Adam J. Wells, William P. McCormack, Tyler C. Scanlon, Nadia S. Emerson, David R. Williams, Gerald T. Mangine, Adam M. Gonzalez, Maren S. Fragala, Jay R. Hoffman, Jeffrey R. Stout Human Performance Laboratory, University of Central Florida, Orlando, FL, VLMT of the dominant leg was significantly correlated to peak power in both bilateral and unilateral countermovement jumps VLMT of the non-dominant leg was significantly correlated to bilateral jump power only. Table 2. Correlations between muscle architecture and measures of power and velocity Table 1. Mean ± SD. Mean measures across all 20 subjects for jumping performance and muscle architecture in both dominant (D) and non-dominant (ND) legs. PA of the non-dominant leg was significantly correlated to peak velocity in the bilateral countermovement jump. 1.Knapik JJ, Bauman CL, Jones BH, Harris J, Vaughan L. Preseason strength and flexibility imbalances associated with athletic injuries in female collegiate athletes. Am. J. Sports Med. 1991. 19(1): 76-81. 2.Newton RU, Gerber A, Nimphius S, Shim JK, Doan BK, Robertson M, Pearson DR, Craig BW, Hakkinen K, Kraemer WJ. Determination of functional strength imbalance of the lower extremities. J. Strength Cond. Res. 2006. 20(4): 971-977.