OPTIMAL ELASTIC CORD ASSISTANCE FOR SPRINTING IN COLLEGIATE WOMEN SOCCER PLAYERS J. ALBERT BARTOLINI,LEE E. BROWN,JARED W. COBURN,DANIEL A. JUDELSON, BARRY A. SPIERING,NICK W. AGUIRRE,KEVEN R. CARNEY, AND KENTEN B. HARRIS Human Performance Laboratory, Department of Kinesiology, California State University, Fullerton, California ABSTRACT Bartolini, JA, Brown, LE, Coburn, JW, Judelson, DA, Spiering, BA, Aguirre, NW, Carney, KR, and Harris, KB. Optimal elastic cord assistance for sprinting in collegiate women soccer players. J Strength Cond Res 25(5): 1263–1270, 2011—Overspeed exercises are commonly integrated into a training program to help athletes perform at a speed greater than what they are accustomed to when unassisted. However, the optimal assis- tance for maximal sprinting has not been determined. The purpose of this study was to determine the optimal elastic cord assistance for sprinting performance. Eighteen collegiate women soccer players completed 3 testing sessions, which consisted of a 5-minute warm-up, followed by 5 randomized experimental conditions of 0, 10, 20, 30, and 40% body weight assistance (BWA). In all BWA sessions, subjects wore a belt while attached to 2 elastic cords and performed 2 maximal sprints under each condition. Five minutes of rest was given between each sprint attempt and between conditions. Split times (0–5, 5–10, 10–15, 15–20, and 0–20 yd) for each condition were used for analysis. Results for 0–20 yd demonstrated a significant main effect for condition. Post hoc comparisons revealed that as BWA increased, sprint times decreased up to 30% BWA (0%: 3.20 6 0.12 seconds; 10%: 3.07 6 0.09 seconds; 20%: 2.96 6 0.07 seconds; 30%: 2.81 6 0.08 seconds; 40%: 2.77 6 0.10 seconds); there was no difference between 30 and 40% BWA. There was also a main effect for condition when examining split times. Post hoc comparisons revealed that as BWA increased, sprint times decreased up to 30% BWA for distances up to 15 yd. These results demonstrate that 30% of BWA with elastic cords appears optimal in decreasing sprint times in collegiate women soccer players for distances up to 15 yd. KEY WORDS acceleration, body weight, overspeed INTRODUCTION S print running ability is elemental to sporting activities. Attempts to improve sprint running are critical because sprinting is often used as an evaluation of athletic potential. Training to improve sprint running has become increasingly sophisticated while coaches and athletes examine every consideration when developing training programs. These may include training at the appropriate age (7) with proper nutrition (34), ergogenic aids (35), appropriate drills (3,19) and exercises (15), proper recovery (2,20,24) (both inter and intraworkout), sequence (3), and assisted by a coach’s skill and intuition (28). Each of these may lead to optimal sprint running performance. Training methods for improving sprint performance have typically included general speed and strength (3,4,15,32), velocity-specific strength (15), movement specific sprint- associated exercises (3,4,33), and resistance training (32). Stride length can be developed by improving the sprinter’s strength and power, which enables the athlete to apply more force against the ground with the pushing leg while running (15). To enhance force development, athletes need to perform training movements that involve rapid acceleration against resistance, and this acceleration should extend throughout the movement with no intention to decelerate at the end of the movement (27). Technique mastery is said to be essential to increasing stride frequency (28). Mastery of sprint running technique has led to decreased flight time and decreased time in the amortization phase of the running stride (28). Coaches have made many attempts to increase sprint- running performance by increasing stride length and stride frequency (3,4,17,18,30). Other attempts to increase sprint running performance have included some variation of assisted- or resisted-sprint running (6,8,9,11,12,17,30,32). Resisted-sprint training, research indicates, improves the acceleration (drive) phase by shortening strides and increasing ground force application (8,18,26). Assisted sprint training allows the athlete to run faster than they are normally capable of and is commonly referred to as overspeed training (3,4). Overspeed training seems to improve maximal velocity via increasing stride length, stride rate, or muscular activity of the lower extremities (13,21). When examining the effects of hill slope Address correspondence to Lee E. Brown, leebrown@fullerton.edu. 25(5)/1263–1270 Journal of Strength and Conditioning Research Ó 2011 National Strength and Conditioning Association VOLUME 25 | NUMBER 5 | MAY 2011 | 1263 Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.