THE EFFECTS OF “GRUNTING” ON SERVE AND FOREHAND VELOCITIES IN COLLEGIATE TENNIS PLAYERS DENNIS G. O’CONNELL,MARTHA R. HINMAN,KEVIN F. HEARNE,ZACH S. MICHAEL, AND SAM L. NIXON Department of Physical Therapy, Applied Physiology Laboratory, Hardin-Simmons University, Abilene, Texas ABSTRACT O’Connell, DG, Hinman, MR, Hearne, KF, Michael, ZS, and Nixon, SL. The effects of “grunting” on serve and forehand veloc- ities in collegiate tennis players. J Strength Cond Res 28(12): 3469–3475, 2014—The aim of this study was to examine the effects of grunting on velocity and force production during dynamic and static tennis strokes in collegiate tennis players. Thirty-two (16 male and 16 female) division II and III collegiate tennis athletes with a mean age of 20.2 6 1.89 years participated as subjects. Demographic and survey data were obtained before subjects completed a 10- to 15-minute warm-up of serves and ground strokes while grunting and not grunting. The subjects per- formed randomized sets (3 grunting and 3 nongrunting trials) of serves and forehand strokes both dynamically and isometrically. Stroke velocities and isometric forces were measured with a cali- brated radar gun and calibrated dynamometer, respectively. Elec- tromyographic (EMG) data from subjects’ dominant pectoralis major and contralateral external oblique muscles were recorded and averaged for data analysis. A repeated measures multivariate analysis of variance (RM-MANOVA) compared dynamic stroke velocity, isometric muscle force, and peak EMG activity during each breathing condition at the 0.05 alpha level. The RM-MANOVA indicated that dynamic velocity and isometric force of both serves and forehand strokes were significantly greater when the subjects grunted (F = 46.572, p , 0.001, power = 1.00). Peak muscle activity in the external oblique and pectoralis major muscles was also greater when grunting during both types of strokes ( F = 3.867, p = 0.05, power = 0.950). Grunt history, gender, perceived advan- tages, and disadvantages of grunting, years of experience, highest level of competition, and order of testing did not significantly alter any of these results. The velocity, force, and peak muscle activity during tennis serves and forehand strokes are significantly enhanced when athletes are allowed to grunt. KEY WORDS grunt, vocal disinhibition, tennis INTRODUCTION T ennis, one of the most popular sports in the world, is played by .75 million individuals (2,25) and has with widespread appeal involved children and adults of all ages. This widespread interest has spawned over 1,000 annual professional tournaments and team events for juniors, seniors, and wheelchair players (7). Tennis requires that players respond to a continuing series of emergencies with jumping, lunging, changing direction, stop- ping and starting, and sprinting to and reaching a ball (2). Match play is largely anaerobic, and requires intense short duration play (4–10 seconds) with various lengths of recovery between points (20 seconds), changeovers (90 seconds), and sets (120 seconds). Typically, the mean duration of work to rest is 5–10 seconds and 10–20 seconds, respectively (6). Although this work is intermittent, matches can last several hours, and elite players work at approximately 60% of V _ O 2 max over the duration of these matches (3). Circulating lactate concentrations may increase up to 8.0–8.6 mmol$L 21 during match play, which clearly reflects the increased involvement of anaerobic glycolytic energy systems (3,7). Tactically, the serve presents players with a distinct advantage as they consciously determine serve type, velocity, and ball placement while their opponent uses visual and auditory senses, reaction, and movement time to provide a coordinated and strategic return of serve. These senses and physiological attributes allow players to continue until a point is won. Success in the modern game of tennis is dictated by ball velocity and ball placement (31). Matches can be won or lost by a player who can serve more effec- tively than their opponent. If serving is the key to success, then high-velocity serving speed and ball speed may limit an opponent’s ability to reach and return the serve. Dynamic strength of the upper limb is related to ball velocity (18) and service success (22). Peak serving speed and peak down-the-line forehand velocity are strongly correlated with peak isokinetic Torque and peak Torque of the internal rotators of the shoulder, respectively (31). Clearly, faster accurate serves and ground strokes places the receiver at a disadvantage. Stronger players can express increased velocities in forehands, backhands, and volleys, so as players grow stronger, their serve and forehand velocities Address correspondence to Dr. Dennis O’Connell, oconnell@hsutx.edu. 28(12)/3469–3475 Journal of Strength and Conditioning Research Ó 2014 National Strength and Conditioning Association VOLUME 28 | NUMBER 12 | DECEMBER 2014 | 3469 Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.