1. A Proposed Study: The Effects of a Rotator Cuff Strength Training Program on the Flat and Kick Serves in Tennis Evan K. Liu & Andrew Alstot, Ph.D. Department of Exercise Science Pacific University, Forest Grove, OR Background The world of strength and conditioning has been renowned for improving multiple aspects of life and performance. Through many years of evolution, strength and conditioning can contribute to one’s overall well being. An important aspect of strength and conditioning is the process of training itself. Based off of the sliding filament theory, eccentric contractions (active lengthening) produces more force than the two other types of contractions: concentric and isometric. Eccentric actions are the main decelerators of our actions. 7 Some activities that constantly produce eccentric actions are overhead activities such as the tennis and volleyball serve or the baseball throw. The rotator cuff group of the shoulder are a component of the force producing and decelerating aspects of these activities for protection and performance. 2,3,4 Currently, a common practice of these activities emphasizes strengthening of the rotator cuff for increased performance and for possible injury prevention. 1,3,5,6 Tennis is an activity that readily implements a shoulder strengthening program, specifically for the rotator cuff. Studies have shown that strengthening the rotator cuff increases the serve velocity. 3,6 Although the velocity has been shown to increase, the effects of a strength program on different serves have not been studied. In another type of serve, the “kick” or “topspin” serve, the athlete applies topspin on the ball which allows the ball to “bite” or accelerate after the ball contacts the ground. Thus, the purpose of this experiment is to observe the effects of a rotator cuff strength program on the kick serve in tennis. Method Participants & Setting: Collegiate male tennis players from a small university located in the Pacific Northwest of the United States will be used in this study. Each participant will need to be at least a 4.5 level based off of the National Tennis Rating Program (NTRP); a United States Professional Tennis Association (USPTA) certified professional will be used to assess that the ranking is valid. Materials: A Stalker ATS II Pro Radar Gun will be used to measure the velocity and acceleration of the serves. A new can of ProPenn tennis balls will be used for every session in order to keep consistent. Golden Set Tennis String, or the choice of the participants’ string will be kept consistent throughout the duration of the study. The strength training sessions will be conducted using kettle balls. Procedure: Pre/Post Tests: A pre and post test of rotator cuff strength and range of motion will be tested to track changes of rotator cuff strength and range of motion. For the pre- and post-tests of their serves, there will be a box (2 x 2 feet) at the “t” of the service box for flat serves. Velocity will be measured by taking the mean of the first 10 serves that go into the service box. Kick serves will be served out wide (ad-side for right handers and deuce-side for left handers) and will follow the same procedures as the flat serves; the only difference being that acceleration will be measured instead of velocity. Experimental Design: Participants will all eventually be divided into three groups. A multiple baseline across participants design will be used to assess whether there is a functional relationship between rotator cuff strength and serve accelerations. After participants have performed at a stable level (consistent serve velocity and acceleration), the intervention of the strength program will be implemented; if there is an increase in serve velocity and acceleration once the intervention has been applied, then a functional relationship can be established (through a visual analysis of a the data). Intervention: Upon implementation of the intervention, the rotator cuff strength training program will be executed twice a week for six weeks and will be done in the plane of the scapula. Based off of Greenfield, Donatelli, Wooden, and Wilkes’ experiment 5, rotator cuff strengthening should be performed in the plane of the scapula; this is defined as 90° abduction and 30-45° anterior flexion about the glenohumeral joint. Greenfield et al. 5 found a statistical difference when training the rotator cuff in the frontal plane and in the scapular plane; with greater strength resulting from training in the scapula plane. Other studies have also implemented their shoulder training using the plane of the scapula 5,6,8 The exercise that will be used will be executed eccentrically. Using a kettle ball or a medicine ball, the administrator will toss the ball over the participant’s shoulder. The participant will then have to catch the ball before letting it drop, while maintaining the shoulder in the plane of the scapula. This exercise simulates the actions of the serve, thus making it more applicable. Data Collection: All participants will have their serves tested twice a week, once in the middle of the week and once at the end. Participants will have no knowledge of their velocities or accelerations. Participants will also have their strength and ROM tested weekly to track improvements to also show that the increase in strength once the intervention has been implemented, with a possible connection between strength and velocity and acceleration. References 1. Anderson, MB (1979). Comparison of muscle patterning in the overarm throw and tennis serve. Research Quarterly, 50(4), 541-553. 2. Donatelli, R; Ellenbecker, TS; Ekedahl, SR; Wilkes, JS; Kocher, K; & Adam, J (2000). Assessment of shoulder strength in professional baseball pitchers. Journal of Orthopaedic & Sports Physical Therapy, 30(9), 544-551. 3. Ellenbecker, TS; Davies, GJ; & Rowinski, MJ (1988). Concentric versus eccentric isokinetic strengthening of the rotator cuff. The American Journal of Sports Medicine, 16(1), 64-69. 4. Ellenbecker, TS & Rotert, EP (2002). Effects of a 4-month season on glenohumeral joint rotational strength and range of motion in female collegiate tennis players. Journal of Strength and Conditioning Research, 16(1), 92-96. 5. Greenfield, BH; Donatelli, R; Wooden, MJ: & Wilkes, J (1990). Isokinetic evaluation of shoulder rotational strength between the plane of scapula and the frontal plane. The American Journal of Sports Medicine, 18(2), 124-128. 6. Mont, MA; Cohen, DB; Campbell, KR; Gravare, K; & Mathur, SK (1994). Isokinetic concentric versus eccentric training of shoulder rotators with functional evaluation of performance enhancement in elite tennis players. The American Journal of Sports Medicine, 22(4), 513-517. 7. Roig, M; O’Brien, K; Kirk, G; Murray, R; McKinnon, P; Shadgan, B; & et al (2009). The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis. British Journal of Sports Medicine, 43, 556-568. 8. Wooden, MJ; Greenfield, B; Johanson, M; Litzelman, L; Mundrane, M; & Donatelli, RA (1992). Effects of strength training on throwing velocity and shoulder muscle performance in teenage baseball players. Journal of Orthopaedic and Sports Physical Therapy, 15(5), 223-228.