The beneficial effects of strength training as it relates to enhanced performance are well documented for the lower and upper extremity. The following article published in the American Journal of Sports Medicine in 1998 details a 4 week strengthening program and the resultant strength and velocity gains as a result of the training stimulus.

Effects of Theraband and Lightweight Dumbbell Training on Shoulder Rotation Torque and Serve Performance in College Tennis Players

Frank A. Treiber, PhD, Jason Lott, PT, CSCS, Jewell Duncan, MD, Greg Slavens, Harry Davis, MS

Departments of Pediatrics, Augusta, Georgia, Departments of Psychiatry, Augusta, Georgia, Departments of Physical Therapy, Augusta, Georgia, Departments of Orthopedic Surgery, Augusta, Georgia, The Sports Medicine Center, Augusta, Georgia, Georgia Prevention Institute, Augusta, Georgia, Office of Biostatistics at the Medical College of Georgia, Augusta, Georgia

Abstract
The purpose of this study was to determine whether a 4-week isotonic resistance training program using Theraband elastic tubing and lightweight dumbbells would significantly increase concentric shoulder rotator strength or velocity of serve or both in a group of elite-level tennis players. Twenty-two male and female varsity college tennis players were randomly assigned to control or 4-week training groups. Subjects were pre- and posttested in concentric internal and external rotation torque using an isokinetic dynamometer. Functional performance was assessed before and after training by recording the peak and average velocities of eight maximal serves. The experimental group exhibited significant gains in internal rotation torque at both slow (120 deg/sec) and fast speeds (300 deg/sec) for total work and in peak torque to body weight ratio and torque acceleration energy at the fast speed. This group also exhibited significant gains in external rotation torque for the same parameters at fast speed. Regarding speed of serve, the experimental group exhibited significantly greater increase in peak speed (+6.0% compared with −1.8%) and average speed (+7.9% compared with −2.3%) compared with the control group. Men exhibited greater internal and external rotation torque on all parameters and in peak and mean speed of serve on both evaluations. Men also exhibited greater imbalance in external to internal rotation torque ratios. In conclusion, resistance training using Theraband tubing and lightweight dumbbells may have beneficial effects on strength and functional performance in college-level tennis players