Tennis: A Case Study

Balance in TENNIS: A Case Study

Kinesthetic awareness assists tennis player in proper training techniques and reduction of biomechanical dyfunction.
-Daniel Goldstein, MS, PT, OCS, SCS, ATC

Fig. 3 | Fig. 4 | Fig. 5 | Fig. 6 | Fig. 7 | Fig. 8 | Fig. 9 | Fig. 10

TC is a 59 yr. old right-handed WF who plays competitive country club tennis. She has a history of repetitive low back pain with associated “muscle spasms.” Physical findings include bilateral lower lumbar paraspinal muscle tightness, right quadratus lumborum trigger points, with a moderate flattening of the normal lumbar lordotic curve. No sacroiliac involvement, leg length discrepancy or radicular symptoms are noted. Moderate right L4-5 restrictions toward extension are observed but respond will to gentle stretching, muscle energy mobilization techniques and stabilization exercises. Her myofascial symptoms are eased with ultrasound, specific stretching/massage and icing techniques.

Despite being very diligent toward her exercise and pre-competition warm-up routine, TC experienced repetitive “flair-ups.” She reportedly felt “tentative” while performing ground strokes or attempting hard serves. Interestingly, through this season, TC and her tennis coach have been training to have her “stay on the balls of her feet” to help with rapid lateral movements. The coach had observed that “she rarely turned strongly to the right” during competition.

The Dynamic Balance System-DBS* was used to provide visual feedback of her static balance and dynamic movement. The DBS uses a force-platform integrated with specific software to display static weight distribution, active weight transfer, and tracing of movement of the client’s center-of-gravity (COG) during functional and sport-specific motions.

Feedback using Weightbearing Scales:

Weight distribution during static stance (Figure 1) indicates more weight is borne onto her left side, particularly toward the left heel. Interestingly, during active weight transfer exercises, with visual feedback, TC observed difficulties moving into her right heel.

Unilateral balance stance assessment, performed for 6 seconds with the eyes closed, (Figure 2) indicates a little less stability on the right as compared to the left. Interestingly, during gait, TC noted a feeling that she “lands harder” onto her left foot. It is our feeling that these findings possibly indicate a deficit of kinesthetic awareness resulting in inadequate movement onto the right heel during functional activities. The DBS’s feedback provided kinesthetic awareness, which assisted in gait improvement.

Center-of-Gravity (COG) motion:

The Dynamic Balance System-DBS uses a reference “balance zone” for training movements over a stable base of support. The DBS calibrated so when the athlete’s COG is over the metatarsal heads (“balls of the feet”) our COG tracing is approximately across the top (black) line (Figure 3).

Ground Strokes:

While standing on the DBS we asked TC to assumed a tennis “ready” position. She began swaying laterally as is normal for preparation of a return of a serve. Movement of her COG to the right is traced in red, while blue indicates movement to the left. Her COG was maintained forward of our “balance zone” indicating pressure over her toes! Although she and her coach had been working on achieving an athletic “ready” position over the “balls of the feet”, without appropriate feedback this client was weightbearing further anteriorly (Figure 4).

During lateral motions we observed consistent, stable motion to the left while movement to the right is accompanied by increased anterior-posterior (toe-heel) compensations. Duplication of this client’s lower lumbar and right lateral hip pain was reported when simulating this ready position! We speculated the anterior weightbearing position required increased lumbar and posterior hip muscular activity. Note her body position anterior to the postural line in Figure 3.

Visual (balance and lateral video) as well as auditory feedback techniques, on the DBS, assisted in practicing improved movements. This client learned the “feel” (kinesthetic awareness) of movement over the metatarsal heads, as was desired by her tennis coach, for improved performance. She observed less pain and a feeling of greater stability on her right foot (Figures _ &_). Home exercises, provided between sessions, reinforced this new movement pattern.

Serving Motion:

During a simulated serve, TC is observed to shifted her hips forward without being stable on the left foot (Figure 8); right-sided lumbar discomfort was reported. We believe that this motion required an increased lordosis when extending up toward ball contact. The COG tracing (using a staggered foot placement on the forceplate) (Figure 7) indicates motion from the right foot to the left with instability at the top of her serve position. The client used the DBS feedback to train proper transfer onto a stable left leg during the serve; note the improvement in weight transfer and postural alignment (Figures 9 & 10).

Conclusion:

Immediate feedback is extremely helpful for training improved, repetitive movement patterns in sports. Although each participant will have slightly different motion patterns based on flexibility, strength, coaching style and so on, improved performance, with less orthopaedic stress, can result from repetitive training, with appropriate feedback.

Improper execution of repetitive tennis activities may have contributed to recurrent lumbar dysfunction. Identification of movement imbalances, coordination with the tennis coach, the use of specific feedback techniques for training, and sport-specific exercises lead to improved, pain-free performance.

TC has stated; “The DBS demonstrates that your body weight must be balanced equally on both legs using the balls of your feet, not on your toes. If you are not properly balanced both your tennis swing and back are affected. The Dynamic Balance System-DBS shows you how you stand and swing—so take notice and improve your footing.”