Trunk muscle profile in elite tennis players with and without low back pain.

Aim: The aim of this study was to compare tennis players with and without low back pain (LBP) and healthy sedentary participants regarding the trunk muscle strength and flexibility.

Methods: Thirty-eight male elite tennis players and 22 healthy sedentary male students (24.8±4.0 years) participated in this investigation. Tennis players were divided into two groups: 11 players (27.8±5.5 years) with current LBP and 27 players (24.3±5.9 years) without LBP. Maximal isometric strength of trunk extensor, rotator, flexor and lateralflexor muscles was assessed by means of specific trunk dynamometers. Pelvic and lumbar flexion mobility were measured by means of inclinometer technique.

Results: Comparison of tennis players with and without LBP revealed no significant difference regarding trunk muscle strength and ratio or lumbar spine flexibility (all P>0.05). In comparison with sedentary participants, the tennis players showed a sport-specific profile determined by a non-dominant trunk lateralflexors (P=0.02, F=4.05) and rotators (P=0.03, F=3.62) strength significantly higher than the dominant side.

Conclusion: In the current study, comparison of tennis players with and without LBP showed no significant difference regarding trunk strength and spine flexibility. Trunk profile of tennis players showed selective unilateral strength increase of the non-dominant trunk lateralflexors and rotators. This finding could result from the forehand and the service action which involves simultaneously left trunk rotators and lateralflexors, in right-handed players, to generate power. In order to confirm that trunk muscle imbalance has no influence on LBP, further studies should study the effectiveness of a programme aiming to normalize strength ratios in tennis players with LBP.