The hypertrophy of the lateral abdominal wall and quadratus lumborum is sport-specific: an MRI segmental study in professional tennis and soccer players

Abstract

The aim was to determine the volume and degree of asymmetry of quadratus lumborum (QL), obliques, and transversus abdominis; the last two considered conjointly (OT), in tennis and soccer players. The volume of QL and OT was determined using magnetic resonance imaging in professional tennis and soccer players, and in non-active controls (n = 8, 14, and 6, respectively). In tennis players the hypertrophy of OT was limited to proximal segments (cephalic segments), while in soccer players it was similar along longitudinal axis. In tennis players the hypertrophy was asymmetric (18% greater volume in the non-dominant than in the dominant OT, p = 0.001), while in soccer players and controls both sides had similar volumes (p>0.05). In controls, the non-dominant QL was 15% greater than that of the dominant (p = 0.049). Tennis and soccer players had similar volumes in both sides of QL. Tennis alters the dominant-to-non-dominant balance in the muscle volume of the lateral abdominal wall. In tennis the hypertrophy is limited to proximal segments and is greater in the non-dominant side. Soccer, however, is associated to a symmetric hypertrophy of the lateral abdominal wall. Tennis and soccer elicit an asymmetric hypertrophy of QL.

Keywords:

• Asymmetry
• muscle volume
• obliques abdominis
• transversus abdominis

Acknowledgements

The authors wish to thank all professional soccer and tennis players who volunteered in these studies. Special thanks are given to Sánchez-Casal Tennis Academy, and particularly to Emilio Sánchez Vicario for his crucial collaboration. They would like to express their gratitude also to Hospital San Roque Maspalomas (Gran Canaria) for allowing them to use their MRI facilities. This study was granted by Ministerio de Ciencia e Innovación, Spain (DEP2010-21866).