Acute effects of two different tennis sessions on dorsal and lumbar spine of adult players.

The aim of the study was to evaluate the dorsal and lumbar spine of expert and recreational tennis players before (pre) and after (post) two different training sessions. The sample consisted of 17 male tennis players, nine expert and eight recreational males (age 21.2 ± 1.6 years). We assessed the back surface by rasterstereography pre and post two different training sessions both lasting 1.5 h: a standard training and a specific over-shoulder shots training session, respectively. Lordotic and kyphotic angle, length, imbalance, inclination for trunk, pelvic torsion, left and right lateral deviation and surface rotation were measured. Tennis expertise (expert versus recreational) significantly affected the surface rotation and right lateral deviation (P < 0.05). Trunk length was affected by intervention (pre versus post) (P < 0.05). Left lateral deviation differed both for type of session (session 1 versus session 2) and intervention (P < 0.001, P < 0.05). Expert tennis players had higher values on surface rotation and right lateral deviation, around or just above physiological values (0-5° and 0-5 mm, respectively). Type of session significantly affected left lateral deviation, indicating that over-shoulder shots lead to a higher stress for the spine; the workload produced by both single sessions led to a shortening effect on trunk length. A single training session can induce acute modifications in some parameters of dorsal and lumbar spine of players.

Intra- and interday reliability of spine rasterstereography.

To determine intra- and interday reliability of spine rasterstereographic system Formetric 4D with and without reflective markers. Twenty-six healthy volunteers (M group) had two markers placed in correspondence of vertebra prominens and intergluteal cleft, and 24 volunteers (NM group) were assessed without markers. All participants were analyzed two times in the same day and one time on a separate day. Trunk length, kyphotic angle, lordotic angle, pelvic inclination, kyphotic and lordotic apex, right and left lateral deviation, flèche cervicale and lombaire, trunk imbalance, pelvic tilt, inflection point, rotation correction, right and left surface rotation, pelvic torsion, and trunk torsion were measured. Intraclass correlation coefficient (ICC) and Cronbach Alpha (C α ) were calculated. In M group, for intra-, interday, and overall evaluations, the higher reliability coefficients were 0.971, 0.963, and 0.958 (ICC) and 0.987, 0.983, and 0.985 (C α ) for trunk length, kyphotic angle, and lordotic apex, respectively; while in NM group, they were 0.978, 0.982, and 0.972 and 0.989, 0.991, and 0.991 for trunk length. In M group, the lower values were 0.598, 0.515, and 0.534 (ICC) and 0.742, 0.682, and 0.784 (C α ) for trunk and pelvic torsion and in NM group 0.561, 0.537, and 0.461 and 0.731, 0.695, and 0.729 for left lateral deviation. The reliability of most parameters was excellent.