Since tennis is a method of mechanical stimulation on the bone and growth plate. We can extrapolate its effects to other forms of mechanical stimulation.
“The specific aim of the study was to investigate and compare epiphyseal length and extension in the proximal humerus, closure in the growth plate and bone marrow signal intensity related to the proximal humeral physis in the dominant arm and the non-dominant arm of the asymptomatic adolescent elite tennis player.
The study sample included 35 asymptomatic elite young tennis players (15 males and 20 females, mean age 17.4 years ± 2.7). Each player contributed with two shoulders to the MRI measurement. The non-dominant arm was used as a control.
Relative reliability between the radiologists was excellent (ICC 0.78-0.96). Statistically significant differences between dominant arm and non-dominant arm in epiphyseal length (mm) laterally (DA 27.3 vs NDA 26.7) were shown. Statistically significant differences were also found in epiphyseal extension (mm) laterally (DA 36.1 vs NDA 35.1) and ventrally (DA 36.2 vs NDA 34.8). No statistically significant differences were found between dominant arm and non-dominant arm in epiphyseal extension (mm) medially (DA 31.7 vs NDA 31.7) and dorsally (DA 22.6 vs NDA 22.1).
Significant findings assessing MRI measurements of the epiphyseal plate in the asymptomatic adolescent elite tennis player might reflect a development of consecutive alterations in the epiphyseal plate in the dominant arm.”
“The cartilage of the epiphyseal plate might be 2–5 times weaker than surrounding fibrous tissue; therefore, epiphyseal (growth) plates are very sensitive to their surrounding mechanical environment”
“The epiphyseal plate consists of the fibrous part, providing mechanical support and the cartilaginous and bony part, acting together in transforming cartilage cells into bone. The rounded end of a long bone, the epiphysis, is divided into two types: traction epiphysis, primarily subjected to tensile forces, and pressure epiphysis, primarily subjected to compressive forces. Closure of the growth plate of the proximal humerus in the paediatric population starts around 14 years of age, and the last area to close is the posterolateral region that closes at 17 years of age”
“The shear stress arising from high torques during the arm cocking throwing phase in overhead sports is large enough to lead to deformation of the weak proximal humeral epiphyseal cartilage”
The difference in growth plate dimensions is not so much important as is the difference in overall length as higher growth plate height and width can occur in cases of stunted growth.
Playing tennis didn’t appear to have an affect on keeping the growth plate open.
“External rotation force applied to the proximal humeral physis during the overhead motion peaks just before maximal shoulder external rotation”