Cross sectional analysis investigating the concordance of maturity status classifications in elite Caucasian youth tennis players

Background
To evaluate the concordance of skeletal age (SA) with two predicted estimates of biological maturity status in elite British youth tennis players.

Method
Participants were 71 male and female elite youth tennis players aged 8 to 16 years. Weight, height, and sitting height were measured. SA (Fels method) was the criterion indicator of maturity status. Maturity status was predicted with two methods: predicted age at peak height velocity and percentage of predicted adult height at the time of observation. Players were classified as late, average (on time), or early maturing with each method. Concordance of classifications was evaluated with kappa coefficients and Spearman’s rank order correlations.

Results
Kappa coefficients between maturity status classifications were low in both sexes, − 0.11 to 0.22, while Spearman’s rank order correlations between maturity status classifications based on SA and the percentage of predicted mature height were moderate in males (0.35) and females (0.25), but the corresponding correlations based on predicted age at peak height velocity (PHV) varied, moderate and negative in boys (− 0.37) and low and positive in girls (0.11). Concordance of maturity status classifications based on the prediction methods and SA among tennis players was thus limited.

Conclusions
Maturity status based on the percentage of predicted mature height at the time of observation correlated better with maturity status based on SA in contrast to status based on predicted age at PHV in this sample of elite youth tennis players.