Influence of Physical Activity, Physical Fitness, Age, Biological Maturity and Anthropometric Variables on the Probability of Suffering Lumbar, Neck and Shoulder Pain in Spanish Adolescents from the Region of Murcia

<b>Background:</b> Back pain in adolescents is a common injury, mainly affecting the lumbar, cervical and sometimes shoulder region. This has been related to various factors, such as lifestyle habits or physical capacity, but no previous research has shown conclusive results. The aims of this study was to analyze the risk of suffering lumbar, neck and shoulder pain according to anthropometric and physical fitness variables, physical activity level, age and biological maturity in adolescents, as well as the influence of sex in the study results. <b>Methods:</b> A descriptive cross-sectional study was performed, including a sample of 2015 adolescents (boys: <i>n</i> = 1006, mean age = 14.41 ± 1.35 years-old; girls: <i>n</i> = 1009, mean age = 14.48 ± 1.41 years-old). The participants underwent an anthropometric evaluation and physical fitness tests were carried out, including a 20 m shuttle run, a counter movement jump, a horizontal jump, a 20 m sprint and push-up tests, followed by the completion of lumbar, neck and shoulder pain questionnaires. <b>Results:</b> Higher values in age and peak height velocity (PHV) showed an increase in the risk of suffering lumbar, neck and shoulder pain (OR = 0.79-1.55; <i>p</i> = 0.000-0.025). The anthropometric variables related to adiposity showed an increase in the risk of suffering back pain, with significant incidence in the lumbar region (OR = 1.32-1.60; <i>p</i> = 0.000); while muscle mass showed a protective effect (OR = 0.59; <i>p</i> = 0.000). Regarding the fitness tests, a better physical fitness seemed to protect adolescents from suffering from the analyzed back pains in the general sample and in the boys sample (OR = 0.56-1.60; <i>p</i> = 0.000), while in the girls sample the influence of the physical fitness was less relevant. <b>Conclusions:</b> Both anthropometry and physical fitness may influence the occurrence of back pain in adolescents, with some variations in their importance according to sex.