Muscle volumes of the dominant and non-dominant upper extremity (values expressed in cm³, mean ± SD) and asymmetries, comparisons are made between dominant and non-dominant sides into each group.

<p><b>ASY:</b> Asymmetry between the dominant and non-dominant sides ((Dominant-Non-dominant)*100)/Non-dominant. The asymmetry represents the mean value of the individual asymmetries.</p

Muscle volumes of the dominant and non-dominant arms in prepubescent tennis players and non-active controls, after adjustment for height as covariate.

<p>(A) Total muscle volume of the arm, upper arm and forearm; (B) Volume of each muscle group of the upper arm and (C) of the forearm.</p

Differences in the degree of inter-arm asymmetry between prepubescent tennis players and non-active controls.

<p>Differences in the degree of inter-arm asymmetry between prepubescent tennis players and non-active controls.</p

Physical characteristics and training history of tennis players and control group (mean ± SD).

<p>Physical characteristics and training history of tennis players and control group (mean ± SD).</p

Characteristics of age, gender and municipality size of study participants.

<p>Characteristics of age, gender and municipality size of study participants.</p

Prevalence of physical activities and screen-related behaviors among adolescent participants in Gran Canaria Physical Activity Study.

a<p>5 days per week of AFMV +300 minutes per week +1,800 MET per week;</p>b<p>Aerobics, step and similar;</p>c<p>Basketball, handball, volleyball, rugby, field hockey, baseball;</p>d<p>Tennis, badminton, paddle, squash, table tennis;</p>e<p>Surfing, windsurfing, diving, hunting, canoeing, rowing, sailing;</p>f<p>Skateboard, skate;</p>g<p>Judo, karate, taekwondo, fencing, wrestling;</p>h<p>Motocross, trial, motorcycling in track, karts;</p>*<p>p<0.05 for differences between boys and girls.</p

Percentiles of time dedicated to television, computer, video-game, portable mini consoles and total of screen-related behaviors among adolescents participants.

<p>Percentiles of time dedicated to television, computer, video-game, portable mini consoles and total of screen-related behaviors among adolescents participants.</p

Odds ratio for being sufficiently active in relation to screen-related behaviors and social environments variables among adolescents participants in Gran Canaria Physical Activity Study.

a<p>For each increase of 1 hour per day;</p>b<p>For each increase of 1 point in scale (0 =  I don’t like it at all, 5 =  I like it a lot);</p><p>*p<0.05.</p

Percentiles of time dedicated to moderate, vigorous and total of physical activities among adolescents participants.

<p>Percentiles of time dedicated to moderate, vigorous and total of physical activities among adolescents participants.</p