We sought to determine how a stationary activity such as playing a stringed instrument may affect energy expenditure (EE) in adolescents. Using automated indirect calorimetry, we measured EE in eight adolescents (1 male, 7 females, 14.2 +/- 2.1 yr) while they each performed the following activities: watching television (TV) (60 min), playing a stringed instrument (60 min), and walking at 40% of peak oxygen uptake (43 min). Measurements were made during three, 6- to 7-min steady state periods of each activity. EE (mean +/- SD) was lower during TV (1.0 +/- 0.2 kcal.min-1) and instrument playing (1.4 +/- 0.2 kcal.min-1) than during walking (3.4 +/- 0.4 kcal.min-1) (P < 0.05). EE during instrument playing was 41% greater than during television viewing (P < 0.05). We conclude that relatively sedentary activities such as playing a stringed instrument can elevate EE. Conceivably, other stationary, leisure activities performed by adolescents may increase EE and have substantial, cumulative effects on long-term energy balance and fat accretion.