With baby in one arm, engage in single pan cooking, shaking the pan vigorously to try and unstick burnt vegetables. 5 x 10 seconds of vigorous shaking, resulting in singular strong arm and delicious "caramelised" vegetables.
With baby in one arm, search for that elusive piece of lego in the big box. The more elusive the better - for your arm, but maybe not for the impatient lego enthusiast or the ears of a small baby.
With screaming wrigglesome baby in one arm, push buggy homeward for as long as you can bear the noise, discomfort or the looks, to achieve that singular strong arm look.