Summary
This quote humorously suggests that the speaker's friends are so active and physically fit that they require no assistance or exercise themselves, leaving the speaker to simply participate in their friends' activities in a different way - by acting as a pallbearer, carrying their metaphorical "burden" of exercise. It highlights the contrast between the speaker's level of fitness and that of their friends, using exaggeration to relay the idea that their friends are on a whole other level in terms of exercise and physical prowess.