“[Bass clarinetist David] Howard, 59, practices yoga to strengthen his lungs. Timpanist Joseph Pereira stretches damp calfskins across drums and fashions mallets out of wine corks and felt. Thomas Hooten … runs trumpet scales late into the night. And Christopher Hanulik, who calls his 25-pound bass ‘the beast,’ guards against strained ligaments and tendinitis: ‘I’ve got to be nimble, my muscles quick.'”