There are millions of excuses for missing a workout—you're busy, the hotel gym sucks, your kid is sick. Now here's an excuse to never miss another one: "Your body weight is all you need to torch fat and build total-body muscle," says David Jack. Gaining strength, after all, is about challenging your muscles, and these workouts are designed to do just that—no equipment required. They'll also kick your metabolism into high gear by keeping your heart rate elevated. In short, this is the ultimate do-anywhere, zero-excuse fitness plan for guys on the go.