Strength can be built effectively without weights through bodyweight exercises, resistance bands, and functional movements. Bodyweight movements like push-ups, squats, and planks engage multiple muscle groups, enhancing overall strength. Resistance bands offer variable resistance, allowing for progressive challenges without traditional weights. Incorporating unweighted movements, such as lunges or step-ups, into a routine also promotes strength. Furthermore, high-intensity interval training (HIIT) can effectively build strength and endurance simultaneously, making workouts versatile and effective.