what muscle would get me a wide back and a small bum?

Is the OP not stating he is looking for a wider back? Having larger lats and bigger shoulders make you look larger from the back alongside triceps and your obliques/seratus (for the lower portion of the back).

There are exercises for the shoulders too which don't require that much weight either called "Seated bent-over Rear Delt Raises". These work the prosterior deltoid in particular. There are many exercises out there to achieve a 'wide' back.

P.S. DON'T EVEN CONSIDER WATCHING MIKE F-king CHANG, OP!

Training legs is impossible.

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He wants a wider back look, I am saying he can achieve this by doing several isolation exercises for multiple muscle groups across the back portion of the body. A pull-up bar would be great and doing wide grip push-ups will force the back muscles to work out more; if integrated with close-gripped push ups he's ultimately working his triceps too.

He wants a wider back look, I am saying he can achieve this by doing several isolation exercises for multiple muscle groups across the back portion of the body. A pull-up bar would be great and doing wide grip push-ups will force the back muscles to work out more; if integrated with close-gripped push ups he's ultimately working his triceps too.

Not very good. Bodyweight squats? Resistance is too low. It becomes cardio. No beginner can do pistol squats. No hamstring or posterior chain work-- sissy squats again working quads. Everyone has underdeveloped posterior muscles. The main trouble here is progressive overload. You can't do that with these exercises*. You may as well just cycle. Even something as simple as lunges, you need weights. Training legs at home properly without weights and bars is very difficult.

*unlike in gymnastics (upper body) where you lower the leverage to increase difficulty eg by changing angle and position.

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