1. With a buddy it's more fun; you're going to do it more, stick with it longer, and in the end you'll get better results.
As well as being fun, it's also a great confidence builder - the gym is less scary when there's someone by your side to support you!
2. This person is counting on you to be on track with them. What's better motivation than a 'gym tonight?' text from your mate!
You can also share food tips and link your fitness apps to keep each other motivated.
3. You're planning your workouts in advance.
Having days for certain exercises (e.g. Monday is Glutes, Wednesday is Biceps and Triceps... etc) is an effective way to workout and will help you see better results.