I have discussed in the past the problems I have had staying motivated and hitting the gym. I got through the toughest stretch of training in my life through the help of a training partner. For me the training partner saves the day.
When you have someone expecting you at the gym you find a way to get there. You are less likely to miss a session when you need to cancel with someone else. This develops a consistency habit.
When you have a training partner you are able to increase the intensity because the partner is there to spot you. You can push harder than normal because you have some help. At the same time your partner is there to push you harder.
It is always good to have company when you complete a task. Working out is no different. Usually training partners have the same or similar goals. This creates a bond between the two people. It makes the training time more fun. You can talk to each other in between sets. You can encourage each other. It is just a different situation. It makes gym time much more fun.
If you do it right your gym partner knows all of your goals. S/he can hold you accountable for reaching those goals. It is a great dynamic. You set goals and someone helps hold you to the completion of those goals.
So, if you need extra motivation seek out a training partner.