There are different schools of thought in the parkour community when it comes to training in a gym and training outside. There is a group that thinks training in a gym makes you weak and there is a group that believes that training in gyms is all you need to be a successful athlete. Both of these views are wrong though. You need to train in gyms AND you need to train outside. They are not the same thing. They are two very different types of training, two very different types of mental game, and you need both of them to be a successful well rounded athlete. Training in a gym has numerous benefits such as moveable obstacles, ideal training conditions and is filled with people, coaches, and colleagues that want to help you succeed and improve.
Having a place to train where you are constantly supported is a major step in getting comfortable with your movements and making new friends. When training inside a gym you will have all the social support you need. However, the spectators outside can be unforgiving and downright obnoxious while you train. They can yell at you to stop what you're doing, or yell to do a backflip, cat call, etc; which is very different from the encouraging and supportive gym environment that is inside. Dealing with this properly will strengthen your mental game, by teaching you how to block out outside distractions and to hyper focus on your movements.
Another important difference between training inside and outside is learning how to adapt to uncontrollable environmental factors. Training in the rain for example may seem daunting and uncomfortable but if approached with extra caution can strengthen an athletes trust in his or her own abilities. In dryer conditions you might be able to get away with sloppy form for a rail precision, but if it’s raining you will need to focus more on your foot placement and technique. The convenient part about having a space inside is that you can opt out of training outside when weather conditions get to unsafe such as extreme heat or cold.
Non-moving obstacles are as helpful as stationary obstacles. They help fuel your creativity and your ability to adapt to new heights, strange shapes, and weird spots. They also help you overcome fear by forcing you to mindfully work a move slowly instead of just throwing yourself at it with the attitude that a pad will cover up your mistake.Pads and movable obstacles help you in more ways than one. They give you a chance to overcome fears and master skills in incremental ways. With the moveable obstacles your able to recreate the same same challenge over and over, making it bigger and smaller as needed until you’ve successfully and consistently overcome the fear or the move. The pads also benefit this by taking away impact and giving you more confidence to commit to a move.
Training outside is essential for a parkour athlete. It helps you learn to be adaptable and helps you strengthen your mental game. However, training in a gym is also good for you as an athlete. It give you a space to practice consistency, as well as provide an encouraging learning environment. They are two very different styles of training, but at the end of the day you need both outside training and inside training to be a well rounded athlete.