The document contains 8 URLs linking to YouTube videos demonstrating the proper form and technique for various exercises including the contractor, elliptical machine, bench press, bicep curl, triceps extension, rowing machine, chest pull, and leg press. Each URL provides a video on YouTube demonstrating how to perform one of these common weight training or gym exercises.

1. CÓDIGOS QR Y ENLACES DE YOUTUBE
Contractora
http://www.youtube.com/watch?v=9lxcoPgg2Wc&feature=youtu.be
Elíptica
http://www.youtube.com/watch?v=5Nu2DBFmyaA&feature=youtu.be
Banco Scot
http://www.youtube.com/watch?v=6EWM2_cpV7E&feature=youtu.be

2. Polea de Biceps
http://www.youtube.com/watch?v=8Oii35IKJEc&feature=youtu.be
Polea de Triceps
http://www.youtube.com/watch?v=tcBLxmD13PQ&feature=youtu.be
Remo
http://www.youtube.com/watch?v=NQn1x-YzJ98&feature=youtu.be

3. Jalón al pecho
http://www.youtube.com/watch?v=5B5ob3h98Jo&feature=youtu.be
Press de pierna
http://www.youtube.com/watch?v=v-zptZ-wJHw&feature=youtu.be