Greg performs a Concentration Curl during STS March 19, 2008 by Cathe Friedrich Greg performs a Concentration Curl during STS Meso #2 – Back & Biceps. Categories: Behind The Scenes, Blog, STS, STS Mesocycle #2Tags: cathe, concentration curl, exercise dvd, exercise dvds, fitness dvd, fitness dvds, hypertrophy, mesocycle 2, STS, workout dvd, workout dvds Leave a Comment Related PostsResistance Training: How to Use Momentum Properly When You Lift WeightsApril 5, 2020Can You Strengthen Your Tendons?October 9, 2016What’s Your Age from a Fitness Standpoint?October 26, 2014