Eight-week lat pull-down resistance training with joint instability leads to superior pull-up endurance performance and reduced antagonist coactivation in recreationally active male college students

This study aimed to investigate the effects of an 8-week lat pull-down resistance training program with joint instability on pull-up performance in male college students. Thirty-four healthy recreationally active male college students were randomly assigned to either the joint instability resistance training (IRT) or traditional resistance training (TRT) group. Participants of the TRT and IRT groups performed lat pull-down training on stable and joint instability conditions for 8 weeks, respectively. Pull-up endurance (number of repetitions), anthropometry, lat pull-down maximal voluntary isometric contraction (MVIC) peak force, and movement stability of performing unstable lat pull-down were tested before and after the 8-week training. Surface electromyography of biceps brachii (BB), triceps brachii (TB), brachioradialis (BR), anterior deltoid (AD), middle deltoid (MD), posterior deltoid (PD), pectoralis major (PM), and latissimus dorsi (LD) muscles were recorded during the pull-up endurance test. The level of significance is set at p ≤ 0.05. The results demonstrated that the pull-up endurance and lat pull-down MVIC peak force of both IRT and TRT groups were significantly enhanced after 8-week training compared to the pre-training test. Notably, the number of pull-up repetitions of the IRT group was 45.5% higher than the TRT group. These findings suggest that lat pull-down training performed with joint instability may lead to greater improvements in pull-up endurance compared to the stable condition, possibly attributed to enhanced muscle contraction efficiency as indicated by decreased antagonist coactivation activity.