A comparison of muscle activity between strict, kipping and butterfly pull-ups

The kipping pull-up (KPU) and butterfly pull-up (BPU) are variations of the strict pull-up (SPU) where an athlete uses hollow and arched body positions to gain momentum, before accelerating vertically. Understanding the muscle activity of each of these exercises will help coaches better utilise them within a strength and conditioning programme. The aim of this study was to compare upper and lower body muscle activation between the SPU, KPU and BPU during the concentric and eccentric phases of each exercise. 11 participants had surface electromyography data collected from three upper and three lower body muscles while completing each pull-up variation. Peak EMG data from each phase for each muscle from the SPU were used to normalise peak KPU and BPU EMG data. A repeated measures ANOVA with Bonferroni post hoc testing was used to identify significant differences between each variation. The results show significantly reduced muscle activation in the bicep brachii during the concentric (p < 0.05; d = 1.1) and eccentric (p < 0.05; d = 1.1) phases of the BPU, when compared to the SPU. Activation of the latissimus dorsi was significantly lower during the concentric phase of the KPU (p < 0.02; d = 1.2) and eccentric phase (p < 0.01; d = 1.4) of the BPU in comparison to the SPU. Furthermore, significantly greater muscle activation was shown in the rectus femoris, gluteus maximus and rectus abdominus in both the KPU and BPU, when compared to the SPU. However, results differed within the concentric and eccentric phases. These findings show that both styles of kipping increase lower body muscle activation and decrease upper body activation in comparison to the SPU. Further, due to the different style of kip, the KPU and BPU display different muscle activations during both the concentric and eccentric phases.